Exploring the wonders of geology in response to young-Earth claims...

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Tuesday, August 26, 2014

Age of Rocks: the official move

Well, I've finally finished the process of migrating all of my posts to a new domain, which I hope you'll find easier to navigate and read. All content from now on will be posted to the new site:

A special thanks to all of you who have followed the blog to this point, and I hope you'll continue to do so at the new address. Below is a screenshot from the new page. There are some formatting issues with certain articles in adapting to the new template, so please be patient as I work to re-edit every post and especially to redirect the links, which are currently pointing back to this Blogspot page. In time, however, I hope it to be a worthy investment. I will likely leave this page up for a while as an archive database, until I figure out something better. Thanks again!

Saturday, August 23, 2014

Chemostratigraphy: silent objector to 'Flood Geology'

It all began with breakfast in the park.

Years ago, when I was in the middle of writing my master's thesis, I took my then future wife on a trip to meet my family and visit the place where I grew up. We were invited to a picnic with some very close friends, whom I had not seen in far too long. The meal was pleasant, but I found myself having to avoid a potentially awkward confrontation upon being asked to explain my research.

"Well...", I formulated by sentence carefully, "I am basically analyzing the chemistry of limestone rocks to interpret how the atmosphere and ocean changed while the rock layers were being laid down."

I wasn't lying, but I did want to avoid stating explicitly that the rock formation was ~490 million years old or that these changes occurred over the course of 3 million years. You see, this is the family that first introduced me to young-Earth creationism and Flood geology—especially the works of Henry Morris, John Whitcomb, Duane Gish, and others. What they didn't realize was that I no longer held this view, so I was hoping not to interrupt the festivities with critical examination of my new 'heresy'. Still, the question came:

"Have you considered what this has to do with the Flood?"

I gave my quiet response "No, not really" with hesitation, because this time, it was something of a lie. Before graduate school, I had never heard the term chemostratigraphy, but by this point I knew well that this obscure subdiscipline in geology completely undermined every young-Earth interpretation of the geologic column. Regardless, the field has gone largely unmentioned by Flood geologists, who continue to provide fanciful explanations for how miles of sediment were laid down by Noah's flood and sorted into neatly organized fossil zones. Since that day in the park, I've learned much about chemostratigraphy, particularly the use of stable-isotope geochemistry to correlate sedimentary rocks and study the ancient ocean and atmosphere. It truly is the silent objector to Flood geology, and that's what I hope to change.

A crash course in chemostratigraphy

Let's begin with the second half of this term. Stratigraphy is a field in geology devoted to correlating sedimentary rock layers from one point to the next, even across the globe. For a simple example, imagine two mountains separated by a large valley. Each mountain contains four sedimentary layers with unique characteristics. The fact that the same layers appear in the same order allows us to correlate the layers across the valley, despite that the physical connection has been eroded away. This is the basic method by which geologists may construct a geologic column for any given region, and a quick Google image search for "stratigraphic cross section" will yield countless examples.

Simple cross section with correlation lines, from Wikipedia commons.
In the absence of mountainous outcrops, geologists can use boreholes to access the subsurface. Various instruments take measurements down each well to describe the sedimentary layers, and the resulting "well logs" are used to correlate rocks across the subsurface, as in this example from Michigan. 
In addition to matching layers, we might also be interested in their relative and absolute ages. The principle of superposition (i.e. younger layers overly older layers, in their original position) has been utilized since the time when geologists began to divide Earth history into various eras, periods, and epochs. Stratigraphers are the ones who argue, for example, about where to place the boundary between the Jurassic and the Cretaceous periods, into how many stages each period should be divided, and the precise age of each boundary. To accomplish this, stratigraphy borrows from geochronology, which may be used to date markers such as volcanic rocks within the sedimentary sequence.

Determining the relative age of sedimentary strata over a wide region is no simple task, hence oil companies still pay top salaries to professional stratigraphers. The sedimentary characteristics of a given layer (such as its composition) will change, for example, as you trace it over a wide geographic area, or the layer could disappear altogether. Therefore, geologists use additional age markers to define geological periods and sedimentary sequences. Perhaps the best known markers are fossils, and so biostratigraphers are those who use fossil assemblages to identify coeval layers across a great distance.

Geologists typically study the chemical makeup of rocks to obtain details about their origin, but certain chemical ratios are ideal markers to aid in stratigraphic correlation. If the chemical composition of a rock is related to the chemistry of the ocean, for example, perturbations to the ocean system will be recorded in rock layers over time. Sedimentary strata thus work like tape recorders listening to a thunderstorm, during which each lightning strike causes a unique imprint to be made on the tape. Likewise, perturbations to ocean chemistry show up as excursions in the chemical record, so they can used to identify events in geological history and determine which rock layers were laid down simultaneously. This relationship provides the fundamental principle behind chemostratigraphy, which has long been used to correlate ancient strata, particularly those devoid of characteristic fossils.

Carbonate chemostratigraphy: for the love of limestone

Consider now the specific example of carbonates, which make up some 22% of all sedimentary rocks and whose primary mineral constituent is either calcite (CaCO3) or dolomite ((Mg,Ca)CO3). Most carbonates, such as limestone, were deposited in shallow oceans with limited river input—a process that occurs today in places like the Bahamas and the Florida Bay. Limestone is comprised of calcite either in the form of shells from marine critters or minerals precipitated directly from the water column. In either case, the calcium, carbon, and oxygen that combined to make limestone originated from dissolved salts in the ocean. The chemistry of limestone is thus linked organically to the chemistry of the ocean, making it the perfect tool for the chemostratigrapher. But what kind of distinct chemical changes might show up in layers of limestone?

All three elements found in calcite are themselves comprised of multiple stable isotopes. For any given element, various isotopes contain the same number of protons and electrons, but a unique number of neutrons. This causes each isotope to have a different mass, which affects its chemical behavior ever so slightly (the impact is greater for lighter elements like carbon). While geochronologists are interested particularly in radioactive isotopes, because they decay to daughter elements at a known rate, chemostratigraphers mainly study stable isotopes, which never change. Using a mass spectrometer, we can analyze specifically the ratio between stable isotopes in rock samples, such as the relative abundance of "heavy" carbon (13C) versus "light" carbon (12C). In the modern ocean, the average ratio is about 1:99, making heavy carbon by far the rarer form. This ratio is quantified and described by the term δ13C (deviation from a standard value in parts per thousand), which is higher when a sample contains more heavy carbon than the standard and lower when it contains less.

Stable isotopes and ocean chemistry

Try this experiment at home: take a large bowl of two-toned
candy and ask everyone at the table to remove a handful, 
preferring one color to another. After each round, measure 
the ratio between colors to determine how sensitive isotopes
in a large reservoir (the bowl) are to the removal of small
Perhaps the best way to illustrate isotopes of carbon in the ocean is with a bowl of red and green M&M's, where each color corresponds to a different stable isotope of carbon. For the sake of discussion, this bowl contains precisely 50% green M&M's (light carbon) and 50% red M&M's (heavy carbon), for a ratio of 1:1. Now, imagine you leave the room and return later to find that the ratio has shifted to 0.9:1.1, meaning the bowl has been enriched in red M&M's. There are two possibilities that could explain the shift: either someone added a sample containing more than 50% red M&M's, or someone removed a sample containing less than 50% red M&M's. Perhaps you have a child, therefore, who prefers one color to the other, so every handful he takes is biased to that color. This process will leave the bowl preferentially enriched in the other color. If every handful contained precisely half green and half red M&M's, then the ratio of green to red in the bowl would never change. Likewise, any process that removes carbon from the ocean will change the δ13C value of oceanic carbon, so long as the isotopic ratio of the sample differs from that in the bulk ocean.

There are many processes that add carbon to or remove it from the ocean, but the most relevant to this discussion are the burial of organic carbon in marine sediments and the formation of limestone. Organic carbon is any form derived from living tissues, whether algae, bacteria, or whale remains. By far, photosynthetic organisms in the surface layer of the ocean contribute the vast majority of dissolved organic carbon to the oceans. This fact is important, because the process of photosynthesis prefers light carbon to heavy carbon, so organic carbon is heavily depleted in "heavy carbon" relative to the ocean. Whenever organisms like algae remove CO2 from the ocean and convert it to organic matter, they remove CO2 containing the light isotope of carbon at a slightly greater rate. The preference can be explained by the greater mass of 13C, since the CO2 must be absorbed through a cellular wall/fluid—a process made easier for the lighter molecule.

Since organic carbon contains relatively less of the heavy isotope, removing it in large quantities causes the rest of the ocean to become enriched in heavy carbon (just like your child's preference for green M&M's, leaving the bowl a little more red). Normally, this process is offset by the formation of limestone, for which the isotopic preference is the opposite, or the weathering of organic carbon back into the ocean. Perturbations to the normal ocean cycle, however, may cause the carbon-isotope ratio of the ocean as a whole to shift in one direction or another over a long period of time. For example, if photosynthetic productivity in the surface layer was increased for a sustained period (due to enhanced nutrient supply, shifts in ocean currents, etc.) or the rate of sedimentary deposition was increased for a sustained period (due to enhanced delivery of sediments from rivers, climate change, etc.), then the δ13C of the ocean should become more positive (i.e. enriched in the heavy isotope of carbon). This phenomenon is well illustrated by  records of the past million years or so, since the δ13C value of the ocean fluctuates predictably (albeit somewhat chaotically) alongside glacial-interglacial cycles.

Chemostratigraphy: ardent objector to Flood geology

Now that you have a grasp on the principles behind chemostratigraphy, consider the implications for the Flood geologist. Since at least the 1930's, modern 'creation scientists' have been working to reinterpret the geologic column in terms of a catastrophic, worldwide flood. These explanations typically involve giant waves of water depositing sediments over wide regions, only to rinse and repeat. Somehow, sediment types were neatly divided to form distinct layers of gravel, sand, silt, clay, and lime, replete with fine sedimentary structures, including mud cracks, eolian dunes, and beachside cross-bedding. Most impossibly, this chaotic process is said to have produced a precise ordering of fossils, which various young-Earth creationists have tried to rationalize through tales of hydrodynamic sorting, ecological niching, stepwise inundation of the continents, and intelligence gaps. Yes, even thousands of species of flowering plants universally managed to outsmart their gymnosperm counterparts and escape the initial waves of the flood (that is, until the end of the Jurassic, around day 160 of the flood).

Despite the persistent arm-waving of Flood geologists on this point, they have not grown tired in the face of numerous counter examples, where fossil zones are simply too precise to be explained by global flood waters. There is no hydrodynamic or ecological factor that could sort foraminifera, pollen, and trilobites into neat zones that occur in the same order from one side of the continent to another. But even if we do grant the impossible scenario, chemostratigraphy provides a final test and falsification.

In the conventional geological interpretation, we can use index fossils and radiometric dating alongside stratigraphy to determine that, for example, a rock layer in Nevada is the same age as a rock layer in southern China (perhaps they both contain a unique assemblage of Cambrian-aged trilobites). According to the flood geologist, these layers were deposited in a single year, less than 5,000 years ago, but were not necessarily deposited simultaneously. If they both contain the same types of fossils in the same order, it can only be due to the living arrangement of organisms prior to the Flood. Regardless of how the order arose, one thing is certain: if these marine organisms were all buried in a global flood, then all of them made their shells from the same ocean and the same reservoir of carbon with approximately the same isotopic ratio. So when fossilized shells of trilobites, brachiopods, molluscs, etc. are analyzed across the Phanerozoic (542 Ma – Present) for carbon isotopes, are they isotopically homogenous (as predicted by Flood geology) or do patterns emerge?

Phanerozoic evolution of δ13C in seawater, from Veizer et al., 1999.
As we can see from the figure above, the carbon-isotope ratio in carbonate fossils—and therefore the ocean itself—varied substantially over the past 500 million years. Though excluded from this plot, Precambrian variations are even greater in magnitude, though less frequent. Now, if this range in δ13C values on the order of 6–10 parts per thousand does not seem impressive, consider that to increase the oceanic δ13C value by only 5‰ requires a sustained doubling in the rate of organic carbon burial for about 1 million years. Because the carbon reservoir in the ocean is so large (today, about 39,000 billion tons of carbon), the color of this bowl of M&M's does not change appreciably on a whim—certainly not in the space of a 370 days. Therefore, Flood geologists are left with the impossible task of explaining two features of this plot:
1) Variations in the carbon-isotope ratios of fossils are far too great to be explained by shifting ocean chemistry within a single year, meaning these organisms could not have lived in the same ocean at the same time.
2) The pattern of carbon-isotope variations from Cambrian to Quaternary is the same across the entire globe. Whether you're sampling rocks from Texas or Tanzania, layers of limestone determined to be the same age according to their fossil content also exhibit the same pattern of δ13C values over time. These values are invariably high for Permian-aged carbonates and invariably low for Ordovician-aged carbonates.
Figure 2 from Saltzman et al. (2005). Composite of
carbon-isotope records from carbonate rocks of the
Great Basin, USA.
When we examine carbon-isotope records on a finer scale, the advantage of chemostratigraphy in correlating rock layers becomes more apparent. In this figure from Saltzman et al. (2005), numerous isotopic excursions can be distinguished at various stages in the Paleozoic. These are periods when a perturbation to the ocean system caused the average δ13C value of oceanic carbon to shift for a sustained period of time (perhaps 1–3 million years) before returning to an equilibrium value. Whatever the mechanism, these paleoceanographic events show up in the chemical record like thunderous lightning on an audio recording. Any tape players that happen to be running in the vicinity of the storm will record the same events in the same order. As we examine sedimentary records across the globe, therefore, we can synchronize the various tape players with great precision and even determine which players stopped recording for a brief interval (i.e. a depositional hiatus or unconformity). Therefore, we can be confident that biostratigraphic zones indeed represent unique, coeval periods of Earth history, when particular assemblages of organisms were living together in ancient oceans. Otherwise, we would not find a common signal of ocean chemistry, but a jumbled mess of relatively homogenous isotopic values throughout the geologic column. The concept of Flood geology, therefore, is entirely inconsistent with this peculiar subdiscipline called chemostratigraphy.

In the next post, I will briefly explore the means by which a single isotopic excursion—the Steptoean Positive Carbon Isotope Excursion, or SPICE event—has been traced around the globe, being predicted by the handful of trilobite species that defined the Steptoean stage of the Late Cambrian. In establishing that the oceanic carbon reservoir shifted by 5‰ during a single stage of the Cambrian period, we can be all the more confident that thick formations of limestone were deposited over millions of years—not dozens of days.

Friday, August 8, 2014

"Give us, this day, our day in your garden": the eschatological genesis of the Lord's Prayer

"I've never read the Bible in its entirety before... Where do I begin?"

Once upon a time, the didactic use of the Christian Bible in basic literacy and the near ubiquity of religious education in western culture meant that few were unfamiliar with the stories of the Old and New Testaments. But today, whether motived by faith or criticism, millions of adults resolve annually to read every book of the Holy Bible for the very first time. I've heard the question posed countless times: "How do you read the Bible? Do you begin on page one and read straight through, or mix it up somehow?" Everyone seems to have their own opinion, and numerous reading guides are available to implement these views. Whenever a pastor is present, in my experience, the answer seems unanimously to be "Read the Gospels first—Matthew, Mark, Luke, and John—or you're bound to become lost or confused."

For most Christians, the New Testament in general and the Gospels in particular are the appropriate light through which the Hebrew Bible ought to be understood, much like a bright lamp in a dusky cellar. Unfortunately, this attitude toward the Old Testament, however true, can tend to minimize its importance for most readers, who typically understand the first 39 books (give or take) only through distance memories of their childhood Sunday School. It is the cherished foundation on which their house is built, but the best truths are hidden among the cluttered antiquities, and the party's already moved upstairs. Now, I do believe that this somewhat intuitive view is rooted in a sacred truth common to the New Testament authors—namely, that the story of Jesus is the long-awaited climax of Israel's story. As with any movie or play, for example, we understand the first act retrospectively once the climax emerges and the story is resolved. But this approach naïvely assumes that we already know the content of that foundational first act, unlike most of modern society, and so we may be likened to those stumbling into the theater only after the intermission.

If you have determined to read the Bible in its entirety, many will advise you to begin with the Gospel of Matthew. I agree, so let us begin where Matthew himself begins, and that's in Genesis. Once you grasp the reasoning behind this, I hope you'll understand better why the New Testament authors never referred to the Old Testament as such, but called that collection of writings by its more appropriate name: "Holy Scripture" (e.g. 2 Tim. 3:15).

One discovery that changed forever the way I read the Gospel of Matthew

Many years ago, I attended a Bible study with a small group of friends, which may sound familiar to some of you. We took a book—in this case, the Gospel of Matthew—and spent several hours, once a week, attacking each detail the best way we knew how. We drew from commentaries, modern and ancient, and did our best to let "scripture interpret scripture" by cross referencing terms and ideas with other gospels and various references to the Old Testament. After six months, we had covered a whopping ten chapters (in studies like this, we are far prouder for taking longer to cover less). Though I wouldn't see the end of the study, having to move away for graduate school, I felt more confident than ever in my ability to read and teach the Gospel of Matthew. But confidence is a glass house on a pebbly beach, and I was a curious kid on a long walk. What was the stone that changed it all?

– The Gospel of Matthew is a retelling of the Tanakh –

Shorthand for "Torah, Prophets, and Writings", Tanakh is the name traditionally given to the collection of writings that constitute the Hebrew Bible, or the Christian Old Testament. While the content is the same, however, the arrangement and grouping of certain books is not. The Tanakh relies on the Masoretic ordering of the text, which conveys a distinct narratival and theological message: torah identifies the role and obligations of mankind, especially Israel, in God's cosmos and tells the story of the law's reception; the prophets tell of the application of law and covenant to the nations of the land, including by God who judges them; the writings balance the apparent rigidity of the law and covenant in shaping history with patient wisdom, not least to explain the lamentable lot in which Israel found herself after repeated exile and foreign rule. Thus Tanakh is a story without a climax; hope is buried in lamentation, and the covenant God is strangely more distant in the end than in the beginning.

When we read the Hebrew Bible, therefore, as those in the audience of the gospel writers, we begin with the opening words of the Greek Septuagint: βιβλος γενεσεως, or "The Book of Genesis", and its famous opening line:
In the beginning, God created the heavens and the earth...
We do not end, however, in Malachi 4 with the promised return of Elijah and the awesome day of the LORD (a rather obvious transition to John the Baptist). Instead, the Tanakh closes with the words of Cyrus of Persia in 2 Chronicles 36:23:
All the kingdoms of the earth hath the LORD God of heaven given me; and he hath charged me to build him an house in Jerusalem, which is in Judah. Who is there among you of all his people? The LORD his God be with him, and let him go up.
And so, Matthew begins and ends his gospel—the story of Jesus of Nazareth—in the same manner. The opening line (Matt. 1:1), so frequently glossed over as though its sole purpose were to title a genealogy, reads thusly:
Βιβλοσ γενεσεως Ιησου Χριστου, υιου Δαβιδ υιου Αβρααμ...
The Book of Genesis of Jesus Christ, son of David, son of Abraham...
The genealogy that follows proceeds systematically from Abraham to David to Exile to Jesus in precisely 42 generations, or, we might say, six sets of seven generations. Thus Matthew recounts for us the six days of Israel's creation, culminating in one man, born by the breath of God (Matt. 1:20), who would bear the image of God, inaugurate the heavenly kingdom, and promise a new sabbath rest (Matt. 11:28). Chapter 28 opens with a familiar timeline:
Now after the Sabbath, toward the dawn of the first day of the week, Mary Magdalene and the other Mary went to see the tomb...
On the sixth day, the new Adam succumbed to death, and on the seventh day, he rested in the tomb. The old word has died, but now, a new week has begun; it is a new creation. In the final scene, a new hope emerges with the Great Commission to build a holy temple, rooted not in the sympathies of a foreign king, but in the authority granted to the incarnate son of God (Matt. 28:18-20):
All authority in heaven and on earth has been given to me. Go therefore and make disciples of all nations, baptizing them in the name of the Father and of the Son and of the Holy Spirit, teaching them to observe all that I have commanded you. And behold, I am with you always, to the end of the age.
And so Matthew links his gospel conspicuously to the narrative of the Tanakh in its opening and closing lines, so that we might understand his message as a retelling of the story of Israel, in which the character of Jesus has taken up familiar roles. Like Solomon, son of David, he would build God's temple; like Isaac, son of Abraham, he would be led up a hill to the slaughter. He would flee from Egypt, face temptation in the wilderness, and be baptized in the Jordan like Israel. Echoing the story of Adam, he was made alive by the Spirit of God and met his final evening in a garden scene, but the Edenic dilemma had been radically transformed: obedience to God now meant death and exile for one, in hope of life and glory for the many. Like Moses, he met death, but was vindicated through the faithfulness of God; like Joshua, therefore, he would lead his people back into Eden and inaugurate the kingdom of heaven. Jesus' death and resurrection thus constitute the climax of Israel's story, according to the Gospel of Matthew. Retold in this manner, the stories of the Hebrew Bible are thoroughly eschatological, pointing forward to their fulfillment in one like a son of man (Dan. 7:13)—the new Adam.

The eschatological Genesis of the Lord's Prayer

Having established that the book of Genesis was fresh on the gospel writer's mind in shaping his metanarrative, we are made fully aware of the subtle echoes that link Jesus' story with that of Israel. Matthew does not scour the Hebrew Bible for prooftexts to support his messianic claims, however, as though all were written to predict the advent of Christ. Instead, he subverts the stories of land, law, and covenant so that all is fulfilled in this person Jesus of Nazareth (Matt. 2:13–15 is a great example; the gospel usage of Hosea 11:1 is radically different from the original). In the fifth chapter of Matthew's gospel begins the well known Sermon on the Mount. Note the echo of the Exodus narrative in Matthew's phrasing:
Seeing the crowds, [Jesus] went up on the mountain, and when he sat down, his disciples came to him.
Like Moses in ancient days, Jesus led his people to a mountain, where he sat down (in true rabbinical style) to deliver a message on law and covenant to the twelve representatives of a new Israel. In the old covenant, the people of Israel were portrayed as a sort of new mankind, fashioned from the dirt in Egypt, where God had separated the waters from the waters (cf. Gen. 1:6). Having the privilege to name God their Father, they are a new Adam, if you will, facing a fresh choice in a new Eden. The old generation had failed the test in the wilderness, and so the next would inherit the land of Canaan (Deut. 1:35; 38–39):
Not one of these men of this evil generation shall see the good land that I swore to give to your fathers... Joshua the son of Nun, who stands before you, he shall enter. Encourage him, for he shall cause Israel to inherit it. And as for your little ones, who you said would become a prey, and your children, who today have no knowledge of good or evil, they shall go in there. And to them I will give it, and they shall possess it.
Note the language reminiscent of Eden: no knowledge of good or evil. As you may recall, it was Joshua, who shares his name with the New Testament Messiah, who would lead Israel back into the garden of God. The imagery that links these concepts is most evident in Josh. 5:13-15, when Joshua readies his armies to cross into Canaan:
When Joshua was by Jericho, he lifted up his eyes and looked, and behold, a man was standing before him with his drawn sword in his hand. And Joshua went to him and said to him, “Are you for us, or for our adversaries?” And he said, “No; but I am the commander of the army of the LORD. Now I have come.” And Joshua fell on his face to the earth and worshiped and said to him, “What does my lord say to his servant?” And the commander of the LORD's army said to Joshua, “Take off your sandals from your feet, for the place where you are standing is holy.” And Joshua did so. (emphasis mine)
The Garden of Eden, by Wenzel Peter
The unnamed commander of the army of the Lord was last seen during the flight from Eden, where an angel was stationed with a flaming sword to guard its entrance (Gen. 3:24). Thus from beginning to end, Torah roots the flight from Egypt and inheritance of Canaan firmly in the Eden narrative. The law given to Israel, and the covenant terms emphasized in Deuteronomy, strongly echoed that given to Adam, who was cast out of the garden for having breached the terms. So long as Israel held fast to the covenant, they would flourish and see the day when God's kingdom would come on Earth as in heaven (especially under David, God's royal image). But when their transgression became too egregious, like Adam they would see only exile and frustration.
Your Father knows what you need before you ask him. Pray then, like this...
Matthew 6:9 begins the oft-recited Lord's Prayer, which is placed in the middle of the Mosaic sermon. How is it that God knows what we need before we ask him? We might answer that in his omniscience, of course God knows all our needs, but the language of Jesus is not a philosophical truism. It gains meaning in the precedent of God working in similar fashion with his covenant people from the very beginning. Let us consider the echoes of Genesis in these famous lines.
Our Father in heaven... (Matt. 6:9)
Then God said, “Let us make man in our image, after our likeness. (Gen. 1:26)
[Adam] fathered a son in his own likeness, after his image... (Gen. 5:3)
On what grounds do we call God our Father? The answer comes in the very first chapters of scripture, where mankind is commissioned to be the image of God on Earth. In praying to 'our Father in heaven', therefore, we assent to the role and obligations of his covenant people.
Let your name be holy... (Matt. 6:9)

So God blessed the seventh day and made it holy, because on it God rested from all his work that he had done in creation. (Gen. 2:3)
Like the day of rest, which signifies that God has taken reign over his good creation, we pray that the very name of God who made us be set apart from all others. This is, foremost, the binding prerequisite of the covenant to which we are called. Should we forsake it, we attempt to thwart the very will of God in making heaven and Earth anew.
Let your kingdom come... (Matt. 6:10)
And God blessed them. And God said to them, “Be fruitful and multiply and fill the earth and subdue it, and have dominion over the fish of the sea and over the birds of the heavens and over every living thing that moves on the earth.” (Genesis 1:28)
The command to be fruitful and multiply is not simply one to reproduce and increase our numbers. Rather, it is a commission to cultivate God's glory throughout his creation and, by being the image of God, establishing his divine rule and expanding his kingdom on Earth. Mankind's dominion over the orders of creation is not an autonomous one, because it is God who rules over all. The kingdom is his, and so are its laws. In ancient cultures, in which both Genesis and Matthew were written, the royal image—whether a statue or an engraven coin (e.g. Matt. 22:20–21)—signified who specifically had authority over the land. To say that we are God's image on Earth, therefore, is to signify that God reigns here now, and to pray "Let your kingdom come" is also a calling to ourselves to be that image as described in Genesis 1.
Let your will be done, on Earth as in heaven... (Matt. 6:10)
And God said, “Let there be light,” and there was light. (Gen. 1:3)
In praying that God's will be done on Earth as in heaven, we do not simply affirm his providence and omnipotence, but we petition that he make heaven and Earth as it was described in the creation hymn—very good.
Give us this day our daily bread... (Matt. 6:11)
Behold, I have given you every plant yielding seed that is on the face of all the earth, and every tree with seed in its fruit. You shall have them for food. (Gen. 1:29)
And the LORD God commanded the man, saying, “You may surely eat of every tree of the garden... (Gen. 2:16)
Cursed is the ground because of you... By the sweat of your face you shall eat bread, till you return to the ground. (Gen. 3:17, 19)
When we petition that God fulfill our most basic needs—our daily bread—we long for the place in which thorns and thistles are no longer the fruits of our labor. We hope never to thirst or hunger again, but to be fed with manna from heaven, multiplied loaves, or even the garden trees. This symbolism reflects a greater reality that characterizes the cosmos when God reigns visibly: the naked are clothed, the hungry are fed, the alien is housed, and the widow and the orphan are cared for. If we take the covenant seriously, the Earth will reap a great reward and the nations of the land will be blessed on our account.
Forgive us our debts, as we have forgiven our debtors... (Matt. 6:12)
And the Lord God made for Adam and for his wife garments of skins and clothed them... (Gen. 3:21)
It is our transgression against God that keeps us out of his garden and taints the image we were called to be, so we seek the full reconciliation only shadowed during the exit from Eden, when God covered the shame and nakedness of his mankind.
And lead us not into temptation, but deliver us from the evil one. (Matt. 6:13)
Now the serpent was more crafty than any other beast of the field that the LORD God had made... “What is this that you have done?” The woman said, “The serpent deceived me, and I ate.” (Gen. 3:1, 13)
If you do well, will you not be accepted? And if you do not do well, sin is crouching at the door. (Gen. 4:7)
The final petition of the Lord's Prayer provides the strongest echo of the garden scene, where mankind was tempted and led into evil by something innate to the creation. It was mankind who transgressed, but it was God who placed the serpent. Similarly, the Exodus generation wandered the Sinai desert without visible fulfillment of the promise, and Jesus himself was led out to the desert to be tempted. In praying that God not lead us into temptation, we do not propose that he tempts us intentionally for our own demise, but rather we acknowledge that in temptation, we will fall. We ask, therefore, that our Eden be rid of its snakes altogether, that we may cultivate his garden until the glory of God cover the whole land and his kingdom be everywhere visible.

When you pray the Lord's Prayer, be mindful of the echoes of Eden in your petitions to God. Previously, I wrote on the dialogic of Genesis 1–3 and how the literary tension between two creation accounts—an intentional juxtaposition by the editor—leads us to a more profound truth. In Matthew's mind, perhaps, it is almost as though Jesus were telling his disciples: "Ask that God remake heaven and Earth as described by the creation hymn (Gen. 1:1–2:4), but that your narrative will not end like Adam's." I believe we can summarize the Lord's prayer to incorporate the eschatology of Genesis in the following fashion:
Our God in heaven, who formed us from the dust in his own image and likeness, that we may call him Father;
Let your name be holy among us, as the day you set apart to signify your completed work and give us rest;
Let your kingdom come, as we strive to be your image, reflect your heavenly reign, and cultivate your glory over all creation;
Let your will be done, on Earth as in heaven, as in the day when you made all things new;
Give us this day, our day in your garden, where thorns and thistles are no longer the fruits of our labor, but the Earth is finally blessed by our work;
Forgive us our debts, which have kept us from your garden and tainted your image, because in newness of life, we have at last forgiven our debtors;
And lead us not into temptation, as in Eden where the serpent deceived us;
But deliver us from the evil one, who is more crafty than the other beasts of the field and is crouching at the door.


For more reading from this blog on reading Genesis, please see the following posts:
Appearance of age or true age? Better yet—what's the difference?
On reading Genesis as literature: breaking the hermeneutical bonds of a modern controversy
On reading Genesis as literature: the dialogic of Genesis 1–3
Finding Noah, then and now: Part 1—"Where is Noah today?"
Finding Noah, then and now: Part 2—"When and where did Noah sail his ark?"

Sunday, August 3, 2014

Geological death traps and the impossibility of a post-Flood migration from Ararat

Over the past week, Dr. Julie Meachen—a paleontologist with Des Moines University—has been making headlines after obtaining a permit to excavate mammalian fossils from a sinkhole cave in Wyoming. The 85-foot-deep sinkhole likely collapsed more than 100,000 years ago, and has since been collecting the remains of rather unfortunate Pleistocene- and Holocene-aged individuals, who managed to fall through the conspicuous opening at the surface. The researchers intend primarily to recover samples of ancient DNA from the site, which has kept cool since its formation (i.e. a stable, preservative climate) and could provide one of the first North American repositories of ancient DNA from ice-age megafauna. It will be fascinating to learn what may be resolved about these widely debated extinctions, which themselves have made headlines for decades. I wish Dr. Meachen and her team the best as they move forward with this project; repelling 85-feet vertically down a pitch-black chamber of death is by no means an easy task! Hopefully this Indiana Jones-like tale gives you a better appreciation for your neighborhood paleontologist.

While this story is very intriguing by itself, I hope to utilize it as an introduction to a more comprehensive challenge to one young-Earth claim, currently touted by Ken Ham, the Creation Museum, and the upcoming Ark Encounter. According to the young-Earth paradigm, a relatively small population aboard the ark had to repopulate the entire Earth within only several hundred years following the Flood.

Why so quickly?

Well, we know from paleontological evidence that all sorts of mammals, including megafauna like mammoth, mastodon, sloths, giant deer, dire wolves, lions, cheetahs, and many many more, are currently buried within Pleistocene (2.6–0.012 million years ago) and Holocene (11,600 years to present) sediments around the world, including the Americas. Since so-called "Flood geologists" almost universally consider these most recent geological periods to be post-Flood, we must assume that each species migrated from Ararat across the globe in time to have been buried and preserved as fossils. But here's the catch: many of these fossils and sediments are also associated with the most recent ice age. While the last glacial period lasted about 100,000 years and ended 11,600 years ago by conventional geological wisdom, young-Earth geologists speculate that the ice age occurred almost immediately after the flood, lasting as long as ~700 years.

For the sake of discussion, let's grant this already implausible timeline from the young-Earth paradigm. Now, we are left with only ~700 years in which a handful of mammal 'kinds' must have diversified (i.e. evolved) into thousands of species, migrated as far as 16,000 miles (~25,000 km), meanwhile reproducing at rate sufficient to account for millions of individual fossils, which represents but a fraction of the global population during the ice age (I consider only the most previous ice age, but there were actually several dozen!). Does this sound reasonable?

A senseless census: ice-age mammal populations of the 'post-Flood' period

Fortunately for us, we can turn this thought experiment into a testable hypothesis: if modern mammal populations originated from a few kinds aboard Noah's ark, then we should expect regional populations to have been sparse in the first millennium after the flood, due to limitations on reproduction rate. For example, mammoths and mastodons reproduce at around 20–30 years of age, only after a relatively long gestational period. Even under the best-case (but still impossible) scenario of doubling the population every 20 years, it would take 400 years to produce 1 million individuals from a single pair of proboscideans. Of course, not all of these would be mammoth, but would include elephants, mastodons, and other species within this 'kind'.

Geological death traps, like the sinkhole cave in Wyoming, tend to work like a semi-biased population census. Only the most desperate or distracted individuals fell into the trap, but all of them had to be living or migrating in the vicinity of the cave. In other words, the pile of fossils at the bottom of this single cave—reportedly as high as 30-feet!—constitutes but a small fraction of the ice-age population living in the region that would become our great state of Wyoming. If thousands of individuals now rest in the bone graveyard, the regional mammalian population could not have been less than hundreds of thousands, if not millions.

Example of bones amassed in the Berelekh mammoth graveyard, northern Siberia.
Other mass graveyards exist around the globe, such as the Berelekh mammoth graveyard in Siberia. Pitulko et al. (2014; 2011) report that most radiocarbon dates from mammoth bones and associated biological material fall between ~14,000–11,500 years ago—the latest interval of the last ice age, during which most mammoth went extinct around the globe. It is likely that humans played some role in the rapid accumulation of mammoths, given their common association with archaeological sites (e.g. Ugan and Byers, 2008, or see McNeil et al., 2005 for a North American study). In any case, these mass graves are found throughout Eurasia—e.g., Achchagyi–Allaikha in northeast Asia, Lugovskoe in western Siberia, Sevsk in western Russia, and Gary in the Ural mountains, among others, according to Pitulko et al., (2011)—and have been used to estimate ice-age mammoth populations of up to 5 million in Eurasia alone. Conservative estimates might be lower, but we know the actual number is very high, and estimates grow each decade with new fossil discoveries.

Young-Earth geologists would obviously challenge the accuracy of these radiocarbon dates and consider them 'apparently old', so let's consider how our conventional geological timeline might translate into theirs. Radiocarbon ages of ~12,000–18,000 years are everywhere associated with the last stage of the ice age and the extinction of most megafauna. These dates are far too old (or too inflated) to be less than ~3,000 years, because we have abundant corroboratory evidence from archeology and human history to confirm the accuracy of radiocarbon dates during this interval, even to the satisfaction of young-Earth geologists. According to most 'Flood geologists', however, the post-Flood ice age ended no less than ~3,700 years ago. Therefore, we have a small window (~3–4,000 years ago) into which these mass accumulations of mammoth and other ice-age mammals must fall, from the perspective of a 'Creation scientist'. Already, we see that the populations of ice-age mammals, especially mammoth, were far too large to be accounted for within a young-Earth paradigm.

Around the globe: North American death trap, numero uno!

If you follow the Naturalis Historia blog, you might remember reading about Sima de los Huesos, a Spanish cave full of hominid remains, or the Kirkdale Cave Hyena Den. These two repositories are relatively small in terms of the unfortunate population sampled, but they present similarly unrealistic constraints on the young-Earth timeline and have long puzzled creationists. The widespread occurrence of such traps documents the diversity and size of animal populations that must have appeared shortly after the Flood and made the move from Ararat, exacerbating the historical absurdity of biblical literalism. To strengthen this case, I want to consider perhaps the most popular site in North America, which now traps only tourists. In 1828, a peculiar ranch was granted by the governor outside a budding Mexican town called El Pueblo de Nuestra Señora la Reina de los Ángeles de Porciúncula. Unbeknownst to the ranchers of the day, those smelly and unsightly, bubbling pools of natural asphalt that tainted the landscape had been the world's greatest sarcophaguses for thousands of years—mass mausoleums of a former age. Today, we can experience that history through the Page Museum, which houses the collections of the La Brea Tar Pits in downtown West Los Angeles.

Outdoor exhibit at the La Brea Tar Pits. Photo credit.
The La Brea 'Tar Pits', which are formed by asphalt seeps (tar is manmade) from the petroleum-rich Monterey Formation, have been swallowing alive everything from pollen to giant predators for at least 50,000 years. To date, more than 1 million bones from over 230 vertebrate species have been recovered—a testament to the rich faunal diversity and abundance of southern California during the late Pleistocene. Of the vertebrate specimens, gentle giants like mastodon and ground sloth are indeed present, but the collection overwhelmingly consists of ice-age predators like the dire wolf and saber-toothed cats. For every grazing beast that could not escape the gooey grave, about nine predators and scavengers died trying to recover the free meal. Next time you order a hamburger at the drive-thru, just think, "The effort could be worse. At least I'm burning fuel and not breathing it..!"

Dire wolf skulls on display at the Page Museum.
Paleontologists have now recovered the remains of more than 4,000 dire wolves and 2,000 saber-toothed cats from the pits, which provides an impressive census of local populations. Radiocarbon dates suggest at least two episodes of relatively abundant accumulation, around 40–50,000 years ago and ~26,000 years ago. So let's consider the implication of these tar pits for the 'Flood geologist'. If more than 4,000 wolves, to our knowledge, died trying to feast at a small set of tar pits in southern California, how many wolves total must have living in western North America during the last ice age? It is difficult enough to explain how a population of even 4,000 dire wolves could have appeared within 700 years after the Flood, more than 10,000 miles from Ararat, but young-Earth creationists must account for millions of individuals across the entire continent (along with every other species of the 'dog kind' so calmly referenced by Ken Ham). For example, dire wolf fossils have even been recovered near Las Vegas in Tule Springs National Monument, another large repository of Columbian mammoth. If this scenario makes little sense for long-distance runners that breed quickly, how can we possibly explain the distribution and size of giant sloth populations in the Americas? It takes little analysis to see why the La Brea Tar Pits are a clear testament against the upcoming 'Ark Park' in Kentucky.

Be fruitful and multiply

The geological death traps discussed here are but a small sample of those found throughout the globe, which provide gruesome tales of an ancient age. If young-Earth creationists, particularly via the Ark Encounter, continue to make the preposterous claim that a small collection of animal 'kinds' evolved rapidly and distributed themselves across the continents, then we cannot be expected to take their worldview seriously. So long as Ken Ham and others conflate their efforts with evangelism, moreover, they will drag down the Christian church with their sea-unworthy ship. History is rife with warnings against braiding the gospel with bad science and poor politics, which Ham has ignored while taking the helm of a vessel that he deems unsinkable. Still, we are exhorted to pray on Earth as in Heaven, let Your will be done and commissioned with the task of bearing good fruit in a world of nuts. So this is my effort for the day. If you find this raspberry to be sweet, please don't hesitate to share, and pray that so many will no longer disregard God's rich satisfaction of our scientific curiosity.

Wednesday, July 23, 2014

Fragments of the Fossil Record: "Thigh Bone Disconnected from the Hip Bone..."

I still remember as though it was yesterday...

Like a camp of rogue militants being tracked, the secluded site was interrupted suddenly by an unidentified chopper closing in. Everyone scrambled as the downwind thrust of the propeller kicked up more dust than could be warded off by canvases on hand, and indignation grew for the uninvited guest. The engine faded while the researchers regained their sight, only to be met by an elderly man with an ornamented cane. What could he possibly want, worth jeopardizing the operation at hand? He merely wished to broker a business deal like none before; he sought to resurrect dry bones from the dust and bring imagination to life.

Such was the world's baptism into the cult of popular paleontology. Never again would we be unmoved by the sight of a dinosaur skeleton encased in solid rock, or fail to appreciate the paleontologist who reconnected our species with ancient forms of life. On that day in 1993, when Jurassic Park hit the big screen, we all learned something about digging for fossils. But this movie did for geology what Indiana Jones had done for archaeology: exaggerated the discipline to make it exciting and accessible to all of us. Therefore, I hope it's not too late to unlearn something about digging for fossils—namely, that skeletons regularly appear intact.

The Fragmented Nature of the Fossil Record

No doubt, Dr. John "Jack" Horner of Montana State University, on whom the character of Dr. Alan Grant is loosely based, has personally seen a few nearly complete skeletons emerge from from dig sites around the world. But any paleontologist would be quick to point out that intact skeletal remains are by far the exception to the rule. We have been spoiled as spectators by the perfectly preserved Archeopoteryx and the exceptional specimens of the Green River Formation. But for every set of bones found in 'life' position, there are thousands found disconnected, broken, weathered, and scattered throughout the sediments.

Example of a nearly complete juvenile dinosaur (Bolong yixianensis, a species of Iguandontia), found in northeastern China. Image is Figure 2 from Zheng et al. (2014).
Single tooth from a large crocodile.
Note penny for scale.
Several years ago, I had the privilege of assisting with vertebrate fossil collections from the Cretaceous rocks of Bryce Canyon National Park. In less than two months, we had recovered more than 11,000 individual fossils, of which precisely zero were 'intact'. Single specimens of teeth (fish, crocodile, shark, dinosaur), vertebrae, bony scales (especially gar fish), and turtle shell comprised the vast majority. Dinosaur bones were not uncommon, but in all but one case, the bone was so badly weathered down that we could not determine from which limb the fragment actually came (in this one case, the joint was preserved, so that the bone was recognizably a partial tibia). Perhaps the closest exception to this pattern was dense cluster of turtle shell. Of the dozens of individual fragments, we were able to piece together almost half of one turtle's carapace:

Lower carapace of a Late Cretaceous turtle, recovered from southern Utah.
The rarity of well preserved skeletons is explained by a subdiscipline of paleontology called taphonomy, which focuses on the conditions surrounding death and burial of a fossilized organism. Taphonomists analyze the morphological and chemical details of fossils, asking questions like "Was the organism exposed long at the surface or was the burial instant?" or "Was the water alkaline/acidic, oxic/anoxic, still or flowing?" These clues help to reconstruct the paleoevironments in which ancient life lived and ultimately died, aiding our understanding, for example, of how certain animals even behaved.

The vast majority of fossilized bone exhibits at least some evidence of weathering at the surface. Though fossilization commonly involves "rapid" burial, skeletons can and often did spend many days or weeks exposed to the elements before nature locked them away. Exceptional preservation sells well, both at the gift shop and in education, but it remains exceptional. Certain environments, like stratified, alkaline lakes provide the ideal conditions for complete, intact skeletons. But most organism underwent a more brutal decay process after death, which explains the imbalanced levels of preservation, particularly in terrestrial fossil site.

A taphonomic perspective on Young-Earth Creationism

Once we gain a proper perspective on the nature of the fossil record, it becomes clear why paleontologists continue to reject the proposals of so-called 'Flood Geology'. If the majority of fossil specimens were buried suddenly and catastrophically only ~5,000 years ago, then intact skeletons (even partial ones) should be widespread and common. While raging waters do have the potential to dismember fragile lifeforms, it is not to the extent that we actually find in sediments today: nearly every tooth pulled from the jaw, nearly every vertebrae unhinged from the next—basically Dem Bones sung in reverse. Connective tissues like cartilage are sufficiently strong to keep most skulls, limbs, and backbones together, as is evident in the tragic results of natural catastrophes today.

On the other hand, the abundance of weathered fragments of only the most resilient bones (vertebrae, teeth, shells) fits perfectly within the conventional framework of paleontology. The Cretaceous rocks of Bryce Canyon National Park, along with most terrestrial sites from which dinosaurs are recovered, were formed largely by rivers and floodplains. Sedimentary structures help us to interpret features like migrating dune formations, levee overflow, and clay-rich lowlands, where the bony remains of rotting corpses are most likely to accumulate. Perhaps you've hiked past the remains of something like a deer or a snake, where only a pile of disconnected bones remains. If so, you can imagine that in a typical river plain, occasional floods are capable of burying the recently deceased for fossilization. These remains will scarcely resemble that famed velociraptor from the badlands of Hollywood-staged Montana, but such is the true face of vertebrate paleontology and the fragmented nature of the fossil record.

Monday, June 30, 2014

What Georgia Purdom could learn from TED Talks

In her recent blog post, Dr. Georgia Purdom of Answers in Genesis criticized an article by Dr. Scott Kaufman from The Raw Story, who highlighted two projects at a White House science fair to demonstrate some inconsistency on the part of Ken Ham. The Raw Story piece followed up on a claim by Ham that none of the celebrated science fair projects depended on 'molecules-to-man' evolution. Ken Ham apparently sees this as support for his claims that creationism doesn't stifle real scientific development, contrary to the evidence I raised in my last post. Since two of the science fair projects addressed major developments in cancer research, however, Dr. Kaufman was quick to point out the hypocrisy in Ken Ham's claim. He writes:
"The link [Ken Ham] included to the projects presented at the White House Science Fair... lists two studies of the behavior of cancer cells, both of which depend on theories of cellular development that are themselves predicated on evolutionary theory."
According to Dr. Purdom, modern cancer research need not appeal to the principles of evolutionary theory to function. But to make this claim, she must limit evolutionary theory to a piecemeal, nuanced derivative of the original—a rhetorical tactic not well understood by her audience. A more honest approach would be to admit openly: "Well yes, cancer research does draw on principles of evolutionary theory, but I am still critical of and reject several components of evolutionary theory."

I will rely on those of you with stronger backgrounds in biology to clarify, augment, or correct my own position, but to my knowledge, human cancer research interacts with and depends on evolutionary theory in at least two important ways:
1. The genetic elements of cancerous cells are subject to (and often derive from) mutation, and so a major challenge of cancer research is understanding the evolution of individual diseases and the response by individual species (e.g. Davies et al., 2002Domazet-Lošo et al., 2014).
2. The behavior and treatment of human cancers can be assessed through other mammals, like mice (e.g. O'Brien et al., 2007), on the grounds that humans share a common ancestry with these animals.
Like many Americans (perhaps including some of you), Georgia Purdom rejects that humans share a common ancestry with other animals, and she is free to try and defend that position. Chances are, she and likeminded creationists could contribute to ongoing cancer research. But it is fairly misleading to characterize this research as employing only the "tools of good observational science"—presumably in contrast with broken tools of bad, historical science?—or to pretend that evolutionary theory "has nothing to do with it". In the words of Dr. Paul Davies (quoted here), "we will fully understand cancer only in the context of biological history."

Dr. Purdom's mischaracterization of science, which propagates the false dichotomy between 'observational' and 'historical' science, along with her downplaying the role of certain fields in biology, all contribute to the growing negative attitude among evangelicals toward careers in science. The satire piece by Scott Kaufman (who, Dr. Purdom kindly reminds us, only has a Ph.D. in Literature) is thus in line with the thesis of my previous post and elucidates the rhetorical effort by Answers in Genesis to disassociate mainstream geology and evolutionary theory from the rest of science (you know, the part that's 'successful'). So I would like to thank Dr. Kaufman, who—despite his 'meager' credentials—seems to understand the nature of science better than Dr. Purdom and is willing to share that knowledge with others.

"Why we should trust scientists"

The link above is to a recent TED talk given by Naomi Oreskes, a historian of science. Therein, she addresses the paradox of science communication: all of us must appeal to authority—an informal logical fallacy—to accept conclusions reached by scientists outside of our own specialty, but we should still trust scientists and the conclusions they reach in consensus.

Most relevant to this discussion, Dr. Oreskes takes a closer look at the scientific method, which is commonly oversimplified by textbooks. She demonstrates how aspects of observation, hypothesis, laws of nature, and historical evidence have worked in conjunction through a not-so-well defined method. Scientists have to be creative to solve the diversity of research problems they face, and most endeavors will involve both 'historical' and 'observational' methodologies. According to Dr. Oreskes, however, the robustness of the scientific method is not the basis for our trust in scientific consensus. The way she arrives at this conclusion is fairly intriguing, so I won't spoil it here.

In the introduction, this talk appeals to a slight mischaracterization of Pascal's wager and what initially appears to be an unfair contrast of faith and science (keep watching, it's not). In the end, though, I would highly recommend the video to inform your own thoughts on the nature of science and/or facilitate discussion (I suppose that is the goal of TED talks, right?).

Wednesday, June 25, 2014

The U.S. needs more scientists, and Ken Ham isn't helping

In February of this year, millions of Americans tuned in to see how popular scientist Bill Nye would fare in public exchange with Ken Ham, president of the largest organization promoting young-Earth creationism. I've already given my thoughts on the debate, but a few weeks after the fact, a good friend of mine challenged a key accusation from Bill Nye, which got me thinking. During his closing remarks, Nye exhorted the audience to extinguish YEC from the public sphere for the sake of our society:

"I say to the grownups, if you want to deny evolution and live in your world, in your world that's completely inconsistent with everything we observe in the universe, that's fine, but don't make your kids do it because we need them. We need scientifically literate voters and taxpayers for the future. We need people that can — we need engineers that can build stuff, solve problems."

I don't doubt the sincerity of Nye's invitation, with which I (and many of you) can empathize fully. The underlying implication, however, is that one cannot succeed in the natural sciences if one is caught up in the young-Earth paradigm touted by Ken Ham. Being the sharp public speaker that he is, Mr. Ham anticipated this sort of accusation in his opening presentation, during which he broadcasted short interviews with U.S. scientists that accept the young-Earth position. I would conjecture that Nye's exhortation thus fell on deaf ears among the audience, who had just witnessed firsthand that YEC's can be effective scientists and engineers.

Evolution and technological development

In particular, Ken Ham highlighted the work of creationist Raymond Damadian, who invented the MRI. Through this case in point, Ken Ham established well that believing in a young Earth and rejecting evolution does not necessarily cripple you from solving scientific problems and developing the technology needed in our modern world.

Ham proceeded to challenge Nye to cite one piece of technology that could not have been developed apart from accepting an 'old Earth' and 'molecules-to-man' evolution. We should give Mr. Ham credit for making his point clearly, but in the spirit of honest discourse, we must recognize that his challenge is extremely misguided.

In limiting this challenge to 'pieces of technology', Ken Ham subtly tried to link the theory of evolution to all other disciplines, as though this foundational principle of biology were some sort of epistemological framework on which all secular knowledge is built. This overstated connection—completely foreign to actual scientists and most Christians—is illustrated well in a couple graphics used by AiG and creationists around the web. The first appeared in Ken Ham's presentation, as I recall:

According to this cartoon, believing in evolution and/or 'millions of years' constitutes a philosophical framework that sprouts all the world's problems, as well as an attack on the integrity of sacred scripture. Alternatively, this set of beliefs is a tree of 'bad fruit' that is rooted in sin:

What is missing from this implied philosophical connection is a sound argument to support it. The theory of evolution is not morally prescriptive (i.e. it cannot tell you what you ought to do in life); rather, it is an explanatory framework through which relevant data in biology, geology, anthropology, etc. are scientifically coherent. If we share a common ancestry with other primates, it does not logically follow that you can freely rape women (as YEC Darek Isaacs put it). Following the logic of Ken Ham, the observed fact that genocidal dictators with military support often do get their way would imply that they ought to get their way. As for the rest of us, we can distinguish between an objectively descriptive theory in science and a morally prescriptive philosophy.

Ham's false dichotomy between a system where "man decides truth" and "God's word is truth" serves well to keep his audience skeptical of both evolution and mainstream geology. Ultimately, however, we must deal with the fact that to read and understand God's word, we utilize the same cognitive abilities that allow us to reconstruct the common ancestry of life on Earth over millions of years.

Coming back to Ken Ham's challenge, we might be hard pressed to find a piece of technology that demands a belief in evolution or an old Earth. Of course, this is as meaningful as finding a successful businessman who rejects string theory. On the other hand, thousands of scientific instruments (including mass spectrometers, seismic detectors, and equipment to read the human genome) were developed to test hypotheses that confirmed 'molecules-to-man' evolution and an old Earth. Genuine scientific inquiry inspires and facilitates technological development like a catalyst, so as far as I'm concerned, Ham's challenge has been answered countless times.

Why are Evangelicals underrepresented in the sciences?

So it's possible to be a creationist that designs medical equipment, invents better cell phones, or builds spacecraft. But how does the prevalence of young-Earth creationism affect public attitudes toward science? I would hypothesize that by selectively undermining entire subdisciplines (like geochronology, climatology, or evolutionary ecology), Ken Ham and his organization have all but extinguished the genuine curiosity that would otherwise drive members of his audience toward those fields. Why spend 6 years in poverty (i.e. graduate school) to specialize in a subject rooted in lies and bad science? Why contribute to scientific research that begins with a rejection of God's word? Intentionally or not, Ken Ham has scared young scientists from taking the necessary steps to realize their dreams and make an impact on the scientific community. If you believe that the Bible is God's word, and God's word is truth, then this is a step backward for Christianity.

And even if you don't, but still believe that science is foundational to modern society, you can agree this is a step backward for humanity.

Only two weeks after the Ham/Nye debate, Christianity Today reported on a study that confirmed my suspicions. Despite the overall positive tone, given that a large percentage of 'rank and file' scientists identify as Christian, I noticed immediately that Christians are underrepresented in the scientific community compared to the general population. This feature is quantified in Table 5 of the original study by Ecklund (2014) from Rice University:

According to these polling data (n = 10,241), Evangelical Protestants are the single most underrepresented religious group among U.S. scientists. Mainline Protestants and Catholics, who are more likely to accept mainstream biology/geology, are slightly better represented, consistent with my purported connection to the 'science skepticism' of creationist claims. Ecklund (2014, p. 13–14) writes:
"Evangelical Protestants... are more than twice as likely as the overall sample to say they would turn to a religious text, a religious leader, or people at their congregation if they had a question about science."
It is important to note that being religious does not necessarily deter one from becoming a scientist in the U.S. While atheists/agnostics are better represented among scientists, unsurprisingly, it is not nearly to the same extent as Jewish Americans or the catch-all category of Middle and Far Eastern faiths. So I would encourage you to read the original study, which I don't intend to review exhaustively here.


Among religious groups where YEC ministries have the greatest impact, relatively fewer congregants pursue careers in the natural sciences. Ken Ham may believe that one can be an effective scientist as a creationist, and he may be right. But Bill Nye's exhortation to extinguish YEC from the public sphere for the sake of modern society is equally valid. It appears the prevalence of YEC in the U.S. can impact our reputation as a leader of research, technology, and design.

Tuesday, June 24, 2014

"Best evidences for a young Earth": Snelling and our salty seas, Part 3

(continued from Part 2)

In case you are now exhausted by the topic of salt in the oceans, I want to reassure you: this is the light at the end of the tunnel.

Thus far, I have tried to examine closely and honestly the methodology of Austin and Humphreys (1990), which I described as unscientific and oversimplified. By no means is this a personal attack, as I have documented precisely how Austin and Humphreys have ignored or miscited key data and thus employed unjustifiably simple models to convince readers that the oceans must be younger than 62 million years. They tout confidence not shared by the very authors they cite. Furthermore, they have been resilient in the face of criticism, refusing to update their model despite that more research is available every year, which could drastically improve it.

In the last post, I focused on the various mechanisms by which sodium is added to the world's oceans. By reading through all sources cited by Austin and Humphreys, as well as newer studies from the past 24 years, I found numerous flaws in the 'sodium inputs' reported by Austin and Humphreys and utilized in their model. Most of their figures far overestimated the amount of sodium carried to the oceans, and some of the proposed mechanisms add no sodium whatsoever on geological timescales. These authors are thus guilty of some basic errors in accounting, as well as some basic misunderstandings of geochemistry, for which they ought to be held responsible. But that is the nature of science: we open our research to criticism, by which it might be refined. If we refuse to accept that criticism, science cannot advance.

In this final post, I will briefly address the 'sodium outputs' reported by Austin and Humphreys (1990), followed by a 'balanced checkbook' of the global sodium cycle that shows why the oceans are not missing salt.

Table 2 from Austin and Humphreys (1990), summarizing
model outputs of Na from the ocean. Units are in 1010 kg/yr.
Sodium Outputs

1. Sea spray

One of the most active and constant processes by which salt is removed from the oceans is felt by anyone that spends much time at (or lives near) the beach. Rust and corrosion are constant worries for any machinery exposed to the sea breeze, which is full of salty droplets of water. Austin and Humphreys (1990, p. 5) describe sea spray rather well:
"Waves of the sea, especially breaking waves along the shore, produce air bubbles in the water. Collapse of these bubbles shoots into the air droplets of seawater which evaporate to form microscopic crystals of halite. Crystals of halite are carried with other aerosols by the winds from the ocean to the continents."
While sea spray does remove massive quantities of salt from the oceans (Austin and Humpreys estimate 60 million tons/year of sodium, Table 2), the vast majority of this salt returns swiftly to the oceans via rivers and groundwater. You may recall from last post, I likened the process to withdrawing $20 and immediately re-depositing the money into your account. Since I determined the long-term sodium input from sea spray to be 0 tons/year, we must also remove sea spray as a sodium output.

By comparing Table 2 to Table 1 from Austin and Humphreys, we find that sodium lost via sea spray is greater than sodium gained by ~5 million tons/year. I cannot say whether this imbalance was intentional, but it may reflect a real, albeit minor, long-term loss of sodium to the continents. For example, some sea spray particles will end up falling as rain over the Great Basin of the United States, but no rivers drain from the Great Basin to the oceans. In other words, these bits of salt will eventually get buried in sediments or groundwater storage on the continent, providing a long-term sodium sink.

From a 'deep-time' perspective of geology, those continental reservoirs of sediment and groundwater may eventually be uplifted and eroded into the oceans. Therefore, it becomes impractical to calculate precisely how much sodium is lost, long-term, via sea spray; we simply know that the amount should be greater than zero.

For the purpose of this discussion, I will follow Holland (2005) and consider the long-term sodium output via sea spray to be 0 tons/year. But we might allow the sodium loss to continents to be as high as the minimum imbalance from Austin and Humphreys (1990), which is 5 million tons/year.

2. Ion exchange

Cation exchange is a blessing to those with 'hard water', as water softeners work by exchanging calcium and magnesium for 'softer' ions like sodium. In the oceans, the process works in reverse: clay minerals tend to absorb sodium while releasing calcium and magnesium back into the oceans. Since clay minerals are abundant as suspended particles in river water, the rivers deliver millions of 'sodium-absorbent' sponges every year.

Austin and Humphreys cite a handful of studies that attempt to estimate the total uptake of sodium via cation exchange. These estimates have not change substantially in recent years, and Holland (2005) uses the same figure (35 million tons/year) in his table. Of course, the total amount depends strongly on the amount and composition of sediments delivered to the oceans, which means that it will vary on geological timescales with riverine inputs of sodium. Therefore, we can take the flux used by Austin and Humphreys as a reasonable, if not a high-end, estimate of sodium lost via cation exchange: 35 million tons/year.

3. Burial of pore water

Marine sediments dominated by clays in particular are extremely porous, meaning that abundant seawater is present between the particles. In short, the seawater gets buried within the sediments, along with the salt it contains. Austin and Humphreys cite an earlier, rather crude estimate of sodium loss via pore-water burial of 22 million tons/year.

We should note that pore-water burial is a complex process, accompanied by numerous chemical reactions (e.g. Scholz et al., 2013). Therefore, it is difficult to estimate precisely the total flux of any element, let alone sodium. In addition, the rate at which marine sediments are buried will vary on geological timescales, depending on the rate and character of global tectonics. During the formation of major mountain belts (like the Andes, Rockies, and Sierra Nevadas), we should expect greater rates of sediment accumulation and pore-water burial, in particular because such mountain ranges are accompanied by deep-water ocean trenches, in which miles of sediment accumulate relatively 'rapidly'.

4. Halite deposition

Austin and Humphreys' assessment of halite (NaCl) deposition is rather misleading. They note correctly that modern marine sediments are "nearly devoid of halite", but do not address completely why this would be characteristic of Earth history. Halite deposition is limited by the fact that halite (NaCl, or 'table salt') is extremely soluble in water. For seawater to precipitate NaCal typically requires that a body of seawater become isolated from the oceans, after which an evaporative basin forms under intensely arid conditions. One example of this phenomenon in relatively recent geological history is the Mediterranean Sea, under which thick deposits of salt are buried under younger sedimentary layers. The Natural Historian blog on this topic provides an excellent graphic description of the process and these Mediterranean deposits.

In their discussion, Austin and Humphreys (1990) do acknowledge the existence of such halite deposits in the geologic column, but do not consider it to be a significant sodium sink. To establish this, they divide the global inventory of Phanerozoic halite deposits (4.4x1018 kg of sodium) by the length of the Phanerozoic (they use 600 million years) to produce a 'time-averaged estimate' of sodium loss through halite deposition: 7.3 million tons/year of sodium. This number is much smaller than other fluxes of sodium to/from the oceans, so they proceed with confidence (p. 8):
"...it is extremely unlikely that the “time averaged” halite output contains a significant error. No major quantity of halite in the earth’s crust could have escaped our detection."
Austin and Humphreys derive their estimate of global halite deposits from an earlier study by Holland (1984). Now, what might have changed since 1984? For one, the ability of salt deposits to prime crude oil for harvest has made them a valuable target for petroleum exploration in recent decades. Hence we know far more now about the extent of halite deposits than we did 30 years ago.

As it turns out, the global inventory of halite deposits (~32x1018 kg; Hay et al. 2006) is ~3 times larger than the estimate used by Austin and Humphreys. Based on fluid inclusion analysis and mass balance calculations, Hay et al. (2006) further estimate that about 50% of halite has eroded back into the oceans over the course of the Phanerozoic (an assumption shared by Austin and Humphreys). According to these data, the time-averaged flux of sodium from the oceans via halite deposition is ~35–41 million tons/year. This figure is close to the maximum flux via halite deposition in Table 2.

Figure 5 from Hay et al. (2006); the distribution of halite deposition by
geological age over the course of the Phanerozoic. Large outcrops of
Cretaceous (K) aged salt deposits are known from Texas, Mexico,
Portugal, and Spain.
In the last post, I suggested that sodium inputs/outputs via chloride solution and halite deposition should not be included in a long-term model of the sodium cycle, because eventually, these halite deposits will be eroded back into the oceans. Technically, we could remove both quantities from the final table. Having included them, however, we can confirm that the estimated fluxes I've provided are consistent with observed data. If, on average, 38 million tons/year of sodium are removed from the oceans via halite deposition, and 17.6 million tons/year of sodium are added to the oceans via chloride solution in rivers, then we can expect that after 600 million years, 12.2x1018 kg of sodium should now be locked up in Phanerozoic halite deposits. Since sodium is 1/3 the mass of halite (NaCl), that makes 36.6x1018 kg of halite. This figure is only slightly more than 32x1018 kg, the documented global inventory of Phanerozoic halite deposits from Hay et al. (2006). Within uncertainty, therefore, my refinement of Austin and Humphreys' model is accurate for the past 600 million years.

5. Alteration of basalt

Sodium removal via low-temperature alteration of basalt on the seafloor constitutes a relatively minor sink. This rate is dependent on that of seafloor spreading, and so it will vary over geological history, but the total flux is too small to impact significantly the final calculation. I don't see anything problematic with the figure, so I will keep Austin and Humphreys' cited flux of 4.4–6.2 million tons/year of sodium.

6. Albite formation

I discussed at length in the last post why albite formation is a significant sink of sodium from the oceans and concluded that 25.3 million tons/year of sodium are removed via this process. This is one of the more significant errors in the model by Austin and Humphreys (1990), who mistakenly supposed that sodium was added to seawater through off-axial vents near mid-ocean ridges.

7. Zeolite formation

This final sodium output is likewise so small, that it will scarcely impact the final calculation. Again, I see nothing problematic with the figure cited by Austin and Snelling, so I will leave it intact.

The Global Sodium Cycle in Perspective

After examining all of the supposed inputs and outputs of sodium to and from the world's oceans, we can evaluate the argument by Austin and Snelling (1990) through an updated table:

Revised table of sodium fluxes to/from the oceans, as compared to Austin and Humphreys (1990). Uncertainty estimates represent 20% of total flux, as suggested by Holland (2005). Therefore, the total sodium input of 138.7 million tons/year is within uncertainty of the total sodium output of 126.4 million tons/year. According to these figures, the oceans are in steady state with respect to the sodium cycle, and the 'salt chronometer' provides no challenge to their conventional age of 3 billion years.
Immediately evident from this revised table is the fact that Austin and Humphreys (1990) significantly inflated and overestimated sodium inputs to the oceans. They accomplished this goal by the selective sampling of literature (some of which was already outdated by the time of their publication) and the use of high-end estimates without reporting uncertainties. In addition, they assumed (sometimes blindly) that these fluxes should stay the same over geological time. In fact, none of them should remain constant over tens of millions of years, given the dynamic complexities of our Earth systems.

The flux of sodium to and from the oceans via these various processes is not extremely well understood, even in the modern day. The processes are complex and must be estimated from limited data. Unfortunately, Austin and Humphreys could not afford to be honest about the nature of geology when it comes to documenting global geochemical cycles. In any case, we may finally put to rest the argument that the ocean's salt content limits the theoretical age to only 62 million years. Given that sodium inputs and outputs are essentially in balance, this upper limit crumbles entirely and is rendered scientifically meaningless.