Friday, 30 January 2015

The evidence for multiple ice ages in the last 1.5 million years from speleothem growth patterns

The evidence for an ancient Earth was compelling even before radiometric dating allowed geologists to quantify its great age. As the evidence for an ancient Earth is beyond rational doubt, some YECs have resorted to the argument that God created the Earth with the appearance of age. As this argument can neither be evaluated nor refuted, it is worthless as an explanation and can be immediately dismissed.

Attempts at justifying the argument usual revolve around the claim that Adam would have been created fully mature with an illusory age. Extrapolating from this to the assertion that the Earth was created 6000 years ago with a completely invented stratigraphic, palaeontological, and geochemical history however does not follow, not just because it makes God out to be deceptive on a colossal scale by embedded an incredibly detailed lie into the very structure of the Earth, but because there is no functional need for a planet to be created with a fictional history embedded in its crust. A rock that is 3000 million years old as determined by Sm-Nd dating would provide the same structural support as it did 6000 years after its formation, making the creation of a planet 6000 years ago with bogus radiometric dates completely unnecessary from a functional point of view – unlike humans, rocks are not living creatures so do not need to be created ‘mature’.

Palaeoclimatology graduate student Jonathan Baker at his excellent Age of Rocks website has an excellent article on how the careful analysis of stalactites and stalagmites (along with other similar formations collectively known as speleothems) provides hard evidence of multiple ice ages over the last 1.5 million years. Baker notes that if water infiltration into a subterranean cave ceases due to drought, speleothem growth slows. Another cause of reduced water flow to cave and subsequent speleothem growth retardation is permafrost. During ice ages, permafrost will expand away from the polar regions, meaning speleothem growth in caves that are normally not under permafrost will show growth cessation during ice ages when the permafrost cover extends over the caves:

Permafrost develops in regions where the average annual temperature is below freezing. Consequently, the ground itself remains frozen year round, along with any water that it contains. Today, permafrost exists mainly at very high latitudes, such as northern Alaska/Canada and northern Siberia, because our global climate is relatively warm. During the ice ages, however, permafrost boundaries extended much further south, and that was the subject of a paper by Vaks et al. (2013).

These authors investigated speleothems from several caves in Siberia that are located near or within the modern permafrost boundary. Knowing only these details, we can formulate their hypothesis ourselves: speleothem growth should have only occurred during warm interglacials, during which permafrost layers melted to allow groundwater infiltration. As it turns out, that’s precisely what the researchers discovered, simply by dating dozens of speleothems from each cave. Speleothem growth ceased during each ice age over the past 500,000 years, due to the advance of permafrost:
Siberian caves and the ice ages

Figure 2 from Vaks et al. (2013), showing U-Th dates of speleothems (A) alongside global proxies for past ice ages, such as oxygen isotopes in marine sediments (B), biogenic silica in nearby Lake Baikal (C), Antarctic greenhouse gas records (E-F), and solar radiation (G). Note that speleothems grew only during the warm interglacials (shaded areas), whereas no growth occurred during the ice ages (B; blue numbers) that separated these periods.
Speleothems can be dated very precisely, because Uranium decays at a known rate into Thorium and Lead. Uranium is soluble in surface waters (unlike Th & Pb) and can be incorporated into the calcite mineral that comprises most cave formations. While U-Th dating (used by Vaks et al., 2013) can only be applied to samples less than ~450,000 years old, however, the U-Pb method can date calcite formations up to tens of millions of years old. By utilizing the U-Pb method, therefore, the researchers recently extended their chronology to cover the past 1.5 million years. Their results were consistent with the 2013 paper, documenting more than a dozen intervals where speleothem growth was halted by permafrost advance and more than a dozen intervals where speleothem growth continued as the permafrost melted.
Young-Earth Creationists frequently claim that only one “multi-stage” ice age occurred, shortly after the Flood. Additionally, they claim that speleothems can grow rapidly enough to exist in a young, post-Flood world. But these claims are thoroughly refuted by overlapping records of dozens of ice ages during the Quaternary period and detailed radiometric analysis of cave formations. So-called ‘Flood geologists’ cannot explain the extensive advance and degradation of permafrost zones over thousands of miles, let alone how speleothems could yield dates well beyond 4,500 years old.
In my experience, tend to get very uncomfortable when confronted with both the evidence for palaeolithic humans and the ice age, as both do not comfortably fit into the naive 6000 year timeline with humans at a bronze age (or neolithic at best) level of culture. Trying to fit several ice ages into a 6000 year age span credibly is simply impossible unless one resorts to dubious tactics such as the 'appearance of age' gambit. That then raises the question of why God is going to create speleotherms hidden in caves with a completely bogus history of multiple ice ages over a 1.5 million year period. When the Omphalos YEC is forced to multiple ad hoc 'appearance of age' explanations to wave away the overwhelming avalanche of evidence for an ancient Earth, the disinterested observer is more than entitled to wield Occam's razor, and conclude that the only reasonable explanation is that the Earth is positively shouting its great age through multiple modalities.


1. Baker J "Monday Minute: Siberian caves reveal multiple ice ages over the last 1.5 million years" Age of Rocks Jan 26 2015