For me, one of the most interesting parts of what I do here is compare the description published by the ICR of a piece of “secular” research with the research itself and the other things that have been written about it. Even when I don’t write my own post on the ICR article – whether through a lack of time, or through boredom – I often take a look at the background to see how well the reality matches that which is presented by the ICR. One example has stuck with me for the last couple of months: Tim Clarey’s August Acts & Facts article, Hot Mantle Initiated Ocean and Flood Beginnings.
Thin, dense oceanic crust is formed at mid ocean ridges and destroyed a subduction zones. Around 130 million years ago the super-continent of Pangaea rifted apart, beginning the formation of the Atlantic ocean. Elsewhere over the same period pretty much all of the ocean floor has been replaced at least the once by the same process. Young Earth creationists obviously don’t believe that 130 million years has passed, but the reality of plate tectonics and its components continental drift and sea-floor spreading is so overwhelming that even they cannot deny it (though some do still insist that it is not happening today – here’s John Baumgardner countering some of Michael Oard’s claims to that extent). Indeed, they now incorporate the concept into their models of the flood in the form of “Catastrophic Plate Tectonics,” which posits that the last 100 million years plus of tectonic movements actually happened during the single Flood year.
The problems with this massive increase in the rate of geologic processes are legion, but not the topic of this post. Instead, we’re looking at what Clarey thinks a paper published online in March in Nature Geoscience means for the beginning of the Flood:
A new discovery may shed light on how the great Flood began. In a paper published in Nature Geoscience, German scientists found evidence suggesting the earth’s mantle was up to 300 degrees Fahrenheit hotter during the initial, formative stages of the Atlantic Ocean—when the continents began to violently pull apart to create it—compared to today. Over time, the mantle cooled to current levels.
Using the chemical composition of the basalt bedrock produced it is possible to determine the temperature of the mantle from which they formed. As a news article commenting on the paper (unfortunately not open access) says:
Volcanic rocks erupted at mid-ocean ridges are ultimately produced by melting of Earth’s mantle. Higher mantle temperatures cause a greater fraction of the mantle to melt, changing the chemical compositions of the erupted melts. In the ocean-ridge setting, hotter mantle generates magma with lower sodium and aluminium and higher iron contents. The compositions of volcanic rocks sampled from mid-ocean ridges can therefore be used to infer the temperature of the underlying mantle at the time the rock formed.
They did indeed find warmer temperatures in the past – to an extent. According to Clarey, this means:
These findings suggest that the initiation of the great Flood began with an anomalously high-temperature mantle beneath the pre-Flood continents. As the continents rifted apart, new ocean crust formed rapidly between them, and molten mantle filled the ever-widening gap, supporting the concept of catastrophic plate tectonics as postulated by creation scientists.
Part of the idea that he is running with is that plate tectonics then was not like it is now, quoting from the aforementioned news article which concludes by saying:
Based on the available data, much of the ancient oceanic crust seems to have been generated under conditions that are rare beneath present-day ridges.
There are two major problems with Clarey’s interpretation. For the first, we must look at what the study was actually trying to look at. The was called “High mantle temperatures following rifting caused by continental insulation“ – here’s a pdf. They were testing the old hypothesis that heat should build up under the continents if they stay in place for too long, eventually causing to to rift apart much like Pangaea did. What they found in the Atlantic and Indian oceans, which formed in this way relatively recently, was that temperatures were indeed hotter in the past by as much as 150 °C, which comes out at around the 300 °F figure Clarey gave earlier. According to the paper these increased temperatures, caused by the large area of continent insulating the mantle beneath, are what caused the continents to rift and persisted until they were sufficiently separated.
Clarey, meanwhile, believes that these increased temperatures allowed the continents to move really really fast. But this breaks down when you look at other ridges. The East Pacific Rise hasn’t been near a continent in a very long time, and while there are some anomalous hot readings in very ancient Pacific rock,
…the Pacific data show no systematic change in mantle temperature with time and the raised mantle temperatures cannot result from continental insulation. Other factors must therefore also contribute to ancient temperature variations beneath the ocean basins.
(To quote from the news article.) The trouble for Clarey here is that if he’s invoking hotter temperatures to explain faster plate movement he still needs the same thing to happen in the Pacific ocean as well. The East Pacific Rise is producing fresh seafloor around two or three times as fast as the Atlantic, but in order to replace the entire ocean in a single year it too would need to move a hundred million times its present rate. If this paper is evidence in favour of this occurring in the Atlantic, then it must also be evidence against it taking place in the Pacific.
For the second it’s important to note that the the study authors were careful to take samples only from areas not affected by hotspots. Hotspots cause phenomena like Hawaii, a chain of young volcanic islands all alone in the middle of the Pacific plate, but can also occur along rifts. Iceland is a spectacular example of this, with a hotspot located there being the reason that the island is raised out of the water above the height of the rest of the mountain chain that makes up the mid-Atlantic ridge. But while the temperatures inferred from their ancient Atlantic samples were unusual, they aren’t completely unheard of in the modern world. For example, hotspots like Iceland are sitting on mantle that is that hot today. While the geology of Iceland is undoubtedly dramatic, it isn’t taking place at a rate that is millions of times faster than everywhere else. The increased temperatures observed are simply insufficient for the task Clarey demands of them.