The team knows that exhumation at this scale, possibly global in extinct, is “difficult to achieve” by rivers or by downslope erosion. Did glaciers do this, or a global catastrophic flood? The anomalous abundance of unconformities near the Proterozoic-Phanerozoic boundary-each one different, and frequently composite, but evidently captured by a globally widespread erosive event-is what makes the Great Unconformity unique.Ĭloseup of the Great Unconformity in Blacktail Canyon, Grand Canyon, showing bedrock granite below and Tapeats Sandstone above. Where did it go? The ocean floor, they think “ Ocean basins serve as the main repository for sediments produced during ice-sheet denudation and, due to the shorter oceanic crust lifecycle (compared to continental crust), provide one explanation for the reduced survival rate of Proterozoic detritus that is evident in the Ronov compilations.” But surely much of the denudation occurred far inland in the supercontinent. Their models require the removal of 3- to 5 kilometers of material by the glaciers. Their measurements, furthermore, were taken from isolated sites in North America and gathered from prior studies.
(This is near one of the sample sites of the Dartmouth team.) Notice bedrock below, and sedimentary layers above the break. Their only empirical support consists of “thermochronology” measurements at various sites, which are estimations of the “temperature that a mineral crystal has experienced over time and its position in the continental crust given a particular thermal structure.” These are assumed to be proxies for glaciers, not direct indications.ĭr Steve Austin, creation geologist, points out the position of the Great Unconformity near Pikes Peak along the Colorado front range, some 440 miles NE of the Grand Canyon. The Great Unconformity, further, is not characterized by moraines, erratics, glacial polish and other indications of glacial activity. Glaciers, however, do not last for hundreds of millions of years. The broad synchronicity of this cooling signal at the continental scale can only be readily explained by glacial denudation. We provide thermochronologic evidence of rock cooling and multiple kilometers of exhumation in the Cryogenian Period in support of a glacial origin for erosion contributing to the composite basement nonconformity found across the North American interior. The cause of this missing time has long eluded explanation, but recently two opposing hypotheses claim either a glacial or a plate tectonic origin in the Neoproterozoic. The Great Unconformity involves a common gap of hundreds of millions to billions of years in the geologic record. Two geologists from the Department of Earth Sciences at Dartmouth College, along with a lab assistant and colleagues from the University of Illinois and from Lehigh University, publishing in the issue of PNAS, sought to identify “ Thermochronologic constraints on the origin of the Great Unconformity.” Their solution calls on a favorite mythical event, the Snowball Earth hypothesis (see ).
Let’s look at how scientists at Dartmouth College seek to fit the Great Unconformity into the Geologic Column. Kuhn had his critics, but the cyclical pattern he described can be seen throughout the history of science in many fields. This continues until they become too severe then another party (often made up of younger scientists not having spent their career in the old paradigm) will begin a scientific revolution largely for the purpose of explaining the anomalies. Kuhn suggested that scientists working within a paradigm will acknowledge anomalies, but will attempt to solve them within the paradigm. Thomas Kuhn ( The Structure of Scientific Revolutions, 1962) and other philosophers of science after him paid close attention to how scientists respond to anomalies within a paradigm (i.e., a consensus).
ANOMALY GAME OF GO DRIVERS
Having just explored the ideological drivers behind secular geology (, ), we can look at this new study for another glimpse at current geological practice: how do they handle anomalies? This month, another attempt has been made to fit the Great Unconformity into evolution’s gradual, uniformitarian worldview. Any event with global effect would, of necessity, speak of a major catastrophe. (Photo by DFC in Blacktail Canyon, Grand Canyon, 2007)Īs shared earlier, numerous aspects of the Great Unconformity suggest a catastrophic break rather than slow-and-gradual processes. Yet evolutionists insist a billion years of geology took place between the basement bedrock and the overlying sediments. Abruptness of the Great Unconformity is evident throughout the Grand Canyon, where it is extremely flat.
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