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MASSIVE LOSS. “In either a constructive or a destructive endmember scenario, if global sediment supply from tectonic uplift is held constant near Phanerozoic levels, then the depressed Proterozoic sediment volume in Fig. 1A suggests that on the order of 109km3 of sediment are absent from the continental crust and deposited instead in the deep ocean basins—either gradually, throughout the Proterozoic due to a diminished sediment storage capacity of the continents in a constructive model, or rapidly during an interval of enhanced erosion near the Proterozoic–Phanerozoic boundary in a destructive model.” https://lnkd.in/d6fatHN View in LinkedIn

EXPECT THE UNEXPECTED. "In contrast with popular theories of evolution, in which evolution is defined with respect to given symbolic genes and rules such as for replication or recombination, a proper theory of evolving life must allow evolution to create new symbolic descriptions and rules to manipulate them." https://lnkd.in/dsMZPii View in LinkedIn

‪“These excursions, the Great Unconformity, preservational irregularities in the terrestrial bolide impact record, and the first-order pattern of Phanerozoic sedimentation can together be explained by spatially heterogeneous Neoproterozoic glacial erosion totaling a global average of 3–5 vertical kilometers, along with the subsequent thermal and isostatic consequences of this erosion for global continental freeboard.”‬" "‪https://lnkd.in/d5waTiU View in LinkedIn

SUPPORTING DATA. “Here we show that the Great Unconformity is associated with a set of large global oxygen and hafnium isotope excursions in magmatic zircon that suggest a late Neoproterozoic crustal erosion and sediment subduction event of unprecedented scale. These excursions, the Great Unconformity, preservational irregularities in the terrestrial bolide impact record, and the first-order pattern of Phanerozoic sedimentation can together be explained by spatially heterogeneous Neoproterozoic glacial erosion totaling a global average of 3–5 vertical kilometers, along with the subsequent thermal and isostatic consequences of this erosion for global continental freeboard.” https://lnkd.in/d6fatHN View in LinkedIn

ELUSIVE EXPLANATIONS. “The Great Unconformity, a profound gap in Earth’s stratigraphic record often evident below the base of the Cambrian system, has remained among the most enigmatic field observations in Earth science for over a century. While long associated directly or indirectly with the occurrence of the earliest complex animal fossils, a conclusive explanation for the formation and global extent of the Great Unconformity has remained elusive.” https://lnkd.in/d6fatHN View in LinkedIn

GLACIAL EROSION THEORY. “The ice would have had to shave only an average of 0.002 inches (0.0625 millimeters) of dirt and rock off the crust each year to accomplish this feat, Keller said. That's a breeze even for modern-day glaciers, he said. Today, erosion rates for continental ice sheets range from 0.004 to 0.19 inches (0.1 to 4.8 mm), with steep mountain glaciers moving nearly 4 inches (100 mm) of rock and dirt annually.” https://lnkd.in/ds7GcBF View in LinkedIn

GLOBALLY VARIABLE. “Keller and his team think that the glaciers of Snowball Earth wiped clean all other impact craters, scraping a bit off the top of Sudbury and Vredefort, too. By their calculations, an average of between 1.8 and 3 vertical miles (3 and 5 km) of crust were scraped away by Snowball Earth's ice sheets over 64 million years. In some spots, Keller said, the loss was greater, and in others, no crust was lost at all.” https://lnkd.in/ds7GcBF View in LinkedIn

CRATER EROSION. “Around 700 million years ago, they found, the Earth's impact craters were wiped nearly clean. Only two huge craters, the Sudbury basin in Canada and the Vredefort crater in South Africa, predate Snowball Earth — and those craters were staggeringly enormous, originally measuring 93 miles (150 km) and 185 miles (300 km) across, respectively. They've been eroded to a fraction of their original size. [Crash! 10 Biggest Impact Craters on Earth].” https://lnkd.in/ds7GcBF View in LinkedIn

UPTICK IN SEDIMENTATION. “Then there’s the huge uptick in sedimentation rates at the start of the Cambrian. All the new sediment required plenty of space to fall into, something that would have only been possible if massive levels of erosion took place beforehand.” https://lnkd.in/ds7GcBF View in LinkedIn

METEORITE THEORY. “For one thing, “around 600 to 700 million years ago, Earth loses its craters,” notes study coauthor Bill Bottke, a planetary scientist and asteroid expert at the Southwest Research Institute in Boulder, Colorado. Some ancient craters still exist on stable continental cores named cratons, but they are few and far between. (Recently, a city-size impact crater was found under the ice in Greenland.).” https://lnkd.in/ds7GcBF View in LinkedIn