Sunday, April 26, 2020

Tephra & the Post Flood Ice Age

And the waters returned from off the earth continually... Genesis 8:3

"Uniformitarians are assigning far too much time to the deep ice cores of Antarctica and Greenland. Since the ice sheets started
forming during the post-Flood Ice Age, these ice sheets can be no more than 4,500 years old.... yet uniformitarian scientists routinely assign six-figure ages to those cores.

Because of low snowfall, visible (and countable) layers are generally not preserved in the deep Antarctic cores.
Hence uniformitarians rely on age-depth models which assume the heights of the ice sheets have been constant or nearly constant for vast ages.

Science popularizer and creation opponent Bill Nye recently highlighted (surely unwittingly!) evidence that presumed ‘annual’ layers within the Greenland ice sheet are not necessarily annual after all. Ironically, this evidence, which involved tephra (volcanic ash and debris), was featured in a recent documentary which
denigrated creation science.

Likewise, in 2010 glaciologists described three layers of tephra discovered within the deepest parts of the Vostok and EPICA Dome C cores.
These are thought to be the oldest volcanic deposits ever found within the ice cores.
One layer was located at a depth of 2,632 m (assigned age of 358 ka) within the EPICA Dome C (EDC) core.
Three others were identified in the Vostok ice core. One was located at a depth of 3,288 m (assigned age of 406 ka). Two were located about a few centimeters apart from one another at a depth of 3,311 m (assigned age of 414 ka).
However, the scientists thought that these two were actually the same tephra layer that had been folded by movement of the ice.

The scientists noted the apparent infrequency of tephra layers within the deepest core sections:
A striking feature emerging from our study is that the
frequency of visible tephra in the Vostok and EDC cores decreases dramatically in the ice older than ca 220 ka. The last [i.e. most recent] 220- ka sections of both records contain about a dozen discrete tephra layers while only one event is identified at EDC and two at Vostok in the interval 220–414 ka, encompassing more than two complete climate cycles. Tephra layers even disappear from 414 to 800 ka, i.e. the bottom of the EDC core.”
They noted that this ‘dramatic’ drop in visible tephra layers was also apparent in the deep Dome Fuji core. Although dozens of tephra layers were visible in the upper part of the core, only two such tephra layers were visible in the deep part of the Dome Fuji core, thought to represent the time from 230,000 to 700,000 years ago.
Because the Dome Fuji core is about 1,500 to 2,000 km from the Vostok and Dome C cores, they concluded that the dearth of visible tephra layers was not an artefact but a ‘regional pattern’.
Although they acknowledged that not all volcanic eruptions necessarily deposit tephra on the ice sheets, and that not all tephra layers are preserved, they concluded that “these factors likely act
randomly at the long timescale of our observations, and were hardly responsible for the systematic absence of old volcanic layers at the different drilling sites”.
They also concluded that the lack of visible tephra layers could not be blamed on thinning of the ice deep within the cores, nor could it be explained by changes in atmospheric transport of aerosols during the Pleistocene.

They concluded that this apparent decrease in tephra frequency might be due to less intense volcanic activity in the South Sandwich Islands in the distant past.
However, this would require greatly reduced volcanic activity. In the case of the Dome Fuji core, ~500,000 years would have elapsed with no apparent tephra fallout!

Of course, the creation model provides another possibility. Because uniformitarian age-depth models (incorrectly) assign vast ages to the greatest depths of the long Antarctic cores, this results in an apparent decrease in the frequency of tephra layers at
greater core depths. Of course, this is exactly what is observed.
In fact, when the tephra layers are plotted as a function of depth, rather than time, the spacing between the deepest tephra layers is not nearly as pronounced, although tephras are generally still absent from the very deepest core sections.
Heavy snowfall early in the post-Flood Ice Age, with decreasing snowfall at later times, might cause volcanic eruptions to appear somewhat less frequent at the greatest depths. It may be that this observed pattern is the result of both factors."
CMI