Been studying rocks. Roughly speaking (and a big, maybe):
Some rocks indicate, that there have been periods of the earth being “flat,” and later, the earth having radically different heights and depths of its surface - changing between “lumpy” and “very mountainous.”
During the “flat” periods, the water depth was very shallow, and the change of depth was barely a few millimeters within a set of 100 to 1,000 years.
The “flat” periods may have been interrupted by major impacts. And those were followed by long periods of the great heights being reduced to the “flats.”
The Appalachian mountain range was as high as 65,000 ft above present day sea level. Such heights periods probably the result of multiple major impacts occurring in a short period of time, shattering the earth.
In the general Los Angeles, California basin, there are indications of a giant impact, about 14 miles in diameter, with a center roughly midway between Azusa and Covina.
A ‘sure sign’ of a meteoric impact is the presence of ‘shocked quartz’ in the underlying rock.
https://en.wikipedia.org/wiki/Shocked_quartz
Further ‘proof’ is the presence of ‘iridium’ which can come from meteors.
https://en.wikipedia.org/wiki/Iridium
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