Comment: 17:49 - 18:37 (00:48)
Source: Annenberg/CPB Resources - Earth Revealed - 17. Sedimentary Rocks: The Key to Past Environments
Keywords: "sedimentary rock", "clastic sediment", "sedimentary structure", geologist, "mud crack", "ripple mark", cross-bedding, landscape, "San Andreas Fault", "San Gabriel Fault", "Ridge Basin", "Southern California", basin, mountain
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Our transcription: By understanding how mud cracks, ripple marks, cross-bedding, and other sedimentary structures and textures form, geologists can, in a sense, read the sedimentary rock record.
This allows them to reconstruct the physical appearance of ancient landscapes.
One place such work is being done is known as the "Ridge Basin," a thick sequence of sedimentary rocks sandwiched between the San Andreas and San Gabriel faults in Southern California.
Today, this area is not a basin at all; it is instead part of a young growing mountain range.
Yet 5 to 10 million years ago it was a deep depression.
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Geology School Keywords
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