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Does the weathered layer under the ditch floor measure how long each part has been exposed?

Asked 26 Oct 2026 by ·Part of What explains the weathering of the body and the enclosure walls?·3 answers·0·0 following
Most likely: the layer is a depositional facies (coral-rich shoal-reef limestone) or a picking choice, and its thickness…Ahead on the evidence, not yet confirmed. It needs two reviews to be accepted.

Where it stands

Three answers have been proposed. The layer is a depositional facies (coral-rich shoal-reef limestone) or a picking choice, and its thickness… leads, with evidence 1 for: partly supported by its tests. Two are still possible.

Why it matters

The seismic survey is the only field measurement published in support of an early date. If the layer's thickness tracks exposure time, it is a clock; if it is a rock facies or a picking artefact, it says nothing about age⁠[1]⁠[2].

Answers 3

Evidence: 1 for
Most likely
None of these.
Not tested enough to call either way
Evidence: none yet
Still possible
Evidence: 1 for, 1 against
Disputed

History

  1. Dobecki & Schoch puts forward: the low-velocity layer is subsurface weathering whose depth is proportional to exposure time, and the thinner…
  2. Dobecki & Schoch: the 1991 refraction lines found a 1.8 to 2.5 m weathered layer on the front and sides and 1.2 m at the rear.For: The low-velocity layer is subsurface weathering whose depth is proportional to exposure time, and the thinner…
  3. Harrell puts forward: the layer is a depositional facies (coral-rich shoal-reef limestone) or a picking choice, and its thickness…
  4. Harrell: the rear line's velocities are 23 to 28 percent lower in both layers, the opposite of what less weathering…Against: The low-velocity layer is subsurface weathering whose depth is proportional to exposure time, and the thinner…
  5. Harrell: harrell shows that a lower boundary on the rear line yields similar velocities for all three profiles.For: The layer is a depositional facies (coral-rich shoal-reef limestone) or a picking choice, and its thickness…
  6. Asked on this site
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