# Does the weathered layer under the ditch floor measure how long each part has been exposed? · Great Sphinx of Giza > Three answers have been proposed. The layer is a depositional facies (coral-rich shoal-reef limestone) or a picking choice, and its thickness… leads… Source: https://mysteriesdept.com/mysteries/great-sphinx/questions/QST0CTWSD7G59TK/does-the-weathered-layer-under-the-ditch-floor-measure-how Publisher: Mysteries Department Licence: CC BY 4.0 (credit Mysteries Department and link the page) Updated: 2026-10-26T11:57:33+00:00 --- **0** # Does the weathered layer under the ditch floor measure how long each part has been exposed? Asked 26 Oct 2026 by [**apollo** ](https://mysteriesdept.com/u/apollo)·Part of [What explains the weathering of the body and the enclosure walls?](https://mysteriesdept.com/mysteries/great-sphinx/questions/QST0CTWSCZP7K5T/what-explains-the-weathering-of-the-body-and-the-enclosure)·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]](https://mysteriesdept.com/sources/SRC0CTWRWCE2JAW/seismic-investigations-in-the-vicinity-of-the-great-sphinx)⁠[[2]](https://mysteriesdept.com/sources/SRC0CTWRW4M7ANG/the-sphinx-controversy-another-look-at-the-geological). ## Answers 3 [**The layer is a depositional facies (coral-rich shoal-reef limestone) or a picking choice, and its thickness…** ](https://mysteriesdept.com/mysteries/great-sphinx/answers/ANS0CTWSS6A5TCB/the-layer-is-a-depositional-facies-coral-rich-shoal-reef) Partly supported by its tests Evidence: 1 for Most likely [**None of these.** ](https://mysteriesdept.com/mysteries/great-sphinx/answers/ANS0CTWSSNY6KK5/none-of-these) Not tested enough to call either way Evidence: none yet Still possible [**The low-velocity layer is subsurface weathering whose depth is proportional to exposure time, and the thinner…** ](https://mysteriesdept.com/mysteries/great-sphinx/answers/ANS0CTWSREW6Q63/the-low-velocity-layer-is-subsurface-weathering-whose-depth) Failed a test; not refuted outright Evidence: 1 for, 1 against Disputed ## History 1. 1992[Dobecki & Schoch puts forward: the low-velocity layer is subsurface weathering whose depth is proportional to exposure time, and the thinner…](https://mysteriesdept.com/sources/SRC0CTWRWCE2JAW/seismic-investigations-in-the-vicinity-of-the-great-sphinx) 1. 1992[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.](https://mysteriesdept.com/sources/SRC0CTWRWCE2JAW/seismic-investigations-in-the-vicinity-of-the-great-sphinx)For: The low-velocity layer is subsurface weathering whose depth is proportional to exposure time, and the thinner… 1. 1994[Harrell puts forward: the layer is a depositional facies (coral-rich shoal-reef limestone) or a picking choice, and its thickness…](https://mysteriesdept.com/sources/SRC0CTWRW4M7ANG/the-sphinx-controversy-another-look-at-the-geological) 1. 1994[Harrell: the rear line's velocities are 23 to 28 percent lower in both layers, the opposite of what less weathering…](https://mysteriesdept.com/sources/SRC0CTWRW4M7ANG/the-sphinx-controversy-another-look-at-the-geological)Against: The low-velocity layer is subsurface weathering whose depth is proportional to exposure time, and the thinner… 1. 1994[Harrell: harrell shows that a lower boundary on the rear line yields similar velocities for all three profiles.](https://mysteriesdept.com/sources/SRC0CTWRW4M7ANG/the-sphinx-controversy-another-look-at-the-geological)For: The layer is a depositional facies (coral-rich shoal-reef limestone) or a picking choice, and its thickness… 1. 26 Oct 2026Asked on this site ## Discussion 0 [Add to the discussion](https://mysteriesdept.com/signin?next=/mysteries/great-sphinx/questions/QST0CTWSD7G59TK/does-the-weathered-layer-under-the-ditch-floor-measure-how%23discussion) Help with this question [ **Propose an answer** Something the evidence could support or rule out ] [ **Propose an answer** Something the evidence could support or rule out ](https://mysteriesdept.com/signin?next=/mysteries/great-sphinx/questions/QST0CTWSD7G59TK/does-the-weathered-layer-under-the-ditch-floor-measure-how%23add-answer) [ **Add evidence** A result for or against an answer ] [ **Add evidence** A result for or against an answer ](https://mysteriesdept.com/signin?next=/mysteries/great-sphinx/questions/QST0CTWSD7G59TK/does-the-weathered-layer-under-the-ditch-floor-measure-how%23add-evidence) [ **Ask a sub-question** A smaller question that would help settle this one ] [ **Ask a sub-question** A smaller question that would help settle this one ](https://mysteriesdept.com/signin?next=/mysteries/great-sphinx/questions/QST0CTWSD7G59TK/does-the-weathered-layer-under-the-ditch-floor-measure-how%23add-question) [ **Add a source** A paper, archive record or image ] [ **Add a source** A paper, archive record or image ](https://mysteriesdept.com/signin?next=/mysteries/great-sphinx/questions/QST0CTWSD7G59TK/does-the-weathered-layer-under-the-ditch-floor-measure-how%23add-source) Where it fits Great Sphinx of Giza [**What explains the weathering of the body and the enclosure walls?** ](https://mysteriesdept.com/mysteries/great-sphinx/questions/QST0CTWSCZP7K5T/what-explains-the-weathering-of-the-body-and-the-enclosure)Key question · most likely salt crystallisation, clay swelling and wet-sand burial, with flooding and wind on exposed parts, produced… **Does the weathered layer under the ditch floor measure how long each part has been exposed?** You're here · the layer is a depositional facies (coral-rich shoal-reef limestone) or a picking choice, and its thickness… [ Ask a question under this one ]