Experimental Measurement of Shell Strength and its Taphonomic Interpretation

Abstract

Other| April 01, 2001 Experimental Measurement of Shell Strength and its Taphonomic Interpretation MARTIN ZUSCHIN; MARTIN ZUSCHIN 1Institut für Paläontologie, Universität Wien, Althanstraße 14, A-1090 Vienna, Austria Search for other works by this author on: GSW Google Scholar ROBERT J. STANTON, JR ROBERT J. STANTON, JR 2Department of Geology and Geophysics, Texas A&M University, College Station, TX 77843 *Present address: Department of Invertebrate Paleontology, Natural History Museum of Los Angeles County, 900 Exposition Blvd., Los Angeles, CA 90007 Search for other works by this author on: GSW Google Scholar Author and Article Information MARTIN ZUSCHIN 1Institut für Paläontologie, Universität Wien, Althanstraße 14, A-1090 Vienna, Austria ROBERT J. STANTON, JR *Present address: Department of Invertebrate Paleontology, Natural History Museum of Los Angeles County, 900 Exposition Blvd., Los Angeles, CA 90007 2Department of Geology and Geophysics, Texas A&M University, College Station, TX 77843 Publisher: SEPM Society for Sedimentary Geology Accepted: 24 Nov 2000 First Online: 03 Mar 2017 Online ISSN: 1938-5323 Print ISSN: 0883-1351 Society for Sedimentary Geology PALAIOS (2001) 16 (2): 161–170. https://doi.org/10.1669/0883-1351(2001)016<0161:EMOSSA>2.0.CO;2 Article history Accepted: 24 Nov 2000 First Online: 03 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation MARTIN ZUSCHIN, ROBERT J. STANTON; Experimental Measurement of Shell Strength and its Taphonomic Interpretation. PALAIOS 2001;; 16 (2): 161–170. doi: https://doi.org/10.1669/0883-1351(2001)016<0161:EMOSSA>2.0.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyPALAIOS Search Advanced Search Abstract Shells were broken experimentally by compressive and compactional loading to determine the best predictors of shell strength among a number of morphologic (length, width, height, weight, thickness) and taphonomic (presence of a drillhole, exposure to seawater, point contacts of shells) features. Compressive strength of fresh (Mercenaria mercenaria, Mytilus edulis) and beach-collected (Anadara ovalis) shells was measured by placing a single valve flat on a surface and compressing it. Compactional strength of beach-collected Mulinia lateralis shells was measured by placing isolated valves and shell layers in fine sand and compacting the sand and shell mixture.The most effective predictor of compressive shell strength of fresh shells was thickness; it was significant for all three species and it easily can be interpreted as an obvious defense against a shell-crushing predator. Size was comparatively less important. The presence of a drillhole reduced shell strength significantly, and strong correlations of weight and shell strength among beach collected Anadara shells may reflect different states of degradation of the original amounts of organic matrix. Supporting this conclusion is the observation that immersion in seawater for seven weeks significantly decreased shell strength of organic-rich shells (Mytilus), but did not affect shell strength of organic-poor shells (Mercenaria). Fracture patterns varied considerably between and within taxa. The breakage pattern of Anadara and Mercenaria shells generally consisted of a set of fractures radiating from the point of loading to the shell margin, including even the thick dorsal margin. The breakage pattern in Mytilus usually consisted of one fracture only, which did not extend from the point of loading but whose path was highly unpredictable. In compaction experiments with beach-collected Mulinia lateralis, the most important factor determining whether or how a shell would break was the contact between shells. Isolated shells, both drilled and undrilled, did not break. Among drilled valves in simulated shell beds, only 26 percent of the fragments > 2 mm fractured through the drillhole. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.