A fossil hash is either a sediment or sedimentary rock composed predominately of fragmented fossils of either shells, tergites, bones, teeth, other hard parts, or some combination of these remains.Bates, R.L., Sweet, W.C., and Utgard, R.O., 1973. Geology: An Introduction, 2nd ed. Boston, Massachusetts, Heath. 541 pp. Dott, R.H., 1958. Cyclic patterns in mechanically deposited Pennsylvanian limestones of northeastern Nevada. Journal of Sedimentary Research, 28(1), pp.3-14. The fossil hard parts of various animals, including brachiopods, corals, crinoids, bryozoans, ostracods, pelecypods, and trilobites, occur in shell hashes. If the fossil hash consists almost exclusively of one type of fossil, it is often named after that fossil, as in the case of crinoidal hash,Zywiecki, M. and Skompski, S., 2004. The Waulsortian-type mound in the Lower Namurian of the Lublin Basin (SE Poland). Marine and Petroleum Geology, 21(6), pp.709-722. trilobites hash,Webster, M., Gaines, R.R., and Hughes, N.C., 2008. Microstratigraphy, trilobite biostratinomy, and depositional environment of the “lower Cambrian” Ruin Wash Lagerstätte, Pioche Formation, Nevada. Palaeogeography, Palaeoclimatology, Palaeoecology, 264(1-2), pp.100-122. and oyster-shell hash.Painter, C.S., York-Sowecke, C.C., and Carrapa, B., 2013. Sequence stratigraphy of the Upper Cretaceous Sego Sandstone Member reveals spatio-temporal changes in depositional processes, northwest Colorado, USA. Journal of Sedimentary Research, 83(4), pp.323-338. Depending on the amount of matrix mud, fossil hashes have been classified as either packstones, grainstones, or more rarely as wackestones, of The Dunham classification system for carbonate sedimentary rocks.Kříž, J. 1998. Recurrent Silurian-Lowest Devonian Cephalopod Limestones of Gondwanan Europe and Perunica. New York State Museum Bulletin, 491, pp. 183–198.
Fossil hashes are associated with a variety of depositional environments. They can be found where either currents or waves erode, fragment, and concentrate the hard body parts of animals after they have died. For example, they have been found as a part of storm deposits (tempestites),Kerr, M. and Eyles, N., 1991. Storm-deposited sandstones (tempestites) and related ichnofossils of the Late Ordovician Georgian Bay Formation, southern Ontario, Canada. Canadian Journal of Earth Sciences, 28(2), pp.266-282. tsunami deposits (tsunamites),Jacobs, S., Brown, D., and Marks, E., 2006. A day on the Palos Verdes Peninsula; Pacific Section SEPM field trip guidebook to commemorate the 60th anniversary of the publication of Geology and paleontology of the Palos Verdes Hills, California. in Brown, A.R., and Cooper, J.D., eds., pp. 29-32. A Day on the Palos Verdes Peninsula: Pacific Section Society for Sedimentary Geology (SEPM) field trip guide, book. Fullerton, California, Pacific Section Society for Sedimentary Geology Pacific Section. 102, pp. and tidal deposits.O’Connell, B., Dorsey, R.J., Hasiotis, S.T. and Hood, A.V., 2021. Mixed carbonate–siliciclastic tidal sedimentation in the Miocene to Pliocene Bouse Formation, palaeo-Gulf of California. Sedimentology, 68(3), pp.1028-1068. Fossil hashes also occur as erosional lag deposits associated with hiatal and ravinement surfaces.Cather, M., Rose-Coss, D., Gallagher, S., Trujillo, N., Cather, S., Hollingworth, R.S., Mozley, P. and Leary, R.J., 2021. "Deposition, diagenesis, and sequence stratigraphy of the Pennsylvanian Morrowan and Atokan intervals at Farnsworth Unit". Energies, 14(4), no.1057, 26 pp. Chan, M.A., Newman, S.L., May, F. E., and Edelman, D.W., 1991. Deltaic and shelf deposits in the Cretaceous Blackhawk Formation and Mancos Shale, Grand County, Utah. Utah Geological Survey Miscellaneous Publication, 91-6. 83 pp.
References
External links New York state museum
See also Encrinite