Carbonate hardgrounds are surfaces of synsedimentarily cemented carbonate layers that have been exposed on the seafloor (Wilson and Palmer, 1992). A hardground is essentially, then, a lithified seafloor. Ancient hardgrounds are found in limestone sequences and distinguished from later-lithified sediments by evidence of exposure to normal marine waters. This evidence can consist of encrusting marine organisms (especially bryozoans, oysters, barnacles, cornulitids, hederelloids, microconchids and crinoids), borings of organisms produced through bioerosion, early marine calcite cements, or extensive surfaces mineralized by iron oxides or calcium phosphates (Palmer, 1982; Bodenbender et al., 1989; Vinn and Wilson, 2010; Vinn and Toom, 2015). Modern hardgrounds are usually detected by sounding in shallow water or through remote sensing techniques like side-scan sonar.
Carbonate hardgrounds often host a unique fauna and flora adapted to the hard surface. Organisms usually cement themselves to the substrate and live as sessile filter-feeders (Brett and Liddell, 1982). Some bore into the cemented carbonate to make protective domiciles (borings) for filter-feeding. Sometimes hardgrounds are undermined by currents which remove the soft sediment below them, producing shallow cavities and caves which host a cryptic fauna (Palmer and Fürsich, 1974). The evolution of hardground faunas can be traced through the Phanerozoic, from the Cambrian Period to today (Taylor and Wilson, 2003).
Middle Jurassic hardground (Carmel Formation) with encrusting oysters and borings.Scientific papers on hardgrounds by period. Serves as a proxy for hardground abundance over time. Aragonite and calcite sea intervals are plotted on the time axis.
Carbonate hardgrounds were most commonly formed during calcite sea intervals in Earth history, which were times of rapid precipitation of low-magnesium calcite and the dissolution of skeletal aragonite (Palmer and Wilson, 2004). The Ordovician-Silurian and the Jurassic-Cretaceous Systems have the most hardgrounds (sometimes hundreds in a single section) and the Permian-Triassic Systems have the least (usually none). This cyclicity in hardground formation is reflected in the evolution of hardground-dwelling communities. There are distinct differences between the Paleozoic and Mesozoic hardground communities: the former are dominated by thick calcitic bryozoans and echinoderms, the latter by oysters, deep bivalve (Gastrochaenolites) and sponge (Entobia) borings (Taylor and Wilson, 2003).
Stratigraphers and sedimentologists often use hardgrounds as marker horizons and as indicators of sedimentary hiatuses and flooding events (Fürsich et al., 1981, 1992; Pope and Read, 1997). Hardgrounds and their faunas can also represent very specific depositional environments such as tidal channels (Wilson et al., 2005) and shallow marine carbonate ramps (Palmer and Palmer, 1977; Malpas et al., 2004)
Hardground in the Liberty Formation (Upper Ordovician) of southern Ohio.
Cross-section of an Upper Ordovician hardground from Kentucky. The light-colored vertical elements are borings (Trypanites) filled with dolomite. The scale bar is 1.0 cm.
A Middle Ordovician hardground from the Kanosh Formation of Utah with echinoderm holdfasts cemented to its upper surface. The scale bar is 1.0 cm.
Carbonate hardground with an encrusting bryozoan; Kanosh Formation (Middle Ordovician) of Utah; scale in mm.
Cross-section of a carbonate hardground encrusted by oysters and bored by bivalves (Gastrochaenolites); Carmel Formation (Middle Jurassic) of southern Utah.
Trypanites borings in an Upper Ordovician hardground from northern Kentucky.
Carbonate hardground; Ora Formation, Upper Cretaceous (Turonian), southern Israel.
Referencesedit
Bodenbender, B.E.; Wilson, M.A.; Palmer, T.J. (1989). "Paleoecology of Sphenothallus on an Upper Ordovician hardground". Lethaia. 22 (2): 217–225. doi:10.1111/j.1502-3931.1989.tb01685.x.
Brett, C.E.; Liddell, W.D. (1981). "Preservation and paleoecology of a Middle Ordovician hardground community". Paleobiology. 4 (3): 329–348. doi:10.1017/s0094837300006035. S2CID 52255847.
Fürsich F.T., Kennedy, W.J., Palmer, T.J. (1981). "Trace fossils at a regional discontinuity surface: the Austin/Taylor (Upper Cretaceous) contact in central Texas". Journal of Paleontology. 55: 537–551.{{cite journal}}: CS1 maint: multiple names: authors list (link)
Fürsich, F.T.; Oschmann, W.; Singh, B.; Jaitly, A.K. (1992). "Hardgrounds, reworked concretion levels and condensed horizons in the Jurassic of western India: their significance for basin analysis". Journal of the Geological Society of London. 149 (3): 313–331. Bibcode:1992JGSoc.149..313F. doi:10.1144/gsjgs.149.3.0313. S2CID 130374753.
Malpas, J.A.; Gawthorpe, R. L.; Pollard, J.E.; Sharp, I.R. (2004). "Ichnofabric analysis of the shallow marine Nukhul Formation (Miocene), Suez Rift, Egypt: implications for depositional processes and sequence stratigraphic evolution". Palaeogeography, Palaeoclimatology, Palaeoecology. 215 (3–4): 239–264. doi:10.1016/j.palaeo.2004.09.007.
Palmer, T.J. Fürsich, F.T. (1974). "The ecology of a Middle Jurassic hardground and crevice fauna". Palaeontology. 17: 507–524.{{cite journal}}: CS1 maint: multiple names: authors list (link)
Palmer, T.J.; Palmer, C.D. (1977). "Faunal distribution and colonization strategy in a Middle Ordovician hardground community". Lethaia. 10 (3): 179–199. doi:10.1111/j.1502-3931.1977.tb00608.x.
Palmer, T.J.; Wilson, M.A. (2004). "Calcite precipitation and dissolution of biogenic aragonite in shallow Ordovician calcite seas". Lethaia. 37 (4): 417–427. Bibcode:2004Letha..37..417P. doi:10.1080/00241160410002135.
Palmer, T.J. (1978). "Burrows at certain omission surfaces in the Middle Ordovician of the Upper Mississippi Valley". Journal of Paleontology. 52: 109–117.
Palmer, T.J. (1982). "Cambrian to Cretaceous changes in hardground communities". Lethaia. 15 (4): 309–323. doi:10.1111/j.1502-3931.1982.tb01696.x.
Pope, M.C.; Read, J.F. (1997). "High-resolution surface and subsurface sequence stratigraphy of the Middle to Late Ordovician (late Mohawkian-Cincinnatian) foreland basin rocks, Kentucky and Virginia". AAPG Bulletin. 81: 1866–1893. doi:10.1306/3b05c654-172a-11d7-8645000102c1865d.
Taylor, P.D.; Wilson, M.A. (2003). "Palaeoecology and evolution of marine hard substrate communities" (PDF). Earth-Science Reviews. 62 (1–2): 1–103. Bibcode:2003ESRv...62....1T. doi:10.1016/S0012-8252(02)00131-9.
Vinn, O.; Wilson, M.A. (2010). "Microconchid-dominated hardground association from the late Pridoli (Silurian) of Saaremaa, Estonia". Palaeontologia Electronica. 2010 (2): 13.2.9A. Retrieved 2012-09-16.
Vinn, O.; Toom, U. (2015). "Some encrusted hardgrounds from the Ordovician of Estonia (Baltica)". Carnets de Géologie. 15 (7): 63–70. doi:10.4267/2042/56744.
Wilson, M.A.; Palmer, T.J. (1992). "Hardgrounds and hardground faunas". University of Wales, Aberystwyth, Institute of Earth Studies Publications. 9: 1–131.
Wilson, M.A.; Wolfe, K.R.; Avni, Y. (2005). "Development of a Jurassic rocky shore complex (Zohar Formation, Makhtesh Qatan, southern Israel)" (PDF). Israel Journal of Earth Sciences. 54 (3): 171–178. doi:10.1560/71EQ-CNDF-K3MQ-XYTA (inactive 31 January 2024).{{cite journal}}: CS1 maint: DOI inactive as of January 2024 (link)
Further readingedit
Vinn, O. (2015). "Sparsely encrusted hardground in the Darriwilian calcareous sandstone of Cape Pakri, NW Estonia (Baltica)" (PDF). Estonian Journal of Earth Sciences. 64: 249–253. doi:10.3176/earth.2015.31. Retrieved 2015-09-23.
Vinn, O.; Wilson, M.A. (2010). "Early large borings from a hardground of Floian-Dapingian age (Early and Middle Ordovician) in northeastern Estonia (Baltica)". Carnets de Géologie. 2010: CG2010_L04. doi:10.4267/2042/35594.
Vinn, O.; Wilson, M.A.; Toom, U. (2015). "Bioerosion of Inorganic Hard Substrates in the Ordovician of Estonia (Baltica)". PLOS ONE. 10 (7): e0134279. Bibcode:2015PLoSO..1034279V. doi:10.1371/journal.pone.0134279. PMC4517899. PMID 26218582.
Vinn, O.; Toom, U. (2016). "A sparsely encrusted hardground with abundant Trypanites borings from the Llandovery of the Velise River, western Estonia (Baltica)" (PDF). Estonian Journal of Earth Sciences. 65: 19–26. doi:10.3176/earth.2016.01. Retrieved 2016-03-05.
January 01, 1970
carbonate, hardgrounds, surfaces, synsedimentarily, cemented, carbonate, layers, that, have, been, exposed, seafloor, wilson, palmer, 1992, hardground, essentially, then, lithified, seafloor, ancient, hardgrounds, found, limestone, sequences, distinguished, fr. Carbonate hardgrounds are surfaces of synsedimentarily cemented carbonate layers that have been exposed on the seafloor Wilson and Palmer 1992 A hardground is essentially then a lithified seafloor Ancient hardgrounds are found in limestone sequences and distinguished from later lithified sediments by evidence of exposure to normal marine waters This evidence can consist of encrusting marine organisms especially bryozoans oysters barnacles cornulitids hederelloids microconchids and crinoids borings of organisms produced through bioerosion early marine calcite cements or extensive surfaces mineralized by iron oxides or calcium phosphates Palmer 1982 Bodenbender et al 1989 Vinn and Wilson 2010 Vinn and Toom 2015 Modern hardgrounds are usually detected by sounding in shallow water or through remote sensing techniques like side scan sonar A carbonate hardground surface with a bryozoan and vertical borings Trypanites from the Upper Ordovician of Kentucky Cretaceous hardground from Texas with encrusting oysters and Gastrochaenolites borings The scale bar is 1 0 cm Carbonate hardgrounds often host a unique fauna and flora adapted to the hard surface Organisms usually cement themselves to the substrate and live as sessile filter feeders Brett and Liddell 1982 Some bore into the cemented carbonate to make protective domiciles borings for filter feeding Sometimes hardgrounds are undermined by currents which remove the soft sediment below them producing shallow cavities and caves which host a cryptic fauna Palmer and Fursich 1974 The evolution of hardground faunas can be traced through the Phanerozoic from the Cambrian Period to today Taylor and Wilson 2003 Middle Jurassic hardground Carmel Formation with encrusting oysters and borings Scientific papers on hardgrounds by period Serves as a proxy for hardground abundance over time Aragonite and calcite sea intervals are plotted on the time axis Carbonate hardgrounds were most commonly formed during calcite sea intervals in Earth history which were times of rapid precipitation of low magnesium calcite and the dissolution of skeletal aragonite Palmer and Wilson 2004 The Ordovician Silurian and the Jurassic Cretaceous Systems have the most hardgrounds sometimes hundreds in a single section and the Permian Triassic Systems have the least usually none This cyclicity in hardground formation is reflected in the evolution of hardground dwelling communities There are distinct differences between the Paleozoic and Mesozoic hardground communities the former are dominated by thick calcitic bryozoans and echinoderms the latter by oysters deep bivalve Gastrochaenolites and sponge Entobia borings Taylor and Wilson 2003 Stratigraphers and sedimentologists often use hardgrounds as marker horizons and as indicators of sedimentary hiatuses and flooding events Fursich et al 1981 1992 Pope and Read 1997 Hardgrounds and their faunas can also represent very specific depositional environments such as tidal channels Wilson et al 2005 and shallow marine carbonate ramps Palmer and Palmer 1977 Malpas et al 2004 Hardground in the Liberty Formation Upper Ordovician of southern Ohio Cross section of an Upper Ordovician hardground from Kentucky The light colored vertical elements are borings Trypanites filled with dolomite The scale bar is 1 0 cm A Middle Ordovician hardground from the Kanosh Formation of Utah with echinoderm holdfasts cemented to its upper surface The scale bar is 1 0 cm Petroxestes borings in an Upper Ordovician hardground southern Ohio Trypanites borings in an Upper Ordovician hardground Indiana Carbonate hardground with an encrusting bryozoan Kanosh Formation Middle Ordovician of Utah scale in mm Cross section of a carbonate hardground encrusted by oysters and bored by bivalves Gastrochaenolites Carmel Formation Middle Jurassic of southern Utah Trypanites borings in an Upper Ordovician hardground from northern Kentucky Carbonate hardground Ora Formation Upper Cretaceous Turonian southern Israel References editBodenbender B E Wilson M A Palmer T J 1989 Paleoecology of Sphenothallus on an Upper Ordovician hardground Lethaia 22 2 217 225 doi 10 1111 j 1502 3931 1989 tb01685 x Brett C E Liddell W D 1981 Preservation and paleoecology of a Middle Ordovician hardground community Paleobiology 4 3 329 348 doi 10 1017 s0094837300006035 S2CID 52255847 Fursich F T Kennedy W J Palmer T J 1981 Trace fossils at a regional discontinuity surface the Austin Taylor Upper Cretaceous contact in central Texas Journal of Paleontology 55 537 551 a href Template Cite journal html title Template Cite journal cite journal a CS1 maint multiple names authors list link Fursich F T Oschmann W Singh B Jaitly A K 1992 Hardgrounds reworked concretion levels and condensed horizons in the Jurassic of western India their significance for basin analysis Journal of the Geological Society of London 149 3 313 331 Bibcode 1992JGSoc 149 313F doi 10 1144 gsjgs 149 3 0313 S2CID 130374753 Malpas J A Gawthorpe R L Pollard J E Sharp I R 2004 Ichnofabric analysis of the shallow marine Nukhul Formation Miocene Suez Rift Egypt implications for depositional processes and sequence stratigraphic evolution Palaeogeography Palaeoclimatology Palaeoecology 215 3 4 239 264 doi 10 1016 j palaeo 2004 09 007 Palmer T J Fursich F T 1974 The ecology of a Middle Jurassic hardground and crevice fauna Palaeontology 17 507 524 a href Template Cite journal html title Template Cite journal cite journal a CS1 maint multiple names authors list link Palmer T J Palmer C D 1977 Faunal distribution and colonization strategy in a Middle Ordovician hardground community Lethaia 10 3 179 199 doi 10 1111 j 1502 3931 1977 tb00608 x Palmer T J Wilson M A 2004 Calcite precipitation and dissolution of biogenic aragonite in shallow Ordovician calcite seas Lethaia 37 4 417 427 Bibcode 2004Letha 37 417P doi 10 1080 00241160410002135 Palmer T J 1978 Burrows at certain omission surfaces in the Middle Ordovician of the Upper Mississippi Valley Journal of Paleontology 52 109 117 Palmer T J 1982 Cambrian to Cretaceous changes in hardground communities Lethaia 15 4 309 323 doi 10 1111 j 1502 3931 1982 tb01696 x Pope M C Read J F 1997 High resolution surface and subsurface sequence stratigraphy of the Middle to Late Ordovician late Mohawkian Cincinnatian foreland basin rocks Kentucky and Virginia AAPG Bulletin 81 1866 1893 doi 10 1306 3b05c654 172a 11d7 8645000102c1865d Taylor P D Wilson M A 2003 Palaeoecology and evolution of marine hard substrate communities PDF Earth Science Reviews 62 1 2 1 103 Bibcode 2003ESRv 62 1T doi 10 1016 S0012 8252 02 00131 9 Vinn O Wilson M A 2010 Microconchid dominated hardground association from the late Pridoli Silurian of Saaremaa Estonia Palaeontologia Electronica 2010 2 13 2 9A Retrieved 2012 09 16 Vinn O Toom U 2015 Some encrusted hardgrounds from the Ordovician of Estonia Baltica Carnets de Geologie 15 7 63 70 doi 10 4267 2042 56744 Wilson M A Palmer T J 1992 Hardgrounds and hardground faunas University of Wales Aberystwyth Institute of Earth Studies Publications 9 1 131 Wilson M A Wolfe K R Avni Y 2005 Development of a Jurassic rocky shore complex Zohar Formation Makhtesh Qatan southern Israel PDF Israel Journal of Earth Sciences 54 3 171 178 doi 10 1560 71EQ CNDF K3MQ XYTA inactive 31 January 2024 a href Template Cite journal html title Template Cite journal cite journal a CS1 maint DOI inactive as of January 2024 link Further reading editVinn O 2015 Sparsely encrusted hardground in the Darriwilian calcareous sandstone of Cape Pakri NW Estonia Baltica PDF Estonian Journal of Earth Sciences 64 249 253 doi 10 3176 earth 2015 31 Retrieved 2015 09 23 Vinn O Wilson M A 2010 Early large borings from a hardground of Floian Dapingian age Early and Middle Ordovician in northeastern Estonia Baltica Carnets de Geologie 2010 CG2010 L04 doi 10 4267 2042 35594 Vinn O Wilson M A Toom U 2015 Bioerosion of Inorganic Hard Substrates in the Ordovician of Estonia Baltica PLOS ONE 10 7 e0134279 Bibcode 2015PLoSO 1034279V doi 10 1371 journal pone 0134279 PMC 4517899 PMID 26218582 Vinn O Toom U 2016 A sparsely encrusted hardground with abundant Trypanites borings from the Llandovery of the Velise River western Estonia Baltica PDF Estonian Journal of Earth Sciences 65 19 26 doi 10 3176 earth 2016 01 Retrieved 2016 03 05 Retrieved from https en wikipedia org w index php title Carbonate hardgrounds amp oldid 1201819512, wikipedia, wiki, book, books, library,
