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Non-Actualistic
Carbonate
Deposystems: Revising The
Carbonate
Factory-Depth Paradigm*
By
Giovanna Della Porta1, Jeroen A.M. Kenter2, and Paul M. (Mitch) Harris3
Search and Discovery Article #40290 (2008)
Posted July 15, 2008
*Adapted from oral presentation at AAPG Annual Convention, Long Beach, CA, April 1-4, 2007.
1Cardiff University, Cardiff, UK ([email protected])
2Chevron Energy and Technology Company, Voorburg, The Netherlands ([email protected])
3Chevron Energy Technology Company, San Ramon, CA ([email protected])
Non-actualistic (e.g., deviating from depositional models developed for recent deposystems)
carbonate
platforms are not the exception in the geologic record because of the wide range of biological and environmental factors controlling
facies
character and architecture.
A fundamental concept is the exponential decrease of
carbonate
production with increasing water depth from a maximum at shallow depths to the base of the photic zone. However, when the dominant factory is microbially induced, high rates of
carbonate
production extend on the slope down to dys-/aphotic depths and new production-water depth profiles must be developed.
Studies of Carboniferous (Asturias, Pricaspian Basin) and Permian (Capitan Reef) high-relief
carbonate
platforms have shown that the microbial-boundstone production extends to 300m water depth: 1) the detrital lower slope consists mostly of matrix-free cemented rudstone sourced by the slope boundstone with subordinated platform-top-derived material; 2)
carbonate
production on the slope is controlled by environmental parameters (temperature, nutrients, oxygenation) that are water-depth dependent, but the microbial boundstone response to relative sea-level changes differs from modern reefs; 3)
carbonate
growth is not seriously reduced during sea-level falls because it can continue downslope, 4) progradation can take place at high rates despite the lack of platform-top shedding (slope vs. highstand shedding); 5) concepts of leeward progradational vs. windward aggradational margins have to be revised. Paleozoic high-relief platforms with microbial boundstone-dominated margins seem to have developed in mesotrophic, starved restricted basins with oxygen-depleted bottom waters that would not be suitable settings for the recent coral-reef rimmed platforms.
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Depositional models based on the Recent need to be revised for margins with microbial cement boundstone or coral-microbial associations.
The “model”provided for progradational, high relief microbial platform margins might be considered for other areas and times. ……But many aspects of the microbial boundstone precipitation, cementation, and slope processes remain poorly understood. For interpretation, modeling and prediction we need a better understanding of types, rates and the environmental controls of the “microbial” factories.
Arp, G., A. Reimer, and J. Reitner, 2003, Microbialite formation in seawater of increased alkalinity, Satonda Crater Lake, Indonesia: Journal of Sedimentary Research, v. 73/1, p. 105-127. Aurell, M., D.W.J. Bosence, and D. Waltham, 1995, Aurell, M., B. Badenas, D.W.J. Bosence, and D. Waltham, 1998, Blendinger, W., 1994, Sea level changes versus hydrothermal diagenesis; origin of Triassic Bosence, D.W.J., L. Pomar, D.A. Waltham, and T.H.G. Lankester, 1994, Computer modeling a Miocene Burne, R.V., and L.S. Moore, 1987, Microbialities; organosedimentary deposits of benthic microbial communities: Palaios, v.2/3, p. 241-254. Bosscher, H., and W. Schlager, 1993, Accumulation rates of DeFarge, C., and J. Trichet, et al., 1996, Texture of microbial sediments revealed by cryo-scanning electron microscopy: Journal of Sedimentary Research, v. 66/5, p. 935-947. Della-Porta, D., J.A.M. Kenter, A. Immenhauser, and J.R. Bahamonde, 2002, Lithofacies character and architecture across a Pennsylvanian inner-platform transect (Sierra de Cuera, Asturias, Spain): Journal of Sedimentary Research, v. 72, p. 898-916. Della-Porta, D., 2003, Microbial boundstone dominated Della-Porta, D., J.A.M. Kenter, and J.R. Bahamonde, 2004, Depositional Garber, R.A., G.A. Grover, P.M. Harris, 1989, Geology of the Capitan shelf margin; subsurface data from the northern Delaware Basin: Subsurface and Outcrop Examination of the Capitan Shelf Margin, Northern Delaware Basin, SEPM Core Workshop, 13, p. 3-269. Guido, A., et al., 2007, Molecular fossils and other organic markers as palaeoenvironmental indicators of the Messinian Calcare di Base formation; normal versus stressed marine deposition (Rossano Basin, northern Calabria, Italy): Palaeogeography, Palaeoclimatology, Palaeoecology, v. 255/3-4, p. 265-283. Harris, M.T., 1993, Reef fabrics, biotic crusts and syndepositional cements of the Latemar reef margin (Middle Triassic), northern Italy: Sedimentology, v. 40, p. 383-401. Harris, M.T., 1996, The Harris, P.M., and A.H. Saller, 1999, Subsurface expression of the Capitan depositional system and implications for hydrocarbon reservoirs, northeastern Delaware Basin: Geologic Framework of the Capitan Reef, SEPM Special Publication 65, p. 37-49. Keim, L., and W. Schlager, 1999, Automicrite Kenter, J.A.M., P.M. Harris, and G. Della-Porta, 2005, Steep microbial boundstone-dominated platform margins; examples and implications: Sedimentary Geology, v. 178/1-2, p. 5-30. Neuweiler, F., et al., 1999, Petrology of Lower Cretaceous Parish, J.T., 1982, Upwelling and petroleum source beds, with reference to Paleozoic: AAPG Bulletin, v. 66/6, p. 750-774. Pomar, L., 2001, Types of Reitner, J., et al., 1995, Mud mounds; a polygenetic spectrum of fine-grained Riding, R., 2000, Microbial carbonates; the geological record of calcified bacterial-algal mats and biofilms: Sedimentology, v. 47, p. 179-214. Russo, F., C.Neri, A. Mastandrea, and A. Baracca, 1997, The mud-mound nature of the Cassian platform margins of the Dolomites. A case history: the Cipit boulders from Punta Grohmann (Sasso Piatto Massif, northern Italy): Schlager, W., 1993, Accommodation and supply; a dual control on stratigraphic sequences: Sedimentary Geology, v. 86/1-2, p. 111-136. Schlager, W., 2000, Sedimentation rates and growth potential of tropical, cool-water and mud-mound Schlager, W., 2003, Benthic Schlager, W., 2005, Scotese, C.R., 2002, Paleomap Project (http://www.scotese.com/earth.htm). Tinker, S.W., 1998, Shelf-to-basin Trichet and Defarge, 1996; see DeFarge and Trichet above. Verwer, K., J.A.M. Kenter, B. Maathuis, and G. Della-Porta, 2004, Stratal patterns and lithofacies of an intact seismic-scale Carboniferous Weber, L.J., B.P. Francis, P.M. Harris, and M. Clark, 2003, Stratigraphy, lithofacies, and reservoir distribution, Tengiz field, Kazakhstan: Permo-Carboniferous Wright, V.P., and T.J. Faulkner, 1990, Sediment dynamics of Early Carboniferous ramps; a proposal: Geological Journal, v. 25/2, p. 139-144. Wright, V.P., and P.M. Burgess, 2005, The
Many thanks to V. Paul Wright, Cardiff University, UK, KlaasVerwer, Vrije Universiteit, The Netherlands, Juan R. Bahamonde, Universidad de Oviedo, Spain, Oscar Merino-Tomé, Cardiff University, UK.
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