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Stratigraphy, paleoecology, and origin of Lower Devonian (Emsian) carbonate mud buildups, Hamar Laghdad, eastern Anti-Atlas, Morocco, Africa

2002; Canadian Society of Petroleum Geologists; Volume: 50; Issue: 2 Linguagem: Inglês

10.2113/50.2.217

2368-0261

Steven Andrew Aitken, Charles M. Henderson, Christopher J. Collom, Paul Johnston,

Geological and Geophysical Studies

Research Article| June 01, 2002 Stratigraphy, paleoecology, and origin of Lower Devonian (Emsian) carbonate mud buildups, Hamar Laghdad, eastern Anti-Atlas, Morocco, Africa Steven A. Aitken; Steven A. Aitken El Paso Oil and Gas Canada, Inc., Petro-Canada Centre, 150-6th Avenue SW, Calgary, AB T2P 3Y7 Search for other works by this author on: GSW Google Scholar Charles M. Henderson; Charles M. Henderson Department of Geology and Geophysics, University of Calgary, Calgary, AB T2N 1N4 Search for other works by this author on: GSW Google Scholar Christopher J. Collom; Christopher J. Collom Department of Earth Sciences, Mount Royal College, Lincoln Park Campus, Calgary, AB T3E 6K6 Search for other works by this author on: GSW Google Scholar Paul A. Johnston Paul A. Johnston Royal Tyrrell Museum of Palaeontology, Box 7500, Drumheller, AB T0J 0Y0 Search for other works by this author on: GSW Google Scholar Author and Article Information Steven A. Aitken El Paso Oil and Gas Canada, Inc., Petro-Canada Centre, 150-6th Avenue SW, Calgary, AB T2P 3Y7 Charles M. Henderson Department of Geology and Geophysics, University of Calgary, Calgary, AB T2N 1N4 Christopher J. Collom Department of Earth Sciences, Mount Royal College, Lincoln Park Campus, Calgary, AB T3E 6K6 Paul A. Johnston Royal Tyrrell Museum of Palaeontology, Box 7500, Drumheller, AB T0J 0Y0 Publisher: Canadian Society of Petroleum Geologists Received: 15 Sep 2000 Accepted: 14 Nov 2001 First Online: 02 Mar 2017 Online ISSN: 2368-0261 Print ISSN: 0007-4802 © The Society of Canadian Petroleum Geologists Bulletin of Canadian Petroleum Geology (2002) 50 (2): 217–243. https://doi.org/10.2113/50.2.217 Article history Received: 15 Sep 2000 Accepted: 14 Nov 2001 First Online: 02 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Steven A. Aitken, Charles M. Henderson, Christopher J. Collom, Paul A. Johnston; Stratigraphy, paleoecology, and origin of Lower Devonian (Emsian) carbonate mud buildups, Hamar Laghdad, eastern Anti-Atlas, Morocco, Africa. Bulletin of Canadian Petroleum Geology 2002;; 50 (2): 217–243. doi: https://doi.org/10.2113/50.2.217 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 SocietyBulletin of Canadian Petroleum Geology Search Advanced Search Abstract Recent debates concerning the origin of Emsian carbonate mud buildups exposed at Hamar Laghdad in the eastern Anti-Atlas of Morocco centre around geochemical studies that suggest authigenic or chemosynthetic processes induced precipitation of mud from hydrothermal fluids. Geochemical data alone cannot be used to demonstrate conclusively the origin of the mud comprising the buildups, but an in situ source and early cementation can be inferred from morphology, internal architecture, and sedimentary structures.Morphological types vary from symmetrical mounds up to 12 m high to asymmetrical pinnacles that locally coalesced, forming elongate multicored complexes up to 56 m high. Their steep-sided nature (margins dipping up to 54°) and sporadic occurrence of erect invertebrates suggest localized production of mud rather than hydrodynamic piling or baffling from suspension. Irregular nodular beds that thicken internally imply centralized production and a local source for the mud. Displaced nodules and slump folds indicate early cementation of mud to at least a firm consistency, followed by downslope movement.Abrupt termination of carbonate production during late transgression resulted in drowning of the mud buildups and adjacent platform. Except for a thin condensed bed deposited during maximum flooding, the buildups and platform (transgressive systems tract deposits) remained uncovered for an extended period (upper inversus-laticostatus to lower serotinus zones) before being buried beneath progradational clinoforms of nodular limestone and marlstone (regressive systems tract deposits).Overlying Middle Devonian carbonates contain evidence of hydrothermal seepage, based on the occurrence of solemyid and anomalodesmatan bivalves, which are thought to be chemosymbiotic. These bivalves occur in a mud buildup rooted on an Emsian counterpart, suggesting periodic hydrothermal activity beneath the buildups. A hydrothermal origin for the Hamar Laghdad mud buildups appears to be consistent with other mud buildups of similar age in other parts of northwest Africa. Vast deposits of coeval Minette-type ooidal ironstones, which also have a seep origin in the Tindouf Basin, south of the Anti-Atlas, testify to occasional widespread hydrothermal activity along the northwest margin of Gondwana during much of the Devonian. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.