BIOGENIC STRUCTURES AND DEPOSITIONAL ENVIRONMENTS OF A LOWER PENNSYLVANIAN COAL-BEARING SEQUENCE, NORTHERN CUMBERLAND PLATEAU, TENNESSEE, U.S.A.

1985 ◽  
pp. 67-97 ◽  
Author(s):  
MOLLY FRITZ MILLER ◽  
LARRY W. KNOX
Keyword(s):  
Depositional Environments ◽  
Cumberland Plateau ◽  
Biogenic Structures

Trace fossils from marginal marine facies of the Kanawha Formation (Middle Pennsylvanian), West Virginia

1989 ◽  
Vol 63 (4) ◽  
pp. 389-403 ◽  
Author(s):  
Ronald L. Martino
Keyword(s):  
West Virginia ◽  
Tidal Flat ◽  
Sedimentary Facies ◽  
Trace Fossils ◽  
Tidal Flats ◽  
Depositional Environments ◽  
Carbonaceous Shale ◽  
Biogenic Structures ◽  
Mouth Bars ◽  
Sandstone Facies

Seven sedimentary facies have been identified in a 40-m-thick portion of the Kanawha Formation near Chelyan in southern West Virginia. Lithology, sedimentary and biogenic structures, body fossils, paleocurrent patterns, and facies geometry have been used to identify the following paleoenvironments: Facies 1, fluviodeltaic channels represented by thick, cross-stratified channel sandstone; Facies 2, crevasse splays and tidal creeks represented by thin, cross-stratified wedge and channel sandstone; Facies 3, coastal swamps and lakes represented by coal seat and carbonaceous shale; Facies 4, restricted bay and upper tidal flats represented by dark-gray shale, mudstone; Facies 5, interdistributary bays represented by olive-gray siltstone and shale with brachiopods; Facies 6, bay or tidal flat scour fills represented by sandy limestone with brachiopods and pelmatozoans; and Facies 7, low to mid tidal flats and distributary mouth bars represented by thinly interbedded, rippled sandstone and siltstone.Trace fossils representing 17 ichnogenera are present with most being restricted to certain sedimentary facies. Three ichnoassemblages are recognized. 1) An annulated vertical burrow assemblage, consisting of arthropod(?) dwellings, occurs in an abandoned fluvial channel facies. 2) A Phycodes–Zoophycos assemblage is associated with dark-gray shales and mudstones of a restricted bay and/or upper tidal flat environment. Additional ichnogenera include Planolites and ?Conostichus. 3) An Olivellites assemblage with a high abundance and a high diversity of trace fossils occurs within a rippled sandstone/siltstone facies; trace fossils include (in order of abundance) Olivellites, Teichichnus, Planolites, Aulichnites, transversely ridged surface trails, Rosselia, Scolicia, Curvolithus, Helminthopsis, Tasmanadia, Petalichnus, Ancorichnus, and ?Asterosoma. The associated depositional environments are interpreted as low to mid tidal flats and possibly distributary mouth bars.The occurrence of salinity-sensitive trace fossils such as the assemblages described herein within otherwise faunally barren intervals facilitates the recognition of marine-influenced coastal facies in which stenohaline or brackish body fossils are lacking.

scholarly journals Sedimentology and Ichnology of Paleozoic Estuarine and Shoreface Reservoirs, Morrow Sandstone, Lower Pennsylvanian of Southwest Kansas, USA

1999 ◽  
pp. 1-35
Author(s):  
Luis A. Buatois ◽  
Gabriela M. Mangano ◽  
Timothy R. Carr
Keyword(s):  
Oil And Gas ◽  
Petroleum Industry ◽  
Integrated Approach ◽  
Trace Fossils ◽  
Depositional Environments ◽  
Trace Fossil ◽  
Reservoir Modeling ◽  
Delta Front ◽  
Valley Fill ◽  
Biogenic Structures

Integration of facies and trace-fossil evidence tests and refines depositional models constructed solely on the basis of physical sedimentology. In recent years, the petroleum industry has increasingly used trace-fossil analysis of cores as an aid in reservoir characterization. In particular, ichnologic data have been instrumental in the recognition of estuarine deposits and their distinction from open-marine facies (e.g., MacEachern and Pemberton, 1994). Previous ichnologic analyses of cores, however, have concentrated on post-Paleozoic reservoirs (e.g., Bockelie, 1991; Pemberton, 1992; Taylor and Gawthorpe, 1993; Howell et al., 1996; Martin and Pollard, 1996; MacEachern and Pemberton, 1997). The present study represents one of the first attempts to apply trace-fossil analysis to cores from Paleozoic reservoirs. The Lower Pennsylvanian Morrow Sandstone contains oil and gas reservoirs in a wide variety of shallow and marginal-marine depositional environments. Delta-front, shoreface, and estuarine valley-fill reservoir sandstones are encased in offshore and estuarine mudstones (Sonnenberg, 1985; Krystinik and Blakeney, 1990; Sonnenberg et al., 1990; Wheeler et al., 1990). An integrated stratigraphic, sedimentologic, and ichnologic study provides a more accurate characterization of reservoir facies and geometry. This study allows distinction between marine-shoreface and estuarine valley-fill sandstones from four cores of the lower Morrow in southwestern Kansas. Core analysis subsequently was integrated with well-log information. Previous studies have emphasized the presence of estuarine valley-fills in the upper Morrow (Wheeler et al., 1990). Our integrated approach extends the estuarine valley interpretation into the lower Morrow. Within the midcontinent, trace fossils are useful in distinguishing different facies in estuarine incised valleys and marine shorefaces. Detailed study of biogenic structures provides high-resolution information to solve problems in facies, stratigraphic, and reservoir modeling. In some cases, they represent the only evidence available to develop a reasonable picture of depositional conditions and to estimate reservoir heterogeneity. The present study provides a detailed analysis of the sedimentary facies, documents the associated trace fossils, and illustrates how trace fossils are used to refine environmental interpretations of the lower Morrow sandstone reservoirs.

scholarly journals GEOLOGY AND MINERAL RESOURCES OF EBONYI STATE, SOUTHEASTERN NIGERIA

2020 ◽  
Vol 1 (2) ◽  
Keyword(s):  
Salt Lake ◽  
Mineral Resources ◽  
Depositional Environments ◽  
Mineral Deposits ◽  
Copper Ore ◽  
Southeastern Nigeria ◽  
Benue Trough ◽  
Chemical Structures ◽  
Anambra Basin ◽  
Biogenic Structures

Ebonyi State is underlain at depth by the Precambrian Basement Complex and by Cretaceous sedimentary units which include the Abakaliki Formation, Nkalagu Limestone, Amasiri Sandstone and Afikpo Sandstone and spans through Southern Benue Trough and Anambra Basin. Shales, sandstones, siltstones and limestones which range from shallow to deep marine depositional environments have intermediate to basic intrusive dolerites, extrusives and pyroclastics rocks emplaced in them. The sediments are dominated by physical structures such as faults, folds, fractures, joints, cross beds, mud cracks and an unconformity; chemical structures such as concretions and solution cavity; and biogenic structures such as burrows and bioturbation. The presence of benthic foraminifera such as Bolivina anambra and Haplopragmoides sp. suggest an upper bethyal deep to shallow marine environment for the sediments. Natural resources and mineral deposits such as lead, zinc, granite, limestone, dolerite, pyroclastics, salt-lake/brine, sand, laterites, clay, kaolin, iron ores, chalcopyrite, illmenite, fluorite, marble stone, quartz and copper ore which spread across the area, contribute largely to the gross domestic products of the state. Data gathered shows that 26% of the mineral deposits are partially exploited, 30 % are locally exploited, 4 % are highly exploited, while 39 % are dormant. Unfortunately, the reserve estimate of these mineral deposits are yet to be documented. Keywords: Anambra Basin, Ebonyi State, Mineral deposits, Southern Benue Trough, Structure; Uncomformity

Benthic foraminiferal zonation in deep-water carbonate platform margin environments, northern Little Bahama Bank

1988 ◽  
Vol 62 (01) ◽  
pp. 1-8 ◽  
Author(s):  
Ronald E. Martin
Keyword(s):  
Deep Water ◽  
Benthic Foraminifera ◽  
Carbonate Platform ◽  
Sedimentary Facies ◽  
Depositional Environments ◽  
Near Surface ◽  
Sediment Gravity Flows ◽  
Gravity Flows ◽  
Platform Margin ◽  
Water Carbonate

The utility of benthic foraminifera in bathymetric interpretation of clastic depositional environments is well established. In contrast, bathymetric distribution of benthic foraminifera in deep-water carbonate environments has been largely neglected. Approximately 260 species and morphotypes of benthic foraminifera were identified from 12 piston core tops and grab samples collected along two traverses 25 km apart across the northern windward margin of Little Bahama Bank at depths of 275-1,135 m. Certain species and operational taxonomic groups of benthic foraminifera correspond to major near-surface sedimentary facies of the windward margin of Little Bahama Bank and serve as reliable depth indicators. Globocassidulina subglobosa, Cibicides rugosus, and Cibicides wuellerstorfi are all reliable depth indicators, being most abundant at depths >1,000 m, and are found in lower slope periplatform aprons, which are primarily comprised of sediment gravity flows. Reef-dwelling peneroplids and soritids (suborder Miliolina) and rotaliines (suborder Rotaliina) are most abundant at depths <300 m, reflecting downslope bottom transport in proximity to bank-margin reefs. Small miliolines, rosalinids, and discorbids are abundant in periplatform ooze at depths <300 m and are winnowed from the carbonate platform. Increased variation in assemblage diversity below 900 m reflects mixing of shallow- and deep-water species by sediment gravity flows.

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