Deep-Water Depositional Environments of the Brushy Canyon Formation (Permian), Texas: Recognition Criteria and Stratal Architecture

1994 ◽  
pp. 439-440
Author(s):  
F.B. ZELT ◽  
C. ROSSEN ◽  
M.B. DeVRIES ◽  
Fred B. Zelt ◽  
Emiliano Mutti
Keyword(s):  
Deep Water ◽  
Depositional Environments ◽  
Brushy Canyon Formation ◽  
Stratal Architecture

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.

Cenomanian to Coniacian sea-level changes in the Lower Benue Trough (Nkalagu Area, Nigeria) and the Eastern Dahomey Basin: palaeontological and sedimentological evidence for eustasy and tectonism

2019 ◽  
Vol 498 (1) ◽  
pp. 233-255 ◽  
Author(s):  
Holger Gebhardt ◽  
Samuel O. Akande ◽  
Olabisi A. Adekeye
Keyword(s):  
Sea Level ◽  
Deep Water ◽  
Close Relation ◽  
Depositional Environments ◽  
Sea Level Changes ◽  
Foraminiferal Assemblage ◽  
Benue Trough ◽  
Sea Level Fluctuations ◽  
Dahomey Basin ◽  
Lower Benue Trough

AbstractThe Benue Trough formed in close relation to the opening of the South Atlantic and experienced sea-level fluctuations of different magnitudes during the Cenomanian to Coniacian interval. We identify depositional environments from outcrop sections and a drilling as control record. Lines of evidence for the interpretation include facies analyses, foraminiferal assemblage composition (P/B-ratio) and the presence of planktonic deep-water indicators. While the analysis of the well data from the Dahomey Basin indicates a continuous deep-water (bathyal) environment, the succession in the Nkalagu area of the Lower Benue Trough evolved in a different and more complex way. Beginning with latest Cenomanian shoreface to shelf deposits, a long period of subsidence lasted until the middle Turonian when pelagic shales and calcareous turbidites were deposited at upper to middle bathyal depths. These conditions continued during late Turonian and Coniacian times. The general deepening trend of the Lower Benue Trough was mainly controlled by tectonic subsidence and was superimposed by eustatic sea-level changes, resulting in periodically changing palaeowater depths. We were able to identify eight sea-level rises and falls that can be attributed to 405 kyr eccentricity cycles. The amplitudes of the sea-level changes were most likely in the range of several tens to a few hundred metres. The deposition of carbonate turbidites at Nkalagu was probably triggered by eustatic sea-level lowstands.

Paleocurrents and depositional environments of deep water conglomerates in the Cambro-Ordovician Cap Enragé Formation, Quebec Appalachians

1979 ◽  
Vol 16 (7) ◽  
pp. 1375-1387 ◽  
Author(s):  
Barry A. Johnson ◽  
Roger G. Walker
Keyword(s):  
Deep Water ◽  
Flow Direction ◽  
Depositional Environments ◽  
The West ◽  
Submarine Fan ◽  
Local Flow ◽  
Flow Directions ◽  
La Jolla ◽  
Contrast Flow

The Cap Enragé conglomerates are deep water, resedimented types associated with pebbly and massive sandstones. They resemble other deep water conglomerates in Quebec, especially those at Lévis-Lauzon, L'Islet Wharf, and Grosses Roches. All of these conglomerates were derived from a carbonate shelf to the northwest, and flow directions at Lévis and L'Islet are dominantly southward. By contrast, flow directions at Grosses Roches are to the west and southwest, suggesting deflection of conglomeratic flows by a topographic obstruction.In the Cap Enragé, only published flow directions from sandstones suggest flow toward south and southeast. One published conglomeratic flow direction indicates southwestward flow. Our paleoflow work on the entire outcrop length of the Cap Enragé conglomerates demonstrates dominantly westward and southwestward flow, reinforcing the idea of a topographic obstruction deflecting flows.We have demonstrated some consistent horizontally-fining facies relationships in the conglomerates. Beginning with massive, coarse cobble–boulder conglomerates, there are horizontal passages into finer conglomerates with crude stratification shown up by rows of cobbles and then pebbles, and finally into well stratified coarse sandstones with layers of granules and pebbles. Compared with local flow directions, these horizontally-fining relationships occur in upstream, downstream, and lateral directions.We suggest that southeastward, downslope-flowing currents were forced to swing southwestward by an obstruction, and hence the entire Cap Enragé Formation was deposited in a broad depression or channel trending parallel to the base of slope. Within this overall interpretation, we suggest that the conglomerate members of the Cap Enragé were deposited in meandering talweg channels, similar to those of the modern La Jolla submarine fan channel. Upstream-, downstream-, and laterally-fining facies sequences may be related to the filling of large scours within the talweg, or to facies changes from the talweg to adjacent terraces.

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

1988 ◽  
Vol 62 (1) ◽  
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.

scholarly journals Markov chains and entropy tests in genetic-based lithofacies analysis of deep-water clastic depositional systems

2016 ◽  
Vol 8 (1) ◽  
pp. 45-51
Author(s):  
Szabolcs Borka
Keyword(s):  
Markov Chains ◽  
Deep Water ◽  
Pannonian Basin ◽  
Depositional Environments ◽  
Structural Elements ◽  
Chi Square ◽  
Fine Grained ◽  
Hydrocarbon Reservoir ◽  
Depositional Processes ◽  
Chi Square Test

AbstractThe aim of this study was to examine the relationship between structural elements and the so-called genetic lithofacies in a clastic deep-water depositional system. Process-sedimentology has recently been gaining importance in the characterization of these systems. This way the recognized facies attributes can be associated with the depositional processes establishing the genetic lithofacies. In this paper this approach was presented through a case study of a Tertiary deep-water sequence of the Pannonian-basin.Of course it was necessary to interpret the stratigraphy of the sequences in terms of “general” sedimentology, focusing on the structural elements. For this purpose, well-logs and standard deep-water models were applied.The cyclicity of sedimentary sequences can be easily revealed by using Markov chains. Though Markov chain analysis has broad application in mainly fluvial depositional environments, its utilization is uncommon in deep-water systems. In this context genetic lithofacies was determined and analysed by embedded Markov chains. The randomness in the presence of a lithofacies within a cycle was estimated by entropy tests (entropy after depositional, before depositional, for the whole system). Subsequently the relationships between lithofacies were revealed and a depositional model (i.e. modal cycle) was produced with 90% confidence level of stationarity. The non-randomness of the latter was tested by chi-square test.The consequences coming from the comparison of “general” sequences (composed of architectural elements), the genetic-based sequences (showing the distributions of the genetic lithofacies) and the lithofacies relationships were discussed in details. This way main depositional channel has the best, channelized lobes have good potential hydrocarbon reservoir attributes, with symmetric alternation of persistent fine-grained sandstone (Facies D) and muddy fine-grained sandstone with traction structures (Facies F)

scholarly journals Paleoenvironmental change recorded in submarine fans: the Eocene-Oligocene climate transition in the Alpine foreland basin

2021 ◽  
Author(s):  
Euan Soutter ◽  
Ian Kane ◽  
Ander Martínez-Doñate ◽  
Adrian Boyce ◽  
Jack Stacey ◽  
...  
Keyword(s):  
Environmental Change ◽  
Deep Water ◽  
Foreland Basin ◽  
Depositional Environments ◽  
Sediment Supply ◽  
Submarine Fan ◽  
Paleoenvironmental Change ◽  
Submarine Fans ◽  
Alpine Foreland ◽  
Alpine Foreland Basin

The Eocene-Oligocene transition (EOT) was a period of considerable environmental change, signifying the transition from Paleocene greenhouse to Oligocene icehouse conditions. Preservation of the sedimentary signal of such an environmental change is most likely in net-depositional environments, such as submarine fans, which are the terminal parts of sedimentary systems. Here, using sedimentological and stable isotope data from the Alpine foreland basin, we assess whether this major climatic transition influenced the stratigraphic evolution of submarine fans. Results indicate that submarine fan retreat in the Alpine foreland basin corresponds with positive δ13C excursions related to major global perturbations of the carbon cycle and cooling in the earliest Oligocene. Submarine fan retreat is suggested to be influenced by this cooling through enhanced aridity and reduced subaerial runoff from the Corsica-Sardinia hinterland. The influence of aridity was periodically overwhelmed by local environmental factors, such as hinterland uplift, which increased sediment supply to deep-water during arid periods. These results highlight that: 1) hinterland climate may play a greater role than sea-level in dictating sediment supply to deep-water and, 2) submarine fan evolution occurs through a complex interplay between climate, eustasy and tectonics, which makes robust interpretations of paleoenvironmental change from their stratigraphic record, without multi-proxy records, difficult.

Identification of Natural Gas Hydrates in Blocks 25a, 25b, 26 and 27 Offshore Trinidad Using Available Well Log Data

2014 ◽  
Author(s):  
M. M. Smith ◽  
L. E. Sobers
Keyword(s):  
Natural Gas ◽  
Deep Water ◽  
Gas Hydrates ◽  
Seismic Data ◽  
East Coast ◽  
Depositional Environments ◽  
Well Log ◽  
Borehole Data ◽  
Log Data ◽  
Natural Gas Hydrates

Abstract Natural gas hydrates can be found in conventional hydrocarbon depositional environments such as clastic marine sediments, siltstones and unconsolidated sands and in oceanic environments for reservoir pressures greater than 663 psi (46 bars) and temperatures less than 20 °C. These conditions are found in the deep water (&gt; 300 m) acreage off the South East coast of Trinidad. Natural gas hydrates have been recovered in this area during drilling and seismic data have shown that there may be deposits in some areas. In this study we reviewed all the available borehole data and employed well log interpretation techniques to identify natural gas hydrates in the deep water acreage blocks 25 a, 25 b, 26 and 27 off the Trinidad South East coast. The analysis of well log data for the given depths did not present evidence to suggest the presence of natural gas hydrates in Blocks 25 a, 25 b, 26 and 27. In this paper we present our analysis of the data available and recommend the formation depths which should be logged in during the deep water exploration drilling to confirm the seismic data and core data which indicate the presence of natural gas hydrates in these blocks.

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