Facies Architecture And Evolution of Coastal Lithosomes On The North Texas Gulf Coast and The Occurrence Of Preserved Analogues On The North Texas Inner Continental Shelf

The composition and structure of fish assemblages in the inner continental shelf of the Paraná State are affected by cold fronts and the rainfall regime. Data from fishing activities in this region, as well as the analysis of environmental characteristics, are the main tools available for understanding fish dynamics, under influence of increasing human activities. In order to better understand patterns and temporal variations in fish assemblages in the inner continental shelf of the Paraná State, a total of 24 double trawls were performed with an otter trawl between August 2000 and July 2001, in two sampling areas, the North area in front of the northern mouth of the Paranaguá Estuary Complex, and the South area, in front of the Leste beach. A total of 45,277 fish specimens belonging to 35 families and 97 species were caught. Sciaenidae was the most abundant family, with 37.1% of the total number of individuals caught, and with the highest richness (18 species). Statistical analyses evidenced significant differences in environmental characteristics and in fish fauna, and that both areas disturbances were observed in the fish assemblages during the dry and wet season, being more intense in the Southern area, disturbances that would be related to the shrimp fishing present in the two areas sampled in this study.

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Diapiric shale and coast-perpendicular, fault-related subbasins, south Texas Gulf Coast

Interpretation ◽

10.1190/int-2014-0016.1 ◽

2015 ◽

Vol 3 (2) ◽

pp. T43-T56 ◽

Cited By ~ 2

Author(s):

Osareni C. Ogiesoba ◽

Rodolfo Hernandez

Keyword(s):

Seismic Data ◽

Gulf Coast ◽

Structural Features ◽

South Texas ◽

3D Seismic ◽

Texas Gulf Coast ◽

Vertical Loading ◽

The North ◽

Visualization Tools ◽

3D Seismic Data

Coast-perpendicular shale ridges are rare structural features worldwide, and their origin remains a subject of debate. We studied some coast-perpendicular shale ridges and faults within a minibasin located onshore in Refugio County in the Texas Gulf Coast. We used 3D seismic data, visualization tools, and seismic attributes to examine the geometry of coast-perpendicular diapiric structures associated subbasins (SBs) and faults, and coast-parallel listric faults. Our results indicated that the minibasin is subdivided into four SBs by five diapiric shale ridges that intrude through the fault heaves of down-to-the-basin (synthetic) and coast-perpendicular faults. Three of the SBs are oriented perpendicular to the coast, whereas the fourth has a curvilinear form trending northeast–southwest–southeast. Of the five diapiric shale ridges, three are coast-perpendicular. The other two are curvilinear to the coast. All five diapiric shale ridges are associated with coast-perpendicular faults that bound the flanks of the ridges. On the basis of our mapping results, we deduced that the origin of the coast-perpendicular faults in the study area are related to the coalescing of en echelon synthetic faults, as well as the coalition of synthetic and antithetic fault planes. We inferred that the origin of the shale diapirs is related to vertical loading and, possibly, local southwest–northeast lateral compression of interbedded, overpressured, shale-prone intervals. The coast-perpendicular faults within the Frio formed as a result of reactivation of the Eocene-Vicksburg coast-perpendicular faults. Synthetic faults dominate the pattern within the SB in the north where shale ridges are broad, whereas antithetic faults dominate the pattern in the south where shale ridges are narrow.

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THE EFFECT OF OBLIQUE SHOREFACE-CONNECTED RIDGES ON ALONGSHORE TRANSPORT AND SHORELINE CHANGE

Coastal Engineering Proceedings ◽

10.9753/icce.v36.sediment.65 ◽

2018 ◽

pp. 65

Author(s):

Kevin Haas ◽

Tongtong Xu

Keyword(s):

Continental Shelf ◽

Long Island ◽

Shoreline Change ◽

Delmarva Peninsula ◽

The North ◽

Fire Island ◽

Maximum Expression ◽

Western Half ◽

Inner Continental Shelf

Shoreface-connected ridges (SFCR) are series of ridges and troughs obliquely oriented towards the shore in the inner-continental shelf. They exist sporadically from Long Island to Florida on the North American Atlantic Shelf with maximum expression on the Delmarva peninsula (Swift et al., 1978), including the western half of Fire Island, NY. The long-term historic shoreline record of Fire Island (e.g., Allen and LaBash, 1997) shows persistent undulations in shoreline shape at an alongshore scale similar to the alongshore scale of the ridges. These ridges and troughs are spaced approximately every 2 to 3 km in the alongshore and occupy a total length about 14 km in the cross-shore direction with an average crest to trough height of 2 m.

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