Gulf of Mexico Origin, Waters, and Biota
Volume III, Geology
Publication Year: 2009
Published by: Texas A&M University Press
Title Page, Copyright, Dedication
Foreword: Fifty-Year Update of Bulletin 89
Just over 50 years ago, a group of prominent marine scientists of their day agreed to begin work on a digest of existing knowledge on the Gulf of Mexico. The effort was proposed by Lionel A. Walford of the U.S. Fish and Wildlife Service and Waldo L. Schmitt of the U.S. National Museum of Natural History, during a meeting of the Gulf...
Contemplation of this geology volume was initiated in 2005 and authors began submission of their manuscripts in 2006. It has taken four years of tremendous effort by many people to reach publication. First and foremost, the contents of this book would not have been complete or possible were it not for the contributions of the many geologists whose significant research and years of hard...
“No rock, no water, no ecosystem” is a phrase used repeatedly by Eugene Shinn at the University of South Florida College of Marine Science. The phrase highlights the fact that to understand a region as vast as the Gulf of Mexico, one must know the environmental foundation of the area. According to data stored in the American Geological Institute database GEOREF, there have been over 10,000...
Part 1. Geologic History of the Gulf of Mexico
1. Tectonic Evolution of the Gulf of Mexico Basin
The formation of the Gulf of Mexico basin was preceded by the Late Triassic breakup of Pangea, which began with the collapse of the Appalachian Mountains (ca. 230 Ma; Dewey 1988). Gondwanan terranes of the southern part of the Gulf States, eastern Mexico, and the Yucatan Peninsula remained sutured onto the North American continent as it drift ed away from the African-Arabian-South American continent (or Residual Gondwana, Burke et al. 2003). Early seafloor spreading in the central Atlantic...
2. Geology of the Florida Platform: Pre-Mesozoic to Recent
The Florida Platform is delimited by the 200 m (600 ft) isobath at the shelf break to the approximate location of the Paleozoic suture beneath southern Georgia and Alabama (Fig. 2.1). The Suwannee–Wiggins Suture (Thomas et al. 1989) is the proposed location where terranes with African affinities are welded to the North American Plate (Chowns and Williams 1983; McBride and Nelson 1988; Woods et al. 1991). The basement rocks of the Florida Platform are a fragment of the African...
3. Pre-Holocene Geological Evolution of the Northern Gulf of Mexico Basin
The Gulf of Mexico is a small ocean basin lying between the North American Plate and the Yucatan block. It contains within its depocenter a succession of Jurassic through Holocene strata that is as much as 20 km thick. Sediment supply from the North American continent has filled nearly one-half of the basin since its inception, primarily by offlap of the northern and northwestern margins. The Gulf of Mexico basin is a world-class...
4. Northern Gulf of Mexico Sea-Level History for the Past 20,000 Years
High-resolution, composite sea- level curves have been developed for the northern Gulf of Mexico for the period since the Last Glacial Maximum. The goal of this work was twofold: (1) to define the regional sea-level history of the northern Gulf of Mexico using all of the available geochronological data on sea-level history, and (2) to examine the hypothesis that, for stable coastal regions of the Gulf of Mexico coastline, sea-level history approximates...
Part 2. Eastern Gulf of Mexico
5. Florida Gulf Coast Estuaries: Tampa Bay and Charlotte Harbor
Tampa Bay and Charlotte Harbor are the 2 largest estuaries in the eastern Gulf of Mexico. They lie in close proximity to one another, separated by less than 200 km, along the westward-facing, barrier-island Gulf Coast of peninsular Florida (Fig. 5.1). They have similar dimensions, share the same regional geological setting, have a similar climate (humid subtropical), and share a similar oceanographic setting (tide and wave regimes). Geologic...
6. Beaches, Barrier Islands, and Inlets of the Florida Gulf Coast
The Gulf Coast of Florida includes 4 geomorphically distinct provinces. From south to north they are: (1) southwest Florida, which includes the tide-dominated Ten Thousand Islands and south to Cape Sable at Florida Bay, (2) the mixed-energy barrier–inlet system of the central coast, (3) the tide-dominated Big Bend coast, and (4) the wave-dominated barrier coast of the panhandle (Fig. 6.1). This diverse coastal morphology has been variously...
7. Florida Gulf of Mexico Continental Shelf: Great Contrasts and Significant Transitions
The Florida Gulf of Mexico shelf is ~900 km long (following the 75 m bathymetric line) and passes through 6.5° of latitude (~700 km), ranges from 25 to 250 km wide and features a broad range of seafloor morphologies, bathymetric gradients, sediment types, benthic biology communities, hardbottom exposures, paleo sea-level indicators, reefs and reefal structures, and paleofluvial–paleo-deltaic activity (Fig. 7.1). The shelf can be...
8. West Florida Continental Slope
Prior to the last 30 years, the west Florida shelf and slope had been terra incognita. With the increase in petroleum exploration beginning in the 1950s there was limited exploration carried out on the Florida Platform. This exploration was limited to approximately 30 exploration wells and a few cross-platform seismic traverses (Mitchum 1978). As petroleum reserves dwindled and exploration methods became more diverse, interest in the...
9. A Review of Recent Depositional Processes on the Mississippi Fan, Eastern Gulf of Mexico
The Mississippi Fan is a large, fine-grained, submarine fan that occupies approximately 300,000 km2 of the eastern part of the deep Gulf of Mexico basin (Fig. 9.1). The fan is Plio-Pleistocene in age and contains about 290,000 km3 of sediment that was eroded from the interior of the North American continent, carried by the Mississippi River system to the continental shelf, and transported from the continental shelf to the deep sea by...
Part 3. Northern Gulf of Mexico
10. Recent Geologic Framework and Geomorphology of the Mississippi–Alabama Shelf, Northern Gulf of Mexico
This paper provides a summary of previous studies and a synthesis of the surficial geology of the Mississippi–Alabama shelf, located between the modern Mississippi River Delta and the Florida carbonate platform. Presently, sedimentation processes on the shelf are a function of prevailing winds and currents; however, in the past, the shelf was the focus of numerous delta cycles. Major episodes of deposition and erosion on the shelf have been primarily...
11. Mississippi River Delta Plain, Louisiana Coast, and Inner Shelf Holocene Geologic Framework, Processes, and Resources
Extending nearly 400 km from Sabine Pass on the Texas–Louisiana border east to the Chandeleur Islands, the Louisiana coastal zone (Fig. 11.1) along the north-central Gulf of Mexico is the southern terminus of the largest drainage basin in North America (>3.3 million km2), which includes the Mississippi River delta plain where approximately 6.2 million kilograms per year of sediment is delivered to the Gulf of Mexico (Coleman 1988). The Mississippi River, active since at least Late Jurassic time...
12. Development of the Northwestern Gulf of Mexico Continental Shelf and Coastal Zone as a Result of the Late Pleistocene–Holocene Sea-Level Rise
The first comprehensive geologic investigation of the northwestern Gulf of Mexico was the America Petroleum Institute’s Project 51 (Shepard et al. 1960). The goal of this project was to develop sedimentary models to aid in defining habitats of hydrocarbon formation and accumulation. Since 1951, various features throughout the northwestern Gulf of Mexico have been the subject of many studies, but the scope of those studies has been only regional. In...
13. Surficial Geology of the Northern Gulf of Mexico Continental Slope: Impacts of Fluid and Gas Expulsion
Our understanding of the geology of the northern and northwestern Gulf of Mexico continental slope has taken a quantum leap forward since Fishery Bulletin volume 89 (“Bulletin 89”) was published in 1954. Single-trace echo-sounder profiling, single-point soundings, and data from coring, trawls, and grab samples formed the database from which most interpretations of continental slope geology were made. Less than a decade aft er World War II...
14. Energy Resources of the Northern Gulf of Mexico Basin
Conventional hydrocarbon resources alone make the Gulf of Mexico basin one of the most energy-rich basins of the world, with approximately 9% of the known recovery of petroleum liquids and 11% of the known recovery of natural gas in the world (Nehring 1991). In addition to these resources, there are significant accumulations of uranium, coal, coal-bed gas, and gas hydrates in the northern part of the basin (Fig. 14.1). This brief discussion will...
15. Gas Hydrates in the Gulf of Mexico
“Interest in the Gulf of Mexico has been greatly accelerated in the past decade, and there is much evidence that this interest will continue, which should result in the eventual solution of many of the present riddles of the Gulf of Mexico.” When S. A. Lynch wrote these words half a century ago (Lynch 1954, p. 83), gas hydrates were not anticipated as one of the “riddles” of the Gulf of Mexico. The occurrence of gas hydrates in the Gulf was first predicted...
Part 4. Mexico
16. The Chicxulub Impact Crater and Its Influence on the Regional Hydrogeology in Northwest Yucatan, Mexico
In 1980 Luis Alvarez et al. proposed a revolutionary theory: the large mass extinction that occurred at the Cretaceous–Tertiary (K–T) boundary (65 million years ago) was a consequence of the impact of a large bolide with Earth (Alvarez et al. 1980). This theory was considered highly controversial, particularly because it took over a decade to “discover” the crater. However, research about...
17. Mexican Littoral of the Gulf of Mexico
The Mexican littoral zone of the Gulf of Mexico and the Mexican Caribbean together total 2756 km of generally sandy emergent shorelines associated with lowland terrains. The coast along the Gulf of Mexico forms a concave coastline (Fig. 17.1) with intermittent areas of high relief, and the continental shelf is wide, especially adjacent to the karstic Yucatan Peninsula (Tamayo 2002). This summary emphasizes relevant aspects of the...
Part 5. Coral Reefs
18. Coral Reefs of the Florida Keys: Late Quaternary Stratigraphy
The reef-rimmed south Florida shelf is a windward carbonate-platform margin, yet it differs substantially in morphology and depositional processes from the classic windward carbonate-margin model (James and Ginsburg 1979). The submerged shelf is shallow (generally <12 m), uneven, extends for ~5 to 7 km seaward of the Florida Keys, and slopes westward, transitioning into a non-rimmed ramp morphology in the Gulf of Mexico...
19. Florida Middle Ground Reef Complex
The Florida Middle Ground (FMG) reef complex, located on the west Florida continental margin (see Hine and Locker in chapter 7 in this volume) in the northeastern Gulf of Mexico, is unusual in that it occupies a relatively high-latitude (>28
20. Mexican Coral Reefs
The Mexican reefs of the southern Gulf of Mexico occur in 2 distinct provinces, the Campeche Bank to the north and west of the Yucatan Peninsula and the Veracruz shelf reefs near the coast in the Tuxpan–Veracruz area of the southwestern Gulf of Mexico. Reefs diff er greatly in size, geomorphology, and diversity, reflecting differences in the underlying geologic structures and ambient environments. The reefs of the Campeche Bank, generally...
21. Habitat-Forming Deepwater Scleractinian Corals in the Gulf of Mexico
Throughout the world’s oceans, branching, sessile megafauna play important roles in structuring deepwater ecosystems (Mortensen et al. 1995; Fosså and Mortensen 1998; Sumida and Kennedy 1998; Rogers 1999; Husebø et al. 2002). These megafauna include monospecifi c or mixed species assemblages of scleractinians (Squires 1964; Mortensen et al. 1995; Freiwald et al. 1997; Rogers 1999...
Part 6. Processes
22. Planktic Foraminiferal Relative Abundance and Trends in Gulf of Mexico Holocene Sediments: Records of Climate Variability
Planktic foraminifers are commonly used as proxies in paleoceanographic studies. Information on assemblages and variations in the abundance of individual taxa is used to estimate surface-water temperature, identify the influence of currents and water masses, and infer structure in the upper part of the water column (thermocline depth) (e.g., Imbrie and Kipp 1971; Brunner 1979; Ravelo et al. 1990). In addition, measurement of the isotopic and...
23. Over 300 Years of Anthropogenic and Naturally Induced Low-Oxygen Bottom-Water Events on the Louisiana Continental Shelf
Oxygen-depleted subsurface waters occur on the Louisiana continental shelf when the uptake of oxygen exceeds its resupply. When oxygen concentrations fall below 2 mg / L, it is operationally defined as hypoxic. Measurements of Louisiana continental shelf waters demonstrate that the size of the hypoxic zone has increased since 1985 (Rabalais et al. 1999; CENR 2000; Rabalais and Turner 2001) (Fig. 23.1). The likelihood of hypoxia occurring is...
Page Count: 512
Illustrations: 23 color photos. 89 maps. 104 figs. 22 tables. 3 apps. Bib. Index.
Publication Year: 2009
Volume Title: Gulf of Mexico Origin, Waters, and Biota
Series Title: Harte Research Institute for Gulf of Mexico Studies Series, Sponsored by the Harte Research Institute for Gulf of Mexico Studies, Texas A&M University-Corpus Christi
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