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Geology topics

Thomas G. Gibson

Publications and source records attributed to Thomas G. Gibson.

At least 19 recordsLinked to original sources
USGS2010

Latest Paleocene lithologic and biotic events in neritic deposits of southwestern New Jersey

In the southwestern New Jersey Coastal Plain, four drill holes contain continuous neritic sedimentation across the Paleocene/Eocene boundary (calcareous nannofossil Zone NP 9/NP 10 boundary). Significant lithologic and biotic changes occur in these strata near the top of the Paleocene. Global warming, increased precipitation, and other oceanographic and climatic events that have been recognized in high-latitude, deep-oceanic deposits of the latest Paleocene also influenced mid-latitude, shallow-marine, and terrestrial environments of the western North Atlantic. The diverse, well-preserved calcareous nannofossil flora that is present throughout the entire New Jersey boundary section accurately places these events within the uppermost part of the upper Paleocene Zone NP 9. Several rapid but gradational changes occur within a 1.1-m interval near the top of Zone NP 9. The changes include (1) a change in lithology from glauconitic quartz sand to clay, (2) a change in clay mineral suites from illite/smectite-dominated to kaolinite-dominated, (3) a change in benthic foraminiferal assemblages to a lower diversity fauna suggestive of low-oxygen environments, (4) a significant increase in planktonic foraminiferal abundance, and (5) an increased species turnover rate in marine calcareous nannofossils. Pollen was sparse in the New Jersey drill holes, but terrestrial sporomorph species in Virginia exhibit increased turnover rates at a correlative level. Foraminiferal assemblages and lithology indicate that relative sea level rose in New Jersey at the same time as these late Paleocene events occurred in late Biochron NP 9. The higher sea levels influenced sediment type and absolute abundance of planktonic foraminifers in the deposits. Above the initial increase of kaolinite in the upper part of Zone NP 9, the kaolinite percentage continues to increase, and the maximum kaolinite value occurs in the uppermost part of Zone NP 9. There are few changes in either the sediments or the biota precisely at the Zone NP 9/NP 10 boundary in New Jersey. The clay-rich deposits with a high kaolinite clay mineral suite, the lowered diversity benthic foraminiferal assemblages, the abundant planktonic foraminiferal specimens, and the calcareous nannofossil assemblages continued essentially unchanged into the earliest Eocene Zone NP 10. Within the lower part of Zone NP 10, the kaolinite percentage decreased to very low values.

Paleoceanography↗
USGS1996

Neogene and Quaternary geology of a stratigraphic test hole on Horn Island, Mississippi Sound

During April and May, 1991, the U.S. Geological Survey (USGS) drilled a 510-ft-deep, continuously cored, stratigraphic test hole on Horn Island, Mississippi Sound, as part of a field study of the Neogene and Quaternary geology of the Mississippi coastal area. The USGS drilled two new holes at the Horn Island site. The first hole was continuously cored to a depth of 510 ft; coring stopped at this depth due to mechanical problems. To facilitate geophysical logging, an unsampled second hole was drilled to a depth of 519 ft at the same location.

Open-File Report↗
USGS1994

Neogene and Quaternary foraminifera and paleoenvironments of a corehole from Horn Island, Mississippi

The only semipermanent surface water available on the Southern High Plains plateau of Texas and New Mexico is contained in saline lakes and in the playa lakes that form in shallow depressions, called playa basins, following heavy rainfall. The playas generally are accepted as the main source of recharge to the underlying High Plains (Ogallala) aquifer of the region, and they constitute the major wildlife habitat on the Southern High Plains. Their use as water sources, holding ponds, and waste-disposal sites by agricultural and industrial operations may potentially lead to ground-water contamination and habitat degradation. Therefore, playa lakes will play an essential role in the collection of surface-water quality and ecological data for the Southern High Plains study unit of the National Water-Quality Assessment program of the U.S. Geological Survey.

Open-File Report↗
USGS1994

Paleogene stratigraphy of the Solomons Island, Maryland, corehole

The Solomons Island corehole was drilled in the hope of obtaining a continuous and more nearly complete section of upper Paleocene and lower Eocene strata than are found in the discontinuous and fragmentary sections in the outcrop belt to the west. Consultation with Harry Hansen (Maryland Geological Survey) on possible drilling sites that were within the limits of our equipment and funding led to the selection of Solomons Island. A strong factor in this selection was the stratigraphic information available from the nearby Lexington Park well (Hansen and Wilson, 1984). As anticipated, all Paleogene units previously reported in the Maryland and Virginia Coastal Plain, except for the upper Eocene Chickahominy Formation and the upper Oligocene Old Church Formation, were penetrated at Solomons Island. The upper part of the Solomons Island corehole also penetrated the Calvert Formation of Miocene age and the younger Lowland Deposit. Gibson and Andrews (1994) described the lithology and biostratigraphy of these Miocene sediments. This paper describes the lithologies of the Lower Cretaceous, Paleocene, and Eocene strata that were recovered from the Solomons Island corehole and gives a brief biostratigraphic and paleoenvironmental summary of the beds penetrated there.

Maryland↗
USGS1994

Sedimentary patterns across the Paleocene-Eocene boundary in the Atlantic and Gulf Coastal Plains of the United States

Fossiliferous clay and sand belonging to calcareous nannofossil Zones NP 9 (latest Paleocene) and NP 10 (earliest Eocene) are widespread in the US Gulf and Atlantic Coastal Plains. Although the thickness of Zone NP 9-NP 10 strata is several times greater in the eastern Gulf Coastal Plain than in the Atlantic Coastal Plain, the hiatus that usually is present between these two zones in inner neritic strata is of longer duration in the Gulf Coast. Although 6 sequences are found in Zones NP 10-NP 11 in both the Atlantic and Gulf Coastal Plains, the number of sequences in each NP zone differs in the 2 areas. There is continuous deposition across the Zone NP 9-NP 10 boundary only in the northern Atlantic Coastal Plain, where middle to outer neritic deposits record the presence of several latest Paleocene (upper Zone NP 9) events that occurred at approximately 55.2 Ma.

Atlantic Coastal Plain, Gulf Coastal Plain↗
USGS1989

Planktonic benthonic foraminiferal ratios: Modern patterns and Tertiary applicability

The abundance of planktonic specimens in foraminiferal assemblages was determined in numerous bottom samples from inner neritic to deep oceanic depths along the Atlantic margin of the northeastern United States. The results augment previous studies in other areas that have shown a general increase in percentage of planktonic specimens in total foraminiferal bottom assemblages as water depth increases. The patterns found in this area of complex shelf bathymetry and hydrography illustrate the influence on the planktonic-benthonic percentages of water depth, distance from shore, different water mass properties and downslope movement of tests in high energy areas. The patterns found in the 661 samples from the Atlantic margin were compared with results from 795 stations in the Gulf of Mexico, Pacific Ocean and Red Sea. The relative abundance of planktonic specimens and water depth correlates positively in all open oceanic areas even though taxonomic composition and diversity of the faunas from different areas is variable. The variation of planktonic percentages in bottom samples within most depth intervals is large so that a precise depth determination cannot be made for any given value. However, an approximate upper depth limit for given percentages can be estimated for open ocean environments. A decrease in planktonic percentages is seen in the lower salinity and higher turbidity coastal waters of the Gulf of Maine. Planktonic percentages intermediate between the lower values in the less saline coastal waters and the higher values in the normal open oceanic conditions occur in the transitional area between the Gulf of Maine and the open marine Atlantic Ocean to the east. Similarly lowered values in another area of restricted oceanic circulation occur in the high salinity, clear, but nutrient-poor waters of the Gulf of Aqaba off the Red Sea. A comparison of the similarity of modern planktonic percentage values to those found in earlier Tertiary assemblages was made to confirm the usefulness of this measure in the fossil record. In some stratigraphic sections in upper Paleocene and lower Eocene strata of the eastern Gulf Coastal Plain, water depths inferred from trends and values of planktonic percentages consistently match paleobathymetry constructed from physical stratigraphic characteristics and paleogeographic relationships.

Marine Micropaleontology↗