Quaternary depositional patterns and sea-level fluctuations, Northeastern North Carolina

2007 ◽  
Vol 67 (1) ◽  
pp. 83-99 ◽  
Author(s):  
Peter R. Parham ◽  
Stanley R. Riggs ◽  
Stephen J. Culver ◽  
David J. Mallinson ◽  
John F. Wehmiller
Keyword(s):  
North Carolina ◽  
Sea Level ◽  
Late Quaternary ◽  
Drainage System ◽  
Drill Hole ◽  
Estuarine Sediments ◽  
Early Pleistocene ◽  
Sea Level Fluctuations ◽  
Marine Deposits ◽  
Sea Level Oscillations

AbstractA detailed record of late Quaternary sea-level oscillations is preserved within the upper 45 m of deposits along an eight km transect across Croatan Sound, a drowned tributary of the Roanoke/Albemarle drainage system, northeastern North Carolina. Drill-hole and seismic data reveal nine relatively complete sequences filling an antecedent valley comprised of discontinuous middle and early Pleistocene deposits. On interfluves, lithologically similar marine deposits of different sequences occur stacked in vertical succession and separated by ravinement surfaces. Within the paleo-drainage, marine deposits are separated by fluvial and/or estuarine sediments deposited during periods of lowered sea level. Foraminiferal and molluscan fossil assemblages indicate that marine facies were deposited in a shallow-marine embayment with open connection to shelf waters. Each sequence modifies or truncates portions of the preceding sequence or sequences. Sequence boundaries are the product of a combination of fluvial, estuarine, and marine erosional processes. Stratigraphic and age analyses constrain the ages of sequences to late Marine Isotope Stage (MIS) 6 and younger (∼ 140 ka to present), indicating multiple sea-level oscillations during this interval. Elevations of highstand deposits associated with late MIS 5 and MIS 3 imply that sea level was either similar to present during those times, or that the region may have been influenced by glacio-isostatic uplift and subsidence.

Mode d'empilement et distorsion de sequences genetiques en milieu marin restreint; facies et architecture des depots hettangiens du sud-ouest du bassin de Paris

2000 ◽  
Vol 171 (3) ◽  
pp. 341-353 ◽  
Author(s):  
Gilles Merzeraud ◽  
Raymond Rauscher ◽  
Michel Hoffert ◽  
Francois Verdier
Keyword(s):  
Sea Level ◽  
Paris Basin ◽  
Sea Level Fluctuations ◽  
Marine Deposits ◽  
Geometric Patterns ◽  
Sea Level Oscillations ◽  
Genetic Sequences ◽  
Stacking Patterns ◽  
Eustatic Fluctuations

Abstract In the southwestern part of the Paris Basin (Sologne region), dolomite and limestone deposits of Hettangian age represent an excellent cover for a thick sandstone reservoir, which is being worked by "Gaz de France" for natural gas storage in underground aquifers. The "genetic sequences" of these shallow marine deposits and their stacking patterns are associated with two orders of relative sea-level fluctuations. The thinnest genetic sequences are arranged in transgressive/regressive hemicycles that include distinct facies assemblages. The facies changes are related to rapid palaeogeographic variations that occur during the onset of each genetic sequence. On a different scale, the stacked genetic sequences are organized into three geometric patterns, which are related to long-term eustatic fluctuations (eg. aggradational, retrogradational, and progradational patterns). For each of these stacked geometries, the partitioning of sediment volumes, the degree of symmetry, and the two-dimensional architecture of the genetic sequences had been modified through time. These changes are related to the effects of two superimposed short-term and long-term sea-level oscillations that distort the stratigraphic record.

The Origin of Modern Atolls: Challenging Darwin's Deeply Ingrained Theory

2021 ◽  
Vol 13 (1) ◽  
pp. 537-573 ◽  
Author(s):  
André W. Droxler ◽  
Stéphan J. Jorry
Keyword(s):  
Sea Level ◽  
Late Quaternary ◽  
Direct Interaction ◽  
Evolutionary Model ◽  
Reef Growth ◽  
Sea Level Fluctuations ◽  
Fringing Reefs ◽  
Volcanic Islands ◽  
Karst Model ◽  
The Tropical Pacific

In 1842, Darwin identified three types of reefs: fringing reefs, which are directly attached to volcanic islands; barrier reefs, which are separated from volcanic islands by lagoons; and ring reefs, which enclose only a lagoon and are defined as atolls. Moreover, he linked these reef types through an evolutionary model in which an atoll is the logical end point of a subsiding volcanic edifice, as he was unaware of Quaternary glaciations. As an alternative, starting in the 1930s, several authors proposed the antecedent karst model; in this model, atolls formed as a direct interaction between subsidence and karst dissolution that occurred preferentially in the bank interiors rather than on their margins through exposure during glacial lowstands of sea level. Atolls then developed during deglacial reflooding of the glacial karstic morphologies by preferential stacked coral-reef growth along their margins. Here, a comprehensive new model is proposed, based on the antecedent karst model and well-established sea-level fluctuations during the last 5 million years, by demonstrating that most modern atolls from the Maldives Archipelago and from the tropical Pacific and southwest Indian Oceans are rooted on top of late Pliocene flat-topped banks. The volcanic basement, therefore, has had no influence on the late Quaternary development of these flat-topped banks into modern atolls. During the multiple glacial sea-level lowstands that intensified throughout the Quaternary, the tops of these banks were karstified; then, during each of the five mid-to-late Brunhes deglaciations, coral reoccupied their raised margins and grew vertically, keeping up with sea-level rise and creating the modern atolls.

The physical geography and geology of the estuary and Firth of Forth, Scotland

1987 ◽  
Vol 93 (3-4) ◽  
pp. 235-244 ◽  
Author(s):  
Michael A. E. Browne
Keyword(s):  
Sea Level ◽  
Late Quaternary ◽  
Physical Geography ◽  
Glacial Till ◽  
Estuarine Sediments ◽  
Volcanic Origin ◽  
Quaternary Glaciation ◽  
History Of ◽  
Quaternary History ◽  
Firth Of Forth

SynopsisThe Upper Palaeozoic bedrock, which is of sedimentary and volcanic origin, is briefly described. The origin of the Forth as a series of depressions in the bedrock surface probably owes much to erosion of a pre-existing Tertiary landscape during phases of Quaternary glaciation. The late Quaternary history of the area is described, relating the distribution of the sediments deposited in the Forth to climatic events and changes in relative sea-level. Since the acme of the last main glaciation about 20,000 years ago, late Devensian marine and estuarine sediments have been deposited on the underlying glacial till sheet at altitudes ranging from more than 120 m below O.D. to at least 46 m above O.D. Similarly, raised and buried beaches and their deposits occur at altitudes from 40 m above O.D. down to around 10 m below O.D. in the estuary. During the Flandrian, sea-level has fluctuated, reaching its maximum (about 11 to 15 m above O.D.) about 6500 years ago. The typical deposit of this period is the carse clay which forms a series of extensive, fertile raised mudflats around the estuary. The calcareous marine faunas of the carse clay and older deposits are outlined.

scholarly journals An introduction to causes and consequences of Cretaceous sea-level changes (IGCP 609)

2019 ◽  
Vol 498 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Michael Wagreich ◽  
Benjamin Sames ◽  
Malcolm Hart ◽  
Ismail O. Yilmaz
Keyword(s):  
Sea Level ◽  
Sea Level Changes ◽  
Short Term ◽  
Sea Level Fluctuations ◽  
Groundwater Aquifer ◽  
Sea Level Oscillations ◽  
Short And Long Term ◽  
Geological Timescale ◽  
Land Water

AbstractThe International Geoscience Programme Project IGCP 609 addressed correlation, causes and consequences of short-term sea-level fluctuations during the Cretaceous. Processes causing several ka to several Ma (third- to fourth-order) sea-level oscillations during the Cretaceous are so far poorly understood. IGCP 609 proved the existence of sea-level cycles during potential ice sheet-free greenhouse to hothouse climate phases. These sea-level fluctuations were most probably controlled by aquifer-eustasy that is altering land-water storage owing to groundwater aquifer charge and discharge. The project investigated Cretaceous sea-level cycles in detail in order to differentiate and quantify both short- and long-term records based on orbital cyclicity. High-resolution sea-level records were correlated to the geological timescale resulting in a hierarchy of sea-level cycles in the longer Milankovitch band, especially in the 100 ka, 405 ka, 1.2 Ma and 2.4 Ma range. The relation of sea-level highs and lows to palaeoclimate events, palaeoenvironments and biota was also investigated using multiproxy studies. For a hothouse Earth such as the mid-Cretaceous, humid–arid climate cycles controlling groundwater-related sea-level change were evidenced by stable isotope data, correlation to continental lake-level records and humid–arid weathering cycles.

Relative land-sea-level changes in southeastern England during the Pleistocene

1972 ◽  
Vol 272 (1221) ◽  
pp. 87-98 ◽  
Keyword(s):  
Sea Level ◽  
Sea Level Change ◽  
Estuarine Sediments ◽  
Level Fluctuation ◽  
Sea Level Changes ◽  
Freshwater Sediments ◽  
Marine Deposits ◽  
Level Change ◽  
Lower Pleistocene ◽  
Sea Level Fluctuation

During the Pleistocene, a period covering the last two million years, sea level is known to have risen above and fallen below the present sea level. The evidence for such fluctuations comes from marine and estuarine sediments, including beaches, far above present sea level and from freshwater sediments, beaches and valley systems now submerged. In southeast England there are Lower Pleistocene marine deposits at 183 m O.D . at Netley Heath in Surrey and upper Pleistocene freshwater sediments at - 35 m O.D . in the Channel. Thus we have in this area evidence of an amplitude of sea-level fluctuation relative to the present sea level of some 218 m. While such limits of relative sea-level fluctuation are not so difficult to identify, very considerable difficulties arise in determining the relation of sea-level change to the passage of time, and in the analysis of sea-level change - whether it be a real lowering of sea level relative to land, or an uplift of land relative to sea level. Let us briefly consider each of these two fields of difficulty. To date a particular stand of sea level, we have to know the relation of a particular deposit, say beach or shallow marine sediment to sea level at the time, and we have to know the correlation of this deposit to a part of the sequence of geological events which make up the Pleistocene. Both of these aspects may be problematical. It may not be certain what depth of water a deposit was formed in, and the age and correlation of the deposit may be doubtful.

Biostratigraphic Correlation of Pleistocene Marine Deposits and Sea Levels, Atlantic Coastal Plain of the Southeastern United States

1980 ◽  
Vol 13 (2) ◽  
pp. 213-229 ◽  
Author(s):  
Thomas M. Cronin
Keyword(s):  
North Carolina ◽  
South Carolina ◽  
Sea Level ◽  
Late Pleistocene ◽  
Coastal Plain ◽  
Atlantic Coastal Plain ◽  
Early Pleistocene ◽  
Middle Pleistocene ◽  
Sea Levels ◽  
Atlantic Coastal

AbstractMarine ostracodes from 50 localities were studied to determine the age and elevation of Pleistocene sea levels in the Atlantic coastal plain from Maryland to northern Florida. Using ostracode taxon and concurrent ranges, published planktic biostratigraphic, paleomagnetic, and radiometric data, ostracode assemblage zones representing early (1.8-1.0 my), middle (0.7-0.4 my), and late (0.3-0.01 my) Pleistocene deposition were recognized and used as a basis for correlation. Ostracode biofacies signifying lagoonal, oyster bank, estuarine, open sound, and inner sublittoral environments provided estimated ranges of paleodepths for each locality. From these data the following minimum and maximum Pleistocene sea-level estimates were determined for the southeastern coastal plain: late Pleistocene, 2–10 m from Maryland to northern Florida; middle Pleistocene, 6–15 m in northern South Carolina; early Pleistocene, 4–22 m in central North Carolina, 13–35 m in southern North Carolina, and 6–27 m in South Carolina. Climatically induced glacio-eustatic sea-level fluctuations adequately account for the late Pleistocene sea-level data, but other factors, possibly differential crustal uplift, may have complicated the early Pleistocene record.

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