Subsidence of the Texas Coast - Inferences from Historical and Late Pleistocene Sea Levels

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dc.acquisition-srcDownloaded from-Web of Scienceen_US
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dc.contributor.authorPaine JGen_US
dc.contributor.otherTectonophysicsen_US
dc.date.accessioned2010-02-15T17:17:36Z
dc.date.available2010-02-15T17:17:36Z
dc.date.issued1993 Jul 15en_US
dc.degreeen_US
dc.description445-458en_US
dc.description-otheren_US
dc.description.abstractChanges in sea level observed at tide gauges are caused by actual changes in water level and by changes in elevation at the observing station. Recent research has focused on the relationship between climatic change and sea level, but vertical land movement can be just as important, particularly in subsiding sedimentary basins. The purpose of this study is to compare long-term rates of subsidence estimated from upper Pleistocene strata along the central Texas coast with historical subsidence rates from the same area obtained from geodetic surveys and tide gauge data. This comparison shows that historical subsidence rates are much greater than long-term averages and are equal or greater than actual sea-level change along the Texas coast south of Galveston Bay. Long-term (approximately 10(5) vr) subsidence rates were estimated by establishing the extent of marine, marine-influenced, and nonmarine strata within the upper Pleistocene Beaumont Formation in the Copano Bay area of the central Texas coast, and comparing the maximum elevation of in-place, marine-influenced deposits with published maximum sea level estimates of 5-8 m above mean sea level (MSL) from correlative, well-dated coral terraces from stable and uplifted areas. In-place, shell-bearing horizons deposited at or below sea level occur no higher than 2 m MSL in the Copano Bay area, suggesting that there has been no more than 6 m of subsidence since the probable time of deposition during the Sangamon interglacial at approximately 120 ka. The long-term, average subsidence rate for this part of the Texas coast is thus 0.05 mm/yr or less. Historical subsidence rates were obtained by: (1) calculating relative elevation changes between National Geodetic Survey first-order leveling surveys conducted in the early 1950s with those conducted in the late 1970s to early 1980s; (2) normalizing the relative elevation differences between surveys to annual rates of change relative to an arbitrarily chosen benchmark; (3) referencing these lines to sea level at three tide gauges; and (4) comparing calculated rates of relative sea-level (RSL) rise along the lines with estimates of eustatic sea-level (ESL) rise. Rates of RSL rise for the Texas coast south of Galveston Bay were generally 4-8 mm/yr; locally, rates were as high as 23 mm/yr. These rates are significantly higher than global averages of approximately 1 mm/yr. Much of the difference is probably caused by subsidence of the Texas coastal zone at rates of 1-22 mm/yr, or 20-440 times the long-term average of 0.05 mm/yr. The highest subsidence rates were found locally where there has been historical water-level decline in shallow aquifers. Lower subsidence rates of 3-7 mm/yr occur regionally where groundwater decline is minimal or nonexistent. Increased subsidence over the long-term average in these areas may be caused by pressure decline in underlying oil and gas reservoirsen_US
dc.description.urihttp://gbic.tamug.edu/request.htmen_US
dc.historyen_US
dc.identifier.urihttp://hdl.handle.net/1969.3/23515
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dc.locationen_US
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dc.notesTimes Cited: 9ArticleEnglishPAINE, J. GUNIV TEXAS,DEPT GEOL SCI,UNIV STN,BOX X,AUSTIN,TX 78713Cited References Count: 50LN362PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSAMSTERDAMen_US
dc.placeen_US
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dc.relation.ispartofseries51169.00en_US
dc.relation.urien_US
dc.scaleen_US
dc.seriesen_US
dc.subjectU-SERIESen_US
dc.subjectISLANDen_US
dc.titleSubsidence of the Texas Coast - Inferences from Historical and Late Pleistocene Sea Levelsen_US
dc.typeJournalen_US
dc.universityen_US
dc.vol-issue222(3-4)en_US

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