Environmental Baseline Monitoring in the Area of General Crude Oil- Department of Energy Pleasant Bayou Number 2 A Geopressured Geothermal Test well

A program to monitor baseline air and water quality, subsidence, microseismic activity, and noise in the vicinity of the Brazoria County geopressured geothermal test wells, Pleasant Bayou III and II, has been underway since March 1978 (fig. 1). The findings of certain parts of the work, including the results of an initial first-order leveling survey completed by Teledyne Geotronics, a preliminary noise survey completed by Radian Corporation, a preliminary microseismicity survey completed by Teledyne Geotech, and an archeological survey of the site completed by Texas A&M University, have been reported earlier and will not be repeated here. The initial report on environmental baseline monitoring at the test well contained descriptions of baseline air and water quality, a noise survey, an inventory of microseismic activity, and a discussion of the installation of a liquid tilt meter (Gustavson, 1979). The following report continues the description of baseline air and water quality of the test well site, includes an inventory of microseismic activity during 1979 with interpretations of the origin of the events, and discusses the installation and monitoring of a liquid tilt meter at the test well site. In addition, a brief description of flooding at the test site is presented.Bureau of Economic Geolog

Quaternary Stratigraphy of the Western Rolling Plains of Texas Preliminary Findings

Quaternary deposits, as much as 76 m (250 ft) thick, discontinuously cover more than 7,800 km2 (3,000 mi2) of the western Rolling Plains of northwestern Texas. The stratigraphy of this sedimentary sequence is complex, reflecting changes in paleoclimate during the late Pleistocene and Holocene Epochs. In addition, there are clear indications of syngenetic structural control of deposition and postdepositional deformation of the Quaternary strata. These effects were caused by regional and local karstic subsidence resulting from dissolution of Upper Permian evaporites, particularly halite, at depths of 120 to 240 m (400 to 800 ft). Dissolution created voids within the bedded evaporites. As the voids expanded, the overlying strata collapsed, forming depressions wherein sediment accumulated preferentially. Subsidence also caused local faulting and downwarping of some of the Quaternary deposits. Affected deposits include beds of coarse-grained sediment eroded from the westward-retreating Caprock Escarpment (adjacent to the Rolling Plains). This sediment was trapped within the zone of subsidence, forming a broad bajada at the base of the escarpment. At most sites, the coarse-elastic deposits compose the lowest of three genetic components of the regional Quaternary section.Bureau of Economic Geolog

Regional Strucutal Cross Sections, Mid-Permian to Quaternary Strata, Texas Panhandle and Eastern New Mexico

The Palo Duro and Dalhart Basins of the Texas Panhandle and eastern New Mexico contain bedded Permian salts of sufficient thickness and depth to be considered potential sites for long-term storage and isolation of high-level nuclear waste. Salt (primarily halite) is a desirable host rock because of its low permeability, high thermal conductivity, low moisture content, and high gamma-ray shielding properties (Johnson, 1976b). A major concern that must be addressed if nuclear waste is to be stored in the Texas Panhandle is the long-term integrity of the bedded-salt host rock. Areas where salt has been removed by dissolution have been identified beneath the Southern High Plains, along the eastern and western escarpments of the Southern High Plains, and along the Canadian River valley (Gustavson and others, 1980b; Presley, 1980a, 1980b). Region I cross sections of mid-Permian to Quaternary strata in the Texas Panhandle and eastern New Mexico illustrate lithologic and structural relations that are interpreted to have resulted from the regional dissolution of salt and the collapse of overlying strata. The cross sections were constructed using gamma-ray logs, sample logs, and surface geologic maps (Handford, 1980a; McGillis, 1980). Gamma-ray logs are shown on the cross sections because they best demonstrate variations in evaporite strata. Figure 1 is an index map depicting the locations of the cross sections. Stratigraphic nomenclature used on the cross sections is given in table 1.Bureau of Economic Geolog

A New Function for the LDL Receptor: Transcytosis of LDL across the Blood–Brain Barrier

Lipoprotein transport across the blood–brain barrier (BBB) is of critical importance for the delivery of essential lipids to the brain cells. The occurrence of a low density lipoprotein (LDL) receptor on the BBB has recently been demonstrated. To examine further the function of this receptor, we have shown using an in vitro model of the BBB, that in contrast to acetylated LDL, which does not cross the BBB, LDL is specifically transcytosed across the monolayer. The C7 monoclonal antibody, known to interact with the LDL receptor-binding domain, totally blocked the transcytosis of LDL, suggesting that the transcytosis is mediated by the receptor. Furthermore, we have shown that cholesterol-depleted astrocytes upregulate the expression of the LDL receptor at the BBB. Under these conditions, we observed that the LDL transcytosis parallels the increase in the LDL receptor, indicating once more that the LDL is transcytosed by a receptor-mediated mechanism. The nondegradation of the LDL during the transcytosis indicates that the transcytotic pathway in brain capillary endothelial cells is different from the LDL receptor classical pathway. The switch between a recycling receptor to a transcytotic receptor cannot be explained by a modification of the internalization signals of the cytoplasmic domain of the receptor, since we have shown that LDL receptor messengers in growing brain capillary ECs (recycling LDL receptor) or differentiated cells (transcytotic receptor) are 100% identical, but we cannot exclude posttranslational modifications of the cytoplasmic domain, as demonstrated for the polymeric immunoglobulin receptor. Preliminary studies suggest that caveolae are likely to be involved in the potential transport of LDL from the blood to the brain

Aragonite bias exhibits systematic spatial variation in the late Cretaceous Western Interior Seaway, North America

Preferential dissolution of the biogenic carbonate polymorph aragonite promotes preservational bias in shelly marine faunas. Whilst field studies have documented the impact of preferential aragonite dissolution on fossil molluscan diversity, its impact on regional and global biodiversity metrics is debated. Epicontinental seas are especially prone to conditions which both promote and inhibit preferential dissolution, which may result in spatially extensive zones with variable preservation. Here we present a multi-faceted evaluation of aragonite dissolution within the late Cretaceous Western Interior Seaway of North America. Occurrence data of molluscs from two time intervals (Cenomanian-Turonian boundary, early Campanian) are plotted on new high-resolution paleogeographies to assess aragonite preservation within the seaway. Fossil occurrences, diversity estimates and sampling probabilities for calcitic and aragonitic fauna were compared in zones defined by depth and distance from the seaway margins. Apparent range sizes, which could be influenced by differential preservation potential of aragonite between separate localities, were also compared. Our results are consistent with exacerbated aragonite dissolution within specific depth zones for both time slices, with aragonitic bivalves additionally showing a statistically significant decrease in range size compared to calcitic fauna within carbonate-dominated Cenomanian-Turonian strata. However, we are unable to conclusively show that aragonite dissolution impacted diversity estimates. Therefore, whilst aragonite dissolution is likely to have affected the preservation of fauna in specific localities, time averaging and instantaneous preservation events preserve regional biodiversity. Our results suggest that the spatial expression of taphonomic biases should be an important consideration for paleontologists working on paleobiogeographic problems