Geology topics
Research about Texas
Source-linked reports with geographic coverage including Texas.
Geology and ground-water resources of the Big Spring area, Texas
This report gives the principal results of an investigation of ground water in the Big Spring area, Texas. Big Spring, the county seat of Howard County, has an estimated population of about 16,000. It is situated on the Texas & Pacific Ry. and United States Highway No. 80 in western Texas, about 280 miles west of Fort Worth and along the boundary between the Edwards Plateau and the High Plains. Immediately south of the city is the bold escarpment of the plateau; to the north, west, and southwest lie the High Plains; and to the east lie the Osage Plains. The Edwards Plateau is capped by resistant limestones of Fredericksburg (Lower Cretaceous) age, which have a maximum thickness of about 160 feet. These limestones are underlain by sandstones of Trinity (basal Lower Cretaceous) age, which range in thickness from 60 to 100 feet and which form the principal water-bearing bed of the area. The High Plains are underlain in most places by a varying thickness of silt, clay, sand, and gravel, chiefly of Tertiary age. The Osage Plains are underlain chiefly by Triassic redbeds, which in general form an uneven floor beneath the Cretaceous and younger formations in the High Plains and Edwards Plateau. Beneath the Triassic redbeds is a great thickness of Permian rocks, which in parts of the area contain thick beds of rock salt. Over a large part of the plateau the Cretaceous rocks appear to be fiat lying but actually dip so as to form a northwestward-trending syncline. However, in places the rocks have slumped to form depressions or sinks, which serve as collecting basins for the water from the Trinity sand. As both Triassic and Cretaceous rocks are involved in the deformations, it is believed that they .may have been formed as a result of the solution and removal of the Permian salt by circulating ground water. Two of these sinks have been well known for several years. One of them, usually called the city park sink, is about 2 miles south of Big Spring, and the other, usually called the section 33 sink, is about 6 miles southeast of the city. These sinks are nearly circular. They have a diameter of about 1 mile, and the maximum displacement of the beds is 200 to 300 feet. They serve as collecting basins for ground water drained from the Surrounding Trinity sand, and wells drilled in them yield as much as 300 gallons a minute, largely from the cracks and crevices in the Fredericksburg limestones. As the Trinity sand is mostly fine-grained, wells outside the sinks seldom yield more than 20 to 30 gallons a minute. For many years the water supply of Big Spring and most of the water used there by the Texas & Pacific Ry. Co. has come from wells in the sinks, supplemented by a relatively small supply pumped from well fields between them. It is estimated that the perennial yield of the sinks and intervening well fields amount to an average of about 450,000 gallons a day. For several years-the pumpage has been much more than that, and in 1937 it amounted to an average of about 1,000,000 gallons a day. A large part of the water has therefore come from storage, and as a result the water table in the sinks, where the draft has been greatest, has declined to lower levels each year. If the water supply needed by the city continues to increase at the normal rate, most of the remaining water will be exhausted from the sinks in a few years if no other supply is provided. Although in some areas, such as sees. 44 and 45, the rocks are slightly deformed, no deep sinks that are comparable with the city park and section 33 sinks were found on the Edwards Plateau. A large amount of water is stored in the Trinity sand in areas on the plateau south of the present well fields, but as the sands are fine only small yields can be obtained from wells in them. Near Lees, about 12 miles southwest of Big .Spring, is a structural depression or sink about 1 mile in diameter, which contains Cretaceous limestone that is probably fractured and which is overlain by Tertiary
The quicksilver deposits of the Terlingua region, Texas
Texas is second among quicksilver-producing States because of the Terlingua region, in the Big Bend of the Rio Grande. This region contains Cretaceous strata, largely calcareous, which grade upward into Tertiary volcanics, locally without break. The strata are cut by numerous intrusions, largely alkalic, and are extensively folded and faulted.Many of the lodes are near the base of the impervious Del Rio clay, some at higher horizons, and a few in intrusive masses. The solutions penetrated only along open passageways, such as major fractures or joints in zones of tension, and, especially at horizons above the Del Rio, in fractures related to fault zones.The quicksilver is believed to have been brought in by alkali sulphide solutions. Most other constituents that may once have been present in the solutions had been separated earlier. Precipitation resulted largely from mingling with groundwater. The comparatively low temperature and pressure at the shallow levels where groundwater was present aided the precipitation. As the then-existing zone of groundwater circulation has since been partly exposed by erosion, the lodes are necessarily rather close to the present surface. The gangue minerals, particularly the calcite, are believed to have been derived mainly from the sedimentary rocks with some addition of material from deep sources. The relation of the widespread bitumen to genesis is puzzling here, as in many other quicksilver deposits. Weathering is of slight economic importance. Many minerals that resemble supergene products, including the quicksilver chlorides, are thought to have resulted here from original deposition within the zone of vadose water.
An early Eocene florule from central Texas
In 1916 I described a florule collected by Alexander Deussen and L. W. Stephenson at the town of Earle, in Bexar County, Tex. This florule was tentatively considered of Midway age by these geologists, and examination of the fossil plants tended to confirm this assignment, particularly because of their lack of harmony with the extensive Wilcox flora described in the volume cited above and because of their resemblance to the described floras from the Raton and Denver formations of Colorado and New Mexico.
The Brooks, Steen, and Grand Saline salt domes, Smith and Van Zandt Counties, Texas
No abstract available.
Additions to the flora of the Wilcox group
A rather full account of the extensive flora contained in the lower Eocene strata of the Mississippi embayment which are referred to the Wilcox group was published in 1916. At that time it was not possible to obtain sections of the numerous specimens of petrified wood that had been collected from these beds. These woods have since been sectioned and studied, and it seems eminently desirable to place the results of this study on record, for although much of the material had suffered greatly from decay before silicification, some of it is fairly well preserved and shows, among other results, that conifers were individually much more plentiful during Wilcox time than would be inferred from the almost total absence of their foliage in the very large collections of remains of this class that have been studied.
The floods in central Texas in September, 1921
Heavy rainfall over a large area in south-central Texas from September 8 to September 10, 1921, produced great floods which caused the loss of at least 224 lives and damage to property amounting to more than $10,000,000. The most destructive flood in Texas prior to 1921 occurred in December, 1913. That flood, which is described on pages 46-47, caused the loss of 177 lives and destroyed property valued at more than $8,500,000.
Lithologic subsurface correlation in the "Bend series" of north-central Texas
This paper presents the results of an attempt to obtain, by a study of well drillings, criteria for correlation, by the character of the beds encountered, of horizons in the "Bend series" of north-central Texas. The result of the work most directly applicable to the needs of the oil-well operator is that of enabling him to know more exactly the position of the producing beds in his well- a result that is of particular value in north-central Texas because certain beds in that region which give no show of oil to the drill may on being "shot" yield considerable oil. To know the part of the stratigraphic section reached by the drill at any stage of the boring also enables the driller to be on the alert for indications of oil at horizons where productive sands are encountaered in other wells and to know when the drill has passed all horizons at which the beds are likely to yield oil.
An Eocene flora from trans-Pecos Texas
During the fall of 1916 I received a small collection of fossil plants which had been obtained during a geologic reconnaissance of the trans-Pecos region of Texas, by Charles Lawrence Baker. A preliminary report was sent to Mr. Baker in November of that year and was quoted in his discussion of the geology of that region. I have since made a careful study of the collection, and although it contains only a few species the occurrence of fossil plans in this region is worthy of more definite and detailed record, especially as these plants enabled me to assign a definite age to the beginning of the igneous activity of the region and to establish correlations between the floras of the Mississippi embayment and the Rocky Mountain Region.