Occasional Publications on Northern Life, No. 04

The need to exchange information on research in reindeer and caribou diseases became apparent to investigators attending the Second International Reindeer/Caribou Symposium in Roros, Norway, in 1979. Initially, bibliographies were to be exchanged by being submitted to and subsequently distributed by workers at the University of Alaska. When the bibliographies were submitted, it seemed sensible to computerize the lists to facilitate searches for specific information in the future. An apparently simple task became amazingly complex. This is the resultant collection of publications by reindeer/caribou disease researchers. Because researchers in wildlife diseases tend to work on more than one species or topic, out of interest or necessity, a decision was made to include all of a person's references rather than to limit them to strictly reindeer/caribou diseases. The authors hope this will provide a good basis for exchange of information among all those interested in reindeer/caribou diseases

Shoreline changes on central Padre Island (Yarborough Pass to Mansfield Channel) : an analysis of historical changes of the Texas Gulf shoreline

UT Librarie

Shoreline changes between Sabine Pass and Bolivar Roads : an analysis of historical changes of the Texas Gulf shoreline

UT Librarie

Historical shoreline changes and their causes : Texas Gulf coast

Reprinted from Transactions of the Gulf Coast Association of Geological Societies, vol. xxvii, 1977UT Librarie

Sequence Stratigraphy and Composition of Late Quaternary Shelf-Margin Deltas, High Island Area, Offshore Texas

High-resolution seismic profiles and foundation borings from the northwestern Gulf of Mexico reveal the physical attributes of several late Quaternary depositional sequences that were deposited by wave-modified, river-dominated shelf-margin deltas during successive periods of lowered sea level. Each progressively younger sequence is thinner, and overall they exhibit a systematic decrease in the abundance and concentration of sand, which is attributed to a shift in the axes of trunk streams and greater structural influence through time. Results of the study show that (1) contemporaneous structural deformation controlled the thickness of each sequence, the oblique directions of delta progradation at the shelf margin, and the axes of major fluvial channels; (2) a soil zone capping the oldest sequence is a regressive surface of subaerial exposure that was later preserved during marine transgression; (3) the downlap surfaces are not true surfaces but zones of parallel reflections that become progressively higher and younger in the direction of progradation; (4) the downlap zones are composed of marine muds that do not contain high concentrations of shell debris as would be expected in condensed sections; (5) evidence of submarine erosion and reworking of the delta surface during transgression (ravinement surface) is not widely observed probably because rapid subsidence coupled with rapid eustatic sea-level rise quickly submerged the delta plain below the depth of effective wave reworking; (6) no evidence exists that incised valleys or submarine canyons formed along the paleoshelf margin, even though moderately large rivers were present and sea-level curves indicate several periods of rapid sea level fall; and (7) boundaries of these high-frequency type 1 eustatic sequences are flooding surfaces that occupy the same stratigraphic position as boundaries separating parasequences.Bureau of Economic Geolog

Preliminary Assessment of Offshore Sand Resources, South Padre Island, Texas

The purpose of this report is to provide a preliminary qualitative assessment of potential offshore sand resources that might be suitable for replenishment of beaches along South Padre Island, Texas. The investigation involved a literature search and compilation of published and unpublished data to determine if deposits of beach-quality sand might be located on the shoreface and inner continental shelf near the Town of South Padre Island. The location of the study area and potential offshore sites of beach-quality sand are presented in Figure 1. It should be emphasized that this reconnaissance study does not provide the level of information needed to actually conduct offshore mining operations. Additional work involving sediment cores and high-resolution seismic surveys would be necessary to determine the quantity and quality of sand resources offshore of South Padre Island.Bureau of Economic Geolog

Shoreline changes on Mustang Island and North Padre Island (Aransas Pass to Yarborough Pass) : an analysis of historical changes of the Texas Gulf shoreline

UT Librarie

Physical Evaluation of Proposed Flooding of Bahia Grande, Cameron County, Texas

This report was prepared at the request of the Texas General Land Office in response to certain questions raised concerning the proposed opening of a cut between the Brownsville Ship Channel and Bahia Grande on the Rio Grande delta, Cameron County, Texas (fig. 1). Local interests have suggested that flooding Bahia Grande, according to provisions in State Senate Bill 28, would (1) return the environment to a saltwater wetland similar to its condition before a series of human alterations blocked the flow of saltwater into Bahia Grande, (2) increase biological productivity of the area, which in turn would increase commercial fisheries and improve the local economy, and (3) reduce the dust that blows onto nearby communities such as Laguna Vista. Despite these compelling reasons for flooding Bahia Grande, questions have been raised regarding: (1) the areal extent of inundation, (2) the effects of inundation on storm flooding of adjacent areas, and (3) the requirements needed to maintain a viable wetland habitat. The following report was organized to address these questions. In addition, the report briefly describes the geological origin of Bahia Grande, summarizes the important historical events that altered the area, examines the characteristics of adjacent flooded areas (San Martin Lake), and discusses anticipated effects of the proposed flooding of Bahia Grande.Bureau of Economic Geolog

Physical Attributes of Sand Bodies Within High-Frequency Stratigraphic Sequences

Recently, the stratigraphic concepts of genetic depositional systems (Fisher and McGowen, 1967), systems tracts (Brown and Fisher, 1977), genetic sequences (Frazier, 1974; Galloway, 1989), and seismic sequences (Vail et al., 1977) have been modified and merged to gain a better understanding of the stratal relationships and spatial distribution of both elastic and carbonate sediments using sequence stratigraphic models (Posamentier et al., 1988). These broad conceptual models have primarily been used to analyze the thick fill of sedimentary basins on passive continental margins and to develop regional stratigraphic frameworks emphasizing the global influence of eustatic sea-level fluctuations. Analytical techniques are just now being developed to combine the mapping of seismic sequences with borehole data (electric logs, sediment velocities, and sediment bulk densities) so that lithologies can be predicted within depositional sequences and potential reservoir-quality sand can be located relative to sequence boundaries. Correctly interpreting the presence or absence of sand in elastic depositional sequences on the basis of seismic response represents a key element to sequence stratigraphic studies. These concepts are especially important in offshore or other frontier exploration areas far removed from outcrops or other geological information that would allow forward prediction of subsurface lithologies. Geophysicists using conventional common-depth-point (CDP) data are able to derive general lithologic properties from relative impedance and seismic velocity (Savit and Wu, 1982). Although these derivation techniques are constantly being improved, the pre-drilling prediction of lithologies still relies heavily on seismic facies interpretations as well as a general understanding of sedimentary processes and geological history of the basin fill.Bureau of Economic Geolog

Recent Rates of Shoreline Erosion at Sargent Beach Matagorda County, Texas

The Gulf shoreline at Sargent Beach, Texas, is the most rapidly eroding open coast shoreline in the State and one of the most rapidly retreating beaches in the Gulf of Mexico. Because the Gulf Intracoastal Waterway (GIWW) is so close to the Gulf shoreline along this ten-mile coastal segment, continued erosion will breach the Waterway in the near future and preclude navigation through the GIWW unless preventive action is taken. Protecting the Waterway is of paramount importance considering the large negative economic impacts that would occur if the Waterway were even temporarily closed. A study was conducted to determine the recent rates of erosion at Sargent Beach and to evaluate the factors that control erosion of this beach. Results of the study demonstrate that erosion at Sargent Beach accelerated after 1930, and recent rates of erosion generally are consistent with the higher rates recorded after 1930. Erosion rates increase from northeast to southwest, and the highest erosion rates since 1965 consistently occur in the developed area east and west of State Road 457. Within this segment of rapid beach erosion, the highest measured rates between 1987 and 1991 ranged from 51.6 to 67.3 ft/yr, where the Gulf shoreline intercepted a dredged canal and encountered a former artificial inlet between the Gulf and the GIWW. Since 1974, the width of land between the high water line of the Gulf of Mexico and the south bank of the GIWW has rapidly decreased at some sites as a result of both beach erosion and bank erosion along the GIWW. Recent rates of beach erosion along the Gulf shoreline have depended on storm frequency and intensity as well as on changes in the volume of sediment transported by waves and currents in the Gulf of Mexico. Future erosion rates will probably be similar to the most recent rates unless a major hurricane strikes the area causing a rapid increase in erosion or the sand supply is altered by human activities. Placing sand directly on the beach (beach nourishment) or bypassing sand around the San Bernard River would likely reduce erosion at Sargent Beach, whereas interception of the littoral material by dredging at the San Bernard River mouth or by placing structures perpendicular to the Gulf shoreline would prevent sand from reaching the downdrift coastal segment and would increase erosion at Sargent Beach.Bureau of Economic Geolog