TEMPLATE FOR COMPILING BI-NATIONAL GEOLOGIC MAP DATASETS IN THE US-MEXICO BORDER REGION; AN EXAMPLE FROM SOUTHERN TEXAS AND NORTHERN MEXICO, US-MEXICO BORDER ENVIRONMENTAL HEALTH INITIATIVE

Compilation of new bi-national geologic map datasets from southern Texas and northern Mexico are displayed on an IMS (Internet Map Service) website for analysis and investigations of human health issues in the US-Mexico Border region. The objective of the US-Mexico Border Environmental Health Initiative is to provide earth science data within a GIS framework using an IMS to further our understanding of the linkages between the condition of the physical environment and public health issues. Initial work was in a pilot area in southernmost Texas and parts of Tamaulipas and Nuevo Leon, Mexico, but the long range project goal is to prepare bi-national datasets for the entire US-Mexico border.

We developed a methodology for compiling bi-national geologic map datasets in the pilot area by integrating existing geologic map data with remote sensing, geophysical, and geochemical data. The methodology provides a template for geologic compilation across the entire US-Mexico border area. We analyzed ASTER, Landsat 7, geologic, and geochemical data to map undelineated Quaternary deltaic flood-plain deposits of the Rio Grande in northern Mexico. A high resolution gamma-ray survey and geochemical data indicate these deposits have high concentrations of uranium in Texas, and potentially pose a radon gas hazard in populated areas along the Rio Grande. New mapping of these deposits will help to identify areas of potential radon gas hazard in Tamaulipas.

New mapping of the Pliocene Goliad Formation, and Pleistocene Lissie and Beaumont Formations was based on spectral classification of Aster images and photogeologic interpretation of false color composites. Normalized Difference Vegetation Indices (NDVI) and surface radiant temperatures derived from Landsat 7 and Aster imagery acquired during wet periods, identified soil-moisture saturated areas within the Beaumont Formation that may be potential mosquito breeding habitats and a threat for the spread of West Nile virus or other vector-borne diseases.