The Geology of Palo Alto Battlefield National Historical Park, Texas

Palo Alto Battlefield National Historical Park lies near the U.S.–Mexico border, just north of downtown Brownsville in Cameron County, Texas. The National Park Service's Geodiversity Atlas, drawn from its Geologic Resources Inventory, summarizes the park's rocks, landforms and soils for education, geoconservation and management.

The park

First authorized as Palo Alto Battlefield National Historic Site on November 10, 1978, it became a national historical park on March 30, 2009. Its approximately 1,392 hectares (3,442 acres) form two units — Palo Alto Battlefield and Resaca de la Palma Battlefield — marking the first two battles of the U.S.-Mexican War (1846–1848).

Those opening battles grew out of territorial disputes and set American troops under General Zachary Taylor against Mexican forces under General Mariano Arista. The war was shaped by the emerging idea of "manifest destiny," the belief that U.S. expansion across North America was both justified and inevitable. It ended with the Treaty of Guadalupe Hidalgo, under which Mexico ceded its northern territory and the United States reached the Pacific. The park interprets the fighting, its political, diplomatic and social causes, and its lasting consequences for both countries.

A trail through the chaparral. NPS.

Built by the Rio Grande

The park sits in the Coastal Plain physiographic province of southeast Texas, a geologically young region of gently sloping Cenozoic sediments, and shares its history and some characteristic formations with the wider province. Its geology is bound up with the Rio Grande, which over the last 8 million years has built a broad, meandering floodplain of abandoned channels — resacas, or oxbow lakes — together with terraces and levees.

The park's Geologic Resources Inventory geologic map. NPS.

Maps and inventories

The Geologic Resources Inventory produces digital geologic maps and reports for more than 270 natural resource parks: scoping summaries recording the mapping plan agreed by park staff and local geologists, GIS map data, reports on each park's setting, features, management issues and history, and posters. The park's products are in the NPS DataStore, along with a completed NPS Soil Resources Inventory.

Sources

Rewritten from the National Park Service article "NPS Geodiversity Atlas—Palo Alto Battlefield National Historical Park, Texas" (public domain), in hubnx's own words. The report cover it shows is not reproduced.