Earth and Planetary Sciences ETDs

Publication Date

5-1979

Abstract

In north-central New Mexico the Hagan basin contains the thickest (261 to 1,295 m) and least deformed section of the Eocene Galisteo Formation. The Galisteo unconformably overlies sandstone and carbonaceous shale of the Mesaverde Group (Upper Cretaceous) and provides a record of late Laramide (Eocene) tectonics in this part of the Rocky Mountains.

The Galisteo Formation contains a complex fluvial sequence of abundant red to green mudstone, with varying amounts of red to white laterally continuous and discontinuous sandstone, and buff to white conglomeratic sandstone. Sedimentary structures and facies relationships in seven coarse-grained Galisteo members indicate that the Galisteo Formation was deposited mainly by high and low energy, braided, and low sinuosity meandering streams. Paleocurrent, petrographic, and facies studies indicate that lower Galisteo sandstone was deposited by low sinuosity meandering streams flowing toward the south and southwest. These streams transported medium-to coarse-grained, pebbly, arkosic sand and some reworked Cretaceous detritus derived from a combination of granitic, metamorphic, and sedimentary sources. Middle Galisteo sandstone and red mudstone suggest a major change in provenance with high energy, southeast­flowing streams that transported coarse conglomeratic material derived mainly from sedimentary sources. Upper Galisteo sandstone was deposited in a lower energy environment, characterized by southwest flowing, meandering streams that transported red mud and medium-grained arkosic detritus.

Comparison with the early Tertiary sedimentary record in the San Juan Basin suggests that the emergence of the Nacimiento uplift in early Eocene time coincided with deposition of the Galisteo Formation; however, lower Galisteo sediments were derived primarily from the Brazos-Sangre de Cristo uplift to the north and northeast. Middle Galisteo conglomeratic sandstone suggests that the Nacimiento uplift had emerged as a major Galisteo source area by this time. By late Galisteo time continued uplift along the two southern prongs of the southern Rocky Mountain (i.e., Nacimiento and Brazos-Sangre de Cristo uplifts) resulted in a shallow elongate structural basin between the two uplifts; this basin probably included the present-day Galisteo Basin and Chama Basin to the north. At the close of Galisteo time physiographic relief of the region was probably low, as arkosic sediments lapped onto eroded source areas. In latest Eocene or early Oligocene time the gradual introduction of volcaniclastics signaled the end of Galisteo deposition. This was followed by significant volcanic activity in the area and the deposition of the Espinaso Formation.

Degree Name

Earth and Planetary Sciences

Level of Degree

Masters

Department Name

Department of Earth and Planetary Sciences

First Committee Member (Chair)

Raymond V. Ingersoll

Second Committee Member

Stephen G. Wells

Third Committee Member

Lee A. Woodward

Language

English

Document Type

Thesis

Download

Included in

Geology Commons

Share

COinS