Physical Sciences and Mathematics Commons^™

Provenance Study Of The Westwater Canyon And Brushy Basin Members Of The Morrison Formation Between Gallup And Laguna, New Mexico, Ruben Martinez

Earth and Planetary Sciences ETDs

The objective of this investigation is to study the provenance of the Westwater Canyon and Brushy Basin Members of the Morrison Formation between Gallup and Laguna, New Mexico. The coarse, subarkosic Westwater Canyon Member is separated from the quartzitic sandstones of the underlying Recapture Member by an unconformity that provides a recognizable datum for correlation and a definite base for the Westwater Canyon Member.

The very pale orange, cliff-forming Westwater Canyon Member consists of Oto 137 m of very coarse- to very fine-grained, poorly sorted, subrounded to angular, arkosic to quartzitic sandstone with numerous lenses of arkosic granules and pebbles …

Petrogenesis Of Orbicular Rock, Tijeras Canyon, Sandia Mountains, New Mexico, Kathleen Affholter

Earth and Planetary Sciences ETDs

A new occurrence of orbicular rock is located in the Sandia Granite at W. long. 106° 25' 30", N. lat. 35° 04' 55" close to the granite-gneiss contact near Tijeras Canyon, Sandia Mountains, New Mexico. The orbicules, set in an aplite-pegmatite granitic matrix, have magmatic and metamorphic cores surrounded by a white plagioclase shell and one or two salmon-colored potassium feldspar shells. The outcrop occurs in two dike-like masses with thicknesses of 1 to 4 m trending N. 5° W. and N. 35° E. for exposed lengths of 16m and 46 m, and is surrounded by biotite syenodiorite and biotite …

Geology Of The Cerro Del Grant Area, Rio Arriba County, North-Central New Mexico, John Richmond Lawrence

Earth and Planetary Sciences ETDs

The present study undertook the geologic mapping and investigation of the stratigraphy, structural geology, igneous petrology and mineral resources of the Cerro del Grant area, a 75- (190 ) region near Coyote, Rio Arriba County, north-central New Mexico. The area is situated at the junction of three geologic provinces: the Chama platform, the Española Basin of the Rio Grande rift, and Jemez volcanic field.

Sedimentary rocks include 2,500 ft (830 m) of sandstone, shale, conglomerate and limestone of Late Triassic to Quaternary age. These strata are unconformably overlain by several hundred feet of mafic, intermediate and rhyolitic lavas which make …

Rubidium-Strontium And Related Studies Of The Salado Formation, Southeastern New Mexico, Joseph K. Register Jr.

Earth and Planetary Sciences ETDs

The Salado Formation, a member of the Ochoa Series, is a bedded salt deposit which is found in the Delaware Basin southeastern New Mexico and west Texas. It is comprised primarily of halite and sylvite with minor amounts of sulfate minerals. Rubidium-strontium age determinations of the evaporite minerals in the Salado indicate an age of final equilibration of 214 15 m.y. This age is fairly consistent with the geologic age of the formation, precluding substantial alkali-alkaline earth migration since deposition. Polyhalite and anhydrite samples from the Salado give / values of about .7078, which are consistent with reported valued for …

Oxygen Isotopic Analysis Of Silicates And Oxides Using Both Bromine Pentafluoride And Fluorine Gas As Reagents, Harold Roy Northrop

Earth and Planetary Sciences ETDs

In recent years the preferred analytical procedure for the extraction of oxygen from silicates and oxides for oxygen isotope analysis has been the oxidation of the samples with either fluorine (F2) or bromine pentafluoride (BrF5) to produce oxygen. Several standards are available for monitoring the extraction procedure, and one in particular (NBS-28) is used in many laboratories. The oxygen-18 oxygen-16 ratios obtained for NBS-28 vary by as much as one permil between laboratories. The major cause of this variation lies in the extraction procedure used. Extraction of oxygen from iron bearing minerals and whole rocks (and minerals containing certain other …

Geology Of The Galisteo Formation, Hagan Basin, New Mexico, Timothy Walker Gorham

Earth and Planetary Sciences ETDs

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 …

The Geology And Blueschist Petrology Of The Western Ambler Schist Belt, Southwestern Brooks Range, Alaska, Craig Joseph Nelsen

Earth and Planetary Sciences ETDs

The western Ambler Schist Belt is located in the southern Brooks Range of Alaska and is defined in this study as that part of the Brooks Range schist belt which contains abundant bimodal volcanic, volcaniclastic and related carbonate sediments. The schist belt appears to be the basinal part of Middle Devonian through Mississippian shelf-slope-basin sequence. To the south of the schist belt are upper Paleozoic-Mesozoic (?) ophiolite overlain by Cretaceous greywackes and calc-alkalic intrusives and related extrusives. These two distinct terrains are juxtaposed along a suspected continental suture, the Angayucham-Cosmos Hills-Jade Mountain belt, on with a minimum of 115 km …

The Matrix Of Unequilibrated Ordinary Chondrites: Implications For The Origin And Subsequent History Of Chondrites, Gary Robert Huss

Earth and Planetary Sciences ETDs

The matrices of fourteen unequilibrated (type 3 and 3, 4) ordinary chondrites (all witnessed falls) were analyzed using transmitted and reflected light microscopy, electron microprobe analysis, and instrumental neutron activation analysis. The matrix is defined as the fine-grained silicate material between chondrules, chondrule fragments, other distinct silicate grains, and Fe-Ni and troilite grains. It makes up about 13 percent of each meteorite. Although all meteorites in this study have been altered to some extent since their formation, those with least alteration indicate that the unaltered matrix had submicron grain size, a clastic texture, and was friable even though interstitial pore …