Physical Sciences and Mathematics Commons^™

Precambrian Geology Of The Central Nacimiento Mountains, Sandoval County, New Mexico, Kent Richard Reed

Earth and Planetary Sciences ETDs

The oldest Precambrian rocks in the area of study are represented by abundant inclusions and schlieren of horn­blendite, plagioclase-hornblende schist, and plagioclase-­hornblende-biotite schist. These inclusions are remnants of a pre-batholithic metamorphic terrane.

The next oldest, and dominant rock in the central Nacimiento Mountains is gneiss that ranges in composition from quartz monzonite to granodiorite. Where strongly sheared, the rock is microcline-biotite-quartz-plagioclase schist. Gradational zones of schist within the gneiss were mapped separately. The gneiss and the schist are cut by metamor­phosed spessartite dikes and by leucocratic dikes of various textures and compositions.

Intruding the gneiss in the southeastern part of …

Geology Of The Rammel Mountain Area, Teton County, Wyoming, David W. Love

Earth and Planetary Sciences ETDs

The Rammel Mountain area, on the west side of the Teton Range, Wyoming, includes Precambrian metamorphic and igneous rocks; Paleozoic sandstone, shale, dolomite and limestone; and Cenozoic conglomerate, agglomerate and breccia, ash-flow tuffs and glacial deposits.

The Precambrian layered gneiss, granitic gneiss and migmatite have undergone at least two episodes of deformation and metamorphism in the sillimanite-cordierite-muscovite-almandine subfacies of the Abukuma-type facies series prior to the emplacement of quartz monzonite. Dia-base dikes, quartz-epidote and epidote veins transect these earlier rocks.

The Cambrian-Mississippian shelf-facies rocks were folded, faulted and eroded to a plain in Late Cretaceous time and were buried by …

Structure, Stratigraphy, And Ore Deposits Of The Central Nacimiento Mountains, New Mexico, William H. Kaufman

Earth and Planetary Sciences ETDs

The mapped area is in Sandoval and Rio Arriba Counties, New Mexico, 3 mi southeast of Cuba and includes the eastern margin of the San Juan Basin and the western margin of the Nacimiento Mountains. The emphasis of this report is on the stratigraphy, structure, and ore deposits of this area.

The Precambrian quartz monzonite basement rock is non-conformably overlain by approximately 6000 ft of sedimentary rocks, which range in age from Pennsylvanian to Cretaceous. The Pennsylvanian Madera Formation is predominantly marine limestone and is overlain by the clastic Permian Abo and Yeso Formations. A maximum of 1050 ft of …

Stratigraphic Analysis Of Pennsylvanian Strata In The Lucero Region Of West Central New Mexico., James L. Martin

Earth and Planetary Sciences ETDs

During Pennsylvanian time the Lucero region of west central New Mexico was located along the southeastern part of the Zuni uplift and along the western and central part of the Lucero basin. The Lucero basin is part of the broad Pennsylvanian seaway that extended north-northwestward through central New Mexico to the Paradox basin on the north and the Orogrande basin on the south. Positive elements associated with the Lucero basin were the Zuni uplift to the west, the Penasco-Uncompahgre uplifts to the northeast, the Joyita uplift. to the east,. and the Pedernal uplift farther to the east.

The Pennsylvanian strata …

Petrology And Structure Of Eastern Monte Largo Hills, New Mexico, Jan Ralph Huzarshi

Earth and Planetary Sciences ETDs

In the Monte Largo Hills in the central part of north-central New Mexico, Precambrian metamorphic and igneous rocks, Paleozoic sediments, and Tertiary intrusive and extrusive igneous rocks occur. The metamorphics consist of a series of quartzo-feldspathic gneiss, mica schist, metaquartzite, and hornblende schists. These rocks were

derived from Precambrian sediments, mostly sandstones, arkoses and impure dolomites that were subjected to amphibolite facies synkinematic metamorphism. The Precambrian alkali granite appears to have been allochthonously emplaced with evidence near the contact of the quartzofeldspathic metamorphics for a parautochthonous formation. Quartz veins and pegmatite dikes of Precambrian age are also present. The sediments …

Regressive And Transgressive Phenomena In The Gallup Sandstone In The Northwestern Part Of San Juan County, New Mexico., Francis Amrisar Kaharoeddin

Earth and Planetary Sciences ETDs

The sedimentary history of the Gallup Sandstone is studied through the field investigation and laboratory analysis of samples taken from four measured sections in the vicinity of the San Juan River and one section near the Red Rock Highway. In addition to field data, textural parameters and dolomite and glauconite content of sandstone samples are the basis for interpretations of the sedimentary history and environment of deposition of the Gallup Sandstone.

A plot of the mean grain-size and sorting along with stratigraphic sections reveals that most of the Gallup Sandstone was deposited in a regressive sea, and that the regression …

Geology Of The Hogback Mountain Area, Northern Big Belt Mountains, Montana., William L. Shaffer

Earth and Planetary Sciences ETDs

The Hogback Mountain area is located in the northern part of the Big Belt Mountains, twenty miles northeast of Helena, Montana.

Sedimentary rocks range in age from Precambrian to Recent, and have an aggregate thickness of about 16, 500 feet. The oldest stratified rocks are two conformable formations of the Precambrian Belt Series; the Newland Formation (oldest) and the Greyson Shale. These rocks have an aggregate thickness of about 10,700 feet.

Rocks of the Belt Series are unconformably overlain by about 1,200 feet of strata of Middle and Late Cambrian age separated into five conformable formation: the Flathead Sandstone (oldest), …