Earth Sciences Commons^™

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 …

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 …

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 …

Geochemistry Of Andesites And Related Rocks, Central-Northern Rio Grande Rift, New Mexico, Charles J. Zimmerman

Earth and Planetary Sciences ETDs

Similarities in the petrography, whole rock and mineral chemistries, trace element abundances, and initial Sr ratios of 1-5 MY andesitic through rhyolitic rocks erupted in the central-northern Rio Grande rift, New Mexico allow for their study as a single calc­alkalic volcanic suite. Ti-rich ferroan pargasites and pargasitic hornblendes found in some of these lavas and their inclusions indicate that hornblende is a stable phase from lower crustal/upper mantle to near-surface pressure conditions and may be important in controlling the generation and fractionation of this andesitic suite. Andesitic rocks from Cerro Tome, Cerro de Los Lunas, Cerros del Rio, and the …

Bulk Composition, Mineralogy, And Petrology Of Chondrules In Type H3 To H6 Chondrites, Gayle Elizabeth Lux

Earth and Planetary Sciences ETDs

Chondrules in thin' sections of 18 different H3 to H6 group chondrites were analyzed by 100 µm broad beam electron probe techniques. Chondrule textures, crystal, and chondrule sizes were determined microscopically. Results indicate a decrease in variance or standard deviation from chondrules of petrologic types 3 to 6 of FeO, MgO, TiO₂, MnO, K₂O, and P₂0₅ content. Mean TiO₂ and Cr₂O₃ content decrease from petrologic types 3 to 6 and mean FeO, Al₂O₃, CaO, and Na₂O increase slightly from lower to higher petrologic …

Geology And Mineralogy Of Cave Nitrates, Carol A. Hill

Earth and Planetary Sciences ETDs

ABSTRACT

Southeastern saltpeter caves have temperatures between 10-15° C and humidities between 90-99%. Saltpeter sediments are alkaline (pH= 6-9), dry and porous (moisture = 5-10 wt. %) and non-organic (low levels of compost, guano and animal remains); sediments have nitrate concentrations ranging between 0.01-4.0 wt. %, low total nitrogen (0.08-0.13 wt. %) and relatively low phosphorous (0.1-1.4 wt. %). Lixiviated cave sediments regenerate in nitrate in several years. Areal extent of cave nitrate is uniform; vertical concentration is in the top few meters of sediment. Nitrate is a minor constituent in sulfate speleothems (up to 1 wt. %). Surface and …

Petrology And Structure Of Precambrian Rocks In The Bosque Peak Quadrangle, North Manzano Mountains, Central New Mexico, Duncan L. Edwards

Earth and Planetary Sciences ETDs

Precambrian metamorphic rocks in a part of the North Manzano Mountains, New Mexico, underwent regional synkinematic greenschist facies metamorphism. Abundant green hornblende in greenstones and muscovite, chlorite, and biotite in metapelites tentatively suggest p4 kb and TC during metamorphism. The greenstones were probably derived from basic volcanic rocks; the metapelites were probably derived from shales, siltstones, clay-rich sandstones, cherts (7), and mature quartz sandstones.

The oldest exposed rocks are the Moyos metasediments, a sequence of phyllites and schistose grits that is lithologically transitional to a younger greenstone complex of mostly aphanitic greenstone with intercalated phyllites and metasiltstones and intrusive metadiorite. …

A Petrographic And Chemical Study Of Axinite And Scapolite Occurrences In The White Oaks Mining District, Lincoln County, New Mexico, Karen Ricciardi

Earth and Planetary Sciences ETDs

The purpose of this thesis is to report and discuss the chemistry and petrology of the axinite and scapolite occurrences in the White Oaks mining district, Lincoln County, New Mexico. Sampling, reconnaissance field geology, chemical analysis of rock samples, petrographic studies, and unit-cell d terminations for axinite and scapolite were completed for this investigation. The data was used to determine the conditions of formation for the axinite and scapolite.

The axinite is found in small pods, or nodules, of marble near the contact with the syenite-monzonite porphyry stock. The variety of axinite is ferroaxinite which occurs with calcite, actinolite, and …

Geology Of The Cerros Del Rio Volcanic Field, Santa Fe, Sandoval, And Los Alamos Counties, New Mexico, Jayne Christine Aubele

Earth and Planetary Sciences ETDs

The Cerros del Rio volcanic field is located about 10 km west of Santa Fe, New Mexico and southeast of the Jemez Mountains volcanic complex. The field lies on the Jemez- La Bajada constriction which separates the Española and the Albuquerque-Belen basins of the Rio Grande rift. At this point the rift is laterally offset 30 km. Approximately 180 sq km were mapped for this study. The northwestern map boundary parallels White Rock Canyon, a 300 m gorge which has been cut by the Rio Grande within the past 1 m. y. About 60 vents were discovered in the area, …

Precambrian Geology And Ore Deposits Of The Pecos Mining District, San Miguel And Santa Fe Counties, New Mexico, William Duncan Riesmeyer

Earth and Planetary Sciences ETDs

The Precambrian terrane north of Pecos, New Mexico, contains meta­volcanic and metasedimentary rocks. The subaqueous volcanic rocks are of bimodal composition (basalt-rhyolite). Volcanism was cyclic; three partial or complete cycles are exposed in the study area. A cycle con­sists of basal basalt, overlying rhyolite and a cap of banded iron form­ation. The chemical characteristics of the volcanic rocks are similar to those of several modern island arcs, suggesting the Pecos volcanic sequence may represent a portion of a similar Precambrian system.

Diverse structural elements in the study area. are related to four periods of deformation: 1) a Precambrian compressional event, …

Uranium And Other Trace Element Geochemistry On The Hopi Buttes Volcanic Province, Northeastern Arizona, Catherine E. Sullivan

Earth and Planetary Sciences ETDs

The Hope Buttes volcanic province lies on the southwestern flank of the Black Mesa Basin in northeastern Arizona. Over 200 diatremes occur in this region. The diatremes fill funnel-shaped vents with maar-craters at the surface. They were formed by phreatomagmatic eruptions along existing northwest-southeast fractures during mid-Pliocene time. Anomalous concentrations of uranium occur in at least 20 of the diatremes. The diatremes and dikes which feed them are composed of monchiquite, a feldspar-free lamprophyre containing analcite, and limburgite, a lamprophyre with or without feldspar in a glassy matrix. The presence of zeolites, serpentine, calcite filling fractures, and the high Fe …

Experimental Permeability Studies At Elevated Temperature And Pressure Of Granitic Rocks, Jared Michael Potter

Earth and Planetary Sciences ETDs

Permeability of quartz monzonite from the Los Alamos hot-dry-­rock geothermal well GT-2 was experimentally measured as a function of pressure and temperature. Permeability apparatus slightly modified from that developed by Brace and others (1968) was used in the experiments. Flow rate through the sample was measured using a transient pressure decay method. When combined with the physical characteristics of the sample and several system parameters, this flow rate yielded permeability (k). Permeability of the GT-2 rocks from depths of 8580 ft and 9522 ft behaves like Westerly granite for changes in effective confining pressure. However permeability of these rocks behaves …

A Petrochemical Characterization Of Certain Dsdp Subaqueous Basalts And Andesites From The Indian Ocean, John Lee Berkley

Earth and Planetary Sciences ETDs

Thirty-eight samples of Indian Ocean subaqueous basalt and andesite recovered by the Deep-Sea Drilling Program (DSDP) were analyzed by the following methods: (1) standard petrographic analysis, (2) electron microprobe analysis of major minerals, (3) bulk-rock analyses for major, minor, and trace elements, including eight rare earth elements (REE), and (4) determination of 87Sr/86Sr by mass spectroscopy. A varied suite of basement igneous rocks was studied, including (1) abyssal tholeiites, (2) ferrobasalts, (3) oceanic andesites, (4) transitional basalts (high-Al basalts), and (5) trachybasalts.

Texture, Fabric And Composition Of Fine-Grained Terrigenous Sediments From The Graneros Member Of The Mancos Shale, San Juan Basin, New Mexico, Anthony J. Skeryanc

Earth and Planetary Sciences ETDs

Petrography, scanning electron microscopy (SEM), porosity and permeability, radiography, x-ray diffraction (clay mineralogy), whole rock wet chemistry and organic analysis are used to examine the texture, fabric and composition of fine-grained terrigenous sediments from the Graneros Member of the Mancos Shale, San Juan Basin, New Mexico. Grain content is highly variable and determines the configuration of the fabric during compaction. A scale of the degree of parallel orientation is compared to grain content and reveals a decrease in parallelism with an increase in grain content. Grain content also affects permeability, thus controlling he degree of authigenic mineralization. Although clay composition …

Mineralogy, Petrology, And Geochemistry Of Some Lavas From Kohala Volcano, Hawaii, Steven Sherman Sibray

Earth and Planetary Sciences ETDs

Twelve samples from Kohala volcano, Hawaii, were selected for chemical analyses and electron microprobe study. Seven of the samples are from the Polulu volcanic series. Three of the samples are tholeiitic basalts, two are oceanites, and two are alkali olivine basalts transitional to hawaiite. The five samples from the Hawi volcanic series include one hawaiite, two mugearites, and two benmoreites. Electron microprobe study of the minerals in the basaltic matrix of the two oceanites reveal that one of the oceanites was derived from a tholeiitic magma while the other was derived from an alkalic magma. The alkalic oceanite matrix is …

Mineralogy, Petrology, And Geochemistry Of Some Lavas From Kohala Volcano, Hawaii, Steven Sherman Sibray

Earth and Planetary Sciences ETDs

Twelve samples from Kohala volcano, Hawaii were selected for chemical analyses and electron microprobe study. Seven of the samples are from the Pololu volcanic series. Three of these samples are tholeiitic basalts, two are oceanites, and two are alkali olivine basalts transitional to hawaiite. The five samples from the Hawi volcanic series include one hawaiite, two mugearites, and two benmoreites. Electron microprobe study of the minerals in the basaltic matrix of the two oceanites reveal that one of the oceanites was derived from a tholeiitic magma while the other was derived from an alkalic magma. The alkalic oceanite matrix is …

On The Electrical Evaluation Of Three Southern New Mexico Geothermal Areas, Christian Smith

Earth and Planetary Sciences ETDs

Three electrical resistivity exploration programs have been made at areas of known but unassessed geothermal resources in the Rio Grande rift and Basin and Range province of southern New Mexico: Radium Springs Known Geothermal Resource Area (KGRA), Las Alturas Estates, and Lightning Dock KGRA. The experiments are the framework for a thorough reconnaissance electrical evaluation of these geothermal resource areas. A preliminary experiment was made at Rio Rancho Estates, near Albuquerque, in order to evaluate the applicability and resolution of electrical methods in an area of known subsurface geology within the Rio Grande rift. The interpreted depth to electrical basement, …

Petrology And Geochemistry Of Shonkinite, Syenodiorite, And Nepheline Monzonite Of The Island Of Kauai, Hawaii, Henry Gassaway Brown Iv

Earth and Planetary Sciences ETDs

Boulders of shonkinite, syenodiorite, and nepheline monzoni te occur on Kauai, Hawaii. Boulders of shonkinite and syenodiorite outcrop 1 mile north of Kalaheo and nepheline monzonite boulders have been found in Wailooa Canyon along Koaie and Waialae streams. Detailed petrographic and bulk-rock and mineral geochemical study of samples collected from each locality suggest crystallization in supercooled nephelinic magmas. Shonkinite probably formed after a moderate degree of supercooling, syenodiorite after a high degree of supercooling, and nepheline monzonite after minimal supercooling. Shonkinite, syenodiorite, and nepheline monzonite probably crystallized in hypabyssal magma chambers beneath vents for Koloa Volcanic Group lavas.

Shonkinite formed …

Alkali Basalt-Trachyte Suite And Volcanism, Northern Part Of The Mount Taylor Volcanic Field, New Mexico, L. S. Crumpler

Earth and Planetary Sciences ETDs

This report is the result of detailed mapping of a part of the northern Mount Taylor volcanic field of west-central New Mexico. More than 100 volcanic vents were mapped, including 8 maars, 5 pit craters, and 15 distinct trachyte flow domes. Three successive periods of volcanism were identified: (1) Tapia stage (pre-Mount Taylor, 3.26^± .20 m.y.): an alkali basalt-trachyte suite, identified here for the first time on the North American continent; includes basanitoid, hawaiite, mugearite, benmorite and trachyte. Of these, the trachyte is the most voluminous (about 3 km³), the basanitoid and hawaiite (''early basalt") the least …

Geologic Factors Influencing Speleogenesis In The Capitan Reef Complex, New Mexico And Texas, David Henry Jagnow

Earth and Planetary Sciences ETDs

The purpose of this thesis is to determine the geologic factors that have influenced speleogenesis (origin of caves) in the Capitan reef complex (Permian) exposed along the northeast prong of the Guadalupe Mountains of New Mexico and Texas. This study of 52 caves included mapping caves, joints, and cross sections, determining stratigraphic position, generating joint rose diagrams, and photographing the geologic and hydrologic controls on speleogenesis.

Most Guadalupe caves are strongly controlled by vertical joints that parallel or are nearly perpendicular to the reef escarpment. East of Rattlesnake Canyon, caves generally develop along joint swarms that parallel the reef escarpment; …

The Geology Of The San Antonio Mountain Area, Tres Piedras, Taos And Rio Arriba Counties, New Mexico, Dean Eppler

Earth and Planetary Sciences ETDs

The San Antonio Mountain area is late Tertiary to early Quaternary volcanic terrane on the western edge of the San Luis Basin in the Rio Grande depression.

Calc-alkalic rocks are interlayered with flows of the Servilletta Basalt (Butler, 1946) and consist of a series of early basaltic rocks (Wissmath Craters basalt, basaltic andesites of Los Cerritos de la Cruz, Red Hill, Malette Creek), intermediate age basaltic andesite, andesite and latite of the San Antonio Mountain Volcanic Complex and late basalt of the Piñabetoso Peaks.

Data suggests that the volcanic rocks of the San Antonio Mountain area evolved from two magmas. …

The Geology Of The Caballo Peak Quadrangle, Sierra County, New Mexico, James Trimble Mason

Earth and Planetary Sciences ETDs

The Caballo uplift, along the east side of the southern end of the Rio Grande depression, is comprised of rocks which range in age from Precambrian to Recent. The northern Caballo Mountains do not contain rocks of Silurian, Devonian, Mississippian, Triassic, Jurassic, or Lower Cretaceous ages. The Precambrian rocks consist mainly of granite which encloses small rounded bodies (possibly roof pendants) of biotite-hornblende gneiss and schist, granitic gneiss, and metasediments. The Lower Paleozoic is comprised of the Cambro-Ordovician Bliss Formation, the Ordovician El Paso Group, and the Ordovician Montoya Group. These marine sediments are overlain unconformably by the Pennsylvanian Magdalena …

Geology Of The Apache No. 2 Mining District Hidalgo County, New Mexico, Stephen L. Peterson

Earth and Planetary Sciences ETDs

The Apache Hills, 10 km south of Hachita, New Mexico are a WNW-trending series of low hills, approximately 12 km long.

The rocks range in age from Paleozoic to Holocene. Limestone and sandstone of the Lower Cretaceous U-Bar and Mojado Formations are overlain by a thrust plate of Paleozoic limestone. The Oligocene Chapo Formation (new name) overlies the thrust plate uncomformably. The Formation is over 1,700 m thick and ranges in composition from rhyolite to basalt. The sedimentary and volcanic rocks have been intruded by several igneous rock types, the most prominent of which is a stock of quartz monzonite …

Geology Of The Datil Area, Catron County, New Mexico, David A. Lopez

Earth and Planetary Sciences ETDs

The Datil Mountains, Catron County, New Mexico, are an uplifted fault-block located along the northwestern margin of the San Augustin Plains, a Basin and Range structural basin.

No pre-Tertiary rocks occur in the study-area. All of the volcanic rocks are probably Oligocene in age, although the base of the lowest unit may be late Eocene. The oldest rocks belong to the Spears Formation and are divided into three members: A lower unit composed of andesite breccia flows and interbedded volcaniclastic conglomerate, 700+ ft (220+m); a feldspathic volcaniclastic sandstone, 100 ft (30 m); and upper porphyritic andesite flow rock, 100 ft …

Geology And Ore Deposits Of The Blackbird District Lemhi County, Idaho, Gary Lynn Purdue

Earth and Planetary Sciences ETDs

This report is a supplement to the Geologic Map of the Blackbird district which forms the southeast quadrant of the 15-minute Blackbird Mountain quadrangle, located in the Salmon River Mountains in Lemhi County, east central Idaho. Ore deposits in the district were developed during the first half of the twentieth century, but mining has been hampered by low-grade ores and the small size of the mineralized zones.

Outcrops are poor in the district because of heavy soil cover and talus slopes. Precambrian sedimentary rocks are part of the Belt Supergroup and have been divided into nine units. Precambrian units mapped …

Major And Minor Element Contents Of Coexisting Olivine, Orthopyroxene, And Clinopyroxene In Ordinary Chondritic Meteorites, Frederick D. Busche

Earth and Planetary Sciences ETDs

The chemical compositions of coexisting olivine, orthopyroxene, and clinopyroxene from 50 ordinary chondritic meteorites are presented. The elements, determined by the electron microprobe x-ray analyzer, are Fe, Ca, Mg, Cr and Mn in olivine, and Fe, Ca, Mg, Cr, Mn, Ti and Al in orthopyroxene and clinopyroxene. A method was developed to determine minor elements as low as 50 ppm with a calculated relative error of only +-5% of the amounts present. These data and the calculated Kd2 values were run through the social sciences multivariate analysis program to obtain correlations that would be useful in the classification of meteorites. …

Evaporite Deposits Of The Central Namib Desert, Namibiba, Fred R. Cagle Jr.

Earth and Planetary Sciences ETDs

The extensive evaporite deposits of the Namib desert occur in an area bounded by the Ugab River on the north and the Kuiseb River on the south. Smaller deposits which are concentrated on the coast occur north and south of these boundaries. The deposits occur as a blanket deposit up to 20 feet (6.1 meters) in thickness and extend inland for a distance of approximately 55 miles (90 km) and extend 110 miles (176 km) between the northern and southern boundaries. The deposits are composed mainly of gypsite, but there are two locations where anhydrite is the predominant form present. …

Geochemistry And Petrology Of The Orbicular Rocks, Sandia Mountains, New Mexico, Robert David Enz

Earth and Planetary Sciences ETDs

Orbicular rock located on the west side of the Sandia Mountains, New Mexico, at W. long. 106° 29' 30", N. lat. 35° 13' 04", was first reported by Fitzsimmons (1966). Recently Thompson and Giles (1974) published a paper describing.three types of orbicular rock in the locality which they believed to have been formed by a metasomatic process. Without knowledge of the work of Thompson and Giles, this thesis was initiated as a detailed field, petrographic, geochemical and geochronologic study of these orbicular rocks.

Four types of orbicular rock, including another previously unreported occurrence of orbicular granite about 2 km north …