Geology Commons^™

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 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 …

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 …

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 …

An Experimental Investigation Of Highly Undercooled Magnesium Silicate Chondrule-Like Spherules, Harry Nicholas Planner

Earth and Planetary Sciences ETDs

A series of experiments, involving molten magnesium silicate spherules that were subjected to high initial cooling rates and allowed to nucleate at high temperatures (985-1350°C), were performed so as to compare their thermal histories to the resulting internal features. Such comparisons could be used to decipher the thermal history of chondrules and the conditions surrounding their formation based on their mineralogy, crystal morphology, and overall texture. Various features of the spherules were correlated with the initial high cooling rate process, nucleation temperature, and the maximum temperature attained during the recalescance to demonstrate the restrictions resulting from or their sensitivities to …

Unusual Lavas From Molokai, Hawaii: Alkalic Olivine Basalts Transitional To Hawaiites And Strontium-Rich Mugearites, Paul Frank Hlava

Earth and Planetary Sciences ETDs

ABSTRACT

Systematic data has recently been published on the compositions of major mineral phases in rocks of the tholeiitic, alkalic, and nephelinic suites from the island of Maui, Hawaii. The present study was initiated to provide similar data from the rocks of Molokai, Hawaii, from which the nature of interisland variations could be established. During the study, it became obvious that many of the rocks were unusual and so this study also provides information on the bulk rock, trace element, and mineral compositions of alkalic olivine basalts transitional to hawaiites and Sr-rich mugearites.

From a total of 14 basalts collected …

Geology Of The Northern Part Of The Sierra Cuchillo, Socorro And Sierra Counties, New Mexico, Florian Maldonado

Earth and Planetary Sciences ETDs

The northern Sierra Cuchillo, Socorro and Sierra Counties, New Mexico is approximately 32 miles northwest of Truth or Consequences, New Mexico. The Sierra Cuchillo is a narrow fault-block range in the Basin-Range province and is a structurally high element west of the Rio Grande trough. It is bordered on the west by the Winston graben and the Black Range and on the east by Monticello graben and the San Mateo Mountains.

Permian rocks consist of the Yeso and San Andres Formation, with an aggregate thickness of 2100 ft (640 m). Upper Cretaceous rocks, 40 ft (10 m) thick, consist of …

Growth Line Analysis Of A Recent Scallop Population And It's [Sic] Potential For Paleoecology, John F. Dillon

Earth and Planetary Sciences ETDs

Periodic growth lines can be used to construct a record of variations in the growth rate of a fossil or recent shell. Because growth rate is largely dependent upon environmental conditions, such a record serves also as an indication of variations in the environment during the lifetime of the shell. Although the very presence of such variations is of some paleoecologic interest, the main potential of growth lines in paleoecology lies in an extension of this argument. This is the concept that the contemporaneity of fossil organisms could be tested by examining their growth rate records for similarities; these would …

A Petrologic And Quantitative Compositional Study Of Four Rocks From The Mid-Atlantic Ridge, Jonathan A. Green

Earth and Planetary Sciences ETDs

The composition of major mineral phases in four rocks from the equatorial Mid-Atlantic Ridge, as determined by electron microprobe analysis and supplemented by additional mineralogic and petrographic study, have provided data for comparison with continental mafic assemblages. The compositional range of coexisting minerals in the samples: a nepheline-normative gabbro (teschenite), an olivine tholeiite, and two uralitized norites, is similar to the ranges of comparable continental suites. The teschenite contains pyroxene (Wo_48-46 En_37-23Fs_15-31) with high amounts of CaO (20.3-22.2 wt %), Al₂O₃ (2.9-6.8 wt. %), and Ti02 (1.2-2.9 wt. %) characteristic of continental …

Geology Of The White Oaks Mining District Lincoln County, New Mexico, James R. Grainger

Earth and Planetary Sciences ETDs

The White Oaks mining district is 12 km northeast of Carrizozo, in Lincoln County, New Mexico. Hydrothermal gold and tungsten mineralization occurs in north-trending veins and breccia zones in portions of the central district. Permian sandstones, limestones, and gypsum of the San Andres Formation are upwarped marginal to and by the Lone Mountain intrusive in the northwest portion of the map area. Triassic Santa Rosa and Chinle sandstones and shales are inclined to the south with Cretaceous Dakota, Mancos, and Mesaverde sediments. Approximately 640 m of sedimentary strata is exposed in the district.

Igneous rocks in the map area range …

Structure And Stratigraphy Of The Central Cimarron Range, Colfax County, New Mexico., Craig S. Goodknight

Earth and Planetary Sciences ETDs

The Cimarron Range forms a southeastern extension of the southern Sangre de Cristo Mountains. The area mapped in this study lies mainly between Eagle Nest and Ute Park, New Mexico, and is centered around Cimarron Canyon.

Rocks ranging from Precambrian to Quaternary in age are exposed• - in the central Cimarron Range. Precambrian rocks in the core of the range consist mainly of moderately foliated, low- to medium-grade metamorphics intruded by faintly foliated bodies of meta-granodiorite and meta-diabase.

Approximately 4000 feet of sedimentary rocks ranging from the Sangre de Cristo Formation of Pennsylvanian-Permian age through the Poison Canyon Formation of …

Structure And Stratigraphy Of The San Ysidro Quadrangle, Sandoval County, New Mexico, Richard Luverne Ruetschilling

Earth and Planetary Sciences ETDs

The mapped area is in Sandoval County, New Mexico, and includes the San Ysidro 7-minute quadrangle. Precambrian rocks in the area consist mainly of quartz monzonite gneiss. Quartz diorite xenoliths and leucocratic dike rocks are less abundant.

Strata totaling 1300 meters, ranging from Morrow-age strata of Pennsylvanian age through the Zia Sand Formation of Miocene age, are exposed in area (fig. 3). Overlying the marine Pennsylvanian Morrow-age strata and Madera Formation is 900 meters of continental, marginal marine, and evaporite deposits consisting, in ascending order, of the Permian Abo Yeso, Glorieta, San Andres and Bernal Formations, the Chinle Formation of …

A Test Of The Non-Uniform Distribution Of Azimuths Of Overlapping Lunar Craters, John Richard Dickson

Earth and Planetary Sciences ETDs

The azimuths between the centers of overlapping lunar craters show a statistically strong preferred orientation over most of the lunar globe for those crater pairs where the younger crater is of relatively small diameter (10-25 km). A strong north-south preferred lineation also exists in a narrow belt along the east and northern limb of the full moon for those crater pairs involving relatively large diameter craters (45 km). Various endogenic and exogenic mechanisms which might create a preferred orientation of overlapping craters are considered in the light of these findings. The preferred orientation of the smaller craters could result from …

The Chemistry Of Groundwaters In The Jemez Area And A Magnetic Survey Of A Potential Source Of Magmatic Fluids, David Woltz

Earth and Planetary Sciences ETDs

The Jemez Mountain area of north-central New Mexico has a geologic history of intense volcanism. Active geologically related phenomena are still present in the form of hot springs and fumaroles. This thesis undertook a study of the concentration of the elements Calcium, Chlorine, Fluorine, Magnesium and Sodium, and the compound Silicon Dioxide in the groundwaters of the Jemez Mountains. The concentrations in some of the waters indicate that they may possess magmatic components. A ground magnetic survey was undertaken to investigate the possibility of intrusions in the area. Data gathered in the survey has been interpreted as an intrusion at …

Petrology And Geochemistry Of Varved Halite Ii Member, Permian Castile Formation, Delaware Basin, Texas And New Mexico, Saleh Mohammad Billo

Earth and Planetary Sciences ETDs

The Halite II Member of the Permian Castile Formation in the Delaware Basin of Texas and New Mexico constitutes a 1778-year record of evaporite laminations. They are composed of rhythmic halite-anhydrite layers interrupted by four distinct carbonate-laminated beds of anhydrite. The average thickness of the varves is 2.3 cm for the halite-anhydrite couplets and 3.9 mm for the carbonate-laminated anhydrite couplets. They are correlative over distances of 70 miles (113 km). Halite occurs either as hopper crystals, grains, or as compact masses with many inclusions, bubbles, and vacuoles. Matrix crystals, rectangular crystals, nodules, and laths are the main petrographic types …

A Study Of Trace Metal Concentrations In Two Species Of Mytilus Along The Pacific Coast Of The United States., George Harry Fullas

Earth and Planetary Sciences ETDs

An investigation of iron, zinc, copper, and cadmium concentrations in Mytilus californianus and Mytilus edulis was conducted on specimens collected along the west coast of the United States. Animals and sea water were collected at six different areas and analyzed using an Atomic Absorption Spectrophotometer. Trace metal concentrations in the animals were influenced by the collection conditions of age, species, temperature, pollution, and metal relationships. Younger animals, of both species, contained higher concentrations of all the metals. Larger, or older animals, contained the smallest metal concentrations. Copper concentrations in the animals were higher in sea water with high copper content. …

Geology Of The Country East Of The Santa Rita Mining District, Grant County, New Mexico: The San Lorenzo Area, Raymond S. Lambert Jr.

Earth and Planetary Sciences ETDs

The settlement of San Lorenzo is approximately 19 miles east of Silver City, New Mexico. The area consists of rolling hills, relatively steep slopes and the broad Mimbres River Valley. The land surface reflects partial erosion of Basin and Range fault blocks. The maximtun elevation is 7,170 feet, with relief of 1,400 feet.

The main structural feature is a northwest trending mountain range, which is a west-southwest-dipping fault block bounded on the northeast by the Mimbres fault. Vertical displacement ranges from 150 meters (500 feet) to 1,200 meters (4,000 feet). Rocks exposed along the steep northeastern escarpment range in age …

Gravity Survey Of The Mogolion Plateau Volcanic Province, Southwestern New Mexico., Douglas Hugh Krohn

Earth and Planetary Sciences ETDs

A regional gravity survey has been conducted over the Mogollon Plateau, a mid-Tertiary volcano-tectonic complex 125 km in diameter located in southwestern New Mexico. The complete Bouguer gravity map (3 milligal contour interval) shows gravity values ranging form -167 milligals over an outcrop of Precambrian rocks near Silver City, on the southern rim of the Plateau to -251 milligals over an alluvium filled graben east of Reserve, in the northwestern part of the Plateau giving a maximum relief of 84 milligals. Gravity data show that in general the Mogollon Plateau is an area of low density rocks: gravity values within …

The Dacites Of The Washakie Needles, Bunsen Peak, And The Birch Hills, Wyoming, And Their Relationship To The Absaroka-Gallatin Volcanic Province, Linda Lou Anderson Love

Earth and Planetary Sciences ETDs

ABSTRACT

TI1e Washakie Needles, Bunsen Peak, and Birch Hills dacites are three of many plugs which intrude the Eocene flows and volcaniclastic rocks of the Absaroka-Gallatin volcanic province. The dacites contain phenocrysts of plagioclase (oligoclase to andesine), biotite, and resorbed quartz. The dacites of the Washakie Needles and Bunsen Peak also contain phenocrysts of hornblende. The rocks of Bunsen Peak and the Birch Hills have two feldspar phases (oligoclase to andesine and sanidine) and quartz in the groundmass. The Washakie Needles dacite groundmass is composed of one feldspar (andesine to anorthoclase) and quartz. The fission track ages of the dacites …