Geology Commons^™

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 …

Geology And Ore Deposits Of The Southwest Nacimiento Range, Sandoval County, New Mexico, Otto L. Schumacher

Earth and Planetary Sciences ETDs

The mapped area is in Sandoval County, New Mexico, 4 miles east of La Ventana. Precambrian rocks in the core of the Nacimiento uplift in this area consist mainly of quartz monzonite gneiss which has been intruded by granite. Hornblende schist xenoliths, zones of sheared quartz-plagioclase schistose gneiss, and mafic and leucocratic dike rocks are less abundant. Strata totaling 6200 feet, ranging from the Pennsylvanian Madera Formation through the Cretaceous Mancos Formation, are exposed in the area. Overlying the marine Madera Formation is 3400 feet of continental, marginal marine, and evaporite deposits consisting in ascending order of the Permian Abo, …

Structural Geology Of The Northern Part Of The East Helena Quadrangle, Lewis And Clark County, Montana., Jon A. Durham

Earth and Planetary Sciences ETDs

The map-area is located along the northwest flank of the Big Belt Mountains, Montana and includes the Eldorado thrust which marks the zone of frontal breakthrough where thrusts of the Cordilleran foldbelt are in contact with the Rocky Mountain foreland. Sedimentary rocks range in age from Precambrian to Cretaceous. Two formations of the Precambrian Belt Series, the Greyson Shale (Oldest) and Spokane Shale are present. Overlaying the Spokane Shale are five formations of the Cambrian; Flathead Quartzite (oldest), Wolsey Shale, Meagher Limestone, Park Shale, and Pilgrim Limestone. Their total aggregate thickness is about 1200 feet.

A Geochemical Study Of Distribution Of Elements In Ores And Limestones From New Jersey Zinc Mines, Hanover, New Mexico, Dasharatham Sayala

Earth and Planetary Sciences ETDs

Limestone samples (424) from both surface and subsurface horizons in the New Jersey Zinc mines at Hanover have been analyzed by atomic absorption spectrophotometry for Ag, Cd, Mn, Pb, Zn, Cu and Sn. The lead­zinc ore bodies, occurring in Paleozoic limestones are a typical example of hydrothermal deposits; and are related to the Hanover intrusive. The distribution of trace elements in surface limestones was mainly due to primary dispersion, partly due to secondary dispersion. The depth of ore mineralization, concentration of element in ore solutions, porosity of limestones, diffusion coefficients of element, and the chemical nature of elements in the …

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 And Stratigraphy Of The Florida Mountains, Luna County, New Mexico., Lonnie Leroy Corbitt

Earth and Planetary Sciences ETDs

Precambrian rocks in the Florida Mountains have a long and complex history of orogeny and epeirogeny. The oldest recorded event is regional metamorphism (amphibolite facies) of sedimentary and igneous rocks which are intruded by granite. Following a long period of erosion, diamictite was deposited on a deeply weathered surface of igneous and metamorphic rocks.

At least 3,000 feet of Paleozoic strata is preserved above the Precambrian rock1s. The Paleozoic strata are mostly shelf carbonates; the Bliss Formation and the Devonian Percha Shale are the only major Paleozoic elastic units present. From Cambrian through Mississippian time the Florida Mountains area was …

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 …