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Articles 211 - 240 of 325
Full-Text Articles in Geology
Structure And Stratigraphy Of The Northern Part Of The South Virgin Mountains, Clark County, Nevada, J. R. Morgan
Structure And Stratigraphy Of The Northern Part Of The South Virgin Mountains, Clark County, Nevada, J. R. Morgan
Earth and Planetary Sciences ETDs
The northern part of the South Virgin Mountains is within the transition zone between the Basin and Range Province and the High Plateaus of the Colorado Plateau. Sedimentary formations in the Paleozoic are represented by more than 6,800 feet of carbonate and elastic sediments. Ordovician rocks are thought to be present, but are not confirmed. Rocks of Silurian age are absent from the area. Triassic and Jurassic units, the Moenkopi Formation, Chinle Formation and the Aztec Sandstone, have a composite thickness of more than 3,700 feet. There are elastic and minor carbonate rocks, all of continental origin, that are of …
Criteria For The Determination Of Flow Direction In Volcanic Rocks, Eugene Irwin Smith
Criteria For The Determination Of Flow Direction In Volcanic Rocks, Eugene Irwin Smith
Earth and Planetary Sciences ETDs
A statistical method employing the Tukey Chi-square test and the vector method was used for determining the direction of primary flow lineation in volcanic rocks. Oriented samples were collected from the McCartys Basalt, the porphyritic andesite of Mount Taylor and the Bandelier and Battleship Rock Rhyolite Tuffs of the Jemez Mountains. All these localities are in New Mexico. Measurements were taken of the elongate particles in each horizontal thin section. The flow lineation direction in each slide was determined statistically by computing values of vector mean or chi-square orientation. The McCartys flow samples showed the lowest reliability. This was probably …
A Petrochemical Study Of Compositionally Zoned Ash-Flow Tuffs, David L. Giles
A Petrochemical Study Of Compositionally Zoned Ash-Flow Tuffs, David L. Giles
Earth and Planetary Sciences ETDs
Vertical compositional zoning occurs within the basal simple cooling units of two welded ash-flow tuff sheets, the Kneeling Nun and Caballo Blanco formations, in the Cobre Mountains of southwestern New Mexico. The sheets are on the southern edge of the Datil-Mogollon volcanic province. The Kneeling Nun (33.4 m.y.) varies abruptly but systematically upward from a modal quartz latite to latite, and the Caballo Blanco (29.8 m.y.) from a modal rhyolite to capping quartz latite. Both are crystal-rich, and in each the amount of ferromagnesian and plagioclase phenocrysts and phenocryst percent increases upward, while the quartz and alkali feldspar/plagioclase ratio decreases. …
Geology Of The Cerro Pelon-Arroyo De La Jara Area, Santa Fe County, New Mexico, Alvis Lee Lisenbee
Geology Of The Cerro Pelon-Arroyo De La Jara Area, Santa Fe County, New Mexico, Alvis Lee Lisenbee
Earth and Planetary Sciences ETDs
The Cerro Pelon-Arroyo de la Jara area is a north-northwesterly plunging syncline at the southern end of the Española basin. Exposed rock units consist of more than 5,000 feet of Mesozoic and Cenozoic shale and sandstone intruded by Oligocene diorite sills and andesite and latite dikes related to the Ortiz intrusive center to the west.
The syncline is affected by several fault systems with both normal and strike-slip movement represented. Northerly trending faults of the east limb combine with a monoclinal flexure to produce an over-all lowering of the section to the west. These faults appear to be related to …
A Stratigraphic Study Of The Navajo Sandstone, Navajo Mountain, Utah And Arizona, William O. Hatchell
A Stratigraphic Study Of The Navajo Sandstone, Navajo Mountain, Utah And Arizona, William O. Hatchell
Earth and Planetary Sciences ETDs
The Navajo Sandstone of the Triassic(?) and Jurassic age is approximately 1, 000 feet thick at Navajo Mountain, Utah, and is composed of sets of cliff-forming, highly cross-stratified sandstone and horizontally stratified limestone, siltstone, and sandstone. it is intertongued on a large scale with the underlying, fluvial Kayenta Formation of Triassic(?) age, and is comfortably overlain by the marine Carmel Formation of the Jurassic age.
In the highly cross-stratified Navajo, tabular-planner and wedge planner sets are more common than simple wedge sets, and persistent horizontal bedding and truncation planes distinguish individual sets. Ripple marks, a distinctive type of "graded bedding", …
Mineralogy Of Coesite And Petrographic Association And Distribution At Meteor Crater, Arizona., Alfred A. Burgoyne
Mineralogy Of Coesite And Petrographic Association And Distribution At Meteor Crater, Arizona., Alfred A. Burgoyne
Earth and Planetary Sciences ETDs
Natural coesite, the high density monoclinic polymorph of silica, is found in shocked and melted sandstone at Meteor Crater, Arizona. Structural, morphological, and optical data have been obtained from synthetic coesite crystals and aggregates. Natural coesite occurs as microcrystalline anhedral grains which are unsuitable for the above determinations. In this study the following new data have been obtained for natural and synthetic coesite.
(1) The calculated and observed d spacings and their intensities for both natural and synthetic coesite have been reinvestigated through a 28 range from 100 to 750 for CuKo
(2) Nearly all grains of synthetic …
Stratigraphy Of The Lower Morrison Formation Along The Defiance Monocline, New Mexico And Arizona, Robin Clair Lease
Stratigraphy Of The Lower Morrison Formation Along The Defiance Monocline, New Mexico And Arizona, Robin Clair Lease
Earth and Planetary Sciences ETDs
Along the western border of the San Juan Basin a prominent cliff-forming, orange sandstone has been incorrectly mapped as a part of the Recapture Shale Member of the Morrison Formation. This stratigraphic unit is here given the informal name, Beautiful Mountain member, and has stratigraphic continuity with the Salt Wash Sandstone Member in Red Rock Valley and the Cow Springs Sandstone in Todilto Park, New Mexico. The Recapture Shale Member is restricted to the pink and pale-green, slope-forming sandstone above these orange sandstone beds and below the Westwater Canyon Sandstone Member.
The Beautiful Mountain member is predominantly a lenticularly bedded, …
Relationship Of Pleochroism And Specific Refractivity Of Cupric Compounds To Cupric Ion Coordination., Pilsum Phiroze Master
Relationship Of Pleochroism And Specific Refractivity Of Cupric Compounds To Cupric Ion Coordination., Pilsum Phiroze Master
Earth and Planetary Sciences ETDs
The ion has a 6-fold coordination. The CU-polyhedron is distorted due to the Jahn-Teller effect. There is, hence, varying polarizability in each Cu-polyhedron. Also since the nature (and size) of the ligands in each Cu-polyhedron varies, the polarizability varies from one Cu-polyhedron to the next.
Light waves passing through the Cu-polyhedra cause electron polarization. Conversely the polarizing action of light waves upon the atoms is accompanied by a reaction of the atom upon the light waves. Hence, absorption of light energy is directly proportional to polarizability. This thesis demonstrates this relationship by:
l) Showing that the projection of the square-planar …
Geology And Structure Of A Portion Of The Rio Puerco Fault Belt, Western Bernalillo County, New Mexico, Jock Campbell
Geology And Structure Of A Portion Of The Rio Puerco Fault Belt, Western Bernalillo County, New Mexico, Jock Campbell
Earth and Planetary Sciences ETDs
The Rio Puerco fault belt is a transitional feature between the Colorado Plateau and the Rio Grande depression in west-central New Mexico.
The major purpose of this report has been to map in detail a portion of the Rio Puerco fault belt not previously investigated thoroughly. The main interest herein is the structure of the area. Particular attention has been given to the determination of the character of the Apache graben. Secondary emphasis is placed on stratigraphy, as more complete reports concerning the sedimentary section can be found elsewhere.
An X-Ray Diffraction Study Of Some Of The Naturally Occurring Iodates., Seymour F. Kaplan
An X-Ray Diffraction Study Of Some Of The Naturally Occurring Iodates., Seymour F. Kaplan
Earth and Planetary Sciences ETDs
The iodate minerals, bellingerite, dietzeite, lautarite, and schwarzembergite were studied using x-ray diffraction methods.
The unit cell dimensions of lautarite, Ca(IO3)2, previously reported, are ao=7.18, bo=11.38, co=7.32, b=106 22’. Those dimensions are confirmed by powder diffraction methods for American Museum of Natural History Specimen No. 17150. The space group is either P2, Pm, or P2/m. The pattern listed os ASTM Card No. 1-0386 corresponds to CA(IO3)2*nH2O, not to lautarite as stated.
Geology Of Copper-Lead-Zinc-Turquoise Deposits, Southern Part Of The Cerrillos Mining District, Santa Fe County, New Mexico, William G. Gustafson
Geology Of Copper-Lead-Zinc-Turquoise Deposits, Southern Part Of The Cerrillos Mining District, Santa Fe County, New Mexico, William G. Gustafson
Earth and Planetary Sciences ETDs
ABSTRACT
The southern part of the Cerrillos mining district is underlain by a sequence of igneous rocks which have been altered and mineralized. The rocks are intrusive equivalents of the Oligocene (?) Espinaso Volcanics. Four stages of intrusion are recognized. A hornblende monzonite porphyry stock was emplaced during stage T1. Several small hornblendeaugite monzonite stocks intruded stage T1 rocks during stagesT2 and T3. During stage T4, stocks of augite-biotite monzonite, hornblende-biotite monzonite porphyry, and andesineaugite-biotite monzonite porphyry were intruded into the older igneous rocks. The stage T1, T2, and T3 stocks are flanked by sills and laccoliths.
Three sets of …
Conodonts Of The Mississippian System In The Sacramento Mountains, New Mexico, Robert C. Burton
Conodonts Of The Mississippian System In The Sacramento Mountains, New Mexico, Robert C. Burton
Earth and Planetary Sciences ETDs
Each formation of the Mississippian System in the Sacramento Mountains of New Mexico yields conodonts. Six distinctive conodont assemblages are recognized. The lowest assemblage coincides with the Caballero Formation (Kinderhook). Three distinct assemblages occur in the Lake Valley Formation (Osage). The Rancheria Formation (Meramec) and the Helms Formation (Meramec and Chester) also yield distinctive faunas. The assemblages correlate locally, regionally, and interregionally. The limestones and interbedded shales of the entire stratigraphic sequence were sampled continuously. The shale sequences were barren. The limestones yielded large, diversified, indigenous faunas. The lower part of the Lake Valley Formation contains Kinderhook and Osage species …
Geology Of The Lamy-CañOncito Area, Santa Fe County, New Mexico, Robert S. Goolsby
Geology Of The Lamy-CañOncito Area, Santa Fe County, New Mexico, Robert S. Goolsby
Earth and Planetary Sciences ETDs
The area studied lies in the vicinity of Lamy and Canoncito in Santa Fe County, about 17 miles southeast of Santa Fe, New Mexico.
The rocks range in age from Precambrian through Quaternary, Precambrian rocks include dark schist and pink gneiss, with minor amounts of greenstone and quaritzite, Overlying the Precambrian rocks is a sequence of sandy limestone called the Basal Limestone, of Mississippian and possibly Devonian age. The Pennsylvanian System is represented by the Sandia formation and Madera Limestone, which are dominantly dark shale and fossiliferous limestone. The Sangre de Cristo and Yeso Formations, Glorieta Sandstone, San Andres Linestone, …
Geology Of The San Mateo Peak Area, Socorro County, New Mexico., James W. Furlow
Geology Of The San Mateo Peak Area, Socorro County, New Mexico., James W. Furlow
Earth and Planetary Sciences ETDs
The San Mateo Mountains of south-central New Mexico consist of an uplifted block of Tertiary volcanics 20 miles wide by 4 miles ling. The San Mateo uplift is one of the bounding uplifts along the western side of the Rio Grande depression.
The basement rock as exposed just east of the San Mateos is a Precambrian granite; it is overlain in order by the Cambrian Bliss formation, the Ordovician Sierrite Limestone, Cable canyon sandstone, and Upham Dolomite, the Pennsylvanian Magdalena Group, and the Permian Abo Formation. These sedimentary rocks are unconformably overlain by Tertiary volcanic rocks of the Lower volcanic …
Geology Of The Rayado Area, Colfax County, New Mexico, Richard W. Simms
Geology Of The Rayado Area, Colfax County, New Mexico, Richard W. Simms
Earth and Planetary Sciences ETDs
The Rayado area is 25 miles west of Springer, New Mexico, in the southeastern foothills of the Cimarron Mountains. The range is a northward-plunging anticline with a core of Precambrian crystalline rocks. The mountains are bordered on the west by a normal fault and on the east by the high-angle Fowler Pass thrust fault of Laramide age. Rocks of Permian through Upper Cretaceous age were turned upward along the fault forming a prominent north-south hogback through the western part of the area.
On The Solar Magnetic Field In Inter-Planetary Space, Jacqueline H. Hill
On The Solar Magnetic Field In Inter-Planetary Space, Jacqueline H. Hill
Earth and Planetary Sciences ETDs
The purpose of this thesis is to determine, experimentally and theoretically, an axially symmetric current distribution which would simulate the currents believed to flow in interplanetary space around the sun. The general magnetic field of the sun is assumed to originate as a dipole field which induces currents in the plasma of the solar atmosphere. The dipole field is in turn modified by the induced currents. This phenomenon is often described in terms or a diamagnetism of the plasma. In the limiting case, this diamagnetism would almost completely prevent the inducing field from penetrating the plasma.
The Geology Of The Northern And Eastern Parts Of The Ladron Mountains, Socorro County, New Mexico., Bruce A. Black
The Geology Of The Northern And Eastern Parts Of The Ladron Mountains, Socorro County, New Mexico., Bruce A. Black
Earth and Planetary Sciences ETDs
The Laron Mountains are & westward-tilted fault block and an important western bounding structure of the Rio Grande depression in the Albuquerque-Belen basin. The main massif is a complex of both igneous and metamorphic Precambrian rocks. It consists of a thick sequence of steeply east-dipping quartzite & and schists which are predominantly a product of low- to medium- grade regional Precambrian metamorphism. Granitic gneiss is ptygmatically folded with abundant schist remnant in a large area on the eastern flank of the mountains and represents an ultrametamorphic product of anatexis. All metamorphic rocks have been invaded by two later Precambrian granites. …
Petrography Of A Cyclical Sequence, Upper Madera Limestone, Sandia Mountains, New Mexico, Fred Yale
Petrography Of A Cyclical Sequence, Upper Madera Limestone, Sandia Mountains, New Mexico, Fred Yale
Earth and Planetary Sciences ETDs
Chemical determinations of calcium and magnesium carbonates, iron, Kjeldahl nitrogen, and sulfate with supplementary petrographic thin-section and insoluble-residue studies and differential thermal analyses were used to study a Virgilian sedimentary cycle in the upper Madera Limestone of New Mexico. In 120 meters of section 4 cycles were recognized; one of these was studied in detail. Cyclic subsidence and subsequent basin filling produced a sequence of gross environmental changes accomplished by organisms in a definite ecological succession. Biologic communities were progressively modified by the changing marine sedimentary cycle. The cycles of the upper Madera Limestone begin with a lower fusulinid claystone, …
Slope Deposits Of The Pennsylvanian Haymond Formation, Marathon Region, Texas, Walter E. Dean Jr.
Slope Deposits Of The Pennsylvanian Haymond Formation, Marathon Region, Texas, Walter E. Dean Jr.
Earth and Planetary Sciences ETDs
The Haymond Formation of the Marathon basin, Texas consists mainly of a sequence of more than 12,000 siltstone-shale couplets which, combined with the similar couplets of the older Tesnus Formation, form a sequence of "flysch" sediments more than 10,000 feet thick deposited on the eastern slope of the subsiding Llanoria geosyncline. The Haymond Formation contains no diagnostic fossils; its age is known only as Lower Pennsylvanian, probably Atokan.
Origin Of Some Recent Tractional Sedimentary Structures In The Rio Puerco Near Bernardo, Socorro County, New Mexico, Lawrence H. Wagner
Origin Of Some Recent Tractional Sedimentary Structures In The Rio Puerco Near Bernardo, Socorro County, New Mexico, Lawrence H. Wagner
Earth and Planetary Sciences ETDs
The Rio Puerco, in the area of study, occupies a valley eroded in the Santa Fe formation. The silty alluvium is incised by the present channel of the Rio Puerco to a depth of 10 to 25 feet. The depth of the alluvial fill in the area is not known. The channel is 50 to 300 feet wide with braod meanders interspersed with straight reaches. The Rio Puerco is ephemeral in the lower reaches with flow produced by local rains on the watershed.
Petrography Of The Olalla Stock, Okanagan Mountains, British Columbia, James Anton Sturdevant
Petrography Of The Olalla Stock, Okanagan Mountains, British Columbia, James Anton Sturdevant
Earth and Planetary Sciences ETDs
The Olalla stock is located in the Okanagan Mountains of south-central British Columbia, about 20 miles north of the international boundary. It occupies approximately 6 square miles and consists of late Mesozoic mafic and ultramafic rocks and subordinate alkalic rocks, which have intruded previously folded and metamorphosed sediments of the Triassic (?) Shoemaker Foundation.
The rocks of the stock may be broadly grouped into two major categories: (1) those formed from the differentiation of a crystallizing magma that probably entered during the Nevadan orogeny, and (2) those formed by metasomatic replacement of pyroxenite. The rocks of the first category are, …
The Geology Of The South Mountain Area, Bernalillo, Sandoval, And Santa Fe Counties, New Mexico, Tommy B. Thompson
The Geology Of The South Mountain Area, Bernalillo, Sandoval, And Santa Fe Counties, New Mexico, Tommy B. Thompson
Earth and Planetary Sciences ETDs
South Mountain is approximately 30 miles northeast of Albuquerque in the southern end of the San Pedro-Ortiz porphyry belt. It is a Tertiary monzonite laccolith that intrudes the Permian Abo and Yeso Formations and, in places, the Permian Glori eta Sandstone. The base of the laceolith lies on the Abo except in the southeastern part where it overlies the Mes eta Blanca Member of the Yeso. The incompetence of the Yeso appears to nave allowed the monzonitic magma to spread laterally throughout the stratigraphic interval up to the Glorieta Sandstone which was more resistant and broken only locally by the …
Stratigraphic Analysis Of The Queen And Grayburg Formations, Southeastern Chaves County, New Mexico, James L. Mcswain
Stratigraphic Analysis Of The Queen And Grayburg Formations, Southeastern Chaves County, New Mexico, James L. Mcswain
Earth and Planetary Sciences ETDs
The area of study lies in southeastern Chaves County, New Mexico, and is a part of the northwest shelf or backreef province of the Permian Basin. The area encompasses all or parts of Tps. 10 through 15 S., Rs. 24 through 31 E.
The Queen and Grayburg formations comprise the lower part of the Artesia group, an upper Guadalupian sequence of Permian shelf rocks above the San Andres formation and below the Ochoan series. The Queen-Grayburg sequence has an average thickness of about 600 feet and is correlative with the Goat Seep reef at the margin of the Delaware Basin, …
Paleoecology Of The Varved Rita Blanca Lake Deposits, Hartley County, Texas, Douglas W. Kirkland
Paleoecology Of The Varved Rita Blanca Lake Deposits, Hartley County, Texas, Douglas W. Kirkland
Earth and Planetary Sciences ETDs
The Rita Blanca lake deposits in the northwestern part of the panhandle of Texas have been dated as Blancan age by vertebrate remains. During maximum development, Rita Blanca lake probably had an elliptical shape with a length of about 6 miles and breadth of about 3 1/2 miles.
The subject of this report is the petrology and paleontology of a 4 1/2-foot laminated clay bed of Blancan age low in the exposed Rita Blanca lake deposit of Hartley County, Texas. The main purpose is to determine the paleoecology, in particular the nature of the climatic regime which prevailed during deposition …
Mineralogy Of Rose Muscovite And Lepidolite From The Harding Pegmatite, Taos County, New Mexico, Durga Nath Rimal
Mineralogy Of Rose Muscovite And Lepidolite From The Harding Pegmatite, Taos County, New Mexico, Durga Nath Rimal
Earth and Planetary Sciences ETDs
The main purpose of the present work is to obtain quantitative data on alkali metals present in rose muscovite and lepidolite of the Harding pegmatite and to try to correlate them with the present knowledge of the geology of this pegmatite body.
Geology Of The Sedillo-Cedro Canyon Area, Bernallio County, New Mexico, Bert Norman Brown
Geology Of The Sedillo-Cedro Canyon Area, Bernallio County, New Mexico, Bert Norman Brown
Earth and Planetary Sciences ETDs
This report was undertaken primarily as a study of Pennsylvanian strata which crop out in the Sedillo-Cedro Canyon area. The subdivision of the Madera formation as proposed by Read and others (1944) was adopted for purposes of mapping. This subdivision is based on a dominance of either limestone or clastic rocks in the formation.
The writer was unable to measure a Pennsylvanian section in the field due to thickness changes, facies gradations, and faults which were often concealed by dense soil cover. However, by visually traversing the area on aerial photographs using arbitrarily chosen zones, estimated thicknesses for the members …
Permian Stratigraphy And Stratigraphic Paleontology Of The Colorado Plateau, Peggy L. Kirkland
Permian Stratigraphy And Stratigraphic Paleontology Of The Colorado Plateau, Peggy L. Kirkland
Earth and Planetary Sciences ETDs
The purpose of this study is to synthesize a portion of this vast source of data in order to arrive at a better understanding of Permian stratigraphy.
Geology Of Torreon And Pedricenas Quadrangles, Coahuila And Durango, Mexico, Russell E. Clemons
Geology Of Torreon And Pedricenas Quadrangles, Coahuila And Durango, Mexico, Russell E. Clemons
Earth and Planetary Sciences ETDs
The Torreon and Pedricenas quadrangles are in central Mexico between parallels 25 degrees and 26 degrees N. and meridians 103 degrees 20' and 104 degrees W.; together they embrace 7,600 square kilometers. The northeastern corner of the area lies in the Bolson de Mapimi; most of the area, however, is in the Sierra Madre Oriental.
Hypogene Zoning In The Lordsburg Mine District, Hidalgo County, New Mexico, K. F. Clark
Hypogene Zoning In The Lordsburg Mine District, Hidalgo County, New Mexico, K. F. Clark
Earth and Planetary Sciences ETDs
Although descriptions of the Lordsburg mining district have been in the literature for more than fifty years, no reference to hypogene zoning of the ores has been made. The present work is mainly concerned with hypogene zoning and related phenomena. Hypogene zoning, temperature of formation, and paragenesis are interrelated factors in ores differentiated from magmas. All three processes are discussed in this thesis. Other aspects of the mining district are mentioned only where relevant.
Stratigraphy And Paleontology Of The Pennsylvanian Rocks Of The Rim Of The Sandia Mountains, Sandoval And Bernalillo Counties, New Mexico, Paul Anthony Catacosinos
Stratigraphy And Paleontology Of The Pennsylvanian Rocks Of The Rim Of The Sandia Mountains, Sandoval And Bernalillo Counties, New Mexico, Paul Anthony Catacosinos
Earth and Planetary Sciences ETDs
The primary purpose of this investigation was to determine the presence or absence of pre-Pennsylvanian strata in the central part of the Sandia Mountains, along their western scarp. No strata older than Pennsylvanian were found by the author in this area.
The strata present in the Sandia Rim include the upper clastic member of the Sandia formation and part of the lower gray limestone member of the Madera limestone, both of Pennsylvanian age.
The Sandia formation is a predominantly clastic unit of sandstone, shale, limestone, and conglomerate which rests unconformably on a profound erosion surface formed on the Precambrian Sandia …