Author: Franklin Howard OlmstedPublisher:
ISBN:
Category : Geology
Languages : en
Pages : 60
Book Description
Geologic Reconnaissance of San Clemente Island, California
Author: Franklin Howard OlmstedPublisher:
ISBN:
Category : Geology
Languages : en
Pages : 60
Book Description
Geologic Reconnaissance of San Clemente Island, California
Author: F. H. OlmstedPublisher: BiblioGov
ISBN: 9781289018900
Category :
Languages : en
Pages : 22
Book Description
The United States Geological Survey (USGS) is a scientific organization created in 1879, and is part of the U.S. government. Their scientists explore our environment and ecosystems, to determine the natural dangers we are facing. The agency has over 10,000 employees that collect, monitor, and analyze data so that they have a better understanding of our problems. The USGS is dedicated to provide reliable, investigated information to enhance and protect our quality of life. This is one of their bulletins.
Geologic Evaluation of San Clemente Island as a Location for a Rock-site I Installation
Author: C. F. AustinPublisher:
ISBN:
Category : Geology
Languages : en
Pages : 42
Book Description
San Clemente Island has been studied to determine the geologic suitability of employing the island as a candidate site for the construction of a Rock-Site I installation, the land-linked experimental laboratory. The studies of the island consisted of a review of the geologic literature, aerial reconnaissance, geologic mapping, core drilling, borehole pumping, and offshore geophysical studies and sampling operations. Based on the results of these investigations the recommendation is made that the laboratory area beneath the sea floor be located off Mail Point with access tunnels to the laboratory originating at either Mail Point or Lost Point. As a candidate site, San Clemente Island is considered to be feasible but difficult. (Author).
San Clemente Island Rocksite Project, Offshore Geology: Detailed survey off Eel and Lost Points area
Author: James Barr RidlonPublisher:
ISBN:
Category : Marine geophyscs
Languages : en
Pages : 108
Book Description
A Geological Sketch of San Clemente Island
Author: William Sidney Tangier SmithPublisher:
ISBN:
Category : Geology
Languages : en
Pages : 74
Book Description
Estampes
Author: Engineering Geology of Rocks in Core Hole, Eel Point, San Clemente Island, California
Author: D. L. LamarPublisher:
ISBN:
Category : Engineering geology
Languages : en
Pages : 28
Book Description
A 1,200-foot core hole drilled near Eel Point on the west coast of San Clemente Island, California, penetrated a homogeneous series of andesite flows varying in thickness from 11 to 169 feet. Petrographic examination revealed that textural variations within flows as a result of different cooling rates are more distinct than differences in composition between individual flows. Potassium-argon dates indicate that these flows were extruded in less than one-half million years during Miocene time. The flows are inferred to dip seaward at between 10 and 30 degrees. The rock will provide sound material for excavation. Problems of water leakage can be expected at faults and zones of decomposed rock. (Author).
Engineering Geology of Central San Clemente Island, California
Author: P. M. MerifieldPublisher:
ISBN:
Category : Engineering geology
Languages : en
Pages : 20
Book Description
Geology of the California Continental Margin
Author: Michael P. KennedyPublisher:
ISBN:
Category : Continental margins
Languages : en
Pages : 124
Book Description
Bathymetry and Structure of San Clemente Island, California, and Tectonic Implications for the Southern California Continental Borderland
Author: James Barr RidlonPublisher:
ISBN:
Category : Bathymetric maps
Languages : en
Pages : 310
Book Description
Five lithologic units, ranging in age from Middle Miocene to Recent, are defined on the basis of continuous seismic reflection profile records. Two of the units are Miocene sedimentary and volcanic rocks that have been truncated to form a major unconformity (post-orogenic surface) related to the most recent major tectonism of the region. The remaining units are post-orogenic unconsolidated sediments. The fault pattern offshore is generally related to that exhibited on the island. The pattern conforms to a wrench-fault system hypothesized by Moody and Hill (1956) modified by a general north-south tensional fracturing. The San Clemente Fault is assumed to be the primary wrench fault of the system. Anomalies in the thicknesses and the structure of the unconsolidated sediment and rock units tend to confirm the structural model. A canyon (Eel Ridge Canyon) off the west side of San Clemente Island appears to have been caused by pivotal faulting and erosion, and represents a boundary between different structural trends north and south. A prominent terrace around the island is postulated to have been wave-cut during and since the Late Pleistocene. The island has been tilted slightly to the west by Recent tectonism. A steep magnetic gradient off the east side of the island is considered the consequence of faulted volcanic flows comprising the island itself and a deep basic rock mass responsible for a large positive magnetic anomaly off the northwest side. Other magnetic anomalies reflect major structural trends. Earthquake epicenter data suggest a recent and possibly cyclical occurrence of fault activity in the northern Continental Borderland region and the study area. Fault offsets at the sea floor and earthquake epicenters along the San Clemente fault zone imply recent adjustments along the fault. Wrench-fault movement resulting from a simple shear or shear couple is considered to have caused the zone of brecciation along the San Clemente Fault and produced the fault-trace curvature so evident in a series of en echelon, northwest-striking major faults of the Borderland. Tensile release during periods of wrench-fault development has been a fundamental factor in the structural development of the Borderland basins. The entire structure of the Continental Borderland is believed to have developed by right-lateral movement along the series of wrench faults. These faults are believed to have resulted from a translation of force by sea-floor spreading originating on the East Pacific Rise in the Gulf of California region. This force is considered to have moved a northern Continental Borderland crustal plate westward by east to west release along major wrench faults bordering the north and south ends of this plate. Sediments, transported along channels developed along faults in the island block, were deposited in basins developed by faulting and folding of the pre-orogenic rocks. Transportation appears to have been by means of turbidity-current flows, sand flows, and slides. A maximum average depositional rate of 35 to 47 centimeters per 1,000 years is estimated for post-orogenic sediments. The following findings are suggested for inclusion in the Neogene history of the island: (1) the top 365 meters of Miocene andesitic lavas were deposited above sea level and tend to become slightly more basic in composition with depth; (2) subsidence of the island region and temporary sea-level stand(s) occurred after the deposition of the volcanic rocks, with possible periods of foundering to about the Late Pliocene; (3) emergence, lengthy subaerial exposure, and a period of partial submergence took place from about Late Pliocene through Early Pleistocene; (4) a north-south compressive force developed or recurred across the Borderland during Late Pliocene, developing the present northwest-southeast and east-west wrench-fault systems that have been intermittently active to the present time; (5) much of the present Borderland topography formed during the Pleistocene to Recent.