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Arnold H. Bouma

Publications and source records attributed to Arnold H. Bouma.

9 recordsLinked to original sources
USGS1981

Submarine topography and physiography of lower Cook Inlet, Alaska

The submarine topography of lower Cook Inlet, Alaska, is complex because the bathymetric aspects and water depths change rapidly over short distances. The folded upper Tertiary subbottom was eroded during the first of five major Quaternary glacial advances over the inlet, and later fluvial, fluvioglacial, glacial, and marine erosional and depositional processes shaped the bottom to its present configuration. Most of lower Cook Inlet has a relative smooth topography showing small local highs and lows, and slopes with gradients generally ranging from less than a degree to locally about 5°. Around the southwestern Kenai Peninsula and the Barren and Kodiak Islands, strong faulting with vertical movement has added to the complexity of bottom topography. Less complex, nonfaulted areas occur near Kalgin Island and south Kachemak Bay and around Augustine Island. To facilitate description of lower Cook Inlet the estuarine body is divided into three large regions, northern and central, southern, and eastern; and these regions are divided into smaller physiographic areas on the basis of submarine topographic characteristics and 20-m depth zonations. Each area is named by combining the geographic name of a nearby place or feature on land with a common term for a marine physiographic feature -- trough, platform, ramp, slope, plateau. Local highs and deeps having lees than 5-m relief, which can be important to fisheries and specific research or economic studies, are not named, mentioned in text, or shown on the figures.

Alaska↗
USGS1981

Seismic stratigraphic characteristics of upper Louisiana continental slope: an area east of Green Canyon

A high-resolution seismic reflection survey was conducted in a small area of the upper Louisiana Continental Slope known as Green Canyon Area. This area includes tracts 427, 428, 471, 472, 515, and 516, that will be offered for sale in March 1982 as part of Lease Sale 67. The sea floor of this region is, slightly hummocky and is underlain by salt diapirs that are mantled by early Tertiary shale. Most of the shale is overlain by younger Tertiary and Quaternary deposits, although locally some of the shale protrudes the sea floor. Because of proximity to older Mississippi River sources, the sediments are thick. The sediment cover shows an abundance of geologic phenomena such as horsts, grabens, growth faults, normal faults, and consolidation faults, zones with distinct and indistinct parallel reflections, semi-transparent zones, distorted zones, and angular unconformities. The major feature of this region is a N-S linear zone of uplifted and intruded sedimentary deposits formed due to diapiric intrusion. Small scale graben development over the crest of the structure can be attributed to extension and collapse. Large scale undulations of reflections well off the flanks of the uplifted structure suggest sediment creep and slumping. Dipping of parallel reflections show block faulting and tilting. Air gun (5 and 40 cubic inch) records reveal at least five major sequences that show masked onlap and slumping in their lower parts grading into more distinct parallel reflections in their upper parts. Such sequences can be related to local uplift and sea level changes. Minisparker records of this area show similar sequences but on a smaller scale. The distinct parallel reflections often onlap the diapir flanks. The highly reflective parts of these sequences may represent turbidite-type deposition, possibly at times of lower sea level. The acoustically more transparent parts of each sequence may represent deposits containing primarily hemipelagic and pelagic sediment. A complex ridge system is present along the west side of the area and distinct parallel reflections onlap onto this structure primarily from the east. Much of this deposition may be ascribed to sedimentation within a submarine canyon whose position is controlled by this ridge.

Louisiana Continental Slope↗
USGS1979

Clay mineralogy, fine-grained sediment dispersal, and inferred current patterns, lower Cook Inlet and Kodiak shelf, Alaska

Because lower Cook Inlet and Kodiak shelf are being explored and developed for their petroleum resources, it is essential for environmental reasons to understand the sediment dispersal routes and current patterns. The Susitna River flows into upper Cook Inlet and is the source of clay minerals in Holocene deposits found in western lower Cook Inlet. The Copper River, in the northern Gulf of Alaska, provides clay minerals to the Kodiak shelf and southeastern lower Cook Inlet. In addition, crosion of local bedrock outcrops on the shelf produces some clays that are deposited on the Kodiak shelf. Current patterns can be inferred from the clay-mineral distribution pattern. This is true even if the clay-size fraction is a minor sediment component, and in areas where coarse-grained relict deposits occur. Some potential dangers from offshore petroleum development include: (1) rapid and complete mixing of Cook Inlet waters, (2) adsorption of pollutants by clay deposited in quiet bays, and (3) ion-exchange and adsorption of chemical pollutants on clays that are part of the suspended sediment load in lower Cook Inlet.

Alaska↗
USGS1976

A summary of petroleum potential, environmental geology, and the technology, time frame, and infrastructure for exploration and development of the western Gulf of Alaska

This summary of the regional geology, petroleum potential, geologic hazards and time frame for exploration of the western Gulf of Alaska has been written to aid the Bureau of Land Management in preparing the Draft Environmental Impact Statement. A preliminary version was written in Sept., 1975.(von Huene and others, 1975) in support of the Call for Nominations, Proposed OCS Oil and Gas Lease Sale #46. Since that time, there has been a substantial increase in information as the result of a two-month examination of recent studies of the adjacent Gulf of Alaska Tertiary Province and a preliminary interpretation of some publicly available common depth point (CDP) seismic reflection data recently acquired by the U.S. Geological Survey. The main source of geologic and geophysical data used in the preparation of this summary is published and unpublished information of the U.S. Geological Survey (Plafker and others, 1975,Bruns and Plafker, 1975; Carlson, Bruns and Molnia, 1975; Carlson and Molnia, 1975; Core, Mattick, and Bayer, 1975; Molnia and Carlson, 1975 a & b; von Huene and others, 1975). Prior to 1975, data were gathered mainly for purposes other than for assessment of oil and gas resources and of the environmental consequences of exploration and development. A systematic survey for such an assessment is planned for the summer of 1976 and, therefore, this summary is tentative. Although the major problems and regional setting are discussed in this paper, a great deal more specific data and interpretations will begin to become available in about one year. In this summary we consider the geology of a broad region on the continental shelf off the Kodiak group of islands and the Kenai Peninsula. We will concentrate on the area proposed for leasing in Sale #46. The area lies between about 56°N latitude and 60°N latitude (Fig. 1), and it measures approximately 660 km x 100 km. Water depths are generally less than 200 m.

Alaska↗