Download or read book Fourier Grain Shape Analysis of Sediments from the Continental Shelf Off the Coast of Northern Oregon written by Gerald Kirk Swilley and published by . This book was released on 1986 with total page 218 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Sources Transport and Dispersal History of Southern Oregon Continental Shelf Sediments written by Marc A. O'Neal and published by . This book was released on 1986 with total page 214 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Provenance and Transport History of Sediments on the Southern New England Continental Shelf Fourier Grain Shape Analysis written by Mary Ann Hemming and published by . This book was released on 1981 with total page 74 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Literature Review on the Geologic Aspects of Inner Shelf Cross shore Sediment Transport written by J. Bailey Smith and published by . This book was released on 1995 with total page 168 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Petroleum Abstracts written by and published by . This book was released on 1980 with total page 1608 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Sediment Textures and Internal Structures written by Robert Cornelius Roush and published by . This book was released on 1970 with total page 150 pages. Available in PDF, EPUB and Kindle. Book excerpt: A study of sedimentary structures and sediment texture of beach and continental shelf sediments provides a basis for the interpretation of the recent history of sedimentation on the Oregon continental shelf. The texture of various sediment types suggests that coastal rivers supply a considerable quantity of very fine sand in addition to modern mud to the continental shelf. Relict sediments remain uncovered on areas of the shelf not under the influence of major river runoff and are mixed or covered by modern mud and very fine sand where rivers influence shelf sedimentation. Primary sedimentary structures show that sands ranging from very fine to medium in mean grain size are capable of being moved at shelf water depths from at least 38 to 88 meters. No net transport of sand, however, can be determined from these structures. Organic structures apparently are controlled by water depth and/or grain size and sediment type which determine faunal composition and concentration. At mid-shelf depths fine sand cores are characterized by shell fragments, worm tubes, and worm trails. Beyond 100 meters water depth worm tubes were not found, but worm trails become abundant, and large burrows appear in the sediment.

Download or read book Continental Shelf Sediments Columbia River to Cape Blanco Oregon written by Erwin John Runge and published by . This book was released on 1966 with total page 330 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Identification of Sediment Sources in a Fluvial Network written by Robert Steven Przygocki and published by . This book was released on 1977 with total page 124 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Fourier Grain Shape Analysis written by and published by . This book was released on 1978 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Quartz sand derived from alluvial fans that drain different lithologies at the Nevada Test Site can be distinguished on the basis of grain shape as described by the Fourier series in closed form. Specifically, we examined tuff units from the Piapi Canyon and Indian Trail Formations as well as carbonate-bearing clastic units from the Eleana Formation. Discrimiation between rock types was accomplished by examining the mean harmonic amplitude spectra and the grain shape frequency distributions at those harmonics that exhibit significant chi-square values. The results of these analyses indicate that the tuffs can be easily distinguished from the clastics. However, differences between samples from genetically similar rock types are not as prominent. Grain shape frequency distributions of tuffs and clastics show such strong differences that they can be characterized by standardized distributions. By comparing the shape frequency distributions of mixed sediment samples, it is possible to determine the relative contribution of tuff and clastics to any sediment sample taken within the drainage network. The Piapi Canyon, Indian Trail, and Eleana Formations have produced the thick alluvium sequence in the Rainier Mesa region of Yucca Flat. We believe it is likely that these grain shape relationships can also be applied to subsurface samples. Not only would this extended application enable more accurate correlation of alluvial layers, but more precise determination of the clastic-tuff contact within the alluvium sequence might also be possible.

Download or read book Geology of the Continental Terrace Off the Central Coast of Oregon written by Neil Joseph Maloney and published by . This book was released on 1965 with total page 466 pages. Available in PDF, EPUB and Kindle. Book excerpt: The continental terrace west of Oregon between 43° 50'N and 44° 40' N latitude is 50 to 55 miles wide. It consists of a continental shelf, 16 to 35 miles wide, and a continental slope, 16 to 37 miles wide. The eastern portion of the shelf is a smooth, sediment covered area that slopes very gently west. The western portion of the shelf contains four rocky bank areas. The banks are topographically irregular and appear to be of structural origin. West of the banks the shelf edge occurs at depths of 71 to 90 fathoms. The continental slope extends from the edge of the shelf to the abyssal plain at depths of 1530 to 1610 fathoms. A smooth upper slope of less than three degrees extending to depths of 117 to 250 fathoms occurs north and south of Heceta Bank. West of Heceta Bank the upper slope is formed by a scarp that slopes 10° to 16° to 560 to 725 fathoms. West of the upper slope there is an area of irregular topography, including benches, hills and scarps, which extends to depths of 380 to 1100 fathoms. The lower part of the slope is formed by a north-striking scarp which is 3000 to 6000 feet high and slopes 04° to 15°. The bathymetry indicates that the continental slope was formed by step-type, block faulting. Sediments form a thin surface layer over much of: the terrace. Detrital sand, similar to the coastal sand, covers the shelf from the shoreline to approximately 50 fathoms. The deeper areas on the shelf and upper part of the slope are covered by glauconitic sands and silts on the topographic highs and olive green, clayey silts in the topographic lows. The intermediate and lower portions of the slope are blanketed with olive-green, clayey silt. In these sediments the sand fraction, which generally comprises less than five percent of the sample, is composed chiefly of diatoms, Foraminifera, Radiolaria, and sponge spicules. Sands are also present on the intermediate and deep portions of the slope. Dredge hauls west of Newport obtained sand composed mainly of detrital grains which may have been derived from an underlying friable sandstone. Thin layers of sand occur in cores from other portions of the slope. These sands may have been derived by down slope movement of sediment from the upper slope and the shelf. Sedimentary rocks of Upper Miocene and Pliocene age crop out on the shelf banks and on the continental slope. The banks consist of a sequence of diatomaceous, clayey siltstones with interbeds and concretions of calcareous siltstones. Glauconite sandstone, gray wacke sandstone, and limestone breccia are exposed along with the siltstone, on the northern end of Heceta Bank. Most of the rocks obtamed from the slope are similar to those from the shelf. Friable, wacke sandstone is exposed on the slope west of Newport. Foraminifera, the sand fraction compositions, and textural analyses all indicate that the sediment forming the siltstones from the shelf were deposited at lower littoral to lower bathyal depths. The sediments forming the rocks were deposited in one or more sedimentary basins during the Miocene and Pliocene. The subsidence continued until the. Late Pliocene when the area began to rise. The area was uplifted as much as 1000 fathoms by the Late Pleistocene when the shelf was eroded by transgressions and regressions resulting from sea level changes. The last rise in sea level resulted in the erosion of the shelf to its present form and the deposition of a thin layer of sediment. Sand is presently being deposited on the shallow areas adjacent to the continent, and silt and clay are being laid down on the slope and the sheltered areas of the outer shelf.

Download or read book Fourier Grain Shape Analysis as a Stratigraphic Tool written by Marian McNally Smith and published by . This book was released on 1981 with total page 112 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Fourier Grain Shape Analysis written by B. T. Grothaus and published by . This book was released on 1978 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Comprehensive Dissertation Index written by and published by . This book was released on 1973 with total page 1016 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book River Mouth and Beach Sediments Russian River California to Rogue River Oregon Part A Introduction and Grain Size Analyses written by M. Glogoczowski and published by . This book was released on 1971 with total page 78 pages. Available in PDF, EPUB and Kindle. Book excerpt: 65 SAND SAMPLES ON INTERTIDAL, BEACH, AND RIVER MOUTH AND BAR FROM THE COASTS OF Northern California and Southern Oregon are analyzed for grain size properties. These samples were taken to provide source area information for a projected study of the offshore sediments of the Northern California Continental Shelf. The data are presented graphically as cumulative weight percent curves and histograms with respect to grain size. The following statistical parameters are calculated for each sample: median diameter, sorting coefficient, skewness and kurtosis. (Author).

Download or read book Onshore offshore Geologic Cross Section from the Mist Gas Field Northern Oregon Coast Range to the Northwest Oregon Continental Shelf written by Alan R. Niem and published by . This book was released on 1990 with total page 62 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Sediment Transport on the Northern Oregon Continental Shelf written by John Charles Harlett and published by . This book was released on 1972 with total page 240 pages. Available in PDF, EPUB and Kindle. Book excerpt: The distribution of surface sediments on the northern Oregon continental shell is characterized by a nearshore sandy facies and an outer shelf muddy facies, separated by a mid-shelf zone of mixed sand and mud. Currents which have been measured at 130 centimeters above the bottom indicate that the distribution of the surface sediment is a reflection of the hydraulic regime. The strongest bottom currents which were measured were in the nearshore region at a depth of 36 meters. Here currents of over 40 cm/sec generated by surface waves are capable of placing the nearshore sands in suspension, where they are transported shoreward by the wave surge. At mid-shelf, in 90 meters of water, the bottom current veolcity ranges from zero to over 25 cm/sec, although the mean is normally about 10 cm/sec. The strongest currents at this depth are capable of eroding some of the fine sediments, but probably do not rework the older sediments which have been compacted. Currents which are similar in character to those at mid-shelf were observed at the shelf edge in a depth of 165 meters. A significant departure, however, is the difference in frequency where the most energy is found. At the shelf edge the dominant frequency was about four cpd whereas the dominant frequency at mid-shelf was two cpd or lower. The dominant frequencies indicate that tides are important in the generation of continental shelf bottom currents. The twelve - hour period is that of the semi-diurnal tide; the six-hour period is the second harmonic of the semi-diurnal component. No indication of surface wave influence was found at mid-shelf or shelf-edge depths. Profiles of turbidity made at four east-west transects of the continental shelf indicate suspended sediment transport occurs principally at three levels in the water column. An upper layer is at the level of the seasonal thermocline, a mid-water layer is located at the level of the permanent pycnocline, and the third layer is at the bottom. The surface layer is important in transporting suspended sediment of the Columbia River plume, although there is also a contribution to the surface layer from the surf zone by the process of diffusion of fine particles. The mid-water layer thickens vertically and becomes less intense seaward, indicating a nearshore source for the suspended material. This source is diffusion of fine particles from the surf zone at mid-water depths. The mid-water layer is located at the level of the permanent pycnocline. The layer is sub-parallel to the bottom over the shelf but becomes diffuse at the shelf edge. Sediment transport in the mid-water layer provides a mechanism by which sediment bypasses the outer shelf and upper slope area. The bottom layer receives its suspended material from erosion of the bottom, from the water column above, and from fine material moving seaward from the surf zone. The amount of eroded material contributed to the bottom layer depends on the bottom current strength and on the bottom roughness characteristics. Over a rough bottom the erosive power of a given bottom current is increased drastically. For this reason, the presence or absence of rippling is important to sediment transport on the shelf. The fine material of the bottom layer may concentrate by settling during quiescent periods, allowing low-density flows to initiate. Several time-series observations of turbidity indicate that the bottom layer thickens and thins in response to increases and decreases in current velocity. The mid-water layer migrated somewhat in a vertical direction, but its thickness and intensity remained nearly the same. The thickness and intensity of the upper layer responded to changes in the structure of the thermocline, becoming thick and dispersed when the upper part of the water column is mixed. A model of sediment transport proposes that mid-water and bottom currents transport suspended sediments diagonally across the shelf toward the south-southwest. The sediments of the Columbia River plume are also transported in a southerly direction in the surface waters. Relatively little deposition takes place on the shelf and upper slope, with the bulk of the sediments bypassing the shelf and depositing on the lower slope and continental rise.

Download or read book The Utility of Fourier Estimates of Grain Shape in Sedimentological Studies written by Brian Thomas Redmond and published by . This book was released on 1969 with total page 320 pages. Available in PDF, EPUB and Kindle. Book excerpt: