Sedimentology Commons^™

The Geologic History Of The Chehalis Forearc Basin, Washington State, Usa, Rud Lamb Moe

Dissertations and Theses

The Chehalis Basin, in southwest Washington, is one of a series of forearc basins between the Cascade Arc and the Coast Range in the Pacific Northwest. While the Seattle basin to the north, and the Portland-Tualatin basins to the south are both relatively well studied, the geologic evolution of basins in between is poorly constrained. The Chehalis basin is underlain by accreted Eocene oceanic basalt of the Crescent Formation. The basin fill consists of sedimentary rocks and volcanic rocks deposited throughout the Cenozoic. It has undergone N-S shortening driven by transpressional stress from oblique subduction of the Juan de Fuca …

An Analysis Of Suspended Sediment Dynamics In A Partially Mixed Estuary, Riyadh Hamad Muttaleb

Dissertations and Theses

The purpose of this work is to investigate via data analysis and numerical modeling the SPM (suspended particulate matter) dynamics of a heavily contaminated partially urban estuary, the Lower Passaic River estuary (LPR), NJ. Accordingly, I investigate the quantity and mechanics of variation of fine and coarse SPM in the LPR via data analysis. Data analysis focuses on the parameters that affect SPM dynamics at six moored stations occupied during the Fall and Spring seasons, from near the estuary mouth to tidal freshwater. A 3D hydrodynamic model (Delft3D-FM) is used to analyze the effects of estuary topography on the dynamic …

Slope, Grain Size, And Roughness Controls On Dry Sediment Transport And Storage On Steep Hillslopes, Roman A. Dibiase, Michael P. Lamb, Vamsi Ganti, Adam M. Booth

Geology Faculty Publications and Presentations

Existing hillslope sediment transport models developed for low-relief, soil-mantled landscapes are poorly suited to explain the coupling between steep rocky hillslopes and headwater channels. Here we address this knowledge gap using a series of field and numerical experiments to inform a particle-based model of sediment transport by dry ravel—a mechanism of granular transport characteristic of steep hillslopes. We find that particle travel distance increases as a function of the ratio of particle diameter to fine-scale (1m) topographic variability associated with rocky landscapes. Applying a 2-D dry-ravel-routing model to lidar-derived surface topography, we show how spatial patterns of local and nonlocal …

A Novel Approach To Flow And Sediment Transport Estimation In Estuaries And Bays, Hamed Moftakhari Rostamkhani

Dissertations and Theses

Reliable estimates of river discharge and sediment transport to the ocean from large tidal rivers are vital for water resources management, efficient river and harbor management, navigational purposes, and climate analyses. Due to the difficulties inherent in measuring tidal-river discharge, hydrological and sedimentological records are typically too short to adequately characterize long-term (decadal) trends. Also, uncertainties associated with observation and calibration of hydrological models suggest a need for more accurate methods based on longer records of hydrodynamic parameters (e.g. tides). Tidal theory indicates that tides and river discharge interact through quadratic bed friction, which diminishes and distorts the tidal wave …

Applications Of Remote Sensing To The Study Of Estuarine Physics: Suspended Sediment Dynamics In The Columbia River Estuary, Austin Scott Hudson

Dissertations and Theses

Estuarine circulation and its associated transport processes drive the environmental integrity of many near-shore habitats (the coastal ocean, rivers, estuaries and emergent wetlands). A thorough understanding and consideration of this circulation is, therefore, vital in the proper management of these habitats. The aim of this study is to bring together theory and new satellite observations in the Columbia River Estuary to increase our understanding of estuarine circulation and transport. Surface reflectance measurements gathered by the Moderate Imaging Spectroradiometer (MODIS) are first compared to in situ observations to develop an empirical model for remotely derived surface turbidity. Results indicate that MODIS …

Macroinvertebrates And Excessive Fine Sediment Conditions In Oregon Coastal Streams, Patrick M. Edwards

Dissertations and Theses

The Pacific Coastal ecoregion contains large tracts of economically important forest lands that also serve as critical stream habitat for endangered Salmonids. Excessive fine sediment deposition in streams of this region is a major environmental concern in the region but difficult to measure directly. The use of stream invertebrates to monitor fine sediment conditions in streams requires careful consideration of several important factors that complicate their use as bioindicators including high spatial and temporal variability and covariance with other environmental variables.

To evaluate the use of stream invertebrates as bioindicators of excessive fine sediment, three hypotheses were tested. The first …

Relational Database Analysis Of Dated Prehistoric Shorelines To Establish Sand Partitioning In Late Holocene Barriers And Beach Plains Of The Columbia River Littoral Cell, Washington And Oregon, Usa, Tamara Causer Linde

Dissertations and Theses

Studies of episodic shoreline accretion of the Columbia River Littoral Cell (CRLC) have been ongoing since 1964. In this study, the sediment volumes in the late Holocene barriers and beach plains are compiled and formatted in GIS compatible databases for the four sub-cells of the CRLC.

Initial evaluation involved the creation of a geodatabase of 160 dated retreat scarp positions, that were identified on across-shore GPR and borehole profiles. Ten primary timelines were identified throughout the CRLC (0-4700 ybp) and those were used to develop polygon cells. Elevation, distance measurements, and position information were all linked to the polygon through …

Accommodation Space Controls On The Latest Pleistocene And Holocene (16–0 Ka) Sediment Size And Bypassing In The Lower Columbia River Valley: A Large Fluvial–Tidal System In Oregon And Washington, Usa, Curt D. Peterson

Geology Faculty Publications and Presentations

In this study, we establish the roles that increasing basin accommodation space have on sediment size and bypassing in the transgressive fill (16–0 ka) in the submerged Lower Columbia River Valley (LCRV). The antecedent forearc valley (225 km in length, 4–8 km in width, and 60–115 m in axial valley depth) is characterized by high sediment supply rates (10–15 million t y-1) but no delta at its mouth to the Pacific Ocean. Core sample sediment textures (N ¼ 1600) are analyzed from 3000 m of borehole sections in 58 representative boreholes to characterize the ancestral valley fill: 57% sand, 17% …

Do Cryoconite Holes Have The Potential To Be Significant Sources Of C, N, And P To Downstream Depauperate Ecosystems Of Taylor Valley, Antarctica?, Elizabeth A. Bagshaw, Martyn Tranter, Andrew G. Fountain, Kathleen A. Welch, Hassan J. Basagic, W. Berry Lyons

Geology Faculty Publications and Presentations

Nutrient recycling occurs in hydrologically isolated cryoconite holes on the glaciers of the McMurdo Dry Valleys, Antarctica. Biogeochemical processes enrich the cryoconite holes with solute and nutrients compared to the source sediment and glacier ice. The position of the glacier within the landscape affects the physical and biogeochemical character of the cryoconite holes, with those found in more biologically productive areas of the valley having higher concentrations of C, N, and P and higher pH. Comprehensive assessment of the quality and quantity of bioavailable C, N, and P shows that the cryoconite holes represent a significant store of nutrient in …

Distribution Of Heavy Metals And Trace Elements In Soils Of Southwest Oregon, Rafiqul Alam Khandoker

Dissertations and Theses

Soil samples from 118 sites on 71 geologic units in southwest Oregon were collected and analyzed to determine the background concentrations of metals in soils of the region. Sites were chosen in areas that were relatively undisturbed by human activities. The U.S. Environmental Protection Agency approved total-recoverable method was used to recover metals from samples for analysis. The twenty six metals analyzed were: Ag, AI, As, Ba, Be, Ca, Cd, Co, Cr, Cu, Fe, Hg, K, La, Li, Mg, Mn, Mo, Na, Ni, Pb, Sb, Se, Tl, V and Zn.

The Klamath Mountains followed by the Coast Range contain the …

Sediment Dynamics On The Shore Slopes Of The Puget Island Reach Of The Columbia River, Oregon And Washington, Timothy Abbe

Dissertations and Theses

Water waves generated by wind and ships; ebb tidal currents; water level fluctuations; and dredging impact sediment transport in shallow water of the lower Columbia River. Observations were made over a one-year period after sand dredged from the navigation channel was placed at three study sites in the Puget Island region, 46°15'N 123°25'W, Oregon and Washington. Sediment composition is fine to medium grained, low density dacitic volcanics with small percentages of pumice, heavy minerals, and basalt.

Stratigraphy And Sedimentology Of Paleogene Arkosic And Volcaniclastic Strata, Johnson Creek-Chambers Creek Area, Southern Cascade Range, Washington, Warren Jon Winters

Dissertations and Theses

Over 1150 m of middle to late Eocene nonmarine arkose, lithic arkose, mudstone, and siltstone, referred to here as the Chambers Creek beds, are int~r.stratified with, and overlain by over 1600 m of late Eocene-Oligocsne(?) andesitic volcaniclastic and subordinate volcanic rocks assigned to the Ohanapecosh Formation, in a dissected structural high in the southern Washington Cascade Range, about 18 km south-southeast of the town of Packwood.

Stratigraphy And Sedimentation Of The Spencer Formation In Yamhill And Washington Counties, Oregon, Fathi Ayoub Al-Azzaby

Dissertations and Theses

The Spencer Formation in Yamhill and Washington Counties, Oregon, is exposed in a narrow belt 27 km long, from 1/4 to 3 km wide and with a maximum thickness of about 400 m. The formation is composed entirely of sandstone with interbedded thin layers of mudstone in the uppermost member. The sedimentary structure and paleoecology indicate a shallow marine depositional environment. The upper member of the Spencer Formation contains more quartz, plagioclase, and hornblende than does the lower member, but K-feldspar is less than that of the lower member. Shallower water conditions for the deposition of the upper member are …

The Petrology And Stratigraphy Of The Portland Hills Silt, Rodney Thomas Lentz

Dissertations and Theses

Topics in geology, which inevitably excite professional discussion and even tempered debate, often present challenging targets for the exploratory jabs of Master's degree candidates. The Portland Hills Silt and the controversy concerning its genesis provides just such an object.

Although the physical descriptions of the silt are generally in agreement, they remain somewhat generalized and, at present, no single definition is generally accepted. Moreover, incongruities concerning structural and textural details--notably, the presence of minor stratification and/or scattered pebbles in the silt--have resulted in considerable disagreement regarding its mode of origin.

The Geology Of The Southeast Quarter Of The Bone Mountain Quadrangle, Oregon, Richard Cortland Kent

Dissertations and Theses

This thesis is a study of the geology of the southeast quarter of the Bone Mountain Quadrangle. The bedrock geology mapped includes about 56 square miles.The Klamath Mountain and Coast Range Provinces of southwestern Oregon are represented in the area. Rocks in the area include the Rogue, Dothan Riddle, Days Creek, upper member of the Umpqua and Tyee Formations. The ages of these rocks range from Late Jurassic to middle Eocene. Late Jurassic ultramafic and mafic intrusive rocks associated with the Rogue Formation occur in the Klamath Province. The metavolcanics of the Rogue Format ion and an associated linear belt …