Skip to main content
Advanced Search

Filters: Tags: Grain size (X)

75 results (51ms)   

View Results as: JSON ATOM CSV
Permeability–porosity relationships for sediments from the northern Barbados, Costa Rica, Nankai, and Peru subduction zones were examined based on sediment type, grain size distribution, and general mechanical and chemical compaction history. Greater correlation was observed between permeability and porosity in siliciclastic sediments, diatom oozes, and nannofossil chalks than in nannofossil oozes. For siliciclastic sediments, grouping of sediments by percentage of clay-sized material yields relationships that are generally consistent with results from other marine settings and suggests decreasing permeability as percentage of clay-sized material increases. Correction of measured porosities for smectite content...
thumbnail
Variability in sediment properties with depth and the thickness of individual sedimentary layers are critical determinants of seabed acoustic response. The New England Mud Patch (NEMP), located south of Cape Cod, is an unusual feature on the U.S. Continental Shelf in that it is composed of fine-grained sediment layers containing a relatively-homogeneous mix of sand, silt, and clay-sized particles bounded by more typical sandy shelf sediments. The unique characteristics and nature of this deposit is due to a derivation of sediments that have been transported to, and deposited in, a basal bowl-shaped depression since the last glacial maximum. Ninety-two piston, vibra-, and gravity cores with a maximum length of 8.2...
Sand transport in the Colorado River in Marble and Grand canyons was naturally limited by the upstream supply of sand. Prior to the 1963 closure of Glen Canyon Dam, the river exhibited the following four effects of sand supply limitation: (1) hysteresis in sediment concentration, (2) hysteresis in sediment grain size coupled to the hysteresis in sediment concentration, (3) production of inversely graded flood deposits, and (4) development or modification of a lag between the time of a flood peak and the time of either maximum or minimum (depending on reach geometry) bed elevation. Construction and operation of the dam has enhanced the degree to which the first two of these four effects are evident, and has not affected...
thumbnail
The drilling project at Owens Lake commenced in April,1991. This Open-File Report represents an effort to makeavailable to other researchers our preliminary datacollected during the first year of study followingcompletion of the core-drilling phase. Nineteen datacollections and preliminary interpretations are presentedin the following sections. They are the work of fifteenfirst-authors and their numerous co-authors. Broadly,their topics include a field log of the core(1 contribution), sedimentological analyses (1), clay-mineral identification (1), geochemical analyses (5),dating and age estimates of the cored sediments (4), andidentifications of fossil materials (7).
In settings where the transport of sand is partially or fully supply limited, changes in the upstream supply of sand are coupled to changes in the grain size of sand on the bed. In this manner, the transport of sand under the supply-limited case is ‘grain-size regulated’. Since the closure of Glen Canyon Dam in 1963, the downstream reach of the Colorado River in Marble and Grand Canyons has exhibited evidence of sand-supply limitation. Sand transport in the river is now approximately equally regulated by changes in the discharge of water and changes in the grain sizes of sand on the channel bed and eddy sandbars. Previous work has shown that changes in the grain size of sand on the bed of the channel (driven by...


map background search result map search result map Core OL-92 from Owens Lake, southeast California Sediment Magnetic and Paleomagnetic Data from Buck Lake, Oregon Summary of analytical data for sediment cores from the New England Mud Patch collected on USGS Field Activity 2016-001-FA Summary of analytical data for sediment cores from the New England Mud Patch collected on USGS Field Activity 2016-001-FA