Quartz size/shape relationships: variable size/shape relationships of detrital quartz reflect differences in source/transport parameters

Conference · Tue Jan 01 00:00:00 EST 1985 · Geol. Soc. Am., Abstr. Programs; (United States)

OSTI ID:6653586

Ehrlich, R; Eggers, M R; Goodman, E D

A common misconception is that as size decreases, quartz grains become progressively more angular. All possible size/shape relationships can and do occur including: 1) no relationship, 2) fine sizes, more rounded, 3) finer sized more angular, and 4) size/shape discontinuities where shape is constant over a wide range and then changes and stays constant over the remaining range. Detritus from large, long established flood plains (Mississippi, Ganges, Amazon) display a continuous change in shape with size. Detritus from primary sources generally display no size/shape effect. Small rivers commonly exhibit size/shape discontinuities. The origin of a particular size/shape relationship arises from two opposing tendencies. Finer detritus travel much faster than coarser sands. Thus silts from one provenance can overtake coarser material of different provenance. If flood plains are large and long-lived, the contribution of individual tributaries is diluted almost to indetectibility and all sizes have time enough to reach the sea. In such situations the size/shape relationship reflects a steady state of equilibrium. In smaller rivers individual tributaries can provide significant proportions of grains to flood plains with characteristic sizes and shapes leading to discrete shifts in the size/shape curve.

• Research Organization: Univ. of South Carolina, Columbia (USA)
• OSTI ID: 6653586
• Report Number(s): CONF-8510489-
• Journal Information: Geol. Soc. Am., Abstr. Programs; (United States), Vol. 17; Conference: 98. annual meeting of the Geological Society of America, Orlando, FL, USA, 28 Oct 1985
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
SEDIMENTS
ABRASION
PHYSICAL PROPERTIES
SURFACE PROPERTIES
COMPARATIVE EVALUATIONS
ALLUVIAL DEPOSITS
ENVIRONMENTAL TRANSPORT
EROSION
GRAIN SIZE
QUARTZ
RIVERS
ROUGHNESS
SHAPE
CHALCOGENIDES
CRYSTAL STRUCTURE
GEOLOGIC DEPOSITS
MASS TRANSFER
MICROSTRUCTURE
MINERALS
OXIDE MINERALS
OXIDES
OXYGEN COMPOUNDS
SILICON COMPOUNDS
SILICON OXIDES
SIZE
STREAMS
SURFACE WATERS
580100* - Geology & Hydrology- (-1989)