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The AAPG/Datapages Combined Publications Database

AAPG Bulletin

Abstract


Volume: 55 (1971)

Issue: 2. (February)

First Page: 338

Last Page: 338

Title: Variations in Heavy Mineral Composition During Transport of Short-Headed Stream Sands: ABSTRACT

Author(s): Romeo M. Flores

Article Type: Meeting abstract

Abstract:

Past studies on variation in heavy minerals along large streams have shown that progressive change, or lack of it, during transport is due to abrasion, dilution, hydraulic conditions, and sorting on the basis of size, density, and shape. In the light of these studies assessment of the variation in heavy minerals was made along the short-headed Canadaway and Cattaraugus Creeks in western New York. In that area the glacial drift and moraine deposits are ready sources of heavy minerals. Major annual erosion and transportation of these materials occur during peak streamflow in March-April and deposition during decreased flow in the succeeding months. Thus, during the summer of 1968, efforts were made to collect part of the bedload deposited during the interim period of optimu and minimum streamflow.

Analyses of samples of similar size distributions show that variation in heavy minerals during transit occurs along these creeks and the relation is best developed in the coarse fractions. Results show a decrease in garnet and complementary increase in hypersthene, hornblende, and tourmaline downstream. Comparison of variation in heavy minerals reveals that although overall difference in weight percent exists, the relation of these minerals and the transport direction do not differ significantly between the two creeks.

Consideration of the possible causes of heavy mineral variation indicates that it is not due to dilution and abrasion. This modification may result from progressive sorting on the basis of size, density, and shape as produced by the annual current-flow fluctuations.

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