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Structure and directional properties of some valley sandur deposits in southern Iceland
Author(s) -
BLUCK B. J.
Publication year - 1974
Publication title -
sedimentology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.494
H-Index - 108
eISSN - 1365-3091
pISSN - 0037-0746
DOI - 10.1111/j.1365-3091.1974.tb01789.x
Subject(s) - imbrication , geology , lineation , stratification (seeds) , geomorphology , stage (stratigraphy) , paleocurrent , sedimentary rock , petrology , clastic rock , geochemistry , paleontology , seed dormancy , botany , germination , dormancy , biology , tectonics
Sediments in the valley sandurs of Markarfljot and Landmannalaugar accrete in complex lateral (transverse) bars. Directional structures within the bars are more variable in orientation than the channels which contain them. This greater variability is mainly due to the diversification of the flow, at the low stage, as it moves through the accretion topography of the sandur. Different directional structures preferentially record different stages of the flow: imbrication and lineation form mainly in response to the high flow stage, and have a low degree of dispersion; cross‐stratification records the low stage of flow, and has a wide dispersion. Cross‐stratification is produced in four main ways: by small deltas, by megaripples, by ripple topped bars, and by migrating accretionary bar banks. Small deltas form at low flow stage; accretionary banks at high.