This fraction, which is enriched in heavy minerals relative to the sand fraction, is mainly detrital but contains a strong authigenic component. The authigenic silt heavy-mineral fraction is largely a product of the lateritic weathering and dominated by iron oxides and alterites. Grains of bladed rutile and leached ilmenite are common. Spatial variability in silt-fraction mineralogy is considerable. Within the Rio Cibuco system variability is related to compositional differences in rapidly eroding source rocks. On the shelf, silt heavy-mineral abundances are greatest at the river mouths and decrease seaward. Variability in the shelf samples is controlled primarily by source rivers and shelf sorting processes.
Citation Information
Publication Year | 1995 |
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Title | Silt fraction heavy-mineral distributions in a lateritic environment: The rivers and insular shelf of north-central Puerto Rico |
DOI | 10.1016/0037-0738(94)00114-A |
Authors | L. J. Poppe, J.A. Commeau, G. Luepke |
Publication Type | Article |
Publication Subtype | Journal Article |
Series Title | Sedimentary Geology |
Index ID | 70019612 |
Record Source | USGS Publications Warehouse |
USGS Organization | Woods Hole Coastal and Marine Science Center |