RT Journal Article
T1 Detrital modes in sedimenticlastic sands from low-order streams inthe Iberian Range, Spain: the potential for sand generation bydifferent sedimentary rocks
A1 Arribas Mocoroa, José
A1 Tortosa, A.
AB The composition of modern stream sands derived from sedimentary source rocks in the Iberian Range has been analyzed inorder to evaluate the contributions of the different bedrock types (mainly sandstones, limestones and dolostones). Temperate tosubhumid climate and short transport conditions promote a weathering-limited denudation regime. As expected, sandcomposition proved to be essentially quartzolithic, with variable amounts of penecontemporaneous carbonates.Sand compositional data were compared with the exposure areas of the different bedrocks in the drainage sub-basinsconsidered for semi-quantitative assessment of the sand generation potential of each bedrock type. Siliciclastic formations(sandstones) appear to be by far the most significant sand producers, with Sand Generation Indices (SGIs) in the medium sandfraction ranging from 4 to 20; i.e., 4 to 20 times greater than the SGI of carbonate rocks. Composition and texture are the mainfactors controlling carbonate sand generation. Sparitic limestones yield higher SGIs (2.8 to 20) when source terrains areconstituted exclusively by carbonate rocks. High sparite grain content in the sands is enhanced by supplies from additionalsources, such as calcitized dolostones. Dolomicrite sources are strongly under-represented in the sands analyzed (very low SGI),whereas the proportion of micritic limestone grains tends to be an accurate reflection of that bedrock at the source.Even though the results presented here refer to the first stage of sand generation with negligible transport effects, we thinkthey may be helpful in the analysis and reconstruction of source terrains in ancient sedimenticlastic deposits
PB Elsevier
SN 0037-0738
YR 2003
FD 2003
LK https://hdl.handle.net/20.500.14352/49663
UL https://hdl.handle.net/20.500.14352/49663
LA eng
DS Docta Complutense
RD 26 ago 2024