Braided River Sand, Rio Pitai, Santa Cruz, Bolivia
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Rio Pitai |
Macro |
Location |
Rio Pitai, Santa Cruz, Bolivia |
Depositional facies |
Broad, shallow and sandy riverbed |
Provenance |
The Rio Pitai drains the Subandean Ranges and erodes thick palaeozoic and mesozoic continental sedimentary rocks as well as thick eolian sediments |
Composition |
Quartz |
Texture |
Medium to fine grained, well sorted, subrounded |
Petrographic thin section:
Description |
Moderately sorted, moderately to well rounded quartz sand. Typical for provenance from a fold belt of clastic sedimentary rocks |
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Bright field |
Dark field |
Sample number |
Heubeck0026 |
Collector |
Christoph Heubeck, Institut für Geologische Wissenschaften, FU Berlin |
Date of sampling |
2003 |
Comments:
The meandering and braided Rio Pitai in the Bolivian lowland of the Amazonas Basin erodes the Subandean Miocene-Recent fold-and -thrust belt. This belt exposes thick continental successions of Carboniferous to Cretaceous eolian sandstones. The supermature source, the high mechanical resistance, and weathering of river sands under a tropical climate all contribute to the maturity. These sands are most likely multiply recycled.
