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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.
