Abstract

Cement types and mineralogy of Pleistocene and Holocene eolianites on the northeastern coast of the Yucatan Peninsula reveal that the late Pleistocene climate in that area was drier than the present one. Pleistocene dune rocks were deposited and lithified under the influence of an arid or semiarid climate in which sparse rainfall inhibited loss of metastable mineralogy, and intense evapotranspiration induced precipitation of finely crystalline calcite cement and caliche. Surficial caliche crusts formed an aquiclude that continues to protect the underlying Pleistocene eolianites from effects of the modern subhumid climate. The more humid and moderate climate of Holocene time has produced eolianites which are losing aragonite and Mg calcite at a relatively fast rate and which are cemented with generally coarser sparry calcite. Calcarenites that undergo early subaerial diagenesis in an arid climate may retain substantial intergranular porosity over long periods of geologic time.

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