Facies characteristics and diversity in carbonate eolianites

Abstract

Carbonate eolian dunes can form huge sand bodies along the coasts but are seldom described in the pre- Quaternary record. The study of more than 600 thin-sections collected in present-day, Holocene and Pleistocene dunes from Sardinia, Crete, Cyprus, Tunisia, Morocco, Australia and Baja California conWrms that these deposits can be easily misinterpreted as shallow marine at core or thin-section scale. The classical eolian criteria (Wne-grained and well-sorted sands) are exceptional in carbonate dunes because the diversity of shapes and densities of carbonate particles lowers the critical shear velocity of the sediment thus blurring the sedimentary structures. Wind carbonate deposits are mainly heterogeneous in size and often coarsegrained. The paucity of eolianites in the pre-Quaternary record could be due to misinterpretation of these deposits. The recognition should be based on converging sedimentological and stratigraphic elements at core scale, and diagenetic (vadose diagenesis, pedogenetic imprints) and petrographical (grain verticalization, scarcity of micritic envelopes, broken and/or reworked foraminifera) clues in thin-section. Bioclastic or oolitic grainstones showing evidence of vadose diagenesis or pedogenetic imprints, should always be suspected of having an eolian origin

External controls on the distribution, fabrics and mineralization of modern microbial mats in a coastal hypersaline lagoon, Cayo Coco (Cuba)

“…Pleistocene/Holocene deposits in San Salvador experienced an intense reworking of previously deposited marine carbonates forming aeolianites (Caputo, ; Carew & Mylroie, ; Hagey & Mylroie, ; White, ). Among the aeolian deposits, carbonate aeolianites are peculiar because traditional recognition criteria are rare (Frébourg et al ., ). Studies on modern coastal environments highlight that vadose or pedogenic imprints are common in carbonate aeolianites (e.g.…”

“…Studies on modern coastal environments highlight that vadose or pedogenic imprints are common in carbonate aeolianites (e.g. Flügel, ; Frébourg et al ., ). In the Cayo Coco lagoonal network, the substrate (F1) only crops out several centimetres to decimetres on the surface; thus, a 3D geometric study of these deposits is not possible, because they are covered primarily by mangroves and recent lagoonal sedimentation.…”

Foraminiferal biostratigraphy and sequence stratigraphy across the mid-Carboniferous boundary in the Central Taurides, Turkey

“…Eolianites can occur within transgressive or regressive parts of sequences or both (Carew and Mylroie 2001;Frébourg et al 2008). stated that eolinates overlying subaerial exposure surfaces are interpreted to be deposited during transgressions.…”

Depositional Characteristics of Carbonate-Cemented Fossil Eolian Sand Dunes: Bozcaada Island, Turkey

“…A number of previous publications showed that these rocks are, to a large extent, of Quaternary age with a global distribution (Fairbridge and Johnson, 1978;Thomas, 1997) and were formed during both low and high stands of the global sea level. From the sedimentological point of view, moderate-to-hard cementation, cross-bedding (Frébourg et al, 2008), and rhizolith content as organosedimentary components (Klappa, 1980) are some common properties of those eolian occurrences. Based on the preceding attributes, eolianites provide sound evidence of multifarious dune generation in coastal environments (Brooke, 2001).…”