Solution pans and linear sand bedforms on the bare-rock limestone shelf of the Campeche Bank, Yucatán Peninsula, Mexico. (1st April 2016)

• Record Type: Journal Article
• Authors: Goff, John A.; Gulick, Sean P.S.; Cruz, Ligia Perez; Stewart, Heather A.; Davis, Marcy; Duncan, Dan; Saustrup, Steffen; Sanford, Jason; Fucugauchi, Jaime Urrutia
• Is Part Of: Continental shelf research. Volume 117(2016)
• Page Start: 57
• Page End: 66
• Publication Date: 2016-04-01
• Subjects: Carbonate platform -- Solution pans -- Sand bedforms -- Campeche Bank -- Seafloor -- Multibeam -- CHIRP; Continental shelf -- Periodicals; Submarine geology -- Periodicals; 551.41
• DOI: 10.1016/j.csr.2016.02.005
• Languages: English
• ISSNs: 0278-4343

Abstract

Abstract: A high-resolution, near-surface geophysical survey was conducted in 2013 on the Campeche Bank, a carbonate platform offshore of Yucatán, Mexico, to provide a hazard assessment for future scientific drilling into the Chicxulub impact crater. It also provided an opportunity to obtain detailed information on the seafloor morphology and shallow stratigraphy of this understudied region. The seafloor exhibited two morphologies: (1) small-scale (<2 m) bare-rock karstic features, and (2) thin (<1 m) linear sand accumulations overlying the bedrock. Solution pans, circular to oblong depressions featured flat bottoms and steep sides, were the dominant karstic features; they are known to form subaerially by the pooling of rainwater and dissolution of carbonate. Observed pans were 10–50 cm deep and generally 1–8 m wide, but occasionally reach 15 m, significantly larger than any solution pan observed on land (maximum 6 m). These features likely grew over the course of many 10's of thousands of years in an arid environment while subaerially exposed during lowered sea levels. Surface sands are organized into linear bedforms oriented NE-SW, 10's to 100's meters wide, and kilometers long. These features are identified as sand ribbons (longitudinal bedforms), and contained asymmetric secondary transverse bedforms that indicate NE-directed flow. This orientation is incompatible with the prevalent westward current direction; we hypothesize that these features are storm-generated. Highlights: Extraordinarily large solution pans were discovered on the Campeche Bank. The pans imply a very arid climate in this region during the last glacial period. Modern sediment bedforms on the Campeche Bank may be formed by large storms.