Highlights—Squeezing for Dolomite

Despite considerable effort, the origin(s) of dolomite have remained enigmatic for generations. To explore dolomitization in the Oligocene-Miocene chalks of Barbados, Machel et al. integrate field mapping, petrography, stable isotopes, XRD, and Sr isotopes. The results are interpreted to reveal that the cause of dolomitization in the chalk is similar (if not identical) to dolomite in Pleistocene carbonates at other locations on the island, driven by fluid expulsion from the underlying accretionary prism. The diagenetic history reveals that the Barbados accretionary wedge has undergone a prolonged history of compression, with concomitant expulsion of fluids, that has varied through time and space.  Although dolomitization can result from fluid expulsion in an accretionary prism setting, regionally extensive, pervasive dolomitization is not to be expected from this dolomitizing process.

Episodic fluid flow and dolomitization bymethane-bearing pore water of marine parentage in an accretionary prism setting, Barbados, West Indies by Hans G. Machel, Jonathan B. Sumrall, Patricia N. Kambesis, Joan R. Mylroie, John E. Mylroie, and Michael J. Lace

Highlights—Appalachians: Athabasca Antecessor

Although the Athabasca Oil Sands of Alberta, Canada, form one of the largest sources of hydrocarbons on the planet, and are a common topic in geopolitical debates, the origin of the sediment itself remained largely unknown. In this paper, Benyon et al. use detrital zircon uranium–lead (U-Pb) geochronology to examine the provenance of the McMurray Formation, the most significant Athabasca unit. The data reveal that the majority of the sediment in the Athabasca Oil Sands originally were derived from Appalachian sources in eastern North America. Nonetheless, several major tectonic provinces from across North America contributed sediment to these deposits (Canadian Shield, Appalachians, Cordillera), and their relative contributions changed through time. Collectively, these results emphasize the potentially important role of transcontinental sediment dispersal in these deposits, and other siliciclastic successions as well.

Provenance of the Cretaceous Athabasca Oil Sands, Canada: implications for continental-scale sediment transport by Christine Benyon, Andrew Leier, Dale A. Leckie, Andrew Webb, Stephen M. Hubbard, and George Gehrels

New JSR Co-Editor!

JSR PaperClips readers: Please welcome Dr. Leslie Melim as the new co-editor of Journal of Sedimentary Research. Leslie’s general responsibilities will cover manuscripts in the topical areas of carbonates and diagenesis. 

An SEPM member since 1988, she has served as JSR Associate Editor for Book Reviews (2001-2004) and as Associate Editor since 2004. She also has served on the editorial board for Sedimentary Geology and FACIES. Currently, Leslie is a professor in the undergraduate-only Geology Department at Western Illinois University. Her research has included the diagenesis of Paleozoic through Neogene carbonates, but now focuses on the geomicrobiology of speleothems, principally those that grow in cave pools.

Leslie is enthusiastic about her new position: “I’m excited to serve SEPM as the new co-editor of JSR. I look forward to working with authors, the associate editors, reviewers and the JSR staff to maintain the high standards for which JSR is known.”  And we are looking forward to continuing the journey with you, Leslie!

Highlights – The Curious Queso of Aged Martian Sediment

For years, children and readers of 16^th and 17^th century English literature have fancied the notion of the Proverbs of John Heywood that claimed that “the moon is made of a greene cheese.” Although the proverb has been largely ignored for centuries, new explorations of surface sediment on Mars have re-opened the controversy, albeit on a different celestial body. In this study, Greenman and Neila describe observations of slope angles and grain sorting trends from the Martian surface west of Caseus Rotula that suggest the presence of noncohesive granular materials, like many granular materials from the kitchen (e.g., coffee grinds and Brazil nuts). These data were integrated with data on ultrasonic velocity from sediment, which illustrate that velocity of the Martian surface sediment average ~1600 m/s and show temperature dependence---trends remarkably similar to published measurements of Cheddar cheese (not green cheese, however). These sediments are interpreted to reflect a primal Martian crust source (there's "cheese in the crust"?), perhaps generated as impact ejecta de brie.

Sedimentology, geomorphology, and ultrasonic velocity of Martian surface sediment, Caseus Rotula:  Implications for Martian crustal composition by L.T.L. Greenman, and I. A. Neila