A Late Devonian Hydrocarbon-Seep Deposit Dominated by Dimerelloid Brachiopods, Morocco

Late Jurassic–Early Cretaceous hydrocarbon seep boulders from Novaya Zemlya and their faunas

“…The micrite is accompanied by fans of fibrous cements, possibly former aragonite (Fig. 6F) Peckmann, 2007), as the 13 C values between -15‰ and -25‰ 13 C are similar to the values found in carbonates formed at oil seeps (e.g. Joye et al, 2004).…”

“…Savard et al, 1996;Peckmann et al, 2007;Kiel and Peckmann, 2008). Although our XRD investigation reveals that the Novaya Zemlya seep carbonate is now calcite, the carbonate cementation of pore space in calcareous sandstones and the preservation of aragonitic mollusc shells suggest that the intial mineralogy of this phase was aragonite.…”

“…The scarcity of sites older than late Mesozoic means that knowledge of pre-Cretaceous hydrocarbon seep faunas is poor (Gischler et al, 2003;Campbell, 2006;Peckmann et al, 2011Peckmann et al, , 2013. It has been suggested that since at least the Late Devonian until the Early Cretaceous, seeps were largely dominated by dimerelloid rhynchonellid brachiopods (Peckmann et al, 2007;Sandy, 2010;Kiel et al, 2014), with molluscs also present, although often subordinate (e.g. Peckmann et al, 1999Peckmann et al, , 2001Peckmann et al, , 2011;…”

Evolution of the last koninckinids (Athyridida, Koninckinidae), a precursor signal of the early Toarcian mass extinction event in the Western Tethys

“…They commonly form cluster accumulations as an adaptive response to these very restricted confined habitats. Cold-seep deposits are often characterized by mass occurrences and dense populations of packed individuals (Callender and Powell, 1999;Peckmann et al, 2001Peckmann et al, , 2007Peckmann et al, , 2011Peckmann et al, , 2013Kiel and Peckmann, 2008;Sandy et al, 2012). In addition to the exceptional profusion of specimens, these habitats show monospecific or oligotypical communities (Callender and Powell, 1999;Gischler et al, 2003;Kaim et al, 2010;Peckmann et al, 2013).…”

“…Petrographical proxies.-Fossil cold-seep deposits recurrently show distinctive petrographical attributes and microfabrics. Characteristics such as clotted micrite, fibrous, banded and bothryoidal cement or framboidal pyrite, even in the form of aggregations or laminae, are typically found in the methane-seep carbonates (Campbell et al, 2002;Peckmanm and Thiel, 2004;Peckmann et al, 2007Peckmann et al, , 2011Hammer et al, 2011;Kuechler et al, 2012;Sandy et al, 2012;Kiel et al, 2013;Kaim et al, 2013). These features are completely absent in the lithologies herein studied and petrographic evidences (Fig.…”