Sedimentary fabrics in the authigenic carbonates from Bush Hill: implication for seabed fluid flow and its dynamic signature

Abstract

Seep carbonates, the product of cold seep fluids mediated by microbial activity, archive information on seabed fluid flow and microbiological processes that led to their formation. Sedimentary fabrics are well developed in the authigenic carbonate from active seep sites at Bush Hill, Green Canyon Block 185 of the Gulf of Mexico. This authigenic carbonate has much lower carbon isotope values than typical marine cements and the carbonate is concluded to be derived from the oxidation of seeping petroleum. The authigenic fabrics commonly exhibit microbial or texturally unique sedimentary structures; e.g. framboidal pyrite, clotted microfabric and peloid, botryoidal aragonite, microfilament, and rosette-like aragonite are all preserved in seep carbonate. These fabrics are indicators of biological influence during microbial oxidation of petroleum and sulfate reduction when cold fluids seep on to the seabed. The textures are therefore considered as additional evidence that can be used to identify and interpret ancient cold-fluid seeps on seafloor. The difficulty of the preservation of these biogenic fabrics is thought to be related to the redox condition and dynamic signature (e.g. rate of fluid flow) of cold seeps.

Authigenic carbonates from methane seeps of the northern Congo fan: Microbial formation mechanism

“…2D and 4B-F). Similar framboidal textures have been found in other modern seep carbonates (Kohn et al, 1998;Naehr et al, 2000;Díaz-del-Río et al, 2003;Feng et al, 2008). The rod-shaped habit of carbonate cement found in some foraminiferal tests enclosed in the Congo fan seep carbonates (Fig.…”

“…Accordingly, the study of stable isotopes, lipid biomarkers, and biogenic fabrics of seep carbonates provides further insight into microbially mediated carbonate formation (e.g. Roberts and Aharon, 1994;Thiel et al, 1999;Boetius et al, 2000;Peckmann et al, 2001;Peckmann and Thiel, 2004;Pape et al, 2005;Chen et al, 2005Chen et al, , 2006Chen et al, , 2007Campbell, 2006;Birgel and Peckmann, 2008;Feng et al, 2008). Furthermore, stable carbon and oxygen isotopic compositions of carbonates provide information pertaining to the composition and temperature of seep fluids from which carbonates precipitated (e.g.…”

Tracing the evolution of seep fluids from authigenic carbonates: Green Canyon, northern Gulf of Mexico

“…The stable carbon and oxygen isotopic composition of seep carbonates serves as an indicator of the composition and source of seep fluids (e.g. Chen et al, 2005Chen et al, , 2007Feng et al, 2008;Peckmann et al, 2001b;Peckmann and Thiel, 2004;Roberts et al, 2010;Roberts and Aharon, 1994). Seep carbonates from GC140 are mainly composed of aragonite and HMC, with minor amounts of LMC and dolomite (Table 1).…”

Formation, diagenesis and fauna of cold seep carbonates from the Miocene Taishu Group of Tsushima (Japan)

“…Aïssaoui, 1985;Savard et al 1996), a carbonate Formation, diagenesis and fauna of cold seep carbonates mineral dominating many recent seeps (e.g. Feng et al 2008;Zwicker et al 2018). Aragonite cements form preferentially over calcite cements in waters rich in sulphate anions in aragonite seas (e.g.…”