Benthic anoxia, intermittent photic zone euxinia and elevated productivity during deposition of the Lower Permian, post-glacial fossiliferous black shales of the Paraná Basin, Brazil

Ichnofossils associated with lingulide shells from the Lower Permian of Brazil

“…The Campáleo outcrop (UTM 22J 0.618.473, 7.106. 243) comprises the first 10 m of the Lontras Member (MOURO et al, 2017). At the base of outcrop there is a 1-m-thick silty bioturbated argillite bed (i.e., the Glossifungites suite) and is overlain by a fossiliferous, 1.10-m-thick black shale layer (i.e., the Lontras Shale), followed by a non-fossiliferous, 7m-thick shelly rhythmite layer (MOURO et al, 2017).…”

“…243) comprises the first 10 m of the Lontras Member (MOURO et al, 2017). At the base of outcrop there is a 1-m-thick silty bioturbated argillite bed (i.e., the Glossifungites suite) and is overlain by a fossiliferous, 1.10-m-thick black shale layer (i.e., the Lontras Shale), followed by a non-fossiliferous, 7m-thick shelly rhythmite layer (MOURO et al, 2017). Lontras Shale can be informally divided into four levels, including sublevels, distinguished on the bases of rock features, fossil content, and pyrite concentration (MOURO et al, 2016(MOURO et al, , 2017.…”

“…At the base of outcrop there is a 1-m-thick silty bioturbated argillite bed (i.e., the Glossifungites suite) and is overlain by a fossiliferous, 1.10-m-thick black shale layer (i.e., the Lontras Shale), followed by a non-fossiliferous, 7m-thick shelly rhythmite layer (MOURO et al, 2017). Lontras Shale can be informally divided into four levels, including sublevels, distinguished on the bases of rock features, fossil content, and pyrite concentration (MOURO et al, 2016(MOURO et al, , 2017. Based on the quantity and preservation of the fossils that have been recovered in the Lontras Shale and are exposed at the Campáleo outcrop, this site has been identified as an important lower Permian (Cisuralian, 299 myr to 275 myr) Fossil-Lagerstätte (RICETTI et al, 2016;MOURO et al, 2016MOURO et al, , 2017.…”

Organic and inorganic geochemical study of the Lower Permian Walchia shale of the Intrasudetic Basin (SW Poland)

“…Some trace el e ments, such as U, Th, Ni, V, Mo, Co, Cr and their ra tios, have been widely used for iden ti fi ca tion of diagenetic re dox en vi ron ments due to their lower sol u bil ity under re duc ing con di tions, re sult ing in pre cip i ta tion un der ox ygen-de pleted sed i men tary con di tions (e.g., Hatch and Leventhal, 1992;Jones and Man ning, 1994;Zhou and Jiang, 2009;Zhou et al, 2012;Wójcik-Tabol, 2015;Lecomte et al, 2017;Mouro et al, 2017). The Mo con cen tra tions dem on strate a gen eral in crease with in creas ing TOC con tent, and range from 0.4 to 59 ppm, at tain ing even 609 ppm in one sam ple repre sent ing com plex II (Ap pen dix 1).…”

“…The Mo con cen tra tions dem on strate a gen eral in crease with in creas ing TOC con tent, and range from 0.4 to 59 ppm, at tain ing even 609 ppm in one sam ple repre sent ing com plex II (Ap pen dix 1). Mo con cen tra tions in di cate vari able re dox con di tions dur ing de po si tion of the Walchia shale (e.g., Mouro et al, 2017). The V/(V + Ni), V/Cr, U/Th, and Ni/Co ra tios have been ap plied to eval u ate the pres ence or ab sence of dis solved O 2 or H 2 S in the wa ter col umn dur ing de po si tion of the Walchia shale.…”