Demise of Ediacaran dolomitic seas marks widespread biomineralization on the Siberian Platform

Cavity‐filling dolomite speleothems and submarine cements in the Ediacaran Dengying microbialites, South China: Responses to high‐frequency sea‐level fluctuations in an ‘aragonite–dolomite sea’

“…Recent studies demonstrated that fibrous dolomite with length‐slow, rhombic crystals and well‐preserved growth bands, probably had been directly precipitated from seawater rather than from replacement of the fibrous calcite (Fig. A; Hood et al ., ; Hood & Wallace, ; Wood et al ., ). On the other hand, the growth of this primary dolomite on fibrous calcite precursor is non‐syntaxial (Fig.…”

“…A, B, E and F). On the other hand, the seawater secular variation model suggested a high Mg/Ca (>2) ratio during the Neoproterozoic (Hardie, ), fairly coincident with the deposition of a high percentage of mimetic dolomite (Corsetti et al ., ; Hood et al ., ; Hood & Wallace, ; Wood et al ., ). The high‐Mg/Ca seawater could have not only preferentially precipitated metastable calcium carbonate precursors (for example, Mg‐calcite) since Mg 2+ was a growth inhibitor for low‐Mg calcite, but also provided sufficient Mg 2+ for dolomite precipitation or mimetic dolomitization.…”

“…This homogeneous growth pattern suggests a subaqueous environment in which the water was invariably supersaturated with respect to carbonate minerals. Thus, the isopachous fibrous dolomite cements widely present in the Neoproterozoic successions were probably precipitated from seawater in submarine environments, as suggested by previous studies (Hood et al ., ; Hood & Wallace, ; Wood et al ., ). Recent studies demonstrated that fibrous dolomite with length‐slow, rhombic crystals and well‐preserved growth bands, probably had been directly precipitated from seawater rather than from replacement of the fibrous calcite (Fig.…”

Resolving Terreneuvian stratigraphy in subtidal–intertidal carbonates: palaeontological and chemostratigraphical evidence from the Turukhansk Uplift, Siberian Platform

“…; Wood et al . ) and taxonomically abundant assemblages of the lower Cambrian small skeletal fauna (Rozanov et al . ; Khomentovsky & Karlova ; Parkhaev & Karlova ; Kouchinsky et al .…”

“…One of the key regions supplying our knowledge of the development of Phanerozoictype ecosystems in the latest Ediacaran and early Cambrian is the Siberian Platform. This region provides some of the oldest palaeontological evidence of biologically controlled mineralization (Zhuravlev et al 2012;Nagovitsin et al 2015;Wood et al 2016) and taxonomically abundant assemblages of the lower Cambrian small skeletal fauna (Rozanov et al 1969;Khomentovsky & Karlova 1993;Parkhaev & Karlova 2011;Kouchinsky et al 2017). However, the complicated facies structure of the Siberian Platform in the late Ediacaran and early Cambrian hinders precise intraregional and interregional correlation, as well as localization of the main bio- (Peng et al 2012) and chemostratigraphical (Zhu et al 2006;Maloof et al 2010a) boundaries within the studied sections.…”