Organotemplate structures in sedimentary manganese carbonates of the Neoproterozoic Penganga Group, Adilabad, India

Journal of Earth system science

Jens Gutzmer1¹  Nicolas J Beukes1¹  Joydip Mukhopadhyay1 2¹ 

[1] Rand Afrikaans University, Department of Geology, PO Box 524, Auckland Park, Johannesburg 2006, South Africa.$$

关键词: Organotemplate;    manganese carbonate;    microbial;    EPS;    Neoproterozoic;    Penganga Group;    India.;   

DOI  :  

学科分类：天文学(综合)

来源: Indian Academy of Sciences

【 摘 要 】

Manganese carbonates interstratified with bedded chert in the Chanda Limestone of the Neoproterozoic Penganga Group at Adilabad, south India, have been studied for possible evidence that microbiota played a role in the mediation of early diagenetic Mn-carbonate formation in Precam- brian marine sedimentary successions. The manganese carbonate and chert beds occur within a below wave base, deep-water distally steepened ramp succession. High resolution SEM petrogra- phy of the manganese carbonates revealed two basic morphologies — spherical to oval-cylindrical shaped microconcretions, and tubular to irregular, elongated, film-like microstructures. Infolded filmy to hollow tubular strand-like internal morphologies of the spherical to oval-cylindrical shaped microconcretions suggest their microbial affinity. The tubular and film morphologies with mesh- like interconnections closely resemble architectures of microbial extracellular polymeric substance (EPS). Mineralization took place on these organotemplates by the process of permineralization as well as replacement in an early diagenetic pore-water environment with reduction of higher manganese oxy-hydroxides by organic matter and consequent increase in dissolved carbonate.

【 授权许可】

Unknown