Biogenic signature and ultra microfossils in ferromanganese nodules of the Central Indian Ocean Basin

Nayak, B and Das, Swapan K and Munda, Parikshit (2013) Biogenic signature and ultra microfossils in ferromanganese nodules of the Central Indian Ocean Basin. Journal of Asian Earth Sciences, Volume 73, 5 September 2013, Pages 296–305 (IF-2.379). pp. 296-305.

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Theories related to the precipitation mechanism of the metallic elements in marine manganese nodules have remained controversial between two schools of thoughts (1) chemical oxidation (abiotic origin) and (2) deposition of the metals through microbial enzymatic processes (biogenic origin). One of the most important evidence in support of the biogenic origin is the occurrence of fossilized microbes. However, well-documented literature in this regard is either lacking or very scanty in case of Indian Ocean nodules. Using high resolution FEG-SEM we have recorded various biogenic signatures and ultra microfossils in the ferromanganese nodule samples from Central Indian Ocean Basin (CIOB) that are presented in this paper. The microfossils are mostly protozoans belonging to varieties of bacteria, diatoms and foraminifera. Some of the features recorded in this study have perhaps never been reported before from any manganese nodules. The chemical compositions of these ultra microfossils indicate a high-level of manganese precipitation in and around them in comparison to the distant surrounding areas. While clumpy microbes are enriched with nickel, the rod shaped bacteria are rich in copper. Up to 4.70 wt.% nickel and 5.31 wt.% Cu have been recorded in the fossilized microbe bodies. The high abundance of biogenic features as well as microfossils in the ferromanganese nodules and their chemical compositions support arguments in favor of a dominant role of the microorganisms in the construction of the nodules of the CIOB.

Item Type:Article
Official URL/DOI:
Uncontrolled Keywords:Manganese nodule; Ultra microfossils; Biogenic origin; Central Indian Ocean Basin
Divisions:Mineral Processing
Material Science and Technology
ID Code:6720
Deposited By:Dr. A K Sahu
Deposited On:27 Sep 2013 16:14
Last Modified:04 Apr 2014 15:54
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