Biological Weathering and Geochemical Fractionation by Termites: A Case Study of Loessic Sediments

Author: Singh S., Chaudhary A., Handique S., Singh S.K. and Jayant K. Tripathi
Year of Publication: 2017
Published: Jawaharlal Nehru University, New Delhi, India. Earth Science India. Vol. 10 (III): 94 -107

Abstract:
Termites are ecosystem engineers who transform soil and sediments and make mounds. They transport and mix large quantities of sediments across the horizons of the mounds, modify their immediate environment at different depths. We have tried to understand the role of termites in weathering and geochemical transformations of homogeneous sediments of termite mounds of Delhi ridge area. The samples and respective parent sediments were collected from the seven locations of Jawaharlal Nehru University, New Delhi. It has been observed that bioturbation of termites caused fining of the mound samples compared to the parent sediments. The mound samples show higher weathering than the parent sediments. Carbonate precipitation in the alkaline conditions imposed by termites could have enriched Ca and Mg. Whereas, the clay enrichment caused K, Al enrichment. Fe got enriched in the oxic condition of mounds. Ti and Zr got enriched by the enrichment of finer grains of their minerals already present in the parent material. The enrichment of Co, Ni, Cu, Cr, and V show the biogeochemical role of the termites. The organic carbon brought by the termites, and iron oxides, both enriched phosphorus in the mounds. It has found that the termite mounds also have potential in sequestering CO2 by accumulating organic matter, precipitating carbonate minerals, and increasing chemical weathering of silicate minerals.

Keywords:
Termite, Bioturbation, Geochemistry, Weathering, Trace elements

Citation:
Swati Singh, Anurag Chaudhary, Sumi Handique, Singh S.K., Tripathi J.K. (2017): Biological Weathering and Geochemical Fractionation by Termites: A Case Study of Loessic Sediments. Jawaharlal Nehru University, New Delhi, India. Earth Science India. Vol. 10 (III): 94 -107

Link:
https://www.researchgate.net/publication/320099496_Biological_Weathering_and_Geochemical_Fractionation_by_Termites_A_Case_Study_of_Loessic_Sediments_from_Jawaharlal_Nehru_University_New_Delhi_India

Spatial and Temporal Variations in the Geochemistry of the Brahmaputra River Water

Author: Sumi Handique, Pragyan Sharma, Kushal K. Baruah and Jayant K. Tripathi
Year of Publication: 2017
Published: International Journal of Geosciences 8(05): 756

Abstract:
Spatial and temporal variation in the major ion composition of the waters in the Brahmaputra River has been measured to understand chemical weathering and the factors controlling these processes. Samples were collected from the Brahmaputra mainstream at five stations Pasighat, Dibrugarh, Tezpur, Guwahati and Dhubri during monsoon and post monsoon seasons. The total dissolved solids in the waters of the Brahmaputra system ranges between 62.5 and 192.5mgl−1. The (Total dissolved solids) TDS of the Brahmaputra measured in this study are less than the values reported by earlier workers. Gibbs plot was plotted to investigate the dominant process controlling the water chemistry of the Brahmaputra. The plots of TDS vs. (Na + K)/(Ca + Na + K) and TDS vs. Cl Cl + HCO3− indicate that rock weathering is the main process controlling the chemistry of water in the Brahmaputra River. Factor analysis was done to study the factors controlling the water chemistry of the Brahmaputra.

Keywords:
Spatial, Temporal, Weathering, TDS, Brahmaputra

Citation:
Handique, S., Sharma, P., Baruah, K. K., Tripathi, J. K. (2017): Spatial and Temporal Variations in the Geochemistry of the Brahmaputra River Water. International Journal of Geosciences 8(05): 756.

Link:
https://www.scirp.org/journal/paperinformation.aspx?paperid=76684