Bathymetry and sediments on the carbonate platform off western India: Significance of Halimeda bioherms in carbonate sedimentation

Journal of earth system science

Mahale V P^2¹  Purnachandra Rao V^1,2² 

[1] CSIR-National Institute of Oceanography, Dona Paula, Goa 403 004, India.^2;Department of Civil Engineering, Vignan’s University, Vadlamudi, Guntur 522 213, India.^1

关键词: Halimeda bioherms;    early Holocene;    upwelling;    carbonate platform;    western India;   

DOI  :  

学科分类：天文学(综合)

来源: Indian Academy of Sciences

【 摘 要 】

Bathymetry across the carbonate platform off western India indicated small-size pinnacles and their lateral coalescence into 2 -6-m high mounds landward, and linear elongated carbonate ridges and troughs, mounds and banks up to a height of 20-m seaward of the platform. Seismic data indicated that these mounds were transparent with no rigid internal structure and can be defined as bioherms. The sediments were abundantly aragonite faecal pellets, Halimeda grains and ooids and their radiocarbon ages ranged from 11 to 7.5 ka BP. It appears that the growth of Halimeda bioherms on the platform was facilitated by intense upwelling during the early Holocene. The terrigenous sediments brought by rivers were deposited in the inner shelf and have not affected the growth of bioherms. It is estimated that the platform comprises at least 1.85 Gt of mass CaCO$_3$ accumulated during the early Holocene and comparable to those on the Great Barrier Reef. Halimeda bioherms produce abundant carbonate sediments and their growth period represents a geological carbonate sink and release of high CO$_2$ to the atmosphere. Detailed shallow seismic studies and sediment cores are needed to quantify the exact mass content of CaCO$_3$ and model climate change during the early Holocene.

【 授权许可】

CC BY