This dataset contains Mg/Ca and Mg/Ca-derived SST data of sediment core MD161-17 from the Bay of Bengal. For Mg/Ca analysis, 30-40 specimens (>150 µm) of G. ruber (white) were used. The sample preparation followed Barker et al. (2003) with slight modifications. Mg/Ca ratios were measured using an Agilent Technologies 700 Series ICP-OES with a CETAX ASX-520 autosampler housed at the Faculty of Geosciences, University of Bremen. Mg/Ca values were then used to estimate SSTs using the equation Mg/Ca=0.449exp(0.09*T) (Anand et al., 2003).

Radiocarbon ages measured on planktonic foraminifera Globigerinoides ruber alba and stable oxygen isotope and Mg/Ca ratios measured on the same species. For Mg/Ca and d18O measurements shells from the 250-350 micrometer size fraction were used. Mg/Ca measurements are based on 30-40 shells that were cleaned using an oxidative cleaning step. Seawater temperature estimates were calculated using the T = ln(Mg/Ca/0.09)/0.38 following 10.1029/2001GC000200.

Radiocarbon ages measured on planktonic foraminifera Globigerinoides ruber alba and stable oxygen isotope and Mg/Ca ratios measured on the same species. For Mg/Ca and d18O measurements shells from the 250-350 micrometer size fraction were used. Mg/Ca measurements are based on 30-40 shells that were cleaned using an oxidative cleaning step. Seawater temperature estimates were calculated using the T = ln(Mg/Ca/0.09)/0.38 following 10.1029/2001GC000200.

This dataset contains AMS-14C ages of planktonic foraminifera tests of sediment core MD161-17 from the Bay of Bengal. Measurements were performed on mixed planktonic foraminifera species >150 mm fraction at the NSF-Arizona AMS Laboratory of Arizona University, USA. Radiocarbon ages were calibrated to calendar years using the CALIB 7.1 software and the Marine13 calibration curve (Reimer et al., 2009; Stuiver & Reimer, 1993) with the global reservoir correction of 400 years (Southon et al., 2002).

We have deciphered the deep sea carbonate-ion content and associated dissolution in the central Equatorial Indian Ocean (5°N & 77°E). The marine sedimentary core was collected during the 044th Cruise of RV Sindhu Sadhana (SSD-044/GC01) using Gravity corer, which covers the period of the last 43 ka. Variations of dissolution indices were observed for the last 43ka. The overall data set shows the variation in carbonate dissolution during the late Glacial to Holocene epoc.

In this data set, we present the low carbonate ion condition in the deep sea region of the central Equatorial Indian Ocean (5°N & 77°E) over the last 40ka. The marine sediment core SSD044_GC-01 was collected during the 044th Cruise of RV Sindhu (SSD044) Sadhana using a Gravity corer. The age model of the core was obtained using four accelerator mass spectrometry (AMS ) 14C dates on ~15 mg of mixed planktic foraminiferal species, viz, Globigerinoides ruber, Globigerinoides sacculifer, Neogloboquadrina dutertrei and Globorotalia menardii. The radiocarbon dates were calibrated to calendar ages using the calib 7.1 programme (Reimer et al., 2013). For the analysis of shell weights of selected planktic foraminifera, a portion of the Coarse Fraction was adequately cleaned and sonicated. The >63 μm residue was dry sieved between 300 and 355 μm size fractions. Fifty tests of G. ruber, P. obliquiloculata, and N. dutertrei were picked and weighed on a microbalance (1σ precision: ± 2 μg, n =10). Shell weights of selected planktic foraminifera (G. ruber, P. obliquiloculata, N. dutertrei) show a low carbonate ion concentration in the deep sea region of the study area.

In this data set, we present percentage of calcium carbonate (CaCO3), ratio of organic carbon to total nitrogen, coarse fraction (>63 μm), size index percentage, total planktic foraminifera number, foraminifera fragment percentage (>125 μm), the ratio of benthic to planktic foraminifera, Globorotalia spp. percentage and Radiolarian percentage as well as the planktic foraminifera assemblage to show the carbonate dissolution in the deep sea region of the central Equatorial Indian Ocean (5°N & 77°E) over the last 40 ka. The marine sediment core SSD044_GC-01 was collected during the 044th Cruise of Research Vessel Sindhu (SSD044) Sadhana using a Gravity corer. To analyze the species abundance of planktic foraminifera, a portion of the Coarse Fraction (>63 μm) was dry sieved from 125 μm size fractions. Approximately ~300 intact tests of planktic foraminifera were picked and dissolution-sensitive and insensitive species abundance were made to show a carbonate ion concentration in the deep sea region of the study area during the last 43ka.

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Variations in sea surface temperature (SST), d18O of sea water (δ18Ow), and salinity were reconstructed for the past 68 ka using a sediment core (AAS9/21) from the eastern Arabian Sea (EAS) in order to understand the changes in evaporation and precipitation associated with the monsoon system. The Mg/Ca-derived SST record varies by ~4°C; it shows that marine isotope stage (MIS) 4 was warmer than MIS 3, that the Last Glacial Maximum was 4°C cooler than the present, and that there was a 2°C increase within the Holocene. MIS 4 records higher d18Ow and salinity values than MIS 2, suggesting variable flow of low-salinity Bay of Bengal flow into the EAS during glacial periods. The transition from MIS 4 to MIS 3 was marked with a conspicuous shift from higher to lower d18Ow values, which reflects a decrease in the evaporation-precipitation budget in the EAS, perhaps due to the strengthening of southwest monsoon. Monsoon reconstructions based on d18Ow reveal that monsoon-driven precipitation was higher during MIS 3 and MIS 1 and was lower during MIS 2 and MIS 4. This is consistent with earlier monsoon reconstructions based on upwelling indices from the western Arabian Sea. However, the amplitude of monsoon fluctuations derived through upwelling indices and d18Ow varies significantly, which may indicate spatial variability of monsoon rainfall.