¹⁰Be variation in surficial sediments of the Central Indian Basin

Distribution of ¹⁰Be in systematically collected (degree × degree interval at 10 to 16 °S; 73.5 to 76.5 °E) surficial siliceous ooze, siliceous clay and pelagic clay sediments (top 2 cm) from the abyssal Central Indian Basin and the Andaman Sea is used to evaluate sources and to decipher the transport pathways of sediment particles, demarcate sediment depocenters and erosional areas. While ¹⁰Be concentrations display a wide variation (0.12-5.56 × 10⁹ atoms g^-1) with an average of 3.58 × 10⁹ atoms g^-1 in the Central Indian Basin, the values in the Andaman Sea are uniform with an average of 1.49 × 10⁹ atoms g^-1. The ¹⁰Be/⁹Be values in the Central Indian Basin sediments range between 0.06 and 2.99 × 10^-8 atoms atoms^-1 and average to ∼1.56 × 10^-8 atoms atoms^-1. Correlation of ¹⁰Be data with some selected major (Al, Mn, Ti) and trace (Rb and Ba) elements suggest that large part of the isotope has been supplied through direct atmospheric fallout from the water column and minor part from lithogenic detrital flux. Significantly lower ¹⁰Be accumulation rates in the Central Indian Basin and an order of magnitude higher in the Andaman Sea sediments compared to the estimated global average production rates indicate removal of the isotopes at the continental margins. Bottom topography seems to exert control on local ¹⁰Be variation, where sediments deposited in valleys or topographic depressions contain higher ¹⁰Be concentrations in contrast to the probably erosion-dominated areas at the slopes and troughs.