KBH-5 bore-hole

Description

Greenstone volcanics beneath the Deccan Traps, recovered during scientific deep-drilling project undertaken by CSIR-NGRI from 2012-2020.

Steps to reproduce

The samples were crushed to 3 mm size using a tungsten-carbide plated jaw crusher. Thereafter, the sample grains were manually ground to 250 mesh size using an agate mortar and pestle. Subsequently, the hydraulic pressed pellets prepared from the finely powdered samples were analyzed by wavelength-dispersive x-ray fluorescence (WD-XRF; Pan Analytical model: Axios mAX) for the determination of major element oxide concentrations. Loss on ignition (LOI) values were determined using an automated thermogravimetric analyser (model: ELTRA Thermostep). An aliquot (5 mg) of the sample powder was dissolved following standard wet chemistry procedures for the determination of trace element and rare earth elements (REE) concentrations using a high-resolution inductively-coupled plasma mass-spectrometer (HR-ICP-MS; model: Nu Instruments Attom®). The geochemical analysis was performed at CSIR-National Geophysical Research Institute, Hyderabad, India. The representative compositions are reported in Table 1. The complete dataset is given in the online supplementary materials. A dacite sample collected from a depth of ~ 600 m weighing ~ 3000 g was crushed and pulverized for zircon extraction and in situ zircon U-Pb geochronology using a laser ablation system (model: Photon Machines G2 Analyte 193 nm ArF exciplex laser) connected to a high-resolution single-collector ICP-MS (model: Thermo Element 2) in the Center for Elemental Mass Spectrometry at the University of South Carolina, USA following the analytical protocols and data acquisition methods described in (Khanna et al., 2023a). Details of analytical methods are included in the online supplementary materials.

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