A new report of serpentinites from Northern Central Indian Ridge (at 6 degrees S) - An implication for hydrothermal activity

Abstract

Abstract: Serpentinites from the inside corner high (6O38.5'SI 6S019.34'E) from the Northern Central Indian Ridge (NCIR) are comprised mainly of high Mg-rich lizardite and chrysotile pseudomorphs with varying morphologies. 'Meshrim', 'window', 'hourglass' and 'bastite' are the most common textures displayed by both chrysotile and liuardite. Numerous chrysotile veins in association with cross cutting magnetite veins indicate an advanced stage of serpentinisation. The relatively high abundance of chrysotile and lizardite suggest their close association and formation at a temperature below 250°C. Abundant 'mesh rim' and 'bastite' texture and variegated matrix reveal that the present serpentinites might have formed due to the interaction of harzburgite and seawater. Positive Eu anomaly (EuJEu* up to +3.38), higher LaISm (up to 4.40) and NbLa (up to 6.34) ratios suggest substantial hydrothermal influence during the formation of the serpentinites.