Morphometric Data on Miogypsina (Lepidosemicyclina) bifida, Foraminifera from L-III Reservoir, Mumbai Offshore, India

Abstract

ABSTRACT A detailed description of the assemblage of Miogypsina (Lepidosemicyclina) bifida Rutten from the sub-surface Mumbai Offshore is presented by carrying out biometric studies on nineteen equatorial sections. The mean V is 47.2 and the mean DI 212μm. The mean DII is 272.35μm and the mean ε 341.76μm. The larger spire has notational value in the range 4.1/2 to 7.1/2 and the smaller spire 1.1/2 to 3.1/2. The species is recorded to be occurring below M. (L.) excentrica Tan Sin Hok. In terms of the planktonic zonation, it pertains to the planktonic Zone N6 (Burdigalian). This is the first detailed study of M.(L.) bifida Rutten from India. The foraminifer, M.(L.) bifida Rutten, recorded from the L-III, a major producing reservoir of Mumbai High field is found in association with Lepidocyclina sp., Sphaerogypsina sp., Operculina sp., Amphistegina sp., Elphidium sp. and Cibicides sp. along with Bryozoa. The assemblage, recorded from limestone, indicates a shallow inner neritic paleoenvironment (bathymetry 15-20 meters) of deposition.