Micro faunal assemblages in the Ordovician – Silurian successions from the Pin Valley of Tethys Himalaya, India

The Spiti basin together with the Zanskar basin forms the largest basin among the Tethyan Himalayan successions and forms one of the best-developed sec-tions in the Tethyan Tibetan belt. The basin is one of the classical areas, which depicts a continuous fos-siliferous Palaeozoic - Mesozoic successions. The present studies are focused on the Ordovician and Si-lurian successions of the Pin valley of the Spiti basin. Pin valley exposes richly fossiliferous lithological successions from Neoproterozoic to Cretaceous; therefore, it is an ideal section for the detail paleobi-ological and geological studies.     

A NUMERICAL METHOD TO COMPUTE THE RESISTIVITY TRANSFORM FROM WENNER SOUNDING DATA*

A numerical technique to compute the resistivity transform directly from the observed Wenner sounding data has been developed. In principle, the procedure is based on a decomposition method and consists of two steps: the first step determines a function that approximates the apparent resistivity data and the second step transforms this function into the corresponding kernel by an analytical operation. The proposed method is tested on some theoretical master curves. A high degree of precision is achieved with very little computer time. The applicability is shown on two field examples.     

Oldest Asian Record of Snapping Shrimps (Malacostraca: Alpheidae) from the Kutch Basin, Western India and Associated Biota: Biostratigraphic, Paleoenvironmental and Paleoecological Significance

The oldest Asian record of alpheid shrimps, assigned to genus Alpheus, based on snapping claw fingertips from the Miocene Khari Nadi Formation in the Kutch Basin, western India reported herein, extends the fossil record of the family Alpheidae from Asia by ~22 million years. An early Miocene (Aquitanian) age is estimated based on the associated assemblage of calcareous nannofossils, Sphenolithus disbelemnos, Cyclicargolithus floridanus, and Reticulofenestra haqii. The co-occurring microbiota includes bony fish otolith remains, identified as “genus Gobiidarum”, isolated teeth of Dasyatis rays, Sphyrna sharks, and teleosts, ctenoid and placoid scales, ostracods, belonging to the genera Paractinocythereis, Alocopocythere, Ruggieria? Aglaiocypris, Bairdoppilata, and echinoid spines. Taken together, the microfossil assemblage and data from chemical analyses using Energy Dispersive Spectroscopy, X-Ray Diffraction and Wavelength Dispersive X-Ray Fluorescence of host and associated lithologies suggests prevalence of a shallow (neritic) to coastal marine (intertidal) depositional paleoenvironment.     

METAMODELLING APPROACH TO DESIGN THE ALLUVIAL CHANNELS AT INCIPIENT MOTION

The design of an alluvial channel for critical conditions requires information about four basic parameters, i.e., particle size d, water depth y, energy slope Sf and average velocity u. Most of the investigators use a standard or modified form of the critical Shields’ parameter to define the incipient motion of a particular grain size. Shields’ diagram describes an iterative process of determining the incipient motion parameters. To design a process that does not require iteration, one must know the resistance relationship. The absence of a universal resistance equation increases the difficulty of defining the model. Metamodelling techniques are widely used in engineering designs to simulate a complex system. This article describes a Metamodel, which employs the radial basis function (RBF) network to predict the average velocity u and energy slope Sf based on experimental data of incipient condition. With the help of the Metamodel generated by the RBF network, design curves have been presented to predict the u and Sf based on known values of the particle size and water depth. It has been found that this model improves the predictability of incipient motion.