Taxonomic Studies of Fossil Woods From Different Formatios Exposed in Punjab and Sindh, Pakistan

Abstract

The study of petrified wood provides new and very fruitful information about past and the present plant vegetation of the study area. The Fossil wood has the potential to record several aspects of the palaeo- environment in which it grew not only this but the systematic studies of fossil wood provide better understanding of the evolution of the plant and plant community, at the site of deposition. Fossil wood is abundant Tertiary sediments of the Pakistan have one of the world's richest regional records of silicified wood. About 120 specimens of fossilized petrified woods were collected from different formation exposed in Sindh and Punjab provinces of Pakistan. Thirteen taxa, belonging to 5 families of dicotyledonous wood were identified as the new genus species, which includes Ougenioxylon chinjiensis sp.nov. (Leguminosae,) Albizzinum chinjiensis sp.nov. (Leguminosae), Dichrostachyoxylon chinjiensics sp.nov. (Leguminosae), Ormosioxylon chinjiensis sp.nov. (Leguminosae), Ficoxylon chienjiensissp.nov. (Moraceae) were collected from chinji formation Punjab. While other 8 new taxa including Atalantioxylon thanobolensis sp.nov. (Rutaceae) Lagerstromioxylon sindhiensis sp.nov. (Lythraceae) Terminalioxylon thanobolanses sp.nov (combretaceae) Isoberlinioxylon ranikotensis sp.nov. (leguminosae), Stereospermoxylon ranikotensis sp.nov. (Bignoniaceae) Millettioxylon sindhiensis sp.nov (Leguminosae) Pterospermoxylon rehmanensis sp.nov. (Sterculianceae) Tramarindoxylon rahmanensis sp.nov. (leguminosae) occurring in Sindh were fully described. Every specimen has been provided with VI complete morphological, anatomical description, diagnosis and discussion which include the affinities and relationship with living and fossil woods. xylotomical characters used in the identification of the taxa were assessed and those found to be most important are discussed in detail with illustration. For the anatomical investigation of fossil woods the standard techniques were used for the preparation of three dimensional sections (Cross, Tangential and Radial). The photographs were taken with compound microscopic Camera. The anatomical study of the fossil wood under investigation and there distribution in counter parts, it can be revealed that all the wood fossil elements of the tertiary deposits found in Sindh and Punjab were tropical in character. The diffuse porous wood character and absence of growth rings indicates that the overall vegetation of this region, during the late Tertiary period was more luxuriant then the scrubby vegetation of today. Obliviously the present xerophytic condition are a result of sub-recent to recent changes in the element in the area. The Taphonomic studies shows Parautochthonous assemblage the mode of the occurrence of these fossils as scattered fragmentary material and complete absence of root fossil indicate that the plants from which these fossil wood growing were not derived in situ, but they were transported from some other locality. However, the heavy and large sized fossil woods indicates that the source area was not distant from the current site area the sediments shows and the logs were possibly transported by the strong water current and buried near the river. Digenetic studies shows the tree trunks buried in mud or volcanic ashes becomes saturated with water and resulted into the silicified wood