Paleoclimate and Paleoenvironment Implications of the Middle-Late Jurassic Tiaojishan Formation, Western Liaoning Province: Evidence from Fossil Wood Data
Petrified wood with well preserved growth rings and anatomical structure in Middle-Late Jurassic Tiaojishan Formation, western Liaoning Province shows great significant in the study of paleoclimate, paleoenvironment and paleoecology. The main parameters were calculated. The E/L values of the growth rings of fossil wood material were calculated in this study based on field survey on stump materials as well as slide observations. Reconstructions of the height of fossil coniferous trees were made using the Niklas (1994) and Mosbrugger (1994) approaches; the average height of the coniferous trees in the Middle Jurassic was about 25m. It can be infered that the paleoenvironment of Jurassic gymnosperms tree forest was dominated with volcanic rocks and lacustrine sediments,with abundant precipitation. The genaral palaeoclimate was temperate to subtropical type during the Middle-Late Jurasssic and was suitable for forest growth and development. Analyses of the special anatomical structures reveal particular implications of the palaeoclimate and palaeoenvironment of the wood material based on special structural evidences including false rings, traumatic resin canals,twisted growth rings,wormholes and so on. Although the palaeoclimate in the Middle-Late Jurassic in Beipiao,Liaoning was favourable for tree growth, some fluctuation and severe disturb of climatic situations presented including low temperature, heavy wind, volcanic eruption, frost and other abnormal climate.