辽西下白垩统义县组化石木年轮的观察及其意义

GROWTH RINGS OBSERVATION ON FOSSIL WOODS AND THEIR IMPLICATION FROM YIXIAN FORMATION OF LOWER CRETACEOUS IN WESTERN LIAONING PROVINCE

对辽宁省西部下白垩统义县组化石木年轮的研究表明,明显清晰的年轮反映了当时的气候具有明显的季节性特征;连续年轮宽度的变化情况表明当时的气候波动强烈,反映了干旱—半干旱的波动特点;义县组各种化石木的平均敏感度(MS)在0～0.2间,表明树木总体生长在年降水量或水供应较均匀的环境。

The study of growth rings of fossil woods observed from Yixian Formation of Lower Cretaceous in Western Liaoning Province shows that the growth rings of fossil woods,present or absent, exhibit the climate change with seasons. At the same time, the growth rings can provide extensive information on paleoclimate and paleoecology. The clear growth rings of fossil woods from Yixian Formation reflected the climate with obvious seasonal feature at that time, and their width change indicates intensive climatic fluctuation,which implies the aridity-semiarid waving feature. The index of mean sensitivity(MS) from various fossil woods is between 0 and 0.2, as a whole, showing the trees growth under the well environment with annual precipitation or water provided equably in Yixian age.