Middle Permian Fossil Wood From Hulusitai In Inner Mongolia, With Reference To Palaeoclimate

With the applications of analysis of variance and CSDM (Cumulative Sum of Deviation from Mean diameter) curve, Permian fossil woods recently found in Hulusitai colliery of Inner Mongolia are analysed and studied systematically. Combined with correlative reference materials of stratigraphy and palaeontology in this region, Permian stratigraphy here is subdivided in three ways, palaeoecology and palaeoclimate are initially discussed as well.According to the identification of fossil woods, it shows that they all belong to Araucarioxylon, with the stage age of Qixia, though there are some anatomical differences among them; Following two mathematical clustering analysis methods-analysis of variance and CSDM curve, metrical numerical values are quantitatively analysed, then, skew value of curve and its relationship with leaf longevity are showed. Meanwhile, result comes out that seven fossil samples are mostly evergreen Araucarioxylon, deciduous species prapably exists, but their fixed numbers of growing year are extraordinarily variant; Analysis of ariance indicates that, imposing ray cells, radial tracheid diameters-, the ratios of ray cells to radial tracheid diameters on distinguishing seven samples is doable as a whole, while not fitting for individuals. The height of rays differs little amidst them, so it is hard to distinguish them according to this character. As a result, sample 2 is most similar to sample 6, they are the same species, on the other hand, sample 1, 4,7 are likely to be the same; General considerations on the analysis of ariance and CSDM curve suggest that, the distinctions occurring among sample 1, 3, 6 might lead to slight errors in analysis of ariance;Combined integrated characteristics of fossil woods with that of palaeobotany, successive process of palaeobotanical community , evolutive features of palaeoclimate and palaeoecology are analysed, together with 6 assemblage zones sepatated.