摘要
通过光学、扫描电子和透射电子显微镜观察,对云南禄劝中泥盆世晚期角质残植煤层中的植物角质层进行再研究。禄劝的植物角质层定为Orestoviacf.devonica Ergolskaya,1936,具有两种类型:类型Ⅰ,角质层具有规则分布的孔状结构,分布密度为40—45个/mm2,表皮细胞呈不规则多边形或长条形;类型Ⅱ,角质层规则分布似气孔结构,分布密度为50—60个/mm2,表皮细胞呈长方形。根据大植物化石研究,结合生物地层资料,云南禄劝的植物角质残植煤层的成煤时代为中泥盆世晚期(late Givetian)。基于对当时古地理和古气候分析,云南禄劝角质残植煤层的形成主要受控于当时区域古地理环境及其局部古气候条件。
Coal is often considered as one of the important indicators in studying palaeoecology and palaeoclimatology. Late Middle Devonian coals have been reported from South China. Sheng et al. （1992） thought that the precursors of Luquan coals were derived from pteridophyte plants, or bacteria/algae. After studying the cutinites, Quan and Han （1997） thought that Taeniocrada decheniana and primitive lycopsids （such as Drepanophycus sp.） were the principal coal-forming plants. However, there are some ways about the Luquan coals on the geological age and prescursors, it is necessary for us to restudy coals, its geological age and its forming plants.
Based on the study of plants from the underlying and the same beds of coal, and correlation with the Xichong flora, the geological age is considered as the late Middle Devonian （late Givetian）.
By using light microscope （LM）, scanning electron microscope （SEM） and transmission electron microscope （TEM）, we restudied the cuticles from the late Middle Devonian （Givetian） coals of Luquan, Yunnan Province.
The Luauan cuticles are identified as Orestovia cf. devonica Ergolskaya, 1936 with two types. The Type Ⅰ cuticles are characterized by the stomatal structures, which are distributed on both sides of cuticles; the density of stomatal structure is 40 45 units/mm^2; the shape of the epidermal cells is irregular polygonal or long rectangular. The Type Ⅱ cuticles care characterized by stomata-like structures, being divided into lamella, media and stablical layers, and are with pores in. the lamella and media layers; the density of stomata-like structures is 50-60 units/mm^2 ; the epidermal cells is slim rectangular in shape.
After restudying the figures of Quan and Han （1997, Plate Ⅰ, fig. 2）, the cuticles from Luquan coal do not belong to Taeniocrada decheniana and Drepanophycus sp.. The morphological characters are very similar to that of our Orestovia axis fragments, we are very happy to classify the cuticles to Orestovia cf. devonica （same species as our cuticles） . Based on the analyzing of the information of the Middle Devonian coals in the world, Orestovia is one of important coal-forming plants. We agree that is Orestovia the coal-forming plant of Luquan coal.
The disperse Orestovia specimens were also reported from the Lower and Middle Devonian in Yunnan, China. The coal-formation by Orestovia etc. was mainly controlled by palaeogeography and local palaeoclimatology. After marking the coal distribution on the local palaeogeographical map, we consider that the coals were formed in waternear small basins with a plenty of water.
出处
《古生物学报》
CAS
CSCD
北大核心
2007年第3期355-364,共10页
Acta Palaeontologica Sinica
基金
中国科学院知识创新工程重要方向项目(KZCX-YW-105)
国家自然科学基金项目(40523004)
国家重点基础研究发展规划项目(2006CB806400)联合资助
