福建永安坂头组植物及古气候分析

分析了福建永安盆地早白垩世坂头植物群的组成特征。共计报道该植物群化石24属52种左右，包括未定种以及存疑种21个。植物群的组成以具鳞片状叶的松柏类化石为主，苏铁类化石次之，并以本内苏铁目占绝对优势，然后是真蕨类化石，以小羽片小而质厚为特征，银杏化石及其少见，未发现被子植物。坂头组植物的组成面貌与欧洲Wealden植物群、日本外带领石植物群，以及我国南方植物区，如浙江、山东等地的早白垩世植物群比较一致，说明坂头组含化石层位年龄为早白垩世早期。坂头组大多数植物主要分布于热带或亚热带地区，具有耐干旱炎热的特点，反映了较干旱而炎热的气候特征。除此之外，还发现少量适宜生活在温凉潮湿气候环境下的植物。根据这些对气候具有指示意义的代表分子在坂头组中的数量以及分布情况，推断永安盆地早白垩世早期气候总体上比较干旱炎热，且伴随有不同程度季节性的潮湿。

Fossil Plants from the Bantou Formation of Yong’an,Fujian Province and Their Paleoclimatic Significance

The composition of fossil plants from the Bantou Formation of Yong’an, western Fujian Province, is analyzed and summarized. 52 species  (including 21 indeterminate and suspicious species) ascribed to 24 genus have been reported from the formation up to now. Among them, the conifers with spiral scales are dominant; cycads are mainly composed of Bennettitales; ferns are characterized by small and thick pinnules; Ginkgoales are very few, and angiosperms are absent. The fossil assemblage of the Bantou Florais comparatively consistent with that of the Wealden Flora in Europe, the ryoseki Flora in outer zone of Japan, as well as the Early Cretaceous floras from the South Floristic Region in China, such as Zhejiang and Shandong provinces. This indicates that the age of fossil beds of the Bantou Formation is early Early Cretaceous. Meanwhile, most of the species from the Bantou Formation are xerophilous and are mainly distributed in tropical and subtropical zones. They reflect a dry and hot climate character. However, there exists a certain amount of plants inhabited in moist and warm environments. Therefore, the climate of the Early Cretaceous in Yong’an Basin is generally arid and hot, with humid season, according to the paleobotanic data in the Bantou Formation.