黑龙江嘉荫晚白垩世永安村组植物群及其地层对比

In recent years, with the increasing number of fossil-plants and reports about Yong’ancun Formation in Jiayin of Heilongjiang Province, the Yong’ancun flora, which plays an important role in Late Cretaceous flora appearance, strata evolution, the age of relevant stratigraphy and stratigraphic correlations (especially the correlation with its adjacent area Songliao Basin and Zeya-Bureya Basin) in northeast of China, meanwhile, the associated biota such as dinosaurs and ostracods also could provide solid evidence for stratigraphic correlation. However, all previous work still needs more complemented data due to not well-exposed conditions of outcrops, insufficient quantity of fossils and so on. The deeper research of Yong’ancun flora should be extremely urgent, the more helpful for the study of Upper Cretaceous strata sequence evolution in China and stratigraphic correlation with Songliao Basin. This project mainly aims at further collecting fossil-plants and fine division and correlations of strata, using multiply methods of paleobotany, palynology, and stratigraphy, and combined with correlation relationship with strata of marine-terrigenous facies in Russian Far-East area, which could more-refined analyze the systemic composition and the age of Yong’ancun flora and find more symbols for stratigraphic correlations. To sum up, this project would provide more proves of paleobotany for Late Cretaceous flora evolution in northeast China and stratigraphic correlation with Songliao Basin, and even more evidence for further study of paleoclimate, paleoenvironment and the prospect for finding oil and other fossil fuels in the Jiayin area.

近年来，黑龙江嘉荫晚白垩世永安村组植物化石的不断发现和研究，为揭示我国东北地区晚白垩世植物群的总体面貌、演化序列、相关地层时代认定及对比发挥了重要作用,与其伴生的恐龙及介形类等化石也为此提供了宝贵的实证。但以往限于地层出露、化石采集等原因，有关永安村组植物群及地层等方面，仍需要开展大量研究工作，结合我国晚白垩世演化序列和与松辽盆地地层对比等需要，永安村组植物群的深入研究已迫在眉睫。本项目旨在通过对永安村组植物化石的进一步采集和研究以及地层精细划分与对比，综合运用古植物学、孢粉学、地层学等方法，并结合与俄罗斯远东具海陆交互相地区植物地层对比，较精细地确定永安村组植物群的系统组成、时代及地层对比标识，推动我国东北晚白垩世植物群演化序列研究和与松辽盆地相关地层对比研究，为深入研究黑龙江嘉荫地区晚白垩世古气候、古环境以及找寻石油等化石能源提供更多的古植物学证据。

晚白垩世全球气候总体上高热和干旱，但黑龙江嘉荫及俄罗斯远东等地处在滨太平洋附近，受海洋环境的影响，相对温暖湿润，晚白垩世植物群仍然繁盛，并且嘉荫晚白垩世圣通期（Santonian）—马斯特里赫特期（Maastrichtian）陆相地层连续出露，为研究晚白垩世植物群的演化提供了良好的条件。本项目运用古植物学、孢粉学及地球化学等方法，系统研究晚白垩世永安村组植物群及地层，目前已取得成果主要有：运用LA-ICP-MS技术，测得永安村组下伏地层宁远村组火山岩锆石U-Pb同位素年龄为103.1±1.4Ma，其时代为早白垩世阿尔布期末期；新发现我国最早的水生被子植物莲属化石嘉荫莲（Nelumbo jiayinensis sp. nov.），将我国莲属化石的记录提早了至少3000万年；在永安村组新发现被子植物北极准蓝果树（Nyssidium arcticum）化石的分布，为与俄罗斯北美晚白垩世植物群及地层对比，提供了重要依据。本项目的继续深入研究将为我国陆相白垩纪地层划分、植物群对比、石油找寻等提供更多重要的古生物化石依据。