张广才岭南部杨木岗组疑源类化石特征及其意义  

Characteristics and significance of acritarchs fossils from Yangmugang Formation in southern Zhangguangcai mountains

作　　者：任永健[1] 吴颖慧[1] 张明明[1] 于汪 刘星旺[1] 赵寒 王占兵[1] 张伟胜 王畅 Ren Yongjian;WuYinghui;Zhang Mingming;Yu Wang;Liu Xingwang;Zhao Han;Wang Zhangbin;Zhang Weisheng;Wang Chang(Geological Institute of China Chemical Geology and Mine Bureau,Beijing,100013,China)

机构地区：[1]中化地质矿山总局地质研究院,北京100013

出　　处：《化工矿产地质》2021年第3期201-205,共5页Geology of Chemical Minerals

基　　金：中国地质调查局项目“黑龙江1:5万南蛤拉河子等四幅区域地质调查”(1212011220474)。

摘　　要：本文通过实测地质剖面,在张广才岭南部杨木岗组中获得了富含疑源类在内的较多孢型化石。化石组合主要为光面球藻(未定多种)Leiosphaeridia sp.,瘤面球藻(未定种)Lophosphaeridium sp.,网面球藻(未定种)Dictyotidium sp.,丝状藻类碎片fragment of filamentous algae,底栖藻类碎片fragment of benthonic algae,始瓣藻(未定种)Priscogalea sp.,黑色穴面膜片Brocholaminaria nigrita,连球藻(未定种)Synsphaeridium sp.。研究表明,获取的这些疑源类化石明显分为炭化、成熟度截然不同的两个孢型化石组合:早寒武世地层的常见分子,如瘤面球藻、网面球藻;奥陶纪地层的常见分子始瓣藻。结合区域构造背景,反映了杨木岗组属于再沉积地层。上述微体化石组合特征进一步表明,新元古代晚期-早寒武世随着大洋板块的俯冲作用,地层接受剥蚀,化石表现为高度成熟、炭化;早奥陶世开始再沉积了一套富含始瓣藻的地层,反映此时研究区仍处于大洋环境。保存较好的化石组合,说明搬运距离短,揭示杨木岗组沉积期间周边存在一个古老沉积物源区,该认识为松嫩-张广才岭与佳木斯地块于早古生代晚期拼合的观点提供了新的证据。In this paper,through measured geological profile,many spore fossils are obtained from Yangmugang formation which is rich in Acritarchs in the southern Zhangguangcai mountains.The fossils mainly consist of smooth Leiosphaeridia sp.,Lophosphaeridium sp.,Dictyotidium sp.,fragment of filamentous algae,fragment of benthonic algae,Priscogalea sp.,Brocholaminaria nigrita and Synsphaeridium sp.The results show that these Acritarchs fossils can be divided into two spore fossil assemblages with different carbonization and maturity.This two assemblages contain common molecules such as osphaeridium and Dictyotidium in Early Cambrian strata,and priscogalea in Ordovician strata.combined with the regional tectonic background,This characteristic shows that Yangmugang formation belongs to the redeposited strata.The above-mentioned microfossil assemblage features further indicate that the strata were eroded by the subduction of oceanic plate from the late Neoproterozoic to Early Cambrian,and the fossils were highly mature and carbonized;a set of strata rich in cephalosporium began to redeposit in the early Ordovician,it shows that the research area was still in the oceanic environment at this time.The well preserved fossil assemblage indicates that the transportation distance is short,and reveals that there is an ancient sediment source area around Yangmugang formation during the deposition,the cognition provides new evidence for the idea that Songnen-Zhangguangcai Mountains and the Jiamusi massif were pieced together in the late Early Paleozoic.

关 键 词：张广才岭南部 杨木岗组 疑源类 化石组合特征 

分 类 号：Q913[天文地球—古生物学与地层学]