摘要
浙江寿昌组含有丰富的动、植物化石,又处于侏罗-白垩系的临界层位,一直为地质工作一者所重视。然而,自刘季辰、赵亚曾发表“浙江西部之地质”(1927)以来,经60年的反复研究,寿昌组的时代问题仍在争论之中。古生物工作者曾从各自所研究的化石门类对寿昌组的时代提出过各种意见。将之归入上侏罗统的有顾知微(1962,1980,1982,1983),张璐瑾(1978),张弥曼和周家健(1977),马其鸿(1980);归入上侏罗统一下白垩统的有余汶、潘华璋(1980)和林启彬(1980);归入上侏罗统(?)一下白垩统的有叶春辉等(1980);
The age of the Shouchang Formation developed in western Zhejiang has long been in dispute. Different ages from Late Jurassic, Late JurassicEarly Cretaceous to Early Cretaceous have been proposed by palaeontologists based on evidences of different fossil groups. The present paper deals with two palynological assemblages from this formation, at Shouchange, Jiande County and Xiaqiao, Lishui County, with a discussion on their geological age. A palynological assemblage Was reported by Zhang Lujin (1978) from the Lower Member of the Shouchang Formation in Shouchang. It .contains some 20 species, of palynomorphs; namely, Lygodium sp., Lygodium crassus Zhang, Tlilobosporites applanatus Zhang, Cibotiumspara sp., Selaginella sp., Cyathidites spp., Gleichenia sp., Concavisporite sp., Monosulcites sp., Araucariacites sp., Pagiophyllumpollenites spp., Cedrus sp., Pseudopinus sp., Piceites jacutiensis Bolchovitina, Piceites simplex Zhang, Paleoconiferus sp., Protoconiferus sp., Podocarpus paula Bolchovitina, Podocarpus gracilis Zhang and Podocarpus sp., Zhang assigned some dispered palynomorphs to the genera of living plants with new names given to some forms. Howevel, her Lygodium crassus Zhang and Trilobosporites applanatus Zhang are most likely junior synonyms of Lygodiumsporites subsimplex (Naumova) Gao et Zhao, and her earlier genus Pagiophyllumpollenites Chang 1963, as has been mentioned by Sravastave (1976), is a synoym of Classopollis Pflug 1953. In this assemblage, almost all species are the so-called 'long-range' forms commonly seen the upper Mesozoic strata elewhere over the world, but none of them can play the role of a typical Jurassic representative though the assemblage was referred by Zhang (1978) to late Late Jurassic for its abundant Classopollis pollen with rare 'lygodiaceous' spores. The present assemblage found from the same formation outcropping at Xiaqiao, Lishui County (Text-figure 1) consists of 19 species belonging-to 16 genera (Plate 1), namely, Cyathidites minor Courper, Biretisporites sp., Coneavisporites sp., Leiotriletes? sp., Baculatisporites sp., Echinatisporis sp., Fixisporites sp., Cicatricosisporites sp. C. ct. dangtuensis Li, Cicatricosisporites stoveri Pocock, Cicatricosisporites sp., Schizaeoisporites laevigataeformis (Bolchoyitina) Gao et Zhao, Schizaeoisporues certus(Bolchovitina) Gao et Zhao, Gintgocycadophyius nitidus(Balme) de Jersey, Araucacacites sp., Classopollis annulatus (Verbitzkaya)Li, Caytonipollenites pallidus (Reissinger) Couper, Podocarpidites sp. and Psophosphaera sp. This assemblage is similar to that from Shouchang in possessing abundant Classopollis pollen (amounting to 70—80％ of the assemblage in specimen number), but differs mainly in having Schizaeoisporites, Cicatrieosisporites and Fixisporites as well as some smaller and less diverse bisaccate pollen grains. The study of geology and faunas, especially of ostracods, has shown that the palyniferous strata at Xiaqiao are equivalent to those at Shouchang and belong to the Lower Member of the Shouchang Formation. Considering the poor preservation of palynomorphs and the limited number of productive samples under study, the writer believes that the difference between the above two palynological assemblages does not necessarily imply a chronologi- cal discrepancy. As a whole, the combined assemblage correlates well with those from the Yunheshan Formation (Li, 1979), the Lower Member of the Zhuxiang Formation (Waiig et al., 1985), the Lengshuiwu Formation (Western Jiangxi Team of Geological Survey et al., 1985) and the Upper Member of the Bantuo Formation (Zheng and Li, 1986) in southeastern China, all of which have been referred by palynologists to early Early. Cretaceous. (Wealden) in age dueto the appearance of Schizaeoisporites and Cicatricosisporites.
出处
《古生物学报》
CAS
CSCD
北大核心
1989年第6期724-729,824,共6页
Acta Palaeontologica Sinica
基金
国家自然科学基金 852264
