海南乐东洪帽剖面鹿母湾组孢粉组合及其地层意义

SPOROPOLLEN ASSEMBLAGE FROM THE LUMUWAN FORMATION AT THE HONGMAO SECTION OF LEDONG COUNTY,HAINAN AND THEIR STRATIGRAPHICAL SIGNIFICANCE

作者系统地研究了海南乐东洪帽剖面鹿母湾组孢粉化石,共计26属60种,其中苔藓类植物孢子1属3种,蕨类植物孢子18属30种,裸子植物花粉7属27种,组成以Cicatricosisporites-Schizaeoisporites-Ephedripites-Exesipollenites为特征的孢粉组合。依据组合中主要分子和重要分子地质时限的讨论以及与相关孢粉组合进行比较,将洪帽剖面鹿母湾组的地质时代归为Aptian期-早Albian期。

The Hongmao section is located at Ledong county of Hainan province, and about 8 km northeast of Ledong city. Abundant sporopollen of about 60 species referred to 26 genera were discovered from the Lumuwan Formation of Hongmao section. Based on sporopollen characteristics and their contents, the Cicatricosisporites-Schizaeoisporites-Ephedripites-Exesipollenites assemblage is proposed. This assemblage is found in 7 samples （ BF5, BF7, BF12, BF17, BF32, BF34, BF36 ） with the following palynological characteristics. A. The gymnosperous pollen （74.6%- 94.2%, averaged 84. 1%） are more than the pteridophytic spores （5.8%-20. 6%, averaged 15.2%）, and bryophyte spores are presence in lower content. B. Among the gymnosperous pollen, Exesipollenites （21. 3%-78. 5%, averaged 55. 8%） rank the first in content. The second is Classopollis （4.8%-38. 8%, averaged 13. 2%）.Ephedripites （ 0-20. 4 %, averaged 6. 3 %） and Cycadopites （0- 8. 8%, averaged 4. 3%） are remarkable in quantity. In addition, there are Psophosphaera, Chasmatosporites and Jugalla in lower content. C. Among the pteridophytic spores, the genus Cicatricosisporites （ 0-8. 6%, averaged 4.9%） rank the first in content. Polycingulatisporites （0- 4.8%, averaged 2%）is comparable with Schizaeoisporites（0-3. 9%, averaged 2%） in quantity. Other elements are scarce, such as Cyathidites, Deltoidospora, Todisporites, Toroisporis, Undulatisporites , Guangdongspora , H ymenph yllumsporites, Osmundacidites, Rotverrusporites, Concavissimisporites, Coptospora, Annulispora, Densoisporites, Interulobites and Foraminispontes. The present sporopollen assemblage is assigned to the late Early Cretaceous （Aptian--earlyAlbian） in age.