摘要
本文所研究样品采自甘南寒冷潮湿区沼泽。对其烷烃馏分进行GC—MS分析后,检测出五个新的脱A—羽扇烯和二烯,通过质谱分析,初步确定了它们的烯键位置,并探讨了脱A—羽扇烯形成的可能途径。检测出的类化合物包括C_(27)、C_(30)和C_(31)烯以及C_(27)、C_(29)—C_(32)烷。 根据类化合物的分布,提出了C_(29)烷可能主要来自陆源物。高碳数的类化合物可能主要来自细菌和水生生物。烷构型组成以ββ型为主;烯占较高的比例,这些都反映了早期成岩阶段的特征。有意义的是样品中均含D环芳构化8,14—断烷。
Compositional characteristics of pentacyclic tritepanoids in modern marsh sediments of southern Gansu is discussed by means of GC -MS.
Five novel compounds of de -A-lupenes in 1 - 4 samples were found. By means of mass spectra, they are determined as: de - A - lup -18(19) - ene(two isomers), de -A -lup -12(13) -ene, de -A -lup -5 (10), 18(19) -diene and de -A-lup -5(10) , 11(12)-diene. It is assumed that 3 - ketolupane and 3 -ke-tolupane acid are the precursor of the lupenes. De - A - lupenes are formed by ways of complete loss of ring A, resulting from a 3,4 cleavage and the last of carboxyl,de - A - lupanes acid are degraded products of lu-panoids during early diagenisis stage and also biomarkers indicating higher plant input.
Hopanoids are composed of C27,C30,C31 ,hopenes and Cu27,C29-C32 hopanes. There is a higher propotion of Cu hopane in the 1 - 4 samples. C31 and CM hopanes are only present at small concentration. Therefore it is prorposed that C29 hopanes may mainly originated form higher plants, while high carbon number hopanoids from bacteria and aquatic organism. Isomerides of hopanes are composed of ββ-βα and αβ hopanes. ββ hopanes are predominant ; hopenes have reladtively higher concentration. These points reflect the characteristics of organic material during diagenesis stage. The discovery of C29,C30 ring D momoaromatic 8,14-secohopanes in the 1 - 4 samples is significant ,which is presence may be related to acidic medium (pH=5) and weak oxidation-weak reduction enviromnent as well as activity of microbes in the modern marsh sediments of southern Gansu.
出处
《沉积学报》
CAS
CSCD
北大核心
1993年第3期82-87,共6页
Acta Sedimentologica Sinica
