Analyses of multiple Mississippian and Pennsylvanian aged source rock samples in the Anadarko Basin, Oklahoma, revealed the presence of a compound that was tentatively identified as 18α(H)-oleanane. The identity of the 18α(H)-oleanane was subsequently confirmed by GCMS, GCMSMS, and coinjection with a sample known to contain 18α(H)-oleanane. The approach to identifying 18α(H)-oleanane was similar to that described in previous publications that have noted the presence of 18α(H)-oleanane in pre-Cretaceous samples. The presence of 18α(H)-oleanane in an Early Mississippian Kinderhookian sample appears to be the earliest reported occurrence to date. 18α(H)-Oleanane has typically been reported to be derived from a Late Cretaceous/Early Tertiary angiosperm source which would appear unlikely in this case since there are no Cretaceous or Tertiary aged source rocks in Oklahoma. This paper discusses possible sources for 18α(H)-oleanane including the suggestion that angiosperms, or angiosperm related species, split off from the gymnosperms far earlier than previously proposed. It is proposed that the data and methods discussed in this paper clearly show the presence of a compound identified as 18α(H)-oleanane in Mississippian and Pennsylvanian age samples. However, the source of the 18α(H)-oleanane still remains unclear.

在俄克拉荷马州的阿纳达科盆地，对多个密西西比州和宾夕法尼亚州老化的烃源岩样品进行了分析，发现存在一种化合物，该化合物初步确定为18α（H）-奥兰烷。随后，通过GCMS，GCMSMS和与已知含有18α（H）-亚麻烷的样品共注射来确认18α（H）-亚麻烷的身份。鉴定18α（H）-油烷的方法与先前出版物中描述的方法类似，后者注意到白垩纪前样品中存在18α（H）-油烷。早期密西西比州Kinderhookian样品中18α（H）-油烷的存在似乎是迄今为止报道的最早事件。据报道，通常从白垩纪晚期/第三纪被子植物中提取18α（H）-齐墩果，由于俄克拉荷马州没有白垩纪或第三纪的老生烃，因此在这种情况下似乎不太可能。本文讨论了18α（H）-油烷的可能来源，其中包括被子植物或与被子植物相关的物种从裸子植物中分离出来的建议比以前提出的要早得多。建议本文讨论的数据和方法清楚地表明在密西西比州和宾夕法尼亚州的年龄样本中存在一种鉴定为18α（H）-油烷的化合物。然而，18α（H）-链烷的来源仍然不清楚。从裸子植物中分离出来的时间比以前提出的要早得多。建议本文讨论的数据和方法清楚地表明在密西西比州和宾夕法尼亚州的年龄样本中存在一种鉴定为18α（H）-油烷的化合物。然而，18α（H）-油烷的来源仍然不清楚。从裸子植物中分离出来的时间比以前提出的要早得多。建议本文讨论的数据和方法清楚地表明在密西西比州和宾夕法尼亚州的年龄样本中存在一种鉴定为18α（H）-油烷的化合物。然而，18α（H）-链烷的来源仍然不清楚。