A numerically calibrated reference level (MP28) for the terrestrial mammal-based biozonation of the European Upper Oligocene
A numerically calibrated reference level (MP28) for the terrestrial mammal-based biozonation of the European Upper Oligocene
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欧洲渐新世上游基于陆地哺乳动物的生物区划的数字校准参考水平（MP28）
DOI：
10.1007/s00531-006-0094-6
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发表时间：
2007
影响因子：
2.3
通讯作者：
C. Mödden
中科院分区：
文献类型：
--
作者：
D. Mertz;P. Renne;M. Wuttke;C. Mödden
Enspel(Westwald)和邻近的Kärlich(Neuwied盆地)化石沉积物的动物群分别对应于上渐新世哺乳动物古近纪(MP)参考水平28和28-30。玄武岩流和粗面岩凝灰岩终止并早于化石沉积，允许通过放射性同位素测年来数值校准MP参考水平。激光聚变40Ar/39Ar对火山长石的阶梯加热产生了Enspel的参考水平MP28的时间间隔为24.9-24.5 Ma，而Kärlich的MP28-MP30时间间隔的最大年龄为25.5 Ma。Enspel参考水平MP28确定的时间间隔与从文献中获得的全球渐新世/中新世界线的年龄24.0 Ma±20.1 Ma之间的内插得出较年轻的参考水平MP29和MP30的时间间隔分别为24.5-24.2 Ma和24.2-23.9 Ma。这些≤的间隔为0.4英里/年。对于晚渐新世的MP参考水平，相对于更老的渐新世MP参考水平21-27，介于34-25 Ma之间。由于MP参考水平的划分基本上是基于哺乳动物类群的组合和哺乳动物牙齿形态的进化变化，因此，最新世较短的MP时间间隔表明相对于早渐新世，MP的进化变化很快。
The fauna of the Enspel (Westerwald) and the neighbouring Kärlich (Neuwied basin) fossil deposits correspond to the Upper Oligocene Mammal Paleogene (MP) reference level 28 and 28–30, respectively. Basaltic flows and a trachyte tuff terminating and predating the fossil deposit sedimentation allow to numerically calibrate the MP reference levels by radioisotope dating. Laser fusion 40Ar/39Ar step heating on volcanic feldspars yield a time interval of 24.9–24.5 Ma for reference level MP28 at Enspel and a maximum age of 25.5 Ma for the time interval MP28–MP30 at Kärlich. Interpolation between the time intervals determined for the Enspel reference level MP28 and the age of the global Oligocene/Miocene boundary of 24.0 ± 0.1 Ma taken from literature results in time intervals of 24.5–24.2 Ma and 24.2–23.9 Ma for the younger reference levels MP29 and MP30, respectively. These intervals of ≤ 0.4 m.y. for MP reference levels of the latest Oligocene are short relative to older Oligocene MP reference levels 21–27 between 34 and 25 Ma. Since subdivision into MP reference levels essentially is based on assemblages of mammal taxa and on evolutionary changes in tooth morphology of mammals short MP time intervals during the latest Oligocene indicate a rapid evolutionary change relative to the early Oligocene.