陕西府谷老高川新第三纪“红层”的划分与时代

对陕西府谷老高川新第三纪“红层”岩石地层、磁性地层、生物地层的初步研究结果表明，该区上第三系一般含有中新统上部及上新统下部。上中新统地层的时代相当于Ｔｕｒｏｌｉａｎ的中、晚期，古地磁年龄约为７．４～５．３Ｍａ，其中含有多层哺乳动物化石；下上新统沉积的时代相当于Ｒｕｓｃｉｎｉａｎ的早、中期，古地磁年龄约为５．３～４．３６Ｍａ。二者在岩性、所含动物群的组合及其性质等方面都存在着较大区别。

Age and division of Neogene "Red Bed"of Laogaochuan,Fugu County, Shaanxi

A great number of specimens of Hipparion fauna were found in 1986, which form the basis of this paper, at Wangdaifuliang Village of Logaochuan, Fugu County,Shaanxi Province. There are about a thousand or more pieces of fossils, include skulls, tooth,horns antlers and completed limbs etc. were collected. It is the most important discovery and collection in the past decades in China. Preliminary study of the fossils and fossiliferous strata and correlation of lithostratigraphy, biostratigraphy and magnetostratigraphy showing that the red clay bed in north Shaanxi Province consists of two parts, lower one (Late Miocene)and upper one (Early Pliocene). The upper is brownish red, brick red sand mudstone and there are a lot of scattered calcium nodules, part of which formed net-nodule.The results of palaeomagnetic measurement show that it is of reversal polarity,corresponding to Early to Middle Ruscinian and dated at 5. 3～4. 36 Ma B. P. The lower one is light reddish brown, yellowish red sand clay, fine-sand clay. Fossils in this part from three layers, they are different in element, character and palaeoecology. These fossils are extensively distributed in North China, namely Gansu, Henan, Shanxi, Shaanxi, etc. Most of them are common or key fossils of the Bandenian(Late Miocene),so their age are Banodenian undoutedly. Palaeomagnetic determinations indicate that this part records the palaeomagnetic table 5r, 6r and upper part of 7r geomagnetic epoch, arouse 7. 4 Ma B. P. ～5. 3Ma B. P.,corresponding to the middle and late Turolian.