甘肃灵台晚中新世—早更新世生物地层划分及其意义

将甘肃灵台雷家河地区３个剖面按生物学和地层学原理综合成一个完整的生物地层剖面,并分成 ６个生物地层带：Ⅰ＋Ⅱ带为保德期中晚期; Ⅲ～Ⅴ带为榆社期;Ⅳ带为泥河湾期。探讨了华北各地方动物群在雷家河剖面中的相应位置。

LATE MIOCENE-EARLY PLEISTOCENE BIOSTRATIGRAPHY OF THE LEIJIAHE AREA, LINGTAI, GANSU

Since the first discovery of manunalian fossils in 1964 from the Lejiahe are4 Lingals, GansW there have been bee field teams working there on the "Leijiahe Formation", which developed on the CretaCeous limestone and before accumulation of the Loess. ms FOrmation was thought tO be of Pleistocene (HUang et al., 1979), Pliocene (HUang et al., 1993) and be Miocene tO Early PleistOCene (Zheng, 1994) respechvely. In 1998~ 1999, financed by the NSF we did more detailed biostratigraphic works on three sechons, namely, Loc. 93001, 93002 and 72074(4) sechon (Zheng and Zhang, 2000; Zhang and Zheng, 2000, 2001). The present paper gives synthehc analysis with small mammals from the three sechons and comparison with some faunas from North China. l Skiagraphic conflation and biosthagraphic classification After the work with the 93001 sechon in 1998 (Zheng and Zhang,2000),more horizons added up in 1999, therefore, the Zone I of Loc. 93001 sechon includes WL27WL17, and the Zone V includes WL6~WLI + in this sechon (Fig. l) By lithostlatigraphic and biostratigraphic correlation with the three sechons, a comPOsite Profile is setup (Fig.2) in this area. In aams are4 there recongized 6 bioshatigraphic zones according to the small mammal fossils. Accondng tO the paleomagnehc resultS (Wei et al., 1993), an explanation was adoptod here tempolally,pending new data. There can be tentatively recognized 2 zones of be Miocene, 3 zones of Pliocene and I of Early PleistOCene. 2 Farmal compedson An almost complete stratigraphic sechon in the inijiahe area, calibrated by paleomagnehc dating, suPPlies an ideal farework for comparison with isolated faUnaS, and compallson with other long sequence sechons, such as that of Yushe basin. l) YuShe Basin: The small mammal fossil assemblage from ~ Fm and Taoyang member of GaozhUang fo can be compared with the complex from Lg~ LS in the 72074(4) sechon by sharing: Ochotona lagrelli, Pseudomeriones abbreviatUs, Prosiphneus murinus, Anmimata hiPParionum, and Chardinomys n. sp. etc. Some prindhve species, such as Occitanonys n. sp., and Huahomys n. sp., found from WL27-- WL17 Of irc. 93001 and CLg-- CL7 of LOc. 93002 have no records from YuShe, which suggestS the former horizons maybe lower. The UPPer GaoZhUang Fm (NanZhUanggou and Culiugou member) dated roughly tO 4.8-- 3.6W can be correlated with the WL15~WL14 of Loc. 93001, CLS~ CLI Of 93002 and L7~ L3 of Loc. 72074(4). There both produced: Ochotona lagrelli, Anihthoides, Cricehaus mesolophl'dus, AllocricetUs, Chardina truncatUs, Chardinomys yusheensis, opodemus qt'ui,Mcromys tedfordi, and Huahomys downsi. The heegou assemblage dated 3.6~ 2.6Ma, can be compared with that from WL13--WL7 of Loc. 93001 and LZ~LI of 72074(4). Some chareterishc taxa from Mazegou Fm, such as Ochotona lagrelli, Ochotonoides complicidens, Aninthoides, CriCednus mesolOPhidus, AllocricetUs bursae, A ehi4 CricetUlus, Mesosiphneus paratingi (commpd with M iDtermedius), Cromeromys, Chardinomys IOuisi and Miromps tedfordi are also found from Lingtai. From the Lejiahe sechons, there did not find some tax' such as Yangia dngi, Y epirtngi, Chardinoaps nihewanicus that are abundance from hayan Fm of Yushe. HOWever, Cromeromp gansunicus and Borsodia chinensiS were found from Heshul, GansW The assemblage of Yangia rtDgi. BOrsodia cht'nensis and Chardinomp nihewanicus was also found from Xiashagoll, Mhewan, and ~gou be. 78001. They all can be cormlated with the Wb + ~WLI + of the 93001 sechon. 2) Ehemte FaUna: ms faUna was originally described by Schlosser (1924), and thought to be commpd with the POlgaldi faUna (MN13). By the evolutionary level of fossil murids, Storeh (1987) thought Ans faUna of about 7~ sib From the inijiahe sechons, most Ehemte elementS discovered in the horizons of about 5.0W e.g. Ochotona lagrelli, Eutamias, St'cista, LDPhocricetUs, Paralactaga anderssoni, Aninthol'des, AnocricetUs zdanslyi, NannocricetUs mongolicus, Kowalshe sithilis, K neimengensis, Pseudomeriones abbreviatUs, Prosiphneus, Anmimeta hiPParionum, Micromys chalceus and opodemus orientalis etC. Therefore, the Ehe