Cretaceous Sakhalin and Cretaceous events in North Pacific-II

1993-1994年首次考察库页岛南部后，对克里伦半岛西南部的上白垩统进行了生物地层学研究。此外，还对Naiba地区上白垩统，包括沿着Naiba河和Krasnoyarka河的典型剖面进行了生物地层学和古地磁地层学研究。与比科夫组和Krasnoyarka组有关的从Santoinian到Maastrichtian早期的地层出露于Kril'on的西部和东部，其中连续产出了许多保存完好的菊石，已确认存在虫酰胺和其他无脊椎动物和植物巨化石。在东部沿沿着库拉河发现了几乎完整的坎帕尼亚层序。在这一库拉河断面，7个生物地层学上重要的megafossil组合被确认，包括出现的指标菊石类群Pachydiscus awajiensis和“P。“大豆。在库页岛南部中部的Naiba地区，我们在36个地点（约250个标本）采集了古地磁地层学样品。古地磁测量结果与生物地层学和碳同位素地层学研究结果基本一致。结合这些研究成果，建立了萨哈林岛精确的生物和年代地层学，为萨哈林岛与北海道上白垩统的对比以及北太平洋晚白垩世生物和物理演化的解释提供了可靠的依据。

The Upper Cretaceous System in the southwestern part of the Kril'on Peninsula was studied biostratigraphically, succeeded from our first expedition to Southern Sakhalin in 1993-1994. Supplementary, the Upper Cretaceous in the Naiba area, including the type sections along the Naiba and Krasnoyarka rivers, was also studied in both the biostratigraphy and paleomagnetic stratigraphy.The correlatives to the Bykov and Krasnoyarka formations, ranging from the Santoinian to earlier Maastrichtian, are exposed in the western and eastern parts of Kril'on, from which successive occurrences of many well-preserved ammonoids, inoceramids and other invertebrate and plant megafossils were confirmed. Almost complete Campanian sequence was found along the Kura River in the eastern part. In this Kura River section, seven biostratigraphically important megafossil assemblages were recognized, including the occurrence of such index ammonoid taxa as Pachydiscus awajiensis and "P." soyaensis. In the Naiba area of the central Southern Sakhalin, we collected the samples for paleomagnetic stratigraphy at 36 sites (ca.250 specimens). The result of the paleomagnetic measurements are quite consistent with our results of biostratigraphy and carbon isotope stratigraphy. Combining with these results, precise bio- and chronostratigraphy can be established in Sakhalin, which provide a sound basis for the correlation of the Upper Cretaceous between Sakhalin and Hokkaido, and for the interpretation in biotic and physical evolution during the Late Cretaceous in the North Pacific.