Carboniferous Permian Boundary in Japan

当我们将乌拉尔地区的fusulinid Sphaeroschwagerina vulgaris-fusiformis带的基底视为二叠世的开始时，就有可能在碳酸盐岩相范围内追踪日本的该带。然而，秋吉灰岩高原由于露头为块状、部分角化灰岩的分散尖顶，在野外很难确定碳磷比界。它提供了一个很好的动物序列的例子，特别是从下石炭世到上二叠世的有孔虫。其他类群（牙形刺、小有孔虫、珊瑚、腕足类、头足类、苔藓虫等）在秋吉的出现相当少，以补充识别C/P边界。秋吉地区上石炭统的小灰质灰岩中，黑色亮晶方解石条带和斑块嵌入高能灰岩中，可见明显的环境变化。这一奇特的岩性含有“Microcodium”状结构，C值相对较低，表明淡水对海相秋吉灰岩碳酸盐形成的影响。未来，全球海平面变化的影响可能会在火山海山上形成的明吉石灰岩层序中得到更精确的探测。在日本海盆相的燧石层序中也寻求了碳/磷边界，在那里放射虫和牙形刺已被证明对分带有用。在这种岩性层序中也可以发现环境变化，这解释了海水成分的全球变化。问题是很难将在盆地相内建立的分带与经典地区的陆表相或近岸相的分带联系起来。

When we are to accept the base of fusulinid Sphaeroschwagerina vulgaris-fusiformis Zone in Urals as the beginning of the Permian, it is now possible to trace the zone in Japan within carbonate facies. As exemplified in the Akiyoshi limestone plateau, however, it is difficult to pin-point the C/P boundary in field, owing to the nature of outcrop being scattered pinnacles of massive, partially brecciated limestone.It provides a very good example of faunal sequence though, especially of foraminifers starting from Lower Carboniferous to Upper Permian. Occurrence of other taxa (conodonts, smaller foraminifers, corals, brachiopods, cephalopods, bryozoans, etc.) is rather meager in Akiyoshi to supplement in recognizing the C/P boundary.Significant environmental change may be sought within the Triticites Limestone of Upper Carboniferous in Akiyoshi, where bands and patches of black sparry calcite are intercalated in the high-energy limestones. This peculiar lithology contains "Microcodium" like structure and shows relatively low C value, both indicating the influence of fresh-water to the formation of carbonate in the marine Akiyoshi limestone.The effect of global sea-level change may be more precisely detected in future within the sequence of Akiyoshi limestone formed upon a volcanic sea mount.C/P boundary has been sought also within chert sequence of basinal facies in Japan, where radiolarians and conodonts have proved to be useful for zonation. Environmental change may also be detected in this type of lithologic sequence, which accounts for the global change in sea water composition. Problem is that it has been difficult to correlate zonation thus established within basinal facies with that of epicontinental or near shore facies in classical areas.