Paleokarst observed in Upper Paleozoic Limestone inn the japanese Islands

阐明了北上山下二叠统坂本泽组Sd段底部含铁星状岩的成因。这些沉积物是由碳酸盐岩的古岩溶作用、古土壤和深成岩的风化剥蚀作用的产物沉积而成的。一个Fusulinoidea种Monodiexodina matubaishi表明来自Kanokura组的标本是改造的。对这些样品的生物地层学研究间接地表明了坂本泽碳酸盐岩的古岩溶作用。芦尾山Kuzu地区出露的长见组表明了二叠纪Nabeyama石灰岩组的古岩溶作用。古岩溶作用的产物为细粒至中粒碳酸盐碎屑、泥质岩、残余角砾碳酸盐岩和其它粗碎屑的夹层。石炭纪的市谷组（Ichinotani Formation）夹有含铁高铝质页岩、尖砾（角砾）砾岩和其它残余岩石。这种古岩溶作用侵蚀了早石炭世晚期至早泥盆世的碳酸盐岩序列，米诺地体的赤坂灰岩夹在由灰岩和深成岩组成的古土壤中形成的赤铁矿矿床中。由于大部分矿体已被开采殆尽，有必要进一步研究以阐明这种古岩溶作用。

The present study clarifies the genesis of iron-bearing starata intercalated in the basal part of the Sd Member of the Lower Permian Sakamotozawa Formation in the Kitakami Mountains. These sediments was deposited from the products of paleokarstification, paleosol of the carbonate rocks and weathering decoposition of plutonic rocks, such as the Hikami Granite. A Fusulinoidean species, Monodiexodina matubaishi indicates that the specimens came from the Kanokura Formation are reworked ones. Biostratinomic study of these specimens indirectly shows paleokarstification of carbonate rocks of the Sakamotozawa.The Nagaami Formation exposed in the Kuzu area, Ashio Mountains indicates paleokarstification of the Permian Nabeyama Limestone Formation. Products of the paleokarstification represent the intercalation of fine-to medium-grained carbonate clasts, muddy rocks, residual brecciated carbonate rocks, and others ruubly clasts.The Ichinotani Formation (Carboniferous) intercalates iron-bearing high-aluminous shale, sharpstone (breccia) conglomerate, and other residual rocks. This paleokarstification eroded the carbonate sequence ranging from late Early Carboniferous to Early Devonian.The Akasaka Limestone of the Mino Terrane intercalates hematite ore deposits that derived from paleosol of limestone and plutonic rocks. Further study is necessary to elucidate this paleokarstification, because most of the ore body was quarried out.