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《中国矿产地质志·贵州卷·铝土矿》（2019）第六章“凯里式铝土矿”中，在没有地质依据的情况下，将凯里—黄平地区原中二叠统梁山组肢解成两部分:即将原梁山组上段的碳质页岩、煤层及砂岩等仍称为中二叠统“梁山组（ P2l）”; 而将原梁山组中段的铝土矿、铝土岩等及下段的铁质黏土岩、菱铁矿层等，更改为下二叠统“大竹园组（P1d）”，并将其沉积时代定
摘要
黔北—渝南大竹园组(C2d)与黔东南凯里—黄平地区梁山组(P2l),都是铝土矿含矿岩系,均产有丰富的孢子花粉。基于孢粉学研究,推测大竹园组孢粉应产于“石炭纪”,结合大竹园组与下伏上石炭统黄龙组(C2h) 或下志留统韩家店组(S1hj),以及上覆中二叠统梁山组(P2l),皆为假整合接触等地质特征,推测大竹园组沉积时代大致为晚石炭世逍遥期,即卡西莫夫期—格舍尔期。黔北—渝南大竹园组上覆梁山组与凯里—黄平地区梁山组孢粉丰度较高,基于孢粉组合,推测其沉积时代皆为中二叠世罗甸期早期,即空谷期早期。依据岩石地层特征和化石组合,笔者等认为《中国矿产地质志·贵州卷·铝土矿》(2019)第六章“凯里式铝土矿”中,中二叠统梁山组(P2l)即为原梁山组上段的碳质页岩、煤层及砂岩等,该地区下二叠统“大竹园组(P1d)”,应为原梁山组中段的铝土矿、铝土岩等及下段的铁质黏土岩、菱铁矿层等,其沉积时代不应为“早二叠世紫松期晚期—隆林期”,即撒克马尔期—亚丁斯克期,而应为中二叠世罗甸期早期,即空谷期早期。
Abstract
Both the Dazhuyuan Formation (C2d) in northern Guizhou—southern Chongqing and the Liangshan Formation (P2l) in Kaili—Huangping area of southeastern Guizhou are bauxite-bearing rock series, which are rich in spore pollen. According to the identification of sporopollen experts, the Dazhuyuan Formation is produced in the Carboniferous. Combined with the geological characteristics of the Dazhuyuan Formation and the underlying Upper Carboniferous Huanglong Formation ( C2h) or the Lower Silurian Hanjiadian Formation ( S1hj), as well as the overlying Middle Permian Liangshan Formation (P2l), it is confirmed that the sedimentary age of the Dazhuyuan Formation is the Late Carboniferous Xiaoyao Age, namely the Kasimovian—Gescher Age. The Liangshan Formation overlying the Dazhuyuan Formation in northern Guizhou and southern Chongqing and the Liangshan Formation in the Kaili—Huangping area are very rich in spores and pollen. According to the identification of spore—pollen experts, the sedimentary age is the early Middle Permian Luodian Age, namely the early Kungurian. In the sixth chapter “Kaili-type bauxite” of the book China Mineral Geology · Guizhou Volume · Bauxite ( 2019 ), the original Middle Permian Liangshan Formation in Kaili—Huangping area is dismembered into two parts without geological basis: the carbonaceous shale, coal seam and sandstone in the upper part of the original Liangshan Formation are still called the Middle Permian Liangshan Formation ( P2l); the bauxite, bauxitite in the middle section of the original Liangshan Formation and the iron clay rock and siderite layer in the lower section were changed to the Lower Permian Dazhuyuan Formation ( P1d), and its sedimentary age was determined to be late Early Permian Zisong age—Longlin age, that is, Sakmar Age—Adingska Age. In this way, it will cause confusion to the stratigraphic unit of the Middle Permian Liangshan Formation in Guizhou Province, which has been used for many years, has a clear definition, and is supported by strata and substrata, which deserves serious attention.