Sedimentology and palaeogeographic significance of certain red limestones and associated beds in the Lias of the Alpine region
Sedimentology and palaeogeographic significance of certain red limestones and associated beds in the Lias of the Alpine region
复制标题
高山地区利亚斯某些红色石灰岩及相关层的沉积学和古地理意义
DOI：
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发表时间：
1967
影响因子：
0.7
通讯作者：
A. Hallam
中科院分区：
文献类型：
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作者：
A. Hallam
在阿尔卑斯地区的Lias的几个经典地点，对选定数量的红色石灰岩和相关的灰色石灰岩以及红色和灰绿色泥灰岩进行了地层学和岩石学描述。其中包括瑞士南部和意大利北方的Ammonitico罗索和奥地利萨尔茨堡省的Adnet Limestone和Fleckenmergel等。这些岩石的许多特征与西北欧同等年龄的岩石形成对比。碎屑石英、有机碳、黄铁矿、高岭石、绿泥石和菱铁矿都很少见或不存在，而后者则很常见。相比之下，燧石结核在阿尔卑斯山脉中相当常见，但在更北的地方却很少见。红色石灰岩和泥灰岩在地层学上比灰色石灰岩更致密，更具结核性;在极端致密的情况下，会出现氧化锰包裹的结核和腐蚀表面。地层学的证据显示沉积作用发生在相当浅的水域。地中海地区的动物种类较为多样，但在一定沉积速率的海床上，西北欧的个体丰度较大，最明显的是双壳类。这些相的差异可以通过解释西北欧作为一个沿海和近岸沃茨的地区，其盐度略有降低的淡水从河流流入，带来了大量的陆源碎屑，有机物和铁的海洋。相比之下，地中海区域是一个开阔但相当浅的海域，海洋盐度正常，但缺乏颗粒有机物，因此缺乏底栖动物。这种解释与其他中生代地层的相关性进行了简要讨论。
Synopsis A stratigraphical and petrological description is given of a selected number of red limestones and associated grey limestones and red and grey-green marls, in several classic localities in the Lias of the Alpine region. These include the Ammonitico Rosso of southern Switzerland and northern Italy and the Adnet Limestone and Fleckenmergel, etc. of the Salzburg Province of Austria. There are a number of characteristics of these rocks which contrast with those of equivalent age in north-west Europe. Detrital quartz, organic carbon, pyrite, kaolinite, chamosite and siderite are all rare or absent, whereas they are common in the latter region. Chert nodules are, in contrast quite common in the Alpine beds but rare further north. Red limestones and marls are stratigraphically more condensed and more nodular than their grey equivalents; in cases of extreme condensation manganese oxide-coated nodules and corrosion surfaces occur. Stratigraphical evidence favours deposition in quite shallow water. The fauna of the Mediterranean region is the more diverse, but individual abundance, for beds of a given rate of deposition, is greater in north-west Europe, most notably in the case of bivalves. These facies differences can best be accounted for by interpreting north-west Europe as an area of coastal and inshore waters, whose salinity was lowered slightly by the influx of fresh water from rivers, which brought large quantities of terrigenous detritals, organic matter and iron to the sea. The Mediterranean region was in contrast an area of open but quite shallow sea, of normal marine salinity but deficient in particulate organic matter and hence benthonic fauna. The relevance of this interpretation to other Mesozoic formations is briefly discussed.