THE UPPER CRETACEOUS WHITE SANDSTONE OF LOCH ALINE, ARGYLL, SCOTLAND
THE UPPER CRETACEOUS WHITE SANDSTONE OF LOCH ALINE, ARGYLL, SCOTLAND
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苏格兰阿盖尔艾琳湖上白垩纪白砂岩
DOI：
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发表时间：
1961
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影响因子：
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通讯作者：
D. W. Humphries
中科院分区：
文献类型：
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作者：
D. W. Humphries
摘要 艾琳湖的白砂岩是一种极其纯净、分选良好的易碎岩石。重矿物组以白钛矿和电气石为主，辅有钛铁矿、磁铁矿、褐铁矿、黄铁矿、黄铜矿、锆石、金红石、石榴石、十字石、绿帘石、蓝晶石、尖晶石、榍石、云母（？浸出的黑云母）以及自生锐钛矿和电气石。除石英外，轻质部分还含有白云母（一种与海绿石类矿物有密切关系的绿色“土质”矿物）和微量高岭土。石英克仅呈中等圆形，并显示出磨砂和刻面，这是由于二次二氧化硅的沉积所致。颗粒圆度与尺寸有关，但圆度随尺寸的变化率约为 0.2 毫米；讨论了对此的可能解释。根据对重矿物（特别是电气石）的详细研究，人们认为最终的烃源岩包括莫因片岩和莫文-斯特朗花岗岩，而沉积物的直接来源可能包括下面的塞诺曼阶绿砂。后者被认为在前进的塞诺曼尼亚海中靠近莫文河形成的岛屿的浅滩上遭受了剧烈的局部改造。斯特朗蒂安花岗岩和马尔罗斯花岗岩。苏格兰西部现有的证据并不支持沙漠海岸线到白垩海的假设。
Summary The White Sandstone of Loch Aline is shown to be an extremely pure, well-sorted, friable rock. The heavy mineral suite is dominated by the presence of leucoxene and tourmaline, with subsidiary amounts of ilmenite, magnetite, limonite, pyrites, chalcopyrites, zircon, rutile, garnet, staurolite, epidote, kyanite, spinel, sphene, mica (? leached biotite) and authigenic anatase and tourmaline. The light fraction contains besides quartz, muscovite, a green “earthy” mineral having affinities with the glauconite group of minerals, and a trace of kaolin. The quartz grams are only moderately rounded and show frosting and faceting which are attributed to the deposition of secondary silica. Grain roundness is shown to be related to size, but that the rate of change of roundness with size alters at about 0.2 millimetre; a possible explanation for this is discussed. On the basis of the detailed study of the heavy minerals, in particular tourmaline, it is believed that the ultimate source rocks included both the Moine Schists and the Morven-Strontian Granite, while the immediate source of the sediment may have included the underlying Cenomanian Greensand. The latter is considered to have suffered vigorous localized reworking in the advancing Cenomanian sea on shoals close to islands formed by the Morven. Strontian Granite and the Ross of Mull Granite. The hypothesis of a desert shoreline to the Chalk sea is not supported by the evidence available in the west of Scotland.