Trans-Atlantic correlation of the Palaeogene volcanic successions in the Faeroe Islands and East Greenland
Trans-Atlantic correlation of the Palaeogene volcanic successions in the Faeroe Islands and East Greenland
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法罗群岛和东格陵兰古近纪火山序列的跨大西洋对比
DOI：
10.1144/gsjgs.156.6.1081
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发表时间：
1999
影响因子：
2.7
通讯作者：
M. Storey
中科院分区：
文献类型：
--
作者：
L. Larsen;R. Waagstein;A. Pedersen;M. Storey
在东北大西洋的大陆分裂之前，法罗群岛和格陵兰岛中部的距离在100-120公里之内。在法罗群岛和格陵兰东部南森峡湾地区，通过5公里厚的古近纪同时期溢流玄武岩堆的完整剖面的化学和岩性数据显示出非常相似的玄武岩成分和随时间的演化模式。东格陵兰岛的法罗群岛下部玄武岩地层和相应的南森峡湾地层形成了一个沉积层覆盖的破碎前序列。一个同-断裂序列由法罗群岛中上部玄武岩地层和相当于东格陵兰的米尔恩陆地地层组成，其中5个间隔可以与富钛镁玄武岩和苦橄岩在底部的成分演变相关，以MORB样低钛玄武岩为主。这一系列事件都是在同一个地幔熔融柱中产生的，该地幔熔融柱位于一个逐渐变薄的大陆之下，大陆上的裂谷带最终使大陆破裂。其演化模式与格陵兰东南部边缘非常相似，但根据1973年Palmason模型的扩展尚未建立。前和同破裂序列形成的火山巨系统横跨裂谷带，面积范围为70 000和220 000平方公里，体积为120 000和250 000立方公里。根据简单的主元素图，可以区分前破裂序列和同破裂序列的岩石。格陵兰东部的覆盖层厚度为3-3.5公里，但法罗群岛的覆盖层很薄或不存在;融化的能量来源似乎集中在格陵兰一侧。
Before continental break-up in the NE Atlantic, the Faeroe Islands and central East Greenland were within a distance of 100–120 km. Chemical and lithological data for complete sections through the 5 km thick piles of contemporaneous Palaeogene flood basalts in the Faeroe Islands and in the Nansen Fjord area in East Greenland show very similar basalt compositions and evolution patterns with time. The Faeroes lower basalt formation and the equivalent Nansen Fjord Formation in East Greenland form a pre-break-up succession overlain by a sediment horizon. A syn-break-up succession consists of the Faeroes middle and upper basalt formations and the equivalent Milne Land Formation in East Greenland in which five intervals can be correlated with a compositional evolution from Ti-rich magnesian basalts and picrites at the base to a dominance of MORB-like low-Ti basalts at the top. The successions were generated in the same mantle melting column beneath a thinning continent with a rift zone that eventually ruptured the continent. The evolution pattern is very similar to that seen on the SE Greenland margin, but spreading according to the Palmason model of 1973 was not yet established. The pre- and syn-break-up successions formed volcanic megasystems stretching across the rift zone with areal extents of 70 000 and 220 000 km2 and volumes of 120 000 and 250 000 km3. Rocks from the pre- and syn-break-up successions can be discriminated based on a simple major-element plot. The overlying succession was 3–3.5 km thick in E Greenland but was thin or absent in the Faeroes; the energy source for the melting appears to have been concentrated on the Greenland side.