Geochemistry of basalts from ODP Leg 49, North Atlantic Ocean

The geochemistry of basalts recovered from seven sites in the North Atlantic is described with particular reference to minor elements. Three sites (407, 408, and 409) along the same mantle flow line, transverse to the Reykjanes Ridge at about 63°N, provide information on the composition of basalts erupted over a 34-m.y. interval between 2.3 and 36 m.y. ago. At Site 410, at 45°N, penetration into 10 m.y.-old crust west of the ridge axis permits comparisons with young basalts dredged from the median valley at 45°N. Three sites in the FAMOUS area at about 36°N provided material from very young (1 m.y.) basaltic crust (Site 411), and material to test the geochemical coherence of basalts of different ages (1.5 and 3.5 m.y.) on either side of a fracture zone (Sites 412 and 413). These sites complement earlier data from dredged and drilled sites (Leg 37) in the FAMOUS area. […]

本文对北大西洋7个钻探站位所获玄武岩的地球化学特征进行阐述，重点关注微量元素组成。其中位于北纬约63°、横穿雷克雅内斯海岭（Reykjanes Ridge）的同一条幔流带上的3个站位（407、408、409），可提供距今2.3百万年至36百万年、时间跨度达34百万年的喷发玄武岩的组分数据。位于北纬45°的410站位钻至海岭轴部西侧距今10百万年的洋壳，可与北纬45°中央裂谷拖网采获的年轻玄武岩开展对比分析。北纬约36°的FAMOUS区域（FAMOUS）内设有3个站位：411站位可获取距今仅1百万年的极年轻玄武洋壳样品；412与413站位则可用于检验断裂带两侧不同年龄（1.5百万年与3.5百万年）玄武岩的地球化学一致性。上述站位可补充FAMOUS区域此前由拖网采样与钻探站位所获的大洋钻探第37航次（Leg 37）数据。[…]