Geochemistry and isotopic ratios of basalts obtained during R/V Akademik Nikolaj Strakhov cruise ANS25

Based on the investigation of samples recovered during Cruise 25 of the R/V ''Akademik Nikolai Strakhov'', the character of magmatism was determined in the flank parts of the rift zone at the 74°05'N and 73°50'N region, where the direction of the rift valley changes from the north-northwest in the Knipovich Ridge to the northeast-trending structures of the Mohns Ridge. It was shown that the tholeiitic magmas of this region shows all the geochemical characteristics of TOR-2, which is typical of the Mohns Ridge and most oceanic rift zones worldwide, and differ from the basalts of the Knipovich Ridge, which are assigned to a shallower type of tholeiitic magmatism (Na-TOR). The persistent depletion of the magmas in terms of lithophile element contents and radiogenic isotope ratios of Sr, Nd, and Pb reflects the conditions of their formation during the ascent of the depleted oceanic mantle, which has occurred without significant complications since the early stages of the formation of the Mohns Ridge.

本数据集基于"尼古拉·斯特拉霍夫院士"号（R/V Akademik Nikolai Strakhov）第25航次回收样品的调查，厘定了北纬74°05′与73°50′区域裂谷带侧翼的岩浆作用特征；该区域裂谷谷的走向由克尼波维奇海岭（Knipovich Ridge）的北西北向，转变为蒙斯海岭（Mohns Ridge）的北东向构造走向。研究表明，该区域的拉斑玄武质岩浆（tholeiitic magmas）具备蒙斯海岭及全球多数大洋裂谷带典型的TOR-2型地球化学特征，且与克尼波维奇海岭的玄武岩存在显著差异——后者被归为浅成型拉斑玄武质岩浆作用（Na-TOR）。该区域岩浆的亲石元素含量与Sr、Nd、Pb放射成因同位素比值持续亏损，反映其形成于亏损大洋地幔的上涌过程中，且自蒙斯海岭形成初期以来，该上涌过程未发生显著复杂化。