The Plutonic Foundation of a Slow-spreading Ridge Segment: The Kane Oceanic Core Complex (23 degrees 30'N, 45 degrees 20' W)

缓慢扩张的山脊部分的深成岩基础：凯恩海洋核心复合体（北纬 23 度 30，西经 45 度 20）

• 批准号: 0624408
• 负责人: Henry Dick
• 金额: --
• 依托单位: Woods Hole Oceanographic Institution
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-11-01 至 2009-10-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0624408&HistoricalAwards=false
• 关键词: Plutonic; Foundation; Slow; spreading; Ridge

This is a study of the petrology and geochemistry of the 1st systematic samples representing the plutonic foundation of a slow-spreading mid-ocean ridge. The rocks are from a 20 by 35 km ~3.7 million year old core complex corresponding to the 2nd order ridge segment south of the Kane Fracture Zone. An ODP Site Survey with Seabeam, deep-tow magnetics and bathymetry, dredging and the Jason ROV mapped it in fall 2004. 2667 kg of rock were sampled. Rocks outcrop systematically over the complex, with dunite and troctolite indicating a ~10 km wide focused mantle melt flow zone that fed an ancient southern volcanic center. The scarcity of these rocks to the north indicates that the overlying diabase and pillow basalt likely represent down-axis fissure eruptions from the southern magmatic center. These observations match the volcanic carapace on the opposing tectonic plate, where an axial volcanic high corresponds to the position of the magma center. The samples will allow the study of melt generation and crustal accretion beneath an end-member "normal" Mid-Atlantic Ridge spreading segment for the first time. They can constrain the melting process, and allow comparison of peridotite compositions from a normal ridge-melting environment to those representing extreme low-degrees of melting at the Gakkel Ridge that may lie close to the MORB mantle source composition.

这是对代表慢速中海山脊的岩石基础的第一个系统样本的岩石学和地球化学的研究。 这些岩石来自20 x 35 km的〜370万年历史的核心复合体，对应于凯恩裂缝区以南的第二阶山脊段。 ODP站点的调查，带有海带，深磁磁和测深，挖泥和Jason Rov于2004年秋天绘制了它。采样了2667公斤的岩石。 岩石在综合体上有系统地露头，杜尼石和木糖岩表明宽约10公里的聚焦地幔熔体流动带，供应了古老的南部火山中心。 这些岩石在北部的稀缺性表明，上覆的植物底层和枕头玄武岩可能代表了南部岩浆中心的下轴裂口爆发。 这些观察结果与相反的构造板上的火山甲壳相匹配，轴向火山高的高度对应于岩浆中心的位置。 这些样品将首次允许研究末端的“正常”中山脊传播细分市场下的熔体产生和地壳积聚。 它们可以限制熔化过程，并允许将橄榄岩组成从正常的山脊熔融环境与代表可能位于MORB地幔源组成的Gakkel Ridge的极端低度融化的环境进行比较。