Offset Drilling on the Southeast Greenland Volcanic Rifted Margin: UCDavis Participation on the 1998 DLC Drilling Cruise

OCE 98-11453 Lesher建议的项目涉及资金，供加州大学戴维斯分校的两名研究人员参加丹麦岩石圈中心计划于1998年8月20日在格陵兰岛东南部火山裂谷边缘进行的钻探航行，并对取芯火山岩进行为期三年的后续岩石学研究。 这次航行的主要钻探目标是恢复北纬63度和66度之间向海倾斜反射层序列（SDRS）羽状边缘沿着北纬68度格陵兰-冰岛海隆的基底岩性（第三纪熔岩、沉积物和大陆基底）。这些地点的岩心将用于实现三个主要研究目标：1）更全面地描述最早的岩浆产物和与大陆分裂相关的构造演化; 2）填补我们对格陵兰岛东南缘沿着远离冰岛地幔柱轴的地幔来源的认识中的关键空白（扩大ODP第152和163航段的主要主题）; 3）统一东格陵兰泛滥玄武岩序列的火山记录，包括东格陵兰-冰岛隆起的海上SDRS，以及冰岛西部的火山序列。 工资支持正在建议为加州大学戴维斯分校的参与者在40天的巡航和3年的巡航后科学。 将编制一份供普遍分发的航行后报告，其中包括完整的岩心描述、现场报告和初步结果（仿照ODP初步报告）。后续的分析工作和综合将是加州大学戴维斯分校PI小组、DLC（为钻井船租赁提供资金）和R。邓肯小组在俄勒冈州州立大学（40 Ar/39 Ar年龄测定），建立在与ODP第152和163航段有关的合作科学计划以及东格陵兰岛玄武岩泛滥省的陆上工作的基础上。 加州大学戴维斯分校的研究小组将对岩心材料进行岩石学和电子探针研究，并将通过电感耦合等离子体质谱法进行全岩微量元素分析。 将在哥本哈根地球科学中心进行主要元素分析（X射线荧光法）和放射性同位素研究（Sr-Nd-Pb-Os）。 即将进行的钻探计划将是ODP第152和163航段钻探调查的直接延伸，预计将从根本上促进对裂谷边缘演化、地幔柱-岩石圈相互作用以及大陆-海洋过渡性质的理解。 回收的岩心和相关的科学发现也将与编制供耗氧潜能开发计划-海洋综合开发计划审议的未来北大西洋深水钻探提案密切相关并至关重要。 ***

OCE 98-11453 Lesher The recommended project involves funds for two researchers from the University of California, Davis to take part in the Danish Lithosphere Centre (DLC) drilling cruise to the Southeast Greenland volcanic rifted margin, scheduled for August 20, 1998, and for three years of follow-up petrologic studies on the volcanic rocks cored. The primary drilling objectives of the cruise are the recovery of basement lithologies (Tertiary lavas, sediments, and continental basement) along the feather-edge of the seaward-dipping reflector sequences (SDRS) between latitudes 63 degrees north and 66 degrees north, and on the Greenland-Iceland Rise at latitude 68 degrees north. Drill core from these sites will be used to achieve three primary research goals: 1) to more fully characterize the earliest magmatic products and the tectonic evolution associated with continental breakup; 2) to close critical gaps in our understanding of mantle sources along the southeast Greenland margin away from the axis of the ancestral Iceland mantle plume (expanding on a primary theme of ODP Legs 152 and 163); and 3) to unite the volcanic records for the East Greenland flood basalt succession, the offshore SDRS comprising the East Greenland-Iceland Rise, and the volcanic succession of western Iceland. Salary support is being recommended for the UC Davis participants during the 40 day cruise and for 3 years of post-cruise science. A post-cruise report for general distribution will be produced, containing a complete core description, site reports, and preliminary results (modeled after the ODP Initial Reports). Follow-up analytical work and the synthesis will be a collaborative effort between the PI's group at UC Davis, the DLC (funding the drill ship charter) and R. Duncan's group at Oregon State University (40Ar/39Ar age determinations), building on cooperative science programs related to ODP Legs 152 and 163 and onshore work in the East Greenland flood basalt province. The UC Davis group will conduct petrog raphic and electron microprobe studies of the core material, and will perform whole rock trace element analyses by inductively-coupled plasma mass spectrometry. Major element analyses (by XRF) and radiogenic isotope studies (Sr-Nd-Pb-Os) will be undertaken at the Copenhagen Geoscience Center. This upcoming drilling program will be a direct extension of drilling investigations by ODP Legs 152 and 163, and is expected to contribute fundamentally to the understanding of rifted margin evolution, plume-lithosphere interactions, and the nature of continent-ocean transition. The core recovered and associated scientific discoveries also will be highly germane and crucial to the preparation of future proposals for deep water drilling in the North Atlantic Ocean for consideration by ODP-IODP. ***