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

OCE 98-11453 Lesher建议的项目包括资助加州大学戴维斯分校的两名研究人员参加定于1998年8月20日前往格陵兰东南火山裂谷边缘的丹麦岩石圈中心钻探巡航，以及对取心的火山岩进行为期三年的后续岩石学研究。邮轮的主要钻探目标是沿北纬63度至66度之间的向海倾斜反射层序(SDR)的羽状边缘恢复基底岩性(第三纪熔岩、沉积物和大陆基底)，以及在北纬68度的格陵兰-冰岛隆起上。这些遗址的钻探岩芯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品和与大陆解体有关的构造演化；2)弥合我们对格陵兰东南边缘远离冰岛原始地幔热柱轴线的地幔来源的认识上的关键空白(在ODP152和163这一主要主题上展开)；3)统一东格陵兰洪水玄武岩序列、包括东格陵兰-冰岛隆起的近海SDR和冰岛西部火山序列的火山记录。建议加州大学戴维斯分校的参与者在40天的邮轮期间和邮轮后3年的科学研究期间获得工资支持。将编写一份用于一般分发的巡航后报告，其中包含完整的核心描述、现场报告和初步结果(仿照《臭氧消耗臭氧层物质初步报告》)。后续的分析工作和综合将是加州大学戴维斯分校的PI小组、DLC(为钻探租船提供资金)和俄勒冈州立大学的R.Duncan小组(40Ar/39Ar年龄测定)之间的合作努力，建立在与ODP152和163相关的合作科学项目以及东格陵兰洪水玄武岩省的陆上工作的基础上。加州大学戴维斯分校将对岩心材料进行岩石学和电子探针研究，并将利用电感耦合等离子体质谱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射线荧光分析)和放射性同位素研究(锶-钕-铅-铯)。这一即将到来的钻探计划将是对ODP152和163钻探调查的直接延伸，预计将从根本上有助于理解裂谷边缘演化、羽流-岩石圈相互作用以及大陆-海洋过渡的性质。所发现的岩心和相关的科学发现也将具有很强的关联性，对于拟定今后北大西洋深水钻探的提案至关重要，供南极海生委-IODP审议。***

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. ***