High resolution oxygen isotope stratigraphy of Integrated Ocean Drilling Program sites U1394, U1395 and U1396, off-shore Montserrat, Lesser Antilles

我们拟议的研究基于最近非常成功的综合大洋钻探计划(IODP)考察340期间收集的岩芯。这次探险的目的是通过收集蒙特塞拉特和马提尼克岛近海的一些岩心，调查小安的列斯火山弧的火山作用和滑坡历史。作为船上浮游性有孔虫(单细胞钙质浮游生物)生物地层学家(利用浮游生物化石的出现和消失来确定沉积岩心的年代)，Deborah Wall-Palmer(拟议的PDRA)可以在一年的休止期内接触到这些岩心。直至IODP Exp340年，蒙特塞拉特火山活动的最长连续记录(约25万年)是2002年在该岛西南部采集的一个5.75m的岩芯，Carmon2。该岩芯揭示了比陆地岩芯更广泛和更完整的火山活动记录。实验期间收集的最长连续泥沙记录。340极大地扩大了这一纪录。U1396C洞长139.4米，记录了450万年前的事件。这个洞的大部分将在低分辨率下进行地层分析，这将由其他专家进行。340名科学家(安德鲁·弗拉斯、穆罕默德·阿尔贾达利)。据估计，该孔上部7米的时间跨度为300,000年，与U1394A/B孔(0至125厘米)和U1395B孔(0至30厘米)在沉积物中恢复的时间相当。U1394A/B和U1395B孔是在蒙特塞拉特附近采集的，位于苏弗里尔山火山喷发物质的主要路径上，包含高分辨率但中断的火山喷发和山体滑坡记录。我们建议的研究是提供这三个岩芯上部约30万年的高分辨率(每2000年)年龄框架。这将通过收集浮游有孔虫Globigerinoides ruber的标本并分析其碳酸钙测试(贝壳)中包含的稳定氧同位素比率来实现。氧同位素比率提供了有关全球冰量和全球气候的信息，标准记录可以在世界范围内识别。因此，与这一记录的相关性可以用来提供沉积物的年龄框架，这比单独使用物种的生物地层范围更详细。制定这一年龄框架对于实现Exp的总体目标至关重要。340将与其他几个Exp.340名科学家，重建蒙特塞拉特的火山和山体滑坡历史。此外，为了确保样品的保守使用，将对U1396C孔上部7米处要求的样品进行进一步的工作。这将有助于为该洞其余部分建立低分辨率稳定同位素和生物地层学框架。这项工作的大部分是由马萨诸塞大学的安德鲁·弗拉斯和佛罗里达州立大学的穆罕默德·阿尔贾达利进行的。我们将在低分辨率下分析U1396C孔上方7米处底栖有孔虫Cibiidoides spp.的稳定氧同位素。浮游有孔虫的种类。

Our proposed research is based on cores collected during the recent, and very successful, Integrated Ocean Drilling Program (IODP) Expedition 340. The aims of this expedition were to investigate the volcanism and landslide history of the Lesser Antilles volcanic arc, by collecting a number of cores offshore Montserrat and Martinique. As a shipboard planktic foraminifera (single celled calcareous plankton) biostratigrapher (dating sediment cores using the appearances and disappearances of fossil plankton), Deborah Wall-Palmer (proposed PDRA) has access to these cores during the one year moratorium period. Until IODP Exp. 340, the longest continuous record (~250,000 years) of volcanic activity on Montserrat was a 5.75 m core collected to the south-west of the island in 2002, CAR-MON 2. This core revealed a more extensive and complete record of volcanic activity than that available in terrestrial cores. The longest continuous sediment record collected during Exp. 340 extends this record considerably. At 139.4 m in length, Hole U1396C records events back to 4.5 million years ago. The majority of this Hole will undergo stratigraphic analysis at low resolution, which will be carried out by other Exp. 340 scientists (Andrew Fraass, Mohammed Aljahdali). The upper 7 m section of this Hole is estimated to span 300,000 years and is comparable to the time period recovered in sediments for Holes U1394A/B (0 to 125 cm) and U1395B (0 to 30 cm). Holes U1394A/B and U1395B were collected close to Montserrat, in the main path of eruptive material from the Soufriere Hills volcano and contain a high resolution, but interrupted record of volcanic eruptions and landslides. Our proposed research is to provide a high resolution (every 2000 yrs) age framework across the upper ~300,000 year sections of these three cores. This will be achieved by collecting specimens of the planktic foraminifera Globigerinoides ruber and analysing the stable oxygen isotope ratios contained within their calcium carbonate tests (shells). Oxygen isotope ratios provide information about the global ice volume and global climate, and the standard record can be identified world-wide. Correlation to this record can therefore be used to provide an age framework for sediments, which is more detailed than using the biostratigraphic range of species alone. Producing this age framework is essential for achieving the overall aims of Exp. 340 as it will be used, in collaboration with several other Exp. 340 scientists, to reconstruct the volcanic and landslide history of Montserrat. In addition to this, to ensure the conservative use of samples, some further work will be carried out on samples requested from the upper 7 m of Hole U1396C. This will assist in constructing the low resolution stable isotope and biostratigraphic framework for the remainder of this Hole. The majority of this work is being carried out by Andrew Fraass (University of Massachusetts) and Mohammed Aljahdali (Florida State University). We will analyse the upper 7 m of Hole U1396C, at low resolution, for stable oxygen isotopes of the benthic foraminifera Cibicidoides spp. and for planktic foraminifera datum species.