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High resolution oxygen isotope stratigraphy of IODP sites U1394, U1395 and U1396 offshore Montserrat, Lesser Antilles (NERC grant NE/K002724/1)
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.
We provide here Pb isotope data for the basement rocks cored during IODP Expedition 352 (Bonin Forearc). The data are reported as 206Pb/204Pb, 207Pb/204Pb and 208Pb/204Pb ratios together with their errors. The overall accuracy of the data was determined using international standard NBS SRM 981. Values for this standard achieved during the measurement period were 206Pb/204Pb = 16.9404 ±32,207Pb/204Pb = 15.4969 ±32, 208Pb/204Pb = 36.7149 ±90 (2sd; n=44). The data are separated into four parts one for each drill site that cored basement. Sites 1440B and 1441A both sampled a basalt type known as FAB (Forearc Basalts), whereas Sites 1439C and 1442A both sampled boninites (Mg-rich andesites). Both rock types are typical of the forearc setting and contain information needed to understand the process of subduction initiation. A summary of the Expedition, and hence the petrography and setting of the samples as well as the various scientific objectives for the project to which these analyses contribute) may be found in: Reagan, M.K., Pearce, J.A., and Petronotis, K., Expedition Scientists, 2015, Izu-Bonin-Mariana Fore Arc: Proceedings of the International Ocean Discovery Program, 352. International Ocean Discovery Program, http://dx.doi.org/10.14379/iodp.proc.352.2015.
Elemental and stable isotope data measured in Eocene foraminiferal calcite from Ocean Drilling Program Site 865 and Tanzanian Drilling Project Site 18 (NERC grants NE/H016457/1, NE/I005870/1, NE/I005595/1)
Elemental and stable isotope data measured in Eocene foraminiferal calcite from Ocean Drilling Program Site 865 and Tanzanian Drilling Project Site 18 published in Edgar et al. (2015) "Assessing the impact of diagenesis on δ11B, δ13C, δ18O, Sr/Ca and B/Ca values in fossil planktic foraminiferal calcite" in Geochimica et Cosmochimica Acta, v. 166, p. 189-209. Table 1. δ18O and δ13C values for glassy and frosty foraminifera from TDP Site 18 and ODP Site 865, respectively. Table 2. Sr/Ca and B/Ca values, and test weights for glassy and frosty foraminifera from TDP Site 18 and ODP Site 865, respectively. Table 3. δ11B values for glassy and frosty foraminifera from TDP Site 18 and ODP Site 865, respectively.