Sediment % coarse fraction (>63 microns), and abundance of fish teeth in coarse fraction. 2016 has been a record breaking year in terms of global temperatures. The high temperatures have resulted from a combination of elevated atmospheric pCO2 coupled with the global impacts of a strong El Nino event. There are many important components of the climate system, and the El Nino phenomenon demonstrates the importance of the low latitude Pacific Ocean. The warm pool of water in the western Pacific Ocean has not always had the same characteristics as it has today, and it has been proposed that its evolution over the past 15 million years has had a major impact on global climate. In order to understand how the warm pool might respond to future climate change, it is important to understand the drivers behind its past evolution. Did it respond simply to the changing shape of ocean basins through time? Or did it respond to other components of the climate system, such as sea level or latitudinal temperature gradients? The changes in warm pool structure may also have impacted the biological ecosystems, and hence the cycling of carbon in this region. The carbon cycle is another key component of the Earth's climate system. Understanding the causes and consequences of these long-term changes in the Pacific warm pool requires a two-pronged approach, using modelling in conjunction with proxy records for different parts of the climate system. This proposal aims to generate some key records of past high latitude temperature and ice volume that can be directly compared with changes in the warm pool through time. These records will be derived from geochemical analyses of microscopic marine fossils collected by the International Ocean Discovery Program (IODP).
These data are described fully in the following publication: S. Barker, J. Chen, X. Gong, L. Jonkers, G. Knorr, D. Thornalley, Icebergs not the trigger for North Atlantic cold events. Nature 520, 333-336 (2015). The dataset comprises planktonic foraminiferal census counts and counts of Ice Rafted Debris (IRD) from sediment samples collected during Ocean Drilling Programme (OPD) leg 162 site 983 in the Northeast Atlantic (60.48°N, 23.68°W, 1,984m water depth). The data were collected between Jan 2011 and Dec 2014. The dataset includes values every 2cm from 2 to 51.5m (metres composite depth) along the ship-board splice. Before counts were performed bulk sediments were spun overnight in distilled water, before sieving over a 63µm sieve. All portions were dried, weighed and stored. Counts were performed on a split of the >150µm fraction. The dataset can be employed to assess changes in surface temperature and presence of rafted ice over the site over the past 440kyr or so. This information is of interest to paleoceanographers and paleoclimatologists. The dataset was created and interpreted by a team at Cardiff University, with additional input from other authors named in the publication. The dataset is complete except for one or two samples that were not received from the repository.
The thermal state of marine sediments controls a range of potential dehydration reactions as sediments are subducted. In thick sediment sections it is possible that reactions that would normally occur within a subduction zone start offshore of the deformation front. This scenario may be occurring at the Sumatra subduction zone (e.g. Geersen et al., 2013; Huepers et al., 2017). We have investigated this possibility by modelling the thermal and depth history of sediments offshore Sumatra. We have used a range of different assumptions about how the sediments decompact with depth, as well as testing the dependence on the seismic velocities used for depth conversion of the horizons.
The global carbon cycle - how much carbon is stored in its interconnected reservoirs (ocean, atmosphere, plants and soils on land, sediments in the deep sea) as well as the fluxes between them, is not set in stone. We know from the geological record that the concentration of CO2 in the atmosphere has varied enormously over the last few hundred million years. The chemistry of the oceans also gradually changes with time and the organisms living within it adjust and evolve. As a result, how the carbon cycle 'works', and particularly, how well (or not) atmospheric CO2 (and hence climate) is regulated in the face of disruption, also changes on geological time-scales. This creates challenges to understanding the causes and consequences of past global warming like events and how such events can be related to potential future changes. Sediments slowly accumulating in the deep ocean reflect what goes on around and above them, both chemically and biologically. Of particular interest to us is the mineral calcium carbonate (CaCO3), which can be found in the form of chalk and limestone rocks today. CaCO3 is used by certain marine organisms for constructing shells and skeletons. Hence, the amount of CaCO3 that in buried in sediments tells us something about ancient organisms and ecosystems. In addition, CaCO3 will start dissolving in seawater if the conditions too are acidic or the depth (and thus pressure) too great. How much CaCO3 originally created by organisms at the surface that escapes dissolution in sediments below to be buried and preserved in the geological record can thus tell us something about the chemistry, depth, and when data from many locations is available, the circulation of the ocean in the past. Looking for subtle changes in the composition of ancient mud in the hundreds and hundreds of meters of sediment core recovered from the ocean floor by drill ship would be a little like looking for a needle in a haystack. However, Nature has been kind to us and the transition from white-colored sediments rich in the carbonate shells of dead marine organisms to clays devoid of carbonate is easy to spot. This point represents a fine balance between the amount of shell material being deposited to the sediments and the rate of dissolution of these shells. Hence, this reflects a certain relationship between surface ocean biological processes and deep ocean chemistry and circulation. Any change in these factors will drive sediments rich in CaCO3 or devoid of any trace of carbonate secreting organisms. In this project we will compile the records from many hundreds of different sediment cores that have been recovered since the 1960s. Will identify the 'balance point' in these cores (if one exists) and combine all the confirmation to reconstruct how this balance point has changed in depth and time in the different ocean basins. Because the age of the sediments in some cores extends back to well before the white cliffs of Dover were deposited, we will start our record there. The interpretation of our curve will not be entirely straightforward, because multiple environmental influences all push and pull the balance point in different directions and with different strengths. We will therefore also use a computer model representation of the Earth's climate and oceans, its carbon cycle, ocean chemistry, and the composition of sediments in the deep sea. We will use this model to explore how the different aspects of the global carbon cycle affect the balance point, and by comparing model predictions to our new curve, interpret how the carbon cycling and the sensitivity of atmospheric pCO2 (and hence climate) to being perturbed by massive greenhouse gas release, has changed over the past 150 million years. Hence we will not only be able to answer the question: do we live in a particularly 'lucky' or 'unlucky' time in terms of how sensitive our global environment is burning fossil fuels, but we will know why.
This dataset includes the (stable) oxygen and carbon isotopic composition of benthic foraminifer tests (n= 686) and the (radiogenic) isotopic composition of the terrigenous fraction of marine sediments (n= 75), all sampled from Eocene to Oligocene-aged sediments recovered at Ocean Drilling Program (ODP) Site 689 and 690 (Maud Rise, Southern Ocean)
The concentrations of up to 30 trace elements in approximately 9,000 sea-bed samples from the UK Continental Shelf were determined by BGS using a variety of analytical techniques. In some cases samples were tested using more than one method. The analyses were carried out on freeze-dried samples of the sand and mud fractions of the samples. The data are stored as part of the National Geoscience Data Centre (NGDC) and the Marine Environmental Data and Information Network (MEDIN) Data Archive Centre (DAC) for Geology and Geophysics. Data are delivered via the BGS Offshore GeoIndex www.bgs.ac.uk/GeoIndex/offshore.htm geochemical layers. References: Stevenson, A G (2001) Metal concentrations in marine sediments around Scotland: a baseline for environmental studies, Elsevier Science; Stevenson, A G et al (1995) The geochemistry of sea-bed sediments of the United Kingdom Continental Shelf : the North Sea, Hebrides and West Shetland shelves, and the Malin-Hebrides sea area (http://nora.nerc.ac.uk/507899/).
The data set consists of the results of particle size analysis (PSA) performed on approximetaly 29,000 sea-bed sediment samples collected by BGS from the UK Continental Shelf and adjacent deep water areas, mostly using sediment grabs, but also sediment corers on occasions. Measurements were also made on approximately 8000 downhole sub-samples from shallow cores and boreholes. Data from other UK organisations have also been added to the PSA dataset. The data are stored as part of the National Geoscience Data Centre (NGDC) and the Marine Environmental Data and Information Network (MEDIN) Data Archive Centre (DAC) for Geology and Geophysics. Data are delivered via the BGS Offshore GeoIndex www.bgs.ac.uk/GeoIndex/offshore.htm Seabed Sediment Data layers.
Data are either (1) depths and spacings between stylolites and faults within Unit IV, (2) images from IODP drill core image logs of the locations of samples observed, (3) photomicrographs and flatbed thin section scans of thin sections cut from samples, (4) SEM BSE or EDS data collected at Cardiff University. These data form the basis of: Leah et al. "Brittle-ductile strain localisation and weakening in pelagic sediments seaward of the Hikurangi margin, New Zealand", Tectonics, Submitted. Images and data from samples collected at IODP Expedition 375 Site U1520 (38°58.1532'S, 179°7.9112'E, 3522.1 mbsl). This is just seaward (east) of the trench of the Hikurangi Margin, New Zealand.
The British Geological Survey has collected over 50000 offshore samples using grabs, dredges and shallow coring devices (to a maximum depth of 6m below the sea bed). The collection also includes additional third party data and has assisted in the creation of BGS Marine Geology Maps. The distribution is variable, but in general there are sample stations spaced about every 5 - 10km across the entire UK Continental Shelf (UKCS). In some localised areas the sampling density is much higher. The data held includes digital data and analogue records (sample data sheets), plus associated physical sample material. Sample data sheets which have been scanned contain index information and geological descriptions and are more detailed from 1983 onwards. Coded geological descriptions were entered on sheets which were subsequently digitised, and this information is available for about 10,000 samples. The data also includes results of analyses such as micropalaeontological examination or age dating. Particle Size Analysis, geochemistry and geotechnical data are described in separate metadata entries. Sample material are managed as part of the BGS Materials collection and are available for examination and subsampling. The data are stored within the National Geoscience Data Centre (NGDC) and Marine Environmental Data and Information Network (MEDIN) Data Archive Centre (DAC) for Geology and Geophysics. Data are delivered via the BGS Offshore GeoIndex www.bgs.ac.uk/GeoIndex/offshore.htm.The activity and scan layers contains location information, metadata and links to scanned sample datasheets/core logs, and the geological, geotechnical, geochemical and sea-bed sediment data layers contain observations and/or measurements as digital values. The data are applicable to a wide range of uses including environmental, geotechnical and geological studies. Reference: Fannin, NGT. (1989) Offshore Investigations 1966-87. British Geological Survey Technical Report WB/89/2, British Geological Survey.
The data consist of the results of geotechnical testing carried out at various depth intervals on shallow cores or boreholes collected BGS from the UK Continental Shelf. The bulk of the data north of 56N are in digital form and result from testing carried out on board survey vessels using hand-held test equipment (penetrometers and shear vanes). These values are averaged for each test interval, and are expressed in kiloPascals. There are approximately 6000 test results in the data set. Some more detailed test information, in non-digital and report form is held for selected sites. Also for most sites where digital data is not available, geological descriptions of core material will also contains semi-quantitative information on the stiffness of the material. Geotechnical knowledge is required to understand and interpret the results if they are to be used as a basis for engineering studies. Core material are managed as part of the BGS Materials collection and are available for examination, testing or subsampling. The data are stored as part of the National Geoscience Data Centre (NGDC) and the Marine Environmental Data and Information Network (MEDIN) Data Archive Centre (DAC) for Geology and Geophysics. Data are delivered via BGS Offshore GeoIndex www.bgs.ac.uk/GeoIndex/offshore.htm geotechnical layers. Reference: Fannin, NGT. (1989) Offshore Investigations 1966-87. British Geological Survey Technical Report WB/89/2, British Geological Survey.