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Basic
- Full
metadata
Reference System
referenceSystemIdentifier:
code:
WGS 84 (EPSG::4326)
code:
http://www.opengis.net/def/crs/EPSG/0/4326
Identification
Title:
Scales of preservation and root causes of mantle heterogeneities in the Iapetan Ocean convecting upper mantle NERC grant NE/J00457X/1
code:
http://data.bgs.ac.uk/id/dataHolding/13607011
Abstract:
Although the terrestrial mantle comprises ~80 vol.% of our planet, its compositional architecture is not well understood despite the importance such knowledge holds for constraining Earth's thermal and chemical evolution over ~4.5 billion years of geological time. Our lack of detailed insight into the mantle stems in part from the fact that it is rarely exposed at our planets surface, making direct observation and study difficult. It is clear from recent study, however, that the mantle cannot be assumed to be compositionally homogenous or static over geological time. Peridotites from the ocean basins (abyssal peridotites) and from ophiolites preserve evidence for a convecting upper mantle that is chemically and isotopically heterogeneous at regional (100's km) and small (cm-to-m) scales. Complex formation and alteration upper mantle histories involving processes of melt-depletion, refertilisation (whereby originally refractory residues such as harzburgites become lherzolites again via melt addition) and melt-rock reaction have been held responsible, but the causes, timing and distribution of such processes are poorly resolved. Ophiolites, which represent partially-to-wholly preserved slivers of obducted oceanic mantle, are particularly valuable resources for assessing the timing, causes and extent of mantle heterogeneity, as they allow field-based observation to be coupled with geochemical investigation on otherwise inaccessible mantle material. Furthermore, ophiolites preserve a range of oceanic mantle lithologies (e.g., harzburgites, lherzolite and dunite) and such variation allows detailed assessment of the distribution and relative timing of events acting upon the mantle that is preserved. A distinctive attribute of some ophiolites, which contrasts with abyssal peridotites, is the presence of podiform chromitite seams, typically in the region of the petrological Moho, which are often associated with Platinum-group element mineralization. The timing and genesis of ophiolite podiform chromitites is controversial, but it has been suggested that they represent zones of focused melt channeling in supra-subduction zone settings. The Shetland (UK) and Leka (Norway) supra-subduction zone ophiolites comprise oceanic lithosphere separated at ~620 Ma on either side of a mid-ocean ridge and subsequently obducted over continental crust ~130 Ma later, each on opposite sides of the northern Iapetus Ocean. A pilot study already carried out on the Shetland ophiolite by the PI and Project Partner reveals that it preserves evidence for a complex sequence of melt depletion, percolation and refertilisation events that occurred over the lifetime of the Iapetus mantle. The critical observation made from the pilot dataset is that later mantle events only partially overprint the compositional heterogeneities developed from earlier mantle processes and that the relatively high degrees of partial melting associated with the supra-subduction zone are very effective at generating such heterogeneity. This important observation will be tested in the proposed research by 1) extending the Shetland study to greater levels of detail; 2) inclusion of a comparative study of carefully selected samples from the well-preserved Leka ophiolite; 3) drawing comparisons with existing geochemical and isotopic datasets from ophiolites that formed in other (e.g., mid-ocean ridge) tectonic settings. In order to achieve this, the powerful combination of the Re-Os isotopic system and highly-siderophile element (Os, Ir, Ru, Rh, Pt, Pd, Re, Au) abundance measurements will be utilised to discriminate between the processes responsible for generating mantle heterogeneities such as melt depletion, refertilisation and melt-rock reaction. Thus, profound insight will be gained into the chemical evolution of a piece of oceanic mantle and the development of compositional heterogeneity therein, from outcrop to oceanic plate scales, over much of the lifetime of the Iapetus Ocean.
Individual Name:
Dr Brian O'Driscoll
Organisation Name:
University of Manchester
Position Name:
School of Earth, Atmospheric and Environmental Sciences
Delivery Point:
Williamson Building-1.19
MD_MaintenanceInformation:
maint. / update frequency:
notApplicable
File Name:
https://resources.bgs.ac.uk/images/geonetworkThumbs/3d8fae99-5fb2-7248-e054-002128a47908.png
keyword:
http://www.eionet.europa.eu/gemet/concept?cp=13&langcode=en&ns=5
Title:
GEMET - INSPIRE themes, version 1.0
keyword:
NGDC Deposited Data
Title:
BGS Thesaurus of Geosciences
keyword:
https://webapps.bgs.ac.uk/services/ngdc/accessions/index.html
keyword:
NGDC Deposited Data
Access Constraints:
otherRestrictions
Other Constraints:
licenceOGL
Other Constraints:
http://inspire.ec.europa.eu/metadata-codelist/LimitationsOnPublicAccess/noLimitations
Other Constraints:
Available under the Open Government Licence subject to the following acknowledgement accompanying the reproduced NERC materials "Contains NERC materials ©NERC [year]"
Use Constraints:
otherRestrictions
Other Constraints:
The copyright of materials derived from the British Geological Survey's work is vested in the Natural Environment Research Council [NERC]. No part of this work may be reproduced or transmitted in any form or by any means, or stored in a retrieval system of any nature, without the prior permission of the copyright holder, via the BGS Intellectual Property Rights Manager. Use by customers of information provided by the BGS, is at the customer's own risk. In view of the disparate sources of information at BGS's disposal, including such material donated to BGS, that BGS accepts in good faith as being accurate, the Natural Environment Research Council (NERC) gives no warranty, expressed or implied, as to the quality or accuracy of the information supplied, or to the information's suitability for any use. NERC/BGS accepts no liability whatever in respect of loss, damage, injury or other occurence however caused.
Other Constraints:
Available under the Open Government Licence subject to the following acknowledgement accompanying the reproduced NERC materials "Contains NERC materials ©NERC [year]"
Spatial Representation Type:
textTable
topicCategory:
geoscientificInformation
westBoundLongitude:
4.2500
eastBoundLongitude:
16.2500
southBoundLatitude:
57.0000
northBoundLatitude:
65.5000
Supplemental Information:
NERC grant NE/J00457X/1
Distribution
Digital Transfer Options:
linkage:
http://dx.doi.org/10.1093/petrology/egv055
Digital Transfer Options:
linkage:
http://www.earthchem.org/petdb
Digital Transfer Options:
linkage:
http://www.earthchem.org/petdbWeb/search/ref_info.jsp?singlenum=3011
Digital Transfer Options:
linkage:
http://www.bgs.ac.uk/services/ngdc/accessions/index.html#item71609
Data Quality
Title:
INSPIRE Implementing rules laying down technical arrangements for the interoperability and harmonisation of Geology
explanation:
See the referenced specification
Title:
Commission Regulation (EU) No 1089/2010 of 23 November 2010 implementing Directive 2007/2/EC of the European Parliament and of the Council as regards interoperability of spatial data sets and services
explanation:
See http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=OJ:L:2010:323:0011:0102:EN:PDF
statement:
For lineage see published paper, Generations of Melt Extraction, Melt-Rock Interaction and High-Temperature Metasomatism Preserved in Peridotites of the ~497 Ma Leka Ophiolite Complex, Norway. http://dx.doi.org/10.1093/petrology/egv055
Metadata
File Identifier:
3d8fae99-5fb2-7248-e054-002128a47908
Organisation Name:
British Geological Survey
Delivery Point:
Environmental Science Centre,Keyworth
administrative Area:
NOTTINGHAMSHIRE
e-mail:
enquiries@bgs.ac.uk
Metadata Standard Name:
http://vocab.nerc.ac.uk/collection/M25/current/GEMINI/
Metadata Standard Name:
UK GEMINI
Metadata Standard Version:
2.3
Dataset URI:
http://data.bgs.ac.uk/id/dataHolding/13607011