Geochemistry of oceanic crust beneath Costa Rica
Cobertura |
MEDIAN LATITUDE: 9.575414 * MEDIAN LONGITUDE: -84.916831 * SOUTH-BOUND LATITUDE: 7.470000 * WEST-BOUND LONGITUDE: -86.200000 * NORTH-BOUND LATITUDE: 11.059300 * EAST-BOUND LONGITUDE: -81.447000 * DATE/TIME START: 1996-11-08T14:00:00 * DATE/TIME END: 1996-11-18T12:00:00 |
---|---|
Data(s) |
20/12/2008
|
Resumo |
Resolving flow geometry in the mantle wedge is central to understanding the thermal and chemical structure of subduction zones, subducting plate dehydration, and melting that leads to arc volcanism, which can threaten large populations and alter climate through gas and particle emission. Here we show that isotope geochemistry and seismic velocity anisotropy provide strong evidence for trench-parallel flow in the mantle wedge beneath Costa Rica and Nicaragua. This finding contradicts classical models, which predict trench-normal flow owing to the overlying wedge mantle being dragged downwards by the subducting plate. The isotopic signature of central Costa Rican volcanic rocks is not consistent with its derivation from the mantle wedge (Feigenson et al., 2004, doi:10.1029/2003GC000621; Herrstom et al., 1995, doi:10.1130/0091-7613(1995)023<0617:VILCAW>2.3.CO;2; Abratis and Woerner, 2001) or eroded fore-arc complexes (Goss and Kay, 2006, doi:10.1029/2005GC001163) but instead from seamounts of the Galapagos hotspot track on the subducting Cocos plate. This isotopic signature decreases continuously from central Costa Rica to northwestern Nicaragua. As the age of the isotopic signature beneath Costa Rica can be constrained and its transport distance is known, minimum northwestward flow rates can be estimated (~63-190 mm/yr) and are comparable to the magnitude of subducting Cocos plate motion (approx85 mm/yr). Trench-parallel flow needs to be taken into account in models evaluating thermal and chemical structure and melt generation in subduction zones. |
Formato |
application/zip, 2 datasets |
Identificador |
https://doi.pangaea.de/10.1594/PANGAEA.773166 doi:10.1594/PANGAEA.773166 |
Idioma(s) |
en |
Publicador |
PANGAEA |
Direitos |
CC-BY: Creative Commons Attribution 3.0 Unported Access constraints: unrestricted |
Fonte |
Supplement to: Hoernle, Kaj; Abt, David; Fischer, Karen M; Nichols, Holly; Hauff, Folkmar; Abers, Geoffrey A; van den Bogaard, Paul; Heydolph, Ken; Alvarado, Guillermo; Protti, Marino; Strauch, Wilfried (2008): Arc-parallel flow in the mantle wedge beneath Costa Rica and Nicaragua. Nature, 451(7182), 1094-1097, doi:10.1038/nature06550 |
Palavras-Chave | #143Nd/144Nd; 143Nd/144Nd e; 170-1039C; 170-1040C; 206Pb/204Pb; 206Pb/204Pb e; 207Pb/204Pb; 207Pb/204Pb e; 208Pb/204Pb; 208Pb/204Pb e; 2 sigma; Area; Area/locality; Costa Rica subduction complex, North Pacific Ocean; Depth; DEPTH, sediment/rock; DRILL; Drilling/drill rig; e-Nd; epsilon-Neodymium; Event; Joides Resolution; Label; Latitude; LATITUDE; Lead 206/Lead 204, error; Lead 206/Lead 204 ratio; Lead 207/Lead 204, error; Lead 207/Lead 204 ratio; Lead 208/Lead 204, error; Lead 208/Lead 204 ratio; Leg170; Longitude; LONGITUDE; Neodymium 143/Neodymium 144; Neodymium 143/Neodymium 144, error; Ocean Drilling Program; ODP; Samp com; Sample code/label; Sample comment; Thermal Ionization Mass Spectrometry (TIMS) |
Tipo |
Dataset |