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Titolo:
MAGMA SOURCES AND PLUMBING SYSTEMS DURING BREAK-UP OF THE SE GREENLAND MARGIN - PRELIMINARY-RESULTS FROM ODP LEG-152
Autore:
FITTON JG; SAUNDERS AD; LARSEN LM; FRAM MS; DEMANT A; SINTON C;
Indirizzi:
UNIV EDINBURGH,DEPT GEOL & GEOPHYS,W MAINS RD EDINBURGH EH9 3JW MIDLOTHIAN SCOTLAND UNIV LEICESTER,DEPT GEOL LEICESTER LE1 7RH LEICS ENGLAND GEOL SURVEY GREENLAND DK-1350 COPENHAGEN DENMARK UNIV CALIF DAVIS,DEPT GEOL DAVIS CA 95616 UNIV AIX MARSEILLE 3,PETROL MAGMAT LAB MARSEILLE FRANCE OREGON STATE UNIV,COAS CORVALLIS OR 97331
Titolo Testata:
Journal of the Geological Society
, volume: 152, anno: 1995,
parte:, 6
pagine: 985 - 990
SICI:
0016-7649(1995)152:<985:MSAPSD>2.0.ZU;2-4
Fonte:
ISI
Lingua:
ENG
Soggetto:
CONTINENTAL MARGINS; NORTH-ATLANTIC; OCEANIC-CRUST; MANTLE; COMPLEX; BASIN;
Keywords:
GREENLAND; BASALTS; CONTINENTAL MARGIN; RIFTING; VOLCANISM;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
30
Recensione:
Indirizzi per estratti:
Citazione:
J.G. Fitton et al., "MAGMA SOURCES AND PLUMBING SYSTEMS DURING BREAK-UP OF THE SE GREENLAND MARGIN - PRELIMINARY-RESULTS FROM ODP LEG-152", Journal of the Geological Society, 152, 1995, pp. 985-990

Abstract

ODP Leg 152 drilled a transect across the SE Greenland seaward-dipping reflector sequence. The earliest, and most landward, lava flows (Hole 917A, Lower and Middle Series) represent a pre-break-up continental sequence showing an overall variation from olivine basalt to dacite. Evolution in deep crustal magma reservoirs, with a dwindling supply of primitive magma and an increasing role of crustal contamination, can account for the variation. Eruption of picrite and olivine basalt magmas (917A, Upper Series) marked a dramatic change in the style of magmatism to one of unrestrained passage of primitive magma from the mantle to the surface during the final phase of break-up. The younger parts of the seaward-dipping reflector sequence (915A and 918D) comprise compositionally uniform basalt (7.6 +/- 0.8% MgO), suggesting that an effective magmatic filtering system was established, soon after break-up, in magma chambers associated with a spreading axis. The continental tooceanic magmatic transition is marked by clear changes in composition. The continental magmas had a garnet Iherzolite source (indicated by low Y/Zr) and were contaminated with continental lithospheric mantle and crust (high Ba/Zr). The majority of the break-up and oceanic volcanic rocks show no evidence for lithospheric contamination (low Ba/Zr) and appear to have had a source in progressively shallower, depleted (?MORB-source) asthenosphere (increasing Y/Zr, low Nb/Zr).

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Documento generato il 27/11/20 alle ore 04:25:12