Modelling the composition of melts formed during continental breakup of the southeast Greenland margin

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doi: 10.1016/j.epsl.2008.02.024
Author(s): Armitage, John J.; Henstock, Timothy J.; Minshull, Timothy A.; Hopper, John R.
Author Affiliation(s): Primary:
University of Southampton, National Oceanography Centre, Southampton, United Kingdom
Other:
Texas A&M University, United States
Volume Title: Earth and Planetary Science Letters
Source: Earth and Planetary Science Letters, 269(1-2), p.248-258. Publisher: Elsevier, Amsterdam, Netherlands. ISSN: 0012-821X CODEN: EPSLA2
Note: In English. Includes appendices. 58 refs.; illus., incl. geol. sketch map
Summary: We have developed a generic dynamic model of extension of the lithosphere, which predicts major element composition and volume of melt generated from initial extension to steady state seafloor spreading. Stokes equations for non-Newtonian flow are solved and the mantle melts by decompression. Strengthening of the mantle due to dehydration as melting progresses is included. The composition is then empirically related to depletion. Using a crystallisation algorithm, the predicted primary melt composition was compared with mean North Atlantic mid-ocean ridge basalt (MORB). At steady state, using half spreading rates from 10 to 20 mm yr-1 and mantle potential temperatures of 1300 to 1325°C we predict a major element composition that is within the variation in the mean of North Atlantic MORB. This model is applied to the Southeast Greenland margin, which has extensive coverage of seismic and ODP core data. These data have been interpreted to indicate an initial pulse of magmatism on rifting that rapidly decayed to leave oceanic crustal thickness of 8 to 11 km. This pattern of melt production can be recreated by introducing an initial hot layer of asthenosphere beneath the continental lithosphere and by having a period of fast spreading during early opening. The hot layer was convected through the melt region giving a pulse of high magnesian and low silica melt during the early rifting process. The predicted major element composition of primary melts generated are in close agreement with primary melts from the Southeast Greenland margin. The observed variations in major element composition are reproduced without a mantle source composition anomaly. Abstract Copyright (2008) Elsevier, B.V.
Year of Publication: 2008
Research Program: ODP Ocean Drilling Program
Key Words: 05 Petrology, Igneous and Metamorphic; 18 Geophysics, Solid-Earth; Arctic region; Atlantic Ocean; Basalts; Greenland; Iceland Plume; Igneous rocks; Large igneous provinces; Leg 152; Leg 163; Lithosphere; Magmatism; Major elements; Mantle; Melts; Mid-ocean ridge basalts; Models; North Atlantic; ODP Site 917; ODP Site 918; ODP Site 990; Ocean Drilling Program; Plate tectonics; Rates; Reykjanes Ridge; Rifting; Sea-floor spreading; South Greenland; Southeastern Greenland; Thermal anomalies; Two-dimensional models; Volcanic rocks
Coordinates: N600000 N650000 W0300000 W0500000
Record ID: 2008116285
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from CAPCAS, Elsevier Scientific Publishers, Amsterdam, Netherlands