Melt viscosity, temperature and transport processes, Troodos Ophiolite, Cyprus

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doi: 10.1016/S0012-821X(02)00709-4
Authors:Schouten, Hans; Kelemen, Peter B.
Author Affiliations:Primary:
Woods Hole Oceanographic Institution, Department of Geology and Geophysics, Woods Hole, MA, United States
Volume Title:Earth and Planetary Science Letters
Source:Earth and Planetary Science Letters, 201(2), p.337-352. Publisher: Elsevier, Amsterdam, Netherlands. ISSN: 0012-821X
Publication Date:2002
Note:In English. Woods Hole Oceanogr. Inst., Contrib. No. 10,617. 50 refs.; illus., incl. sketch maps
Summary:The lava section in the Troodos ophiolite, Cyprus, is chemically stratified and divided into a shallow lava sequence with low TiO2 content and a deeper lava sequence with high TiO2 content. We calculate the viscosity at magmatic temperature based on major element chemistry of lavas in Cyprus Crustal Study Project (CCSP) Holes CY-1 and 1A. We find that typical shallow low-Ti lavas have a magmatic viscosity that is two to three orders of magnitude lower than that of the deeper high-Ti lavas. This implies that, after eruption on-axis, Troodos low-Ti lavas would have been able to flow down the same slope faster and farther than high-Ti lavas. The calculated lava viscosity increases systematically from the lava-sediment interface to the bottom of the composite Hole CY-1/1A. This suggests that an efficient process of lava segregation by viscosity on the upper flanks of the paleo Troodos rise may have been responsible for the chemical stratification in the Troodos lava pile. Calculated magmatic temperature and molar Mg/(Mg+Fe), or Mg#, decrease systematically down-section, while SiO2 content increases. Correlation of Mg# in the lavas with Mg# in the underlying, lower crustal plutonic rocks sampled by CCSP Hole CY-4 shows that the shallow lavas came from a high-temperature, lower crustal magma reservoir which is now represented by high-Mg# pyroxenite cumulates, while the deeper lavas were erupted from a lower-temperature, mid-crustal reservoir which is now represented by gabbroic cumulates with lower Mg#. Abstract Copyright (2002) Elsevier, B.V.
Subsections:Oceanic petrology
Subjects:Chemical composition; Cores; Cretaceous; Crust; Cumulates; Dikes; Emplacement; Gabbros; Geochemistry; Geothermal gradient; Heat flow; Igneous rocks; Intrusions; Lava; Lava flows; Lower crust; Magma chambers; Magmas; Major elements; Melts; Mesozoic; Metals; Mid-ocean ridges; Ophiolite; Pillow lava; Plutonic rocks; Pyroxenite; Segregation; Titanium; Troodos Ophiolite; Ultramafics; Upper Cretaceous; Viscosity; Volcanic rocks; Asia; Cyprus; Middle East
Coordinates:N350100 N350300 E0331100 E0330900
Abstract Numbers:03M/1006
Record ID:2002062436
Copyright Information:GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from CAPCAS, Elsevier Scientific Publishers, Amsterdam, Netherlands
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