The depth of the spinel to garnet transition at the peridotite solidus

被引：389

作者：

Robinson, JAC ^{[1
]}

Wood, BJ ^{[1
]}

机构：

[1] Univ Bristol, CETSEI, Dept Earth Sci, Bristol BS8 1RJ, Avon, England

来源：

EARTH AND PLANETARY SCIENCE LETTERS | 1998年 / 164卷 / 1-2期

基金：

英国自然环境研究理事会;

关键词：

peridotites; spinel; garnet group; lherzolite; pyrolite;

D O I：

10.1016/S0012-821X(98)00213-1

中图分类号：

P3 [地球物理学]; P59 [地球化学];

学科分类号：

0708 ; 070902 ;

摘要：

We have determined the pressure and temperature of the spinel-garnet transition close to the solidus of fertile and depleted peridotite from a combination of synthesis, sandwich and garnet-seeded experiments. Garnet is unstable in MORB-Pyrolite below 2.8 GPa (depths <85 km) at a solidus temperature of 1470 degrees C. In Tinaquillo Lherzolite, which is related to MORB-Pyrolite by about 7% fractional melting, the transformation occurs at 3.1 GPa at a solidus temperature of 1520 degrees C. In both cases the transformation interval is narrow, approximately 0.1-0.2 GPa. Because the solidus temperature increases by 7 degrees C and the spinel-garnet transformation pressure by 0.05 GPa for every 1% melt extracted, extremely high potential temperatures (Tp > 1450 degrees C) are required to generate the 3-5% melting in the garnet field implied by recent trace element and isotope studies. It appears likely, therefore, that the 'garnet signature' arises from some mechanism other than anhydrous melting of garnet peridotite. (C) 1998 Elsevier Science B.V. All rights reserved.

引用

页码：277 / 284

页数：8

共 30 条

[1] MELTING OF GOLD, SILVER, AND COPPER - PROPOSAL FOR A NEW HIGH-PRESSURE CALIBRATION SCALE [J].

AKELLA, J ;

KENNEDY, GC .

JOURNAL OF GEOPHYSICAL RESEARCH, 1971, 76 (20) :4969-+

[2] THE GENERATION OF URANIUM SERIES DISEQUILIBRIA BY PARTIAL MELTING OF SPINEL PERIDOTITE - CONSTRAINTS FROM PARTITIONING STUDIES [J].

BEATTIE, P .

EARTH AND PLANETARY SCIENCE LETTERS, 1993, 117 (3-4) :379-391

[3] Heavy REE are compatible in clinopyroxene on the spinel lherzolite solidus [J].

Blundy, JD ;

Robinson, JAC ;

Wood, BJ .

EARTH AND PLANETARY SCIENCE LETTERS, 1998, 160 (3-4) :493-504

[4] Constraints on mantle melting at mid-ocean ridges from global U-238-Th-230 disequilibrium data [J].

Bourdon, B ;

Zindler, A ;

Elliott, T ;

Langmuir, CH .

NATURE, 1996, 384 (6606) :231-235

[5] ANHYDROUS PARTIAL MELTING OF MORB PYROLITE AND OTHER PERIDOTITE COMPOSITIONS AT 10KBAR - IMPLICATIONS FOR THE ORIGIN OF PRIMITIVE MORB GLASSES [J].

FALLOON, TJ ;

GREEN, DH .

MINERALOGY AND PETROLOGY, 1987, 37 (3-4) :181-219

[6] STABILITY FIELDS OF ALUMINOUS PYROXENE PERIDOTITE AND GARNET PERIDOTITE AND THEIR RELEVANCE IN UPPER MANTLE STRUCTURE [J].

GREEN, DH ;

RINGWOOD, AE .

EARTH AND PLANETARY SCIENCE LETTERS, 1967, 3 (02) :151-&

[7] PARTIAL MELTING OF DRY PERIDOTITES AT HIGH-PRESSURES - DETERMINATION OF COMPOSITIONS OF MELTS SEGREGATED FROM PERIDOTITE USING AGGREGATES OF DIAMOND [J].

HIROSE, K ;

KUSHIRO, I .

EARTH AND PLANETARY SCIENCE LETTERS, 1993, 114 (04) :477-489

[8] A possible role for garnet pyroxenite in the origin of the ''garnet signature'' in MORB [J].

Hirschmann, MM ;

Stolper, EM .

CONTRIBUTIONS TO MINERALOGY AND PETROLOGY, 1996, 124 (02) :185-208

[9] Water in the oceanic upper mantle: Implications for rheology, melt extraction and the evolution of the lithosphere [J].

Hirth, G ;

Kohlstedt, DL .

EARTH AND PLANETARY SCIENCE LETTERS, 1996, 144 (1-2) :93-108

[10]

HOLLAND TJB, 1980, AM MINERAL, V65, P129

← 1 2 3 →