Magnetic Petrology of the High Fe-Ti Eclogite from the Chinese Continental Scientific Drilling (CCSD) Main Hole
ZENG Qing-li
LIU Qing-sheng
QIU Ning
Abstract：The high Fe-Ti eclogites appear at the depth intervals from 318-380 m (A), 420-470 m (B) and 530-600 m (C) respectivelys in the Chinese Continental Scientific Drilling (CCSD) Project main hole. They have high FeO_r( total Fe) abundances of average 15. 36%, 14. 09% and 20. 83%, high TiO_2 concentration of average 3. 89%, 3. 28% and 4. 10% and low SiO_2 contents of average 44. 64%. 48. 64% and 41.10%, respectively. Magnetic study of the samples shows that section A has the lowest susceptibility (average 3. 61×10~(-7) m~3· kg~(-1)), NRM (average 0. 12×10~(-3) Am~2· kg~(-1)) and Q-value (average 8. 03) ; section B has the highest susceptibility (average 12. 55×10~(-7) m~3·kg~(-1)), medium NRM (average 1. 47×10~(-3) Am~2·kg~(-1)) and Q-value (average 26. 42); section C samples has medium susceptibility (average 9. 73×10~(-7) m~3~ kg~(-1) ) and the highest NRM (average 10. 05×10~(-3) Am~2× kg~(-1)) and Q-value (average 138. 571). The magnetic property compared with metamorphic petrology of high Fe-Ti eclogites suggests that section A samples represent magnetic properties of the fresh or slightly retrograded eclogites; section B samples show higher metamorphic retrogression than those of section A; section C samples are fresh eclogite, whose density and oxygen fugacity are distinctly higher than those of A and B, containing a lot of hematite-il-menite lamellar textures formed during the slowly exhumation, which can be the main contributors to the high NRM of the section C eclogite.
Keywords：high Fe-Ti eclogiteCCSD main holerock magnetichematite-ilmenite solid solutionsusceptibility.
Publication Date：2009-01-01
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：8( 993-1000 )