caa a22 4500 465790852 CHVBK 20180323112024.0 cr unu---uuuuu 170327e19901101xx s 000 0 eng 10.1007/BF01167283 doi (NATIONALLICENCE)springer-10.1007/BF01167283 Trace element zoning in garnet from the Kwoiek Area, British Columbia: disequilibrium partitioning during garnet growth? [Elektronische Daten] [Donald Hickmott, Nobu Shimizu] Trace element zoning in garnets from two contact-metamorphosed rocks from the Kwoiek area, British Columbia (Hollister 1969a), was measured with an ion microprobe. Zoning profiles have three distinct parts with chemical breaks defined by co-variation of major and trace elements. Important features of the trace element zoning profiles are: (1) roughly ‘bell-shaped' zoning profiles for Y and the HREEs, (2) an abrupt increase in Ti at a point midway through each garnet with inflections in the zoning profiles of other elements (Li, Na, Cr, V, Y, Zr, and the HREE), and (3) irregular Cr and V profiles. Unlike Mn zoning, the zoning profiles of most other trace elements cannot be easily modeled using simple Rayleigh fractionation models. Ti activity in the two samples is buffered by phase relations with ilmenite. Garnets from a continuously heated contact metamorphic environment should display continuous Ti zoning profiles if equilibrium was maintained and provided the Ti buffering assemblage did not change during garnet growth. The irregular Ti profiles suggest disequilibrium behavior. Several elements (Cr, V) may indicate breakdown of a phase enriched in trace elements during metamorphism. The source for the mass excess of these elements is probably the refractory cores of ilmenite grains. Either differing matrix transport rates of trace lements or interface kinetic controlled segregation could explain the unusual trace element behavior at the element inflection point. The preferred explanation involves segregation of elements at the interface of the garnet that were trapped during episodes of rapid garnet growth. Springer-Verlag, 1990 Hickmott Donald Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, 02139, Cambridge, MA, USA aut Shimizu Nobu Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, 02139, Cambridge, MA, USA aut Contributions to Mineralogy and Petrology Springer-Verlag 104/6(1990-11-01), 619-630 0010-7999 104:6<619 1990 104 410 https://doi.org/10.1007/BF01167283 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF01167283 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Hickmott Donald Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, 02139, Cambridge, MA, USA aut NATIONALLICENCE 700 1- Shimizu Nobu Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, 02139, Cambridge, MA, USA aut NATIONALLICENCE 773 0- Contributions to Mineralogy and Petrology Springer-Verlag 104/6(1990-11-01), 619-630 0010-7999 104:6<619 1990 104 410 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer