TY - JOUR
T1 - Metasomatic thorite and uraninite inclusions in xenotime and monazite from granitic pegmatites, Hidra anorthosite massif, southwestern Norway
T2 - Mechanics and fluid chemistry
AU - Hetherington, Callum J.
AU - Harlov, Daniel E.
PY - 2008/5
Y1 - 2008/5
N2 - Thorite and uraninite inclusions are documented in metasomatized regions in three xenotime crystals and one monazite crystal collected from three granitic pegmatites hosted within an anorthosite intrusion located on the island of Hidra, southwestern Norway. Formation of these inclusions is demonstrated to be the result of dissolution-reprecipitation processes that occurred in an effectively closed chemical system. The reaction was initiated by interaction between the early crystallizing orthophosphate minerals and the evolving pegmatite fluid. This fluid was dominated by H2O, but also contained F and minor amounts of Cl, and significant quantities of dissolved Na+ and K+. This is an example of auto-metasomatism and highlights a natural case where Th-U-Si-enriched orthophosphate minerals have been partially altered such that the Th, U, and Si have been converted to secondary inclusions within the now Th-U-Si-depleted orthophosphate via reaction with fluids rich in alkali elements.
AB - Thorite and uraninite inclusions are documented in metasomatized regions in three xenotime crystals and one monazite crystal collected from three granitic pegmatites hosted within an anorthosite intrusion located on the island of Hidra, southwestern Norway. Formation of these inclusions is demonstrated to be the result of dissolution-reprecipitation processes that occurred in an effectively closed chemical system. The reaction was initiated by interaction between the early crystallizing orthophosphate minerals and the evolving pegmatite fluid. This fluid was dominated by H2O, but also contained F and minor amounts of Cl, and significant quantities of dissolved Na+ and K+. This is an example of auto-metasomatism and highlights a natural case where Th-U-Si-enriched orthophosphate minerals have been partially altered such that the Th, U, and Si have been converted to secondary inclusions within the now Th-U-Si-depleted orthophosphate via reaction with fluids rich in alkali elements.
KW - Alkali-rich fluids
KW - Dissolution-reprecipitation
KW - Monazite
KW - Pegmatite
KW - Thorite
KW - Uraninite
KW - Xenotime
UR - http://www.scopus.com/inward/record.url?scp=46649112727&partnerID=8YFLogxK
U2 - 10.2138/am.2008.2635
DO - 10.2138/am.2008.2635
M3 - Article
AN - SCOPUS:46649112727
VL - 93
SP - 806
EP - 820
JO - American Mineralogist
JF - American Mineralogist
SN - 0003-004X
IS - 5-6
ER -