TY - JOUR
T1 - Sr-rich apatite from the Dangzishan leucitite-ijolite xenoliths (Heilongjiang Province)
T2 - Mineralogy and mantle-fluid metasomatism
AU - Zhang, Wen Lan
AU - Shao, Ji An
AU - Wang, Ru Cheng
AU - Xu, Xi Sheng
AU - Che, Xu Dong
AU - Yang, Yue Heng
PY - 2011/1
Y1 - 2011/1
N2 - Abundant apatite grains with elevated SrO content were found in leucitite-ijolite xenoliths in the Dangzi Mountain, Heilongjiang Province. Morphological and mineralogical associations, and compositional analysis of the Sr-rich apatite, were carried out using an electron microprobe. Two principal types of apatite were distinguished. One type occurs as short-prismatic crystals with Sr-rich rims, while another type with acicular or finely columnar shapes constitutes Sr-rich apatite element maps and systematic quantitative analysis of apatite revealed great variations in SrO content (0.42%-26.79%). The calculated structural formula of the measured Sr-rich apatite is: (Ca3.15-4.963Sr0.019-1.510Ba0.00-0.030Na0.006-0.108REE0.106-0.153) (P2.84-3.028Si0.009-0.094)O12(F0.675-1.079, Cl0.000-0.256, OH0.084-0.297). Mineralogical textures of apatite implied a replacement mechanism for the Sr-rich apatite. Sr-rich rims of apatite are suggested to have formed after metasomatism (isomorphic replacement) of early fluorapatite in a Sr-, light rare-earth elements (LREE), lithophile light elements (LILE)- and volatile-rich residual melt during late magmatism. However, the acicular apatite probably directly crystallized from a Sr-rich residual melt. The Sr-Nd isotopic composition of the apatite was distinctive from that of leucitite-ijolite and its host rock. These differences, combined with mineralogical features of apatite, imply that Sr-LREE-LILE-volatile-rich components in the residual melt were derived from deep in the asthenosphere, and subsequently were enriched at a late stage in magma evolution.
AB - Abundant apatite grains with elevated SrO content were found in leucitite-ijolite xenoliths in the Dangzi Mountain, Heilongjiang Province. Morphological and mineralogical associations, and compositional analysis of the Sr-rich apatite, were carried out using an electron microprobe. Two principal types of apatite were distinguished. One type occurs as short-prismatic crystals with Sr-rich rims, while another type with acicular or finely columnar shapes constitutes Sr-rich apatite element maps and systematic quantitative analysis of apatite revealed great variations in SrO content (0.42%-26.79%). The calculated structural formula of the measured Sr-rich apatite is: (Ca3.15-4.963Sr0.019-1.510Ba0.00-0.030Na0.006-0.108REE0.106-0.153) (P2.84-3.028Si0.009-0.094)O12(F0.675-1.079, Cl0.000-0.256, OH0.084-0.297). Mineralogical textures of apatite implied a replacement mechanism for the Sr-rich apatite. Sr-rich rims of apatite are suggested to have formed after metasomatism (isomorphic replacement) of early fluorapatite in a Sr-, light rare-earth elements (LREE), lithophile light elements (LILE)- and volatile-rich residual melt during late magmatism. However, the acicular apatite probably directly crystallized from a Sr-rich residual melt. The Sr-Nd isotopic composition of the apatite was distinctive from that of leucitite-ijolite and its host rock. These differences, combined with mineralogical features of apatite, imply that Sr-LREE-LILE-volatile-rich components in the residual melt were derived from deep in the asthenosphere, and subsequently were enriched at a late stage in magma evolution.
KW - Dangzi Mountain
KW - Depleted-mantle fluids
KW - Heilongjiang Province
KW - Isomorphic replacement
KW - Leucitite-ijolite xenolith
KW - Sr-rich apatite
UR - http://www.scopus.com/inward/record.url?scp=79551590463&partnerID=8YFLogxK
U2 - 10.1007/s11434-010-4228-7
DO - 10.1007/s11434-010-4228-7
M3 - Article
AN - SCOPUS:79551590463
SN - 1001-6538
VL - 56
SP - 53
EP - 63
JO - Chinese Science Bulletin
JF - Chinese Science Bulletin
IS - 1
ER -