TY - JOUR

T1 - Comparison of petrology and isotope geochemistry of the Bulka peridotite–gabbro massif and granitoids of the Kyzykchadra complex (West Sayan)

AU - Borodina, E. V.

AU - Izokh, A. E.

AU - Mongush, A. A.

PY - 2016/4/1

Y1 - 2016/4/1

N2 - The study provides new petrologic and isotope geochemical data for rocks of the 465 ± 5 Ma Bulka massif (Borodina et al., 2011). The primary amphibole from granitoid stocks cutting across the layered series of the massif yielded an Ar–Ar age of 415.9 ± 3.7 Ma. The rocks of the Bulka massif have 143Nd/144Nd ratio of 0.513243 and εNd (Т) values of +12.00. The granitoids have 143Nd/144Nd ratios between 0.512919 and 0.512961 and εNd (Т) values between +8.03 and +9.25. The Nd isotope composition indicates that the rocks of the Bulka massif and granitoids were derived from a depleted mantle source. Depletion of the rocks of the massif in LILE, LREE, and HFSE over LILE is inherited from the mantle source, which has geochemical signatures of N-MORB and subduction-related components. Granitoids are metaluminous I-type granites, which were probably generated either by differentiation of intermediate to mafic mantle-derived magmas or by melting of metabasites. The rocks of the granitoid stocks are characterized by enrichment in LILE and LREE and depletion in HFSE over LILE, which suggests derivation from arc-related parental magmas.

AB - The study provides new petrologic and isotope geochemical data for rocks of the 465 ± 5 Ma Bulka massif (Borodina et al., 2011). The primary amphibole from granitoid stocks cutting across the layered series of the massif yielded an Ar–Ar age of 415.9 ± 3.7 Ma. The rocks of the Bulka massif have 143Nd/144Nd ratio of 0.513243 and εNd (Т) values of +12.00. The granitoids have 143Nd/144Nd ratios between 0.512919 and 0.512961 and εNd (Т) values between +8.03 and +9.25. The Nd isotope composition indicates that the rocks of the Bulka massif and granitoids were derived from a depleted mantle source. Depletion of the rocks of the massif in LILE, LREE, and HFSE over LILE is inherited from the mantle source, which has geochemical signatures of N-MORB and subduction-related components. Granitoids are metaluminous I-type granites, which were probably generated either by differentiation of intermediate to mafic mantle-derived magmas or by melting of metabasites. The rocks of the granitoid stocks are characterized by enrichment in LILE and LREE and depletion in HFSE over LILE, which suggests derivation from arc-related parental magmas.

KW - granitoids

KW - isotopy

KW - layered intrusions

KW - peridotite–gabbro complexes

KW - rare-earth elements

UR - http://www.scopus.com/inward/record.url?scp=84969509037&partnerID=8YFLogxK

U2 - 10.1134/S0016702916040029

DO - 10.1134/S0016702916040029

M3 - Article

AN - SCOPUS:84969509037

VL - 54

SP - 321

EP - 345

JO - Geochemistry International

JF - Geochemistry International

SN - 0016-7029

IS - 4

ER -