阿尔泰南缘中泥盆统北塔山组火山岩的矿物学研究   总被引：2，自引：0，他引：2  

张贺  张招崇 《矿物学报》2012,32(3):386-397

阿尔泰山南缘中泥盆统北塔山组火山岩极为发育。本文对富辉橄玄岩和玄武岩中的单斜辉石和橄榄石斑晶进行了矿物化学分析,并结合矿物的地质温压计和岩浆结晶模拟,约束了两种岩石中矿物的形成过程,推测了原始岩浆的演化过程。提出富辉橄玄岩和玄武岩的原始岩浆属于拉斑玄武系列,富辉橄玄岩中的高压单斜辉石来源于深部（40～50 km）,其结晶早于橄榄石;玄武岩中单斜辉石大多属于岩浆房结晶产物（30～40km）,其结晶晚于橄榄石;两种岩石中橄榄石均属于岩浆房结晶产物（30～40 km）。  相似文献   

Island-arc Ankaramites: Primitive Melts from Fluxed Refractory Lherzolitic Mantle   总被引：7，自引：1，他引：7  

GREEN  D. H.; SCHMIDT  M. W.; HIBBERSON  W. O. 《Journal of Petrology》2004,45(2):391-403

The distinctive island-arc ankaramites exemplified by the activeVanuatu arc may be produced by melting of refractory lherzoliteunder conditions in which melting is fluxed by H₂O + CO₂. Parentalpicritic ankaramite magmas with maximum CaO/Al₂O₃ to  相似文献   

Coexisting High- and Low-Calcium Melts Identified by Mineral and Melt Inclusion Studies of a Subduction-Influenced Syn-collisional Magma from South Sulawesi, Indonesia     

ELBURG  MARLINA; KAMENETSKY  VADIM S.; NIKOGOSIAN  IGOR; FODEN  JOHN; SOBOLEV  ALEXANDER V. 《Journal of Petrology》2006,47(12):2433-2462

Mineral and melt inclusions in olivines from the most Mg-richmagma from the southern West Sulawesi Volcanic Province indicatethat two distinct melts contributed to its petrogenesis. Thecontribution that dominates the whole-rock composition comesfrom a liquid with high CaO (up to 16 wt %) and low Al₂O₃ contents(CaO/Al₂O₃ up to 1), in equilibrium with spinel, olivine (Fo_85–91;CaO 0·35–0·5 wt %; NiO 0·2–0·30wt %) and clinopyroxene. The other component is richer in SiO₂(>50 wt %) and Al₂O₃ (19–21 wt %), but contains significantlyless CaO (<4 wt %); it is in equilibrium with Cr-rich spinelwith a low TiO₂ content, olivine with low CaO and high NiO content(Fo_90–94; CaO 0·05–0·20 wt %; NiO0·35–0·5 wt %), and orthopyroxene. Boththe high- and low-CaO melts are potassium-rich (>3 wt % K₂O).The high-CaO melt has a normalized trace element pattern thatis typical for subduction-related volcanic rocks, with negativeTa–Nb and Ti anomalies, positive K, Pb and Sr anomalies,and a relatively flat heavy rare earth element (HREE) pattern.The low-CaO melt shows Y and HREE depletion (Gd_n/Yb_n 41), butits trace element pattern resembles that of the whole-rock andhigh-CaO melt in other respects, suggesting only small distinctionsin source areas between the two components. We propose thatthe depth of melting and the dominance of H₂O- or CO₂-bearingfluids were the main controls on generating these contrastingmagmas in a syn-collisional environment. The composition ofthe low-CaO magma does not have any obvious rock equivalent,and it is possible that this type of magma does not easily reachthe Earth's surface without the assistance of a water-poor carriermagma. KEY WORDS: melt inclusions; mineral chemistry; olivine; syn-collisional magmatism; ankaramites; low-Ca magma  相似文献