Knowledge Management System Of Guangzhou Institute of Geochemistry，CAS
| Xing, Chang -Ming1,2,3; Cao, Yonghua1,2,3 | |
| Cryptic compositional variation of olivine between interlayered troctolite and net-textured Fe-Ti oxide ore in the Baima layered intrusion, SW China: Implications for the origin of banded Fe-Ti oxide ores | |
| Source Publication | JOURNAL OF ASIAN EARTH SCIENCES
 |
| ISSN | 1367-9120 |
| 2023-10-01 | |
| Volume | 255Pages:13 |
| DOI | 10.1016/j.jseaes.2023.105783 |
| Language | 英语 |
| WOS Research Area | Geology |
| Abstract | The Baima layered intrusion in the Panzhihua-Xichang (Panxi) region in SW China hosts thick Fe-Ti oxide ore layers in its lower zone, including net-textured ores, banded ores and disseminated ores. Particularly, the banded ores are composed of melanocratic layers of net-textured ores alternating with leucocratic layers of troctolite or olivine gabbro, forming a distinct type of layering in the intrusion. Although there are many geochemical and mineralogical studies have been carried out to constrain the origin of Fe-Ti oxide ores in the Baima intrusion, it still remains unclear how such a type of layering formed. In this study, we conducted detailed examination of the textures and compositions of minerals for the interlayered troctolite and net-textured ores, which occur in a scale of centimeters and have sharp, unconformable contacts. Plagioclase laths in the net-textured ores are commonly corroded and show preferred orientation of c-axis parallel to the layering, whereas those in troctolite show random orientation. Olivine grains in the net-textured ore layers are generally rounded, whereas those in the troctolite layers show both granular and poikilitic habits. Analytical results show that plagioclase has nearly consistent An content (55-58) along the profiles. In contrast, olivine shows cryptic variation of Fo content (71-74) across the profiles with multiple reversals of Fo content within the troctolite or plagioclase-rich layers. The olivine grains in the net-textured ore layers have complex P zoning, indicating a two-stage growth process of olivine. Combining with the results of previous studies, we propose that such a layered structure may have formed by slumping of immiscible Fe-rich melts with a troctolitic mush along the inclined floor of the magma chamber. This study provides new evidence for late-stage crystallization of Fe-Ti oxides in a crystal mush, which may have broad implications for the origin of Fe-Ti oxide ores in the layered intrusions elsewhere in the Panxi region. |
| Keyword | Net -textured ore Troctolite Layering Baima layered intrusion Panxi region |
| WOS ID | WOS:001045027800001 |
| Indexed By | SCI |
| Citation statistics | |
| Document Type | 期刊论文 |
| Identifier | http://ir.gig.ac.cn/handle/344008/74632 |
| Collection | 中国科学院矿物学与成矿学重点实验室 |
| Corresponding Author | Xing, Chang -Ming |
| Affiliation | 1.Chinese Acad Sci, Guangzhou Inst Geochem, Key Lab Mineral & Metallogeny, Guangzhou 510640, Peoples R China 2.CAS Ctr Excellence Deep Earth Sci, Guangzhou 510640, Peoples R China 3.Guangdong Prov Key Lab Mineral Phys & Mat, Guangzhou 510640, Peoples R China |
| Recommended Citation GB/T 7714 | Xing, Chang -Ming,Cao, Yonghua. Cryptic compositional variation of olivine between interlayered troctolite and net-textured Fe-Ti oxide ore in the Baima layered intrusion, SW China: Implications for the origin of banded Fe-Ti oxide ores[J]. JOURNAL OF ASIAN EARTH SCIENCES,2023,255:13. |
| APA | Xing, Chang -Ming,&Cao, Yonghua.(2023).Cryptic compositional variation of olivine between interlayered troctolite and net-textured Fe-Ti oxide ore in the Baima layered intrusion, SW China: Implications for the origin of banded Fe-Ti oxide ores.JOURNAL OF ASIAN EARTH SCIENCES,255,13. |
| MLA | Xing, Chang -Ming,et al."Cryptic compositional variation of olivine between interlayered troctolite and net-textured Fe-Ti oxide ore in the Baima layered intrusion, SW China: Implications for the origin of banded Fe-Ti oxide ores".JOURNAL OF ASIAN EARTH SCIENCES 255(2023):13. |
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