Migmatite-like textures in anthracite:Further evidence for low-grade metamorphic melting and resolidification in high-rank coals

• 作者: James C.Hower Susan M.Rimmer Maria Mastalerz Nicola J.Wagner
• 来源期刊: 地学前缘（英文版）
• 年，卷（期）: 2021,（3）
• 所属期刊栏目: Research Paper
• 页码范围: 428-436
• 页数: 9页
• 语种: 英文

摘要

Previous studies demonstrated that melting, initiated by supercritical fluids in the 375–400 °C range, occurred as part of anthracite metamorphism in the Appalachian Basin. Based on the known behavior of vitrinite at high tem-peratures and, to a lesser extent, at high pressures, it was determined that the duration of the heating, melting, and resolidification event was about 1 h. In the current study, featureless vitrinite within banded maceral assem-blages demonstratesthe intimate association of melted and resolidified vitrinite with anthracite-rank macerals. By analogy with metamorphosed inorganic rocks, such associations represent diadysites and embrechites, i.e., cross-cutting and layered migmatites, respectively. Even though the temperature of formation of the anthra-cite structures is several hundred °C lower than that seen in metamorphosed inorganic rocks, anthracites are metamorphic rocks and the nomenclature for metamorphic rocks may be appropriate for coal.