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 temperatures 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 assemblages 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 anthracite 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.

先前的研究表明，在阿巴拉契亚盆地无烟煤变质作用的一部分，是由超临界流体在375-400°C范围内引发的融化作用引起的。基于在高温和较小程度上在高压下镜质体的已知行为，确定加热，熔融和再凝固事件的持续时间为约1小时。在当前的研究中，带状黄斑组合体中无特征的镜质体显示熔化和重新凝固的镜质体与无烟煤级黄体密切相关。通过与变质的无机岩石类比，这样的组合分别代表菱沸石和方晶石，即横切和层状的蒙脱石。