Abstract This paper examines changes in structural and petrographic characteristics of organic and inorganic matter developed in a cored 35 m thick Permian coal seam from the Moatize Basin (Mozambique) in proximity to an Early Jurassic intrusive igneous body. Megascopic and microscopic examinations of hand samples and polished blocks, respectively, were carried out to characterise the deformation and petrographic changes of the coal. SEM/EDS analysis was used for mineral identification and modes of occurrence. The upper part of the core is thermally altered, exhibiting intense megascopic folding of the bedding. At microscopic level, vitrinite presents an incipient mosaic coke texture (semi-coke); whereas fusinite and semifusinite layers are deformed, exhibiting folded structures. Coal petrographic characteristics suggests the temperature in the coal at this location reached no higher than 400 °C but was enough for softening and ductile deformation of bands to occur. Apart from epigenetic chamosite occurring exclusively in the upper section, and monazite that appears only in the lower section of the core, microscopic studies showed similar distribution of the mineral species in both sections of the seam, except with a change in their mode of occurrence. Detrital or syngenetic minerals in the lower section of the seam occur also as epigenetic in the thermally affected upper section. Siderite occurs as syngenetic nodules in the lower section but appears as epigenetic fracture filling developed with the cooling of the organic material in the upper section. Quartz occurs as detrital grains in the lower section, whereas in the upper section this mineral occurs also as an epigenetic euhedral mineral filling the fracture system. Fluorapatite occurs as detrital, syngenetic and euhedral epigenetic. The mineralisation in the fractures also gives indications about the fluid circulation associated with the magmatic intrusion. At least three stages of hydrothermal fluids were distinguished (from the first to the last stage): a P/F- and Si-rich fluid, an Fe-, Ca-, Mg-rich fluid and an Al-, Si-rich fluid. These fluids gave origin to the minerals in the fractures and to some of the minerals inside the cell lumina of the inertinite macerals. Given the euhedral shape of some of the epigenetic minerals, there was sufficient time for them to grow into euhedral forms.

中文翻译：

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莫桑比克莫阿蒂泽盆地热变煤的流动结构和矿化作用

摘要 本文研究了在莫阿蒂泽盆地（莫桑比克）靠近早侏罗世侵入火成岩的 35 m 厚二叠纪岩心煤层中发育的有机和无机物质的结构和岩相特征的变化。分别对手工样品和抛光块进行了宏观和微观检查，以表征煤的变形和岩相变化。SEM/EDS 分析用于矿物鉴定和赋存模式。地核的上部发生了热变，显示出层理的巨大折叠。在微观层面，镜质体呈现出初期的马赛克状焦状结构（半焦状）；而fusinite和semifusinite层发生变形，表现出折叠结构。煤岩学特征表明，该位置的煤中温度不高于 400 °C，但足以使带发生软化和延展变形。除了仅出现在上部的后生菱沸石和仅出现在岩心下部的独居石之外，微观研究表明，煤层的两个部分的矿物种类分布相似，只是它们的出现方式发生了变化。煤层下部的碎屑或同生矿物也作为表观遗传出现在受热影响的上部。菱铁矿在下部以同生结核的形式出现，但表现为随着上部有机物质冷却而发育的后生裂缝充填物。石英在下部以碎屑形式出现，而在上部，这种矿物也作为填充断裂系统的后生自形矿物出现。氟磷灰石以碎屑、同生和自形表观遗传形式出现。裂缝中的矿化也给出了与岩浆侵入相关的流体循环的迹象。至少区分了三个阶段的热液流体（从第一阶段到最后阶段）：富含 P/F 和 Si 的流体，富含 Fe、Ca-、Mg 的流体和富含 Al、Si 的流体. 这些流体是裂缝中矿物质和惰性微晶胞腔内的一些矿物质的起源。鉴于某些表观遗传矿物的自形形状，它们有足够的时间长成自形形式。氟磷灰石以碎屑、同生和自形表观遗传形式出现。裂缝中的矿化也给出了与岩浆侵入相关的流体循环的迹象。至少区分了三个阶段的热液流体（从第一阶段到最后阶段）：富含 P/F 和 Si 的流体，富含 Fe、Ca-、Mg 的流体和富含 Al、Si 的流体. 这些流体是裂缝中矿物质和惰性微晶胞腔内的一些矿物质的起源。鉴于某些表观遗传矿物的自形形状，它们有足够的时间长成自形形式。氟磷灰石以碎屑、同生和自形表观遗传形式出现。裂缝中的矿化也给出了与岩浆侵入相关的流体循环的迹象。至少区分了三个阶段的热液流体（从第一阶段到最后阶段）：富含 P/F 和 Si 的流体，富含 Fe、Ca-、Mg 的流体和富含 Al、Si 的流体. 这些流体是裂缝中矿物质和惰性微晶胞腔内的一些矿物质的起源。鉴于某些后生矿物的自形形状，它们有足够的时间长成自形形式。至少区分了三个阶段的热液流体（从第一阶段到最后阶段）：富含 P/F 和 Si 的流体，富含 Fe、Ca-、Mg 的流体和富含 Al、Si 的流体. 这些流体是裂缝中矿物质和惰性微晶胞腔内的一些矿物质的起源。鉴于某些表观遗传矿物的自形形状，它们有足够的时间长成自形形式。至少区分了三个阶段的热液流体（从第一阶段到最后阶段）：富含 P/F 和 Si 的流体，富含 Fe、Ca-、Mg 的流体和富含 Al、Si 的流体. 这些流体是裂缝中矿物质和惰性微晶胞腔内的一些矿物质的起源。鉴于某些后生矿物的自形形状，它们有足够的时间长成自形形式。