STRUCTURE OF SUPER QUARTZITE AT THE BURAL-SARDYK DEPOSIT, EAST SAYAN MOUNTAINS

IF 0.8 Q4 GEOCHEMISTRY & GEOPHYSICS

Geodynamics & Tectonophysics Pub Date : 2020-06-20 DOI:10.5800/gt-2020-11-2-0472

А. М. Mazukabzov, А. Fedorov, A. I. Nepomnyashchikh

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引用次数: 1

Abstract

The article presents the results of geological and structural studies of the northwestern part of the Gargan quartziferous province, wherein the Bural-Sardyk deposit is located. The early views on this deposit of high-quality siliceous raw materials have been amended using the new data. This deposit is associated with quartzites of the MesoProterozoic Irkut formation and discordantly overlaps the Gargan block. According to the detailed study results on the cover of the Oka-Urik interfluve area, its structure is predetermined by physical and mechanical properties of the rocks, and the degree of rock dislocation depends on the rock viscosity. Most of its section is composed of viscous quartzites that create the structural framework of the study area. Such viscous rocks are not prone to folding. An alternative is detachment taking place concordantly to layering. The only interlayer is composed of limestones that underwent intense plastic deformation reflected in multi-folding. Actually, limestones mark a zone of plastic detachment. The authors propose an interpretation of the formation of the deposit structure. The main deformation event was preceded by the sediment transformation stage in conditions of diagenesis and catagenesis due to the influence of a lithostatic load. Primary recrystallization under lithogenesis led to the formation of high-purity silicon rocks. At the next stage, the rocks were subjected to longitudinal compression in the PT conditions of green-shale metamorphism. This stage is mainly evidenced by sublayer detachments. In parallel with that process, quartzites experienced super-plastic flow and recrystallization, which led to the formation of super-quartzites. The bodies of super-quartzites tend to be layered and less discordant. Such a structural position suggests the possibility of detecting latent manifestations of super-quartzites at different levels in the quartzites of the Irkut formation. Tectonic detachments are observed in the sedimentary cover and do not reach the foundation. Based on these features, there are reasons to use the thin-skinned tectonic model. Rock deformation occurred under stress oriented from the northwest to the southeast. This is indicated by the position of the axial surfaces of the folds, as well as the orientations of the maximum compression axis and the crystallographic axes of quartz. Macroand microstructural data indicate that the tectonic transport of matter was directed to the southeast. The research results were used for compiling a new geological map of the deposit.

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东萨颜山bural-sardyk矿床超石英岩构造

本文介绍了Bural-Sardyk矿床所在的Gargan省西北部的地质构造研究结果。利用新资料修正了对该矿床优质硅质原料的早期认识。该矿床与中元古代伊尔库特组石英岩有关，与加根地块不协调重叠。根据对Oka-Urik断层覆盖层的详细研究结果，其结构是由岩石的物理力学性质决定的，岩石的位错程度取决于岩石的粘度。其大部分剖面由粘性石英岩组成，形成了研究区的构造格架。这种粘性岩石不容易褶皱。另一种选择是分离与分层同时发生。唯一的夹层由石灰石组成，经历了强烈的塑性变形，反映在多次褶皱中。事实上，石灰石标志着一个塑料分离区。作者对矿床构造的形成提出了一种解释。在成岩和变质作用条件下，受静岩载荷的影响，主要变形事件发生在沉积转化阶段之前。造岩作用下的原生再结晶作用形成了高纯硅岩。下一阶段，岩石在绿页岩变质PT条件下遭受纵向压缩。这一阶段主要表现为亚层分离。与此同时，石英岩经历了超塑性流动和再结晶，形成了超石英岩。超石英岩体呈层状，不协调程度较低。这样的构造位置提示了在伊尔库特组石英岩中发现不同层次超石英岩潜在表现的可能性。在沉积盖层中观察到构造分离，但没有到达基础。基于这些特征，有理由采用薄皮构造模型。岩石变形发生在由西北向东南方向的应力作用下。这可以通过褶皱轴面的位置，以及最大压缩轴和石英结晶轴的方向来表示。宏观和微观构造资料表明，构造输运方向为东南。研究成果被用于编制新的矿床地质图。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Geodynamics & Tectonophysics GEOCHEMISTRY & GEOPHYSICS-

CiteScore

1.20

自引率

14.30%

发文量

审稿时长

24 weeks

期刊介绍： The purpose of the journal is facilitating awareness of the international scientific community of new data on geodynamics of continental lithosphere in a wide range of geolchronological data, as well as tectonophysics as an integral part of geodynamics, in which physico-mathematical and structural-geological concepts are applied to deal with topical problems of the evolution of structures and processes taking place simultaneously in the lithosphere. Complex geological and geophysical studies of the Earth tectonosphere have been significantly enhanced in the current decade across the world. As a result, a large number of publications are developed based on thorough analyses of paleo- and modern geodynamic processes with reference to results of properly substantiated physical experiments, field data and tectonophysical calculations. Comprehensive research of that type, followed by consolidation and generalization of research results and conclusions, conforms to the start-of-the-art of the Earth’s sciences.