Abstract The epigenetic siliceous rocks (ESR) are common in the southern part of the Krakow-Czestochowa Upland where they are hosted in Upper Jurassic microbial-sponge megafacies as: (i) coatings on the surfaces of fractures and faults, (ii) irregular bodies enclosed within both the Upper Jurassic limestones and the overlying Cenomanian abrasion platform sediments, and (iii) concentric or irregular rims of silicified limestones on early diagenetic chert concretions. The distribution of ESR is limited to the topmost part of the preserved Upper Jurassic succession. The results of chemical analyses and fluid inclusion microthermometric data clearly demonstrate the hydrothermal origin of the ESR. The epigenetic silicification was triggered by low temperatures and low saline fluids. The age of the ESR is indirectly suggested by: (i) the early diagenetic cherts forming the crystallization nuclei, (ii) the silicification of pressure dissolution structures in limestones and (iii) the silicified carbonate infillings of fractures in chert concretions formed in the local extensional regime, enhancing the migration of thermal fluids during the main, Cenozoic faulting stage of Upper Jurassic sediments.

中文翻译：

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Kraków-Częstochowa Upland（波兰南部）南部的后生硅质岩及其与上侏罗纪早期成岩燧石结核的关系

摘要 后生硅质岩 (ESR) 在克拉科夫-琴斯托霍瓦高地南部很常见，它们位于上侏罗统微生物海绵巨相中：(i) 裂缝和断层表面的涂层，(ii) 不规则体包围在上侏罗统石灰岩和上覆的森诺曼阶磨蚀台地沉积物中，以及 (iii) 早期成岩燧石结核上硅化石灰岩的同心或不规则边缘。ESR 的分布仅限于保存的上侏罗统层序的最顶部。化学分析和流体包裹体显微测温数据的结果清楚地证明了 ESR 的热液来源。表观遗传硅化是由低温和低盐水引发的。ESR 的年龄由以下因素间接暗示：