Post‐tectonic clastic dykes in the Dalradian of Scotland and Ireland: implications for delayed lithification and deformation of sediments     

C. A. Phillips  G. I. Alsop 《Geological Journal》2000,35(2):99-110

Structures associated with soft‐sediment deformation are preserved in the Neoproterozoic Dalradian Supergroup of SW Scotland and NW Ireland. Clastic dykes display a range of age relationships to regional Caledonian D₁ folds and fabrics from pre‐tectonic to hitherto unrecognized post‐tectonic. Evidence for the post‐D₁ timing of some dykes includes the emplacement of centimetre‐scale injections along regional S₁ cleavage, the disorientation and transport of cleaved wall‐rock clasts within larger dykes, and clastic dykes which markedly cross‐cut and transect F₁ fold hinges and axial planes. Collectively, these observations are compatible with the earliest regional (D₁) structures deforming a sequence which contained locally overpressured and unlithified pockets of sediment. These critical relationships indicate that overpressured pockets of unlithified sediment were possibly retained within the Dalradian for significant periods of time spanning at least 120 Ma given existing isotopic constraints. Copyright © 2000 John Wiley & Sons, Ltd.  相似文献   

Geochronology,Geochemistry, and Implications of Aplite Dyke in the Giant Jiama Porphyry Copper System,Tibet          下载免费PDF全文

QI Jing  TANG Juxing  LIN Bin  YANG Hairui  TANG Xiaoqian  TANG Pan  FANG Xiang  ZHANG Tingting  LI Faqiao  SUN Miao  WANG Mengdie  CUI Hao  XIE Jinling 《《地质学报》英文版》2023,97(5):1406-1421

Jiama is a giant, high-grade porphyry copper system in the Gangdese metallogenic belt, Tibet. Multistage intermediate–felsic porphyries intruded in this deposit, some of which are strongly associated with copper-polymetallic mineralization. These ore-bearing porphyries include monzogranite, granodiorite, and quartz diorite porphyries. A new granite aplite dyke was found in the south of Jiama. Its age, genesis, and relationship with ore-related magmatism are obscure. Here, its emplacement age and...  相似文献