Mélange within subduction–accretion complex rocks of Fredriksen Island, South Orkney Islands

• Published in: Geological Magazine
• Main Authors: Storey, B. C., Meneilly, A. W.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Cambridge University Press (CUP) 1983
• Subjects: Geology; Pacific; South Orkney Islands; Fredriksen; Fredriksen Island
• Online Access: http://dx.doi.org/10.1017/s0016756800027710; https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0016756800027710

Summary . A m´lange on Fredriksen Island, South Orkney Islands, is part of a Mesozoic subduction- accretion complex which formed along the western, Pacific side of Gondwana. It consists of a chaotic arrangement of irregular sized blocks, up to 8 m across, of basic pillow lava, chert, felsite and epiclastic sandstone in a pervasively sheared cataclastic matrix. Inclusions are typically lozenge-shaped and are characteristic of a tectonic m´lange. As the m´lange incorporates both possible ocean floor material that was accreted on to the continental margin and inner slope basin sediments it probably formed beneath the trench-slope basin along a shear zone at a high level in the subduction complex.