page_title: Lewisian complex
section_title: Lewisian of the Outer Hebrides
hierarchical_section_title: Lewisian complex / Lewisian of the Outer Hebrides
caption_attribution_description: English: Folded gneiss, old path to Reinigeadal, Harris. Folded gneiss, old path to Reinigeadal, North Harris. This rock is located by the side of the footpath, which was the only way to the isolated community until a road was built, approaching it from the north. Gneiss is the predominant rock type in Harris, and was formed around two billion years ago. The folds resulted from a sequence of mountain building events in the Precambrian.
context_page_description: The Lewisian complex or Lewisian gneiss is a suite of Precambrian metamorphic rocks that outcrop in the northwestern part of Scotland, forming part of the Hebridean Terrane and the North Atlantic Craton. These rocks are of Archaean and Paleoproterozoic age, ranging from 3.0–1.7 billion years. They form the basement on which the Torridonian and Moine Supergroup sediments were deposited. The Lewisian consists mainly of granitic gneisses with a minor amount of supracrustal rocks. Rocks of the Lewisian complex were caught up in the Caledonian orogeny, appearing in the hanging walls of many of the thrust faults formed during the late stages of this tectonic event.
context_section_description: Much of the Lewisian outcrop of the Outer Hebrides consist of rocks of the Scourie complex cut by post-Scourian granites. Laxfordian reworking is extensive and very little unmodified Scourian crust has survived. Amphibolite sheets, interpreted to be deformed members of the Scourie Dykes, are much less common than on the mainland. More of the outcrop area consists of supracrustal rocks, about 5% of the total. The relationship between the supreacrustal rocks and the Scourian gneisses remains unclear.
caption: Folded Lewisian gneiss, Harris
exif: {"Image Orientation": "Horizontal (normal)", "Image XResolution": "72", "Image YResolution": "72", "Image ResolutionUnit": "Pixels/Inch", "Image Software": "Adobe Photoshop Elements 2.0", "Image DateTime": "2006:01:19 21:33:01", "Image ExifOffset": "164", "Thumbnail Compression": "JPEG (old-style)", "Thumbnail XResolution": "72", "Thumbnail YResolution": "72", "Thumbnail ResolutionUnit": "Pixels/Inch", "Thumbnail JPEGInterchangeFormat": "302", "Thumbnail JPEGInterchangeFormatLength": "4021", "EXIF ColorSpace": "Uncalibrated", "EXIF ExifImageWidth": "640", "EXIF ExifImageLength": "427"}