page_title: Old Red Sandstone
section_title: Argyll
hierarchical_section_title: Old Red Sandstone / Stratigraphy / Argyll
caption_attribution_description: English: Gardenstown Old Red Sandstone. Tilted exposure of Old Red Sandstone at the top of the shore at Gardenstown.
context_page_description: The Old Red Sandstone is an assemblage of rocks in the North Atlantic region largely of Devonian age. It extends in the east across Great Britain, Ireland and Norway, and in the west along the northeastern seaboard of North America. It also extends northwards into Greenland and Svalbard. These areas were a part of the ancient continent of Euramerica/Laurussia. In Britain it is a lithostratigraphic unit to which stratigraphers accord supergroup status and which is of considerable importance to early paleontology. For convenience the short version of the term, ORS is often used in literature on the subject. The term was coined to distinguish the sequence from the younger New Red Sandstone which also occurs widely throughout Britain.
context_section_description: There are a scatter of exposures of the Old Red Sandstone around Oban and the Isle of Kerrera on the West Highland coast, this unit is sometimes referred to as the Kerrera Sandstone Formation. The unit is up to 128m thick in its type area and consists of green and red sandstones and conglomerates, typically containing large (10–30 cm or 4–12 in across) elliptical well rounded clasts, accompanied by siltstones, mudstones and limestones. On Kerrera a conglomerate of andesite boulders rests unconformably on Dalradian black, pyritic slates (Easdale Slate) of the Easdale Subgroup. On Oban there is merely an erosional contact incorporating debris of the slate in a basal conglomerate. The ORS around Oban are considered latest Silurian (Pridoli) to earliest Devonian in age. They are interpreted as alluvial fans which filled a depositional basin from the east and northeast.  Small outliers occur near Taynuilt and either side of Loch Avich. The deposits are especially obvious on Kerrera where they form the bedrock across half of the island. These are conformably overlain by peperite and the basaltic and andesitic Lorne plateau lavas. The ORS on Kerrera and isolated localities around Oban are known for their fossils, particularly fish.
caption: Old Red Sandstone at Gardenstown, Aberdeenshire
exif: {"Image Make": "Canon", "Image Model": "Canon DIGITAL IXUS 700", "Image Orientation": "0", "Image XResolution": "180", "Image YResolution": "180", "Image ResolutionUnit": "Pixels/Inch", "Image DateTime": "2005:06:25 18:51:47", "Image YCbCrPositioning": "Centered", "Image ExifOffset": "187", "Thumbnail Compression": "JPEG (old-style)", "Thumbnail XResolution": "72", "Thumbnail YResolution": "72", "Thumbnail ResolutionUnit": "Pixels/Inch", "Thumbnail JPEGInterchangeFormat": "2353", "Thumbnail JPEGInterchangeFormatLength": "7724", "EXIF ExposureTime": "1/500", "EXIF FNumber": "7/2", "EXIF ExifVersion": "0220", "EXIF DateTimeOriginal": "2005:06:25 18:51:47", "EXIF DateTimeDigitized": "2005:06:25 18:51:47", "EXIF ComponentsConfiguration": "YCbCr", "EXIF CompressedBitsPerPixel": "5", "EXIF ShutterSpeedValue": "7937/8192", "EXIF ApertureValue": "29/8", "EXIF ExposureBiasValue": "0", "EXIF MaxApertureValue": "29/8", "EXIF MeteringMode": "CenterWeightedAverage", "EXIF Flash": "Flash did not fire, auto mode", "EXIF FocalLength": "10487/1000", "EXIF FlashPixVersion": "0100", "EXIF ColorSpace": "Uncalibrated", "EXIF ExifImageWidth": "800", "EXIF ExifImageLength": "600", "Interoperability InteroperabilityIndex": "R98", "Interoperability InteroperabilityVersion": "[48, 49, 48, 48]", "Interoperability RelatedImageWidth": "800", "Interoperability RelatedImageLength": "600", "EXIF InteroperabilityOffset": "2205", "EXIF FocalPlaneXResolution": "768000/71", "EXIF FocalPlaneYResolution": "768000/71", "EXIF FocalPlaneResolutionUnit": "2", "EXIF SensingMethod": "One-chip color area", "EXIF FileSource": "Digital Camera", "EXIF CustomRendered": "Normal", "EXIF ExposureMode": "Auto Exposure", "EXIF WhiteBalance": "Manual", "EXIF DigitalZoomRatio": "1", "EXIF SceneCaptureType": "Standard"}