Fig. 3. Cambro-Ordovician rocks rich in organic matter. ( a ) Eriboll Formation sandstone with abundant stylolites, Ullapool; ( b ) Durness Group (Sailmhor Formation) limestone with mottled dark zones rich in organic matter (Leopard Rock, formally Leopard Stone), Durness.

Fig. 8. Schematic petrography of stylolite cutting Eriboll Formation sandstone, Ullapool and Dundonell Forest. Fluid inclusions were measured in each of quartz (Q), albite (A) and K-feldspar (K). F, detrital feldspar grain.

Fig. 2 Fractures in Eriboll Formation exposures and scan line procedure. ( a ) Fracture traces, east-dipping bed surface, view to north from near Loch an Nid [NH077 746]. ( b ) Scan line (red line with gap) and quartz-filled set A fracture; opening displacement (kinematic aperture) is measured

Fig. 1. Outcrop of Cambrian Eriboll Formation and selected fracture strike rose diagrams. Locations and national grid references: ( a ) Polla Bridge [NC390547]; ( b ) Assynt [NC235242]; ( c ) Ullapool [NH138931]; ( d ) Dundonnell [NH114858]; ( e ) Brathan [NH093818]; ( f ) west of Loch an Nid

Fig. 9. Fracture sets containing quartz mineralization, Eriboll Formation sandstone, west of the Moine Thrust Zone.

Fig. 17. Fracture abundance in Applecross Formation sandstone compared with that of Eriboll Formation. ( a ) Fracture length v. distance, late ENE–WSW-striking fractures, Eriboll Formation, showing numerous mostly short fractures. ( b ) Fracture length v. distance, in Applecross Formation, along

to the Eriboll Formation, and D1 is a position to the south based on possible subsequent strike slip on intervening structures that would have displaced outboard units along the Laurentian margin and Baltica northward with respect to cratonic Laurentia (cf. Dewey and Strachan, 2003 ). Abbreviations: D—Dalradian

Fig. 9. Oil inclusions fluorescing under ultraviolet light, in stylolite zone. ( a ) Oil inclusions in trail through quartz grain; ( b ) oil inclusions in altered K-feldspar. Polished wafer, Eriboll Formation, Ullapool. Field widths 200 μm. Microthermometric data are reported in Table 3 .

Fig. 11.  Diagrams showing the paragenetic relationships in three lithologies (vein-filling in Torridon Group sandstone, cement and veining in Eriboll Formation sandstone, mineralized Durness Group limestone) that are dominated by the Component 1 magnetization. The petrographical relationships

Fig. 4. Exposures of Applecross sandstone pavements having low overall fracture abundance. ( a ) Applecross sandstone (Ax), Eriboll Formation (E), and faults (f) near NH0984. Airphotograph. Bing. ( b ) Applecross Formation outcrops. View NW of [NH09788374]. (Note figure and tents for scale.) ( c

Fig. 1 Geological setting. ( a ) Outcrop belt of ESE-dipping Cambrian Eriboll Formation (simplified from Peach et al . 1907 ). MTB, Moine Thrust Belt. Inset (satellite image from Google Maps) shows sample locations (I through IV). ( b ) Sequence of fracture set timing from earliest

Figure 3. Stratigraphic columns for the Ardvreck Group, Scotland, the Trekant and Zebra Series, East Greenland, and the Labrador Group, West Newfoundland. Vertical lines within sandstone units in Eriboll Formation, Zebra Series, and Bradore Formation schematically illustrate the presence

. E, Eriboll Formation: yellow, Basal Quartzite Member; blue, Pipe Rock Member. Key exposure prefixes: A, Set A scanlines; B, Set B scanlines; S, Set L scanlines.

, and South Brook Formations, West Newfoundland— Cawood and Nemchin (2001) ; Green Beds and Keltie Water Grit, Southern Highland Group, northwest Scotland— Cawood et al. (2003) ; Basal Quartzite and Pipe Rock Members, Eriboll Formation, Ardvreck Group, northwest Scotland—Cawood et al. (this paper); Zebra

Fig. 5. Crosscutting relations. ( a ) Microfracture having blue luminescent quartz (F B ) crosscuts and is younger than more numerous fractures filled with red-luminescent quartz, F A , Eriboll Formation, Loch Assynt [NC235242]. Colour-scanned CL image is bed-parallel view of mostly transgranular

. (2003) ; Eriboll Formation (Ardvreck Group), P. A. Cawood et al . (unpubl. data). s, number of samples; n, number of analyses.