The Southern Uplands Terrane in Scotland – a notional controversy revisited

Abstract

SynopsisDevelopment of a regional geological interpretation for the Southern Uplands Terrane This review is a tribute to all those who have contributed.

The Neoproterozoic to Mid-Devonian evolution of Scotland: a review and unresolved issues

“…6) constitute one of the world's finest examples of an extinct subduction-accretion wedge (Dewey 1971;Leggett et al 1979;Stone 1995Stone , 2014b. The Midland Valley Terrane to the north is a fragment of, possibly, Neo-Proterozoic lithosphere and/or Ordovician arc that was overthrust northwards by the Ballantrae Ophiolite Complex in the early Llanvirn.…”

Tectono-magmatic controls of post-subduction gold mineralisation during late Caledonian soft continental collision in the Southern Uplands-Down-Longford Terrane, Britain and Ireland: A review

“…The tectonostratigraphy of the SUDLT is well documented and discussed in detail elsewhere (Floyd, 2001;Leggett et al, 1979a;McKerrow, 1987;Stone, 2014). The succession comprises very low metamorphic grade (anchizone-epizone) meta-volcaniclastic greywacke turbidites deposited in a deep marine basin over a period of ~75 Ma in Ordovician and Silurian times from 495 to 420 Ma (Anderson, 2004;Floyd, 2001;Oliver, 1978;Oliver et al, 2003).…”

“…The age of the Moffat Shale and the oldest overlying turbidites is, in general, diachronous across the terrane, becoming younger from northwest to southeast (Leggett et al, 1982;Leggett et al, 1979a;McKerrow et al, 1977), consistent with southeastward progradation of trench-fill sediments derived from the accretionary complex over northwest subducting Iapetus oceanic lithosphere (Mitchell and McKerrow, 1975). The terrane has traditionally been divided into three 'belts' (Anderson, 2001;Anderson, 2004;Stone, 2014). The Northern Belt is dominantly composed of Ordovician turbidites, mainly greywackes of Caradoc to Ashgill age (458-444 My) and is separated from the Central Belt by the Orlock Bridge Fault (Figure 1).…”

“…Long-standing debate over the origin of the terrane has recently been largely resolved (Stone, 2014). Ordovician rocks, predominantly cropping-out in the Northern Belt of the SUDLT, represent a fore-arc subduction-accretion complex as originally proposed by Dewey (1969) and Mitchell and McKerrow (1975).…”

“…Boast et al, 1990;Brown et al, 1979;Charley et al, 1989;Duller et al, 1997;Leake et al, 1981;Steed and Morris, 1997). The SUDLT provides an exceptionally well-studied example of a Phanerozoic accretionary complex (together with subjacent penecontemporaneous foreland basin foldand-thrust belt; Stone, 2014) and a firm geological framework in which to study geodynamic controls and mineralising processes in orogenic settings and sources of heat, fluids and metals.…”