The reappearance of the Huronian in Wyoming: rifting and drifting of ancient continents

Abstract

Striking stratigraphic and sedimentological similarities between the Early Proterozoic Huronian Supergroup of the Canadian Shield and the Snowy Pass Supergroup of Wyoming suggest that they were deposited in a single, broad, epicratonic basin developed atop a large Archean continent that included the Superior and Wyoming geological provinces. Breakup of the continent after the 2.2 Ga intrusion of widespread gabbro sheets and dykes resulted in the separation of the Archean Superior and Wyoming cratons and their Early Proterozoic covers. These crustal fragments were subsequently reassembled during Early Proterozoic (~1.85 Ga) orogenesis, the end result being the present 2000 km separation of the Huronian and Snowy Pass supergroups and their Archean basements.

7.2 Huronian-Age Glaciation

“…It was suggested by Long (2004) that the early stages of ocean opening were characterised by development of a transtensional extensional basin but the overall setting (rift-to-drift transition) is similar. Noting remarkable stratigraphic similarities with the Snowy Pass Supergroup of Wyoming (Young 1975;Houston et al 1992), Roscoe and Card (1993) proposed that the Wyoming area may represent a craton that was formerly on the "other side" of the developing Huronian ocean, then rotated in a clockwise direction as it was carried about 2,000 km to the SW (present coordinates). Alternatively, the strong similarities between these Palaeoproterozoic basins may reflect their development on the same margin of a largescale developing ocean (Young 2004).…”

“…Close stratigraphic resemblance to the Huronian succession (and to the Hurwitz Group) on the west side of Hudson Bay was pointed out by Young (1975). The similarities between the Snowy Pass and Huronian supergroups are so striking that they led Roscoe and Card (1993) and Dahl et al (2006) to suggest that the Wyoming Craton represents the "other side" of the Huronian basin that has been subsequently displaced about 2,000 km to the southwest and rotated, in a clockwise manner, through about 180 . Whereas this interpretation is possible, a simpler and more conservative alternative is that the Palaeoproterozoic rocks of the Snowy Pass Supergroup were deposited on the same continental margin as the Huronian and record the same tectonic and palaeoclimatic history (Young 2004 , Fig.…”

“…In order to explain these striking similarities, it was suggested by Roscoe and Card (1993) that the Wyoming province was formerly adjacent to the Huronian basin and has been rotated and translocated to its present distant position. Likewise Bleeker and Ernst (2006) proposed that the Hearne province, where the Hurwitz Group is now preserved, on the west side of Hudson Bay, may have been in the same location (see Dahl et al 2006, Fig.…”

Chemostratigraphy of Paleoproterozoic carbonate successions of the Wyoming Craton: tectonic forcing of biogeochemical change?

“…uraninite followed by three glacial horizons; (2) a carbonate unit above the middle of three diamictites, and (3) thick, mature, Al-rich hematitebearing quartzites above the uppermost glacial horizon (Houston et al, 1992;Roscoe and Card, 1993; Table 3). …”

Four-dimensional context of Earth's supercontinents

“…Sclavia may include the Dharwar craton of southern India (French & Heaman 2010). Superia has long been considered to include several North American and Fennoscandian cratons (Ernst & Bleeker 2010), including Wyoming along Superior's southern margin (Roscoe & Card 1993). Kilian et al (2015) provide an expanded palaeomagnetic database for mafic dyke swarms in Wyoming that generally conform to that reconstruction of Wyoming against southern Superior, in a palaeogeographically inverted orientation.…”