Early Triassic peritidal carbonate sedimentation on a Panthalassan seamount: the Jesmond succession, Cache Creek Terrane, British Columbia, Canada

Abstract

The Jesmond succession of the Cache Creek Terrane in southern British Columbia records late Early Triassic peritidal carbonate sedimentation on a mudflat of a buildup resting upon a Panthalassan seamount. Conodont and foraminiferal biostratigraphy dates the succession as the uppermost Smithian to mid-Spathian. The study section (ca. 91 m thick) is dominated by fine-grained carbonates and organized into at least 12 shallowing-upwards cycles, each consisting of shallow subtidal facies and overlying intertidal facies. The former includes peloidal and skeletal limestones, flat-pebble conglomerates, stromatolitic bindstones, and oolitic grainstone, whereas the latter consists mainly of dolomicrite. The scarcity of skeletal debris, prevalence of microbialite, and intermittent intercalation of flat-pebble conglomerate facies imply environmentally harsh conditions in the mudflat. The study section also records a rapid sea-level fall near the Smithian-Spathian boundary followed by a gradual sea-level rise in the early to mid-Spathian.

Lower Triassic anachronistic facies capping the Qinghai-Tibet Plateau seamount: Implications for the extension of extraordinary oceanic conditions deep into the interior Tethys Ocean

“…It is noteworthy that most previous reports of anachronistic facies are from localities in the shallow Tethys Ocean (such as Iran, Turkey, Hungary, Oman and South China) (Pruss et al, 2004;Groves and Calner, 2004;Wang et al, 2005;Baud et al, 2007;Kershaw et al, 2007) and southwestern Pangaea (Woods, 2013), with a few additional examples from seamounts in Panthalassa (Sano and Nakashima, 1997;Sano et al, 2012). Early Triassic ooids and cortoids found in the Bayan Har area occur in the central Palaeo-Tethys Ocean.…”

Comparison of Tidalites in Siliciclastic, Carbonate, and Mixed Siliciclastic-Carbonate Systems: Examples from Cambrian and Devonian Deposits of East-Central Iran

“…The microfacies in Deranjal Formation are dolomudstone, dolomitic mudstone, dolomitic peloidal packstone, dolomitic ooidalintraclastic wackstone-packstone, dolomitic ooidal grainstone, and dolomitic ooidal-intraclast grainstone (Tables 1 and 2). Generally, dolomitic mudstone with fenestral fabric, dolomitic pelloidal wackstone-packstone, ooidal-intraclastic packstone, and domal stromatolitic boundstones indicate low-energy conditions of subtidal lagoon (e.g., [11,49,50]). In addition, ooidal or intraclastic grainstones and stromatolitic boundstones (often planar shaped) are formed in high-energy conditions, especially tidal channels in intertidal and shallow subtidal settings.…”

“…Other sedimentary textures observed in the studied microfacies are fenestral fabrics, calcite pseudomorphs (only in the Padeha Formation), and V-shaped mud cracks within the dolomudstone lithofacies ( Table 2). The presence of such textures indicates deposition of the sediments in the upper intertidal and supratidal zones (e.g., [11,[49][50][51][52]).…”

“…The FF element was clearly recognized within the Top Quartzite and the Padeha Formation. The sandstone lithofacies were mainly deposited during the flood and input of flooding channels to a supratidal subenvironment (e.g., [49]). The flooding channel deposits are 20 cm to 1 m thick and have a limited lateral extension.…”

Evolution of depositional settings in the Torrey area during the Smithian (Early Triassic, Utah, USA) and their significance for the biotic recovery

“…However, for some marine groups such as ammonoids (Brayard et al , ) and conodonts (Orchard, ), or where permitted by favourable environmental conditions (Krystyn et al , ; Twitchett et al , ; Chen et al , ; Beatty et al , ; Zonneveld et al , ; Brayard et al , ; Hautmann et al , , ; Kaim et al , ; Hofmann et al , , 2013 a, b), life seems to have recovered rapidly in the Early Triassic. The timing and modalities of the biotic recovery are therefore still debated, highlighting the importance of its spatio‐temporal variations, especially from the point of view of the underlying depositional settings (Pruss et al , ; Beatty et al , ; Galfetti et al , ; Brühwiler et al , ; Mata and Bottjer, , ; Kershaw et al , ; Sano et al , ; Komatsu et al , ; Olivier et al , ; Pietsch and Bottjer, ). Therefore, detailed sedimentological studies and palaeoenvironmental reconstructions are of primary importance for improving our knowledge of the Early Triassic biotic recovery.…”