Composition and Architecture of Braided and Sheetflood-Dominated Ephemeral Fluvial Strata In the Cambrian–Ordovician Potsdam Group: A Case Example of the Morphodynamics of Early Phanerozoic Fluvial Systems and Climate Change

Early Paleozoic rifting and reactivation of a passive-margin rift: Insights from detrital zircon provenance signatures of the Potsdam Group, Ottawa graben

“…This is in contrast to Sanford and Arnott (2010), who correlated some of these strata to the Chippewa Bay and Edwardsville members of the Ausable/ Covey Hill Formation. The revisions discussed and presented in Lowe et al (2017) are not "contradictions," but rather reflect an improved understanding of the contacts separating units; their depositional paleo-environments based on contemporary facies analysis (e.g., Lowe, 2016;Lowe and Arnott, 2016); and the stratigraphic significance of detrital composition, lithofacies, and grain size rather than a less diagnostic feature like stratal color. Although not considered in Lowe et al's (2017) Lowe et al (2018).…”

“…The first major attempt to provide a genetic basin-wide framework and unified stratigraphic nomenclature was that of Sanford (2007); later documented in Sanford and Arnott, (2010). The objective of subsequent work by Lowe (2016); published in Lowe and Arnott, (2016), Lowe et al (2017), and Lowe et al (2018), was to test that framework, make modifications where appropriate, and elucidate the stratal evolution of the Potsdam Group in the Ottawa graben. These basin-specific works outline, for the first time, the uniqueness of the stratigraphy of the Potsdam Group in the Ottawa graben that were previously unaccounted for and documents the profound tectonic overprint on the eustatic and climatic variations that controlled sedimentation here and on the coeval Laurentian shelf and slope.…”

“…Regrettably, our detailed lithofacies analysis and facies association interpretations were only summarized in Lowe et al (2017Lowe et al ( , 2018 due to the imposed length-limit of a peer-reviewed journal manuscript. As stated in the text, an exhaustive treatment of lithofacies analysis and paleoenvironmental interpretations are available in chapters 2 and 3 of Lowe (2016), and in a previously published paper describing supercritical-flow fluvial deposits by Lowe and Arnott (2016). Landing et al disagree with our interpretation of the Altona lithofacies, and in particular that hummocky cross-stratification (HCS) is restricted to the shallow-marine shoreface and water depths of 13-50 m (e.g., Dumas and Arnott, 2006).…”

Sedimentation, earthquakes, and tsunamis in a shallow, muddy epeiric sea: Grinnell Formation (Belt Supergroup, ca. 1.45 Ga), western North America

“…Setting aside the difficulty in reconciling this scenario with the muds of a floodplain being sourced from the west and intercalated fluvial sands coming from the northeast, flashy discharge leading to unconfined flow is usually associated geographically with nearby alluvial fans and slopes or channels as overbank or avulsion flooding phenomena (e.g., Fisher et al, 2007), but no evidence for channels is present anywhere in the Grinnell Formation or apparently in the correlative units to the west (Winston, 2016). Ephemeral sheetflood deposits are commonly transitional to upperflow-regime beds characterized by low-angle to sinusoidal cross-bedding and abundant planelamination (e.g., Hampton and Horton, 2007;Lowe and Arnott, 2016), although there is much variability, and many examples reflect lowerenergy flows (North and Davidson, 2012).…”

Supercritical-flow sedimentary structures of fluvial deposits in the Plio-Pleistocene Katata Formation, Kobiwako Group, Japan

“…1． 高流砂階の流れ 河川流のような一方向の流れでつくられるベッドフォー ムは，流れが強くなるにつれ，リップル，デューン，プレー ンベッド(平滑床)そしてアンティデューン(反砂堆 : antidunes)に変化する (Simons et al, 1965;Harms et al, 1975;Allen, 1982) ．さらに速い流れになると，シュートアンド プール(chutes-and-pools)やサイクリックステップ(cyclic steps)へと変化する (Taki and Parker, 2005;Yokokawa et al, 2011;Cartigny et al, 2014) (例えば，Harms et al, 1975;Allen, 1982;Bennett and Best, 1996) (Fralick, 1999;Araya and Masuda, 2001;Fielding, 2006;Lowe and Arnott, 2016;McMahon andDavies, 2018) ，氷 河アウトウオッシュ堆積物(Fiore et al, 2002;Russell and Arnott, 2003;Hornung et al, 2007;Duller et al, 2008;Gilbert and Crookshanks, 2009;Girard et al, 2012 ;Lang and Winsemann, 2013) ，海浜堆積物(Araya and Masuda, 2001) ，デルタ堆積 物(岡崎ほか，2000; Normandeau et al, 2016;Massari, 2017;Hage et al, 2018) ，タービダイト層(Fildani et al, 2006酒井 ほか，2007;Heinio and Davies, 2009;Mulder et al, 2009;Straub and Mohring, 2009;石原ほか，2009 ;Cartigny et al, 2011;Paull et al, 2011;Gong et al, 2012Gong et al, , 2017Talling, 2014) ， 火山砕屑性堆積物 (Sisavath et al, 2011;Douillet et al, 2013;Pope et al, 2018 (Fig. 6, Fig.…”