RESEARCH Record of orogenic cyclicity in the Alberta foreland basin, Canadian Cordillera Garrett M. Quinn1, Stephen M. Hubbard1, Reid van Drecht1, Bernard Guest1, William A. Matthews1, and Thomas Hadlari2 1DEPARTMENT OF GEOSCIENCE, UNIVERSITY OF CALGARY, EARTH SCIENCE 118, 2500 UNIVERSITY DRIVE NW, CALGARY, ALBERTA T2N 1N4, CANADA 2GEOLOGICAL SURVEY OF CANADA, 3303 33 STREET NW, CALGARY, ALBERTA T2L 2A7, CANADA ABSTRACT Jurassic–Cretaceous sedimentary rocks of the Alberta foreland basin are a key record of the evolution of the Canadian Cordillera. We test a recent model for cyclical development of Cordilleran orogenic systems using detrital zircon analysis of the major sandstone units deposited between 145 and 80 Ma exposed in the Rocky Mountain Foothills near Grande Cache, Alberta. The basin history is well constrained by decades of study, and the stratigraphy has been previously subdivided into tectonostratigraphic wedges. U-Pb data from 14 detrital zircon samples are included in this study. All the major magmatic provinces of North America are represented in each sample, with the relative proportions varying between samples. The samples are assigned to five groups with the aid of multidimensional scaling. Groups 1–3 are interpreted to record recycling from specific passive-margin units of western North America with varying input from the Cordilleran magmatic arc. Group 4 is interpreted to record recycling from sedimentary strata in the United States and dispersal by basin-axial fluvial systems. Group 5 is dominated by Mesozoic zircon grains interpreted to have originated in the Cordilleran magmatic arc. Detrital zircon age spectra do not form groups based on the tectonostratigraphic wedges from which they were sampled; rather, within each tectonostratigraphic wedge, they exhibit evolution from diverse age spectra to a less-diverse distribution of detrital zircon ages. We constructed a proxy for magmatic flux of the Cordilleran magmatic arc using detrital zircon ages younger than 200 Ma; it shows three modes at ca. 165, 115, and 74 Ma. These ages are considered high-flux episodes of magmatism that are linked to cyclical uplift and plateau formation in the orogen. This cyclical process is interpreted to: (1) control sedimentation rates in the foreland; (2) account for evolving provenance by altering catchments; and (3) be a plausible mechanism for the deposition of the tectonostratigraphic wedges in the Alberta foreland basin. LITHOSPHERE; v. 8; no. 3; p. 317–332; GSA Data Repository Item 2016148 | Published online 5 May 2016 doi:10.1130/L531.1 INTRODUCTION (Bally et al., 1966; Monger et al., 1972; Monger sediments throughout the stratigraphic section and Price, 1979; Coney et al., 1980; Beaumont, remains poorly documented. In this study, we Recent models of cyclical orogenic devel- 1981; Monger et al., 1982; Stott, 1984; Cant analyzed every significant sandstone unit depos- opment attempt to describe a unifying frame- and Stockmal, 1989; Leckie and Smith, 1992). ited between 145 and 80 Ma from the Grande work of interrelated crustal processes, including The Alberta foreland basin formed and filled Cache area of the central Alberta Foothills using underthrusting, eclogite root foundering, crustal in response to tectonic loading of the western U-Pb geochronology of detrital zircon grains. shortening, episodic magmatism, and plateau margin of North America by allochthonous and We tested the hypothesis of orogenic cyclicity development and collapse (DeCelles et al., 2009; parautochthonous terranes starting in the Middle in western Canada through analysis of detrital Vanderhaeghe, 2012). Inherently, these models Jurassic (Monger et al., 1972, 1982; Monger and zircon spectra in the context of a high-resolu- predict episodic sedimentation in foreland basins. Price, 1979). Docking of terranes to the North tion stratigraphic framework from this uniquely As such, foreland basin strata are a key archive American margin progressed until the Eocene, well-constrained foreland basin. in which to sample Cordilleran magmatic arcs resulting in a complex orogenic collage (Monger and test orogenic cyclicity hypotheses. et al., 1972; Coney et al., 1980). STRATIGRAPHIC CONTEXT AND The western North American foreland basin Numerous authors have recognized the cycli- STUDY AREA extends from southern Mexico to the Canadian cal nature of Alberta foreland basin strata and Arctic, ~6000 km along strike, with a maximum subdivided the fill into lithostratigraphic cycles The stratigraphic framework for siliciclas- width exceeding 1000 km (DeCelles, 2004). The or tectonostratigraphic wedges (Stott, 1984; tic Mesozoic units in the Alberta foreland basin Alberta foreland basin is the portion of this basin Cant and Stockmal, 1989; Leckie and Smith, has been extensively analyzed, with several occupying the Canadian province of Alberta. 1992; Ross et al., 2005; Pana and van der Pluijm, studies emphasizing the linkage of sedimentary The Canadian Cordillera and the Alberta fore- 2015). The paleogeographic evolution of the packages to tectonic processes in the adjacent land basin are exceptionally well studied due to basin is well understood, providing constraints Canadian Cordillera (Fig. 1; Table 1; Cant and expansive outcrops and hundreds of thousands on accommodation development and sediment- Stockmal, 1989; Ross et al., 2005; Raines et al., of well penetrations. This linked orogen-basin routing variation (Jackson, 1984; Leckie and 2013; Pana and van der Pluijm, 2015). The stra- system is the focus of classic works on accre- Smith, 1992). tigraphy of the Alberta foreland basin consists tionary margin tectonics, fold-and-thrust belts, Despite this well-established framework of unconformity- or flooding surface–bounded basin analysis, stratigraphy, and sedimentology for the Alberta foreland basin, the origin of sequences, which are variably subdivided into LITHOSPHERE© 2016 Geological | Volume Society 8 of| AmericaNumber 3| |For www.gsapubs.org permission to copy, contact [email protected] 317 Downloaded from http://pubs.geoscienceworld.org/gsa/lithosphere/article-pdf/8/3/317/3046461/317.pdf by guest on 25 September 2021 QUINN ET AL. Terrane Grande Leckie and Cant and Ross et al. Pana and van Accretion Cache Smith Stockmal (2005) der Pluijm Events Age Stratigraphy (2015) Price et al. (Ma) (1992) (1989) (1981) Maastrichtian Pacic Rim/ Tectono- Chuga 72.1 Saunders Cycle 4 stratigraphic Campanian Group Wedge 4 Insular Pulse 3 Superterrane Late 83.6 Santonian 86.3 Smoky Coniacian Quiescence 89.8 Group Turonian Cycle 3 Oblique 93.9 ompression Cenomanian Dunvegan Fm. T.W. 3 C 100.5 Ft. St. John Quiescence Cascadia Albian Group Cretaceous Pulse 2 113.0 Tectono- Cycle 2 stratigraphic e Aptian Wedge 2 Bullhead onic Early Group 125.0 Erosion Barremian and Tect 129.4 Bridge River Hauterivian Quiescenc 132.9 Reworking Valanginian 139.8 Berriasian Monteith 145.0 Formation Tithonian 152.1 Late Kimmeridgian 157.3 Tectono- Oxfordian Intermontane Fernie Cycle 1 stratigraphic Pulse 1 Superterrane 163.5 Wedge 1 ompression Callovian 166.1 Formation C Middle Bathonian 168.3 Bajocian 170.3 Aalenian 174.1 Toarcian Initial Jurassic 182.7 Emplacement Pleinsbachian of Allochtho- Early 190.8 nous Terranes Sinemurian 199.3 Figure 1. Tectonostratigraphic and lithostratigraphic cycles in the Alberta foreland basin compared to the stratigraphic column of lithostratigraphic units considered in this study. Diamonds indicate units sampled. See Table 1 for detailed stratigraphic and sampling information. T.W.—tectonostratigraphic wedge. tectonostratigraphic wedges or lithostratigraphic deposits are represented by the Monteith Forma- River terrane to the margin of North America at cycles (Fig. 1; Stott, 1984; Cant and Stockmal, tion of the Minnes Group, which represents a this time has been linked to deposition of these 1989; Leckie and Smith, 1992; Ross et al., 2005; progradational package of deltaic to fluvial sedi- sediments (Price et al., 1981; Rusmore et al., Pana and van der Pluijm, 2015). These cycles ments (Miles et al., 2012; Kukulski et al., 2013a). 1988; Cant and Stockmal, 1989). provide the framework for the timing of sedimen- The basal bounding surface of the second There is disagreement as to whether the tation and hiatus events, which can be compared tectonostratigraphic wedge is the basinwide sub- Cadotte Member of the Peace River Forma- to tectonic events in the Canadian Cordillera. Cretaceous unconformity, which represents a tion (Fort St. John Group) is part of the sec- Jurassic to earliest Cretaceous deposits in 10–20 m.y. hiatus attributed to isostatic rebound ond tectonostratigraphic wedge or should be the basin are widely assigned to the first tec- during an extended period of tectonic quies- considered as part of an intervening period of tonostratigraphic wedge or depositional cycle in cence (Heller et al., 1988; Cant and Stockmal, tectonic quiescence (Table 1; Cant and Stock- the basin. Protracted subsidence and sedimen- 1989). The Bullhead Group, basal Fort St. John mal, 1989; Leckie and Smith, 1992). Gouge of tation are linked to loading of the lithosphere Group, and equivalents are assigned to the sec- comparable age was absent from major thrust by accretion of the Intermontane superterrane ond cycle of sedimentation in the basin (Table faults in the Rocky Mountains, consistent with to the western margin of North America (Cant 1; Cant and Stockmal, 1989; Leckie and Smith, the tectonic quiescence hypothesis (Pana and and Stockmal, 1989). In the study area,