The syn-orogenic sedimentary record of the Grenville Orogeny in southwest Laurentia

Abstract

Late Mesoproterozoic sedimentary sequences in southwest Laurentia range in age from 1340 to 1035 Ma and record regionally extensive intracratonic sedimentation before and during the Grenville Orogeny in southern Laurentia. This paper examines the specific links between intracratonic sedimentation and orogenesis and develops a new tectonic model for basin formation throughout southwest Laurentia during the Late Mesoproterozoic. New detrital zircon, muscovite, and biotite ages refine the provenance, depositional age, and regional correlations of Late Mesoproterozoic strata throughout southwest Laurentia. These data provide a new view of the Grenville orogen in southern Laurentia as it evolved from a continental margin arc to a continent-continent collision based on the record of inboard sedimentation. Deposition of all Late Mesoproterozoic sequences in southwest Laurentia was facilitated by far-traveled, continental-scale rivers that flowed north off the developing Grenville orogen. Sediment accumulation took place during four discrete basin forming events that can be directly linked to changes in the style of convergence and collision along the southern margin of Laurentia. The oldest basin system (lower Apache and Pahrump Groups) records distal back arc basin sedimentation at 1340-1320 Ma, synchronous with widespread magmatism along the southern margin of Laurentia. Unconformably overlying shallow marine carbonate-bearing sequences (lower Unkar Group and correlatives) were deposited between 1255 and 1230 Ma in a regionally extensive retroarc basin with clastic sediment sourced in part from an active continental arc along the southern margin of Laurentia. Shallow marine and terrestrial siliciclastic sequences (upper Unkar Group and correlatives) were deposited at 1140-1100 Ma and were sourced from unroofing thrust nappes in the orogen to the south in an extensive foreland basin system during continent-continent collision. Finally, coarse-grained siliciclastic deposits of the 1060-1035 Ma Hazel Formation represent a proximal foreland basin recording the final stages of the Grenville Orogeny in southern Laurentia.

Tracking the evolution of the Grenvillian foreland basin: Constraints from sedimentology and detrital zircon and rutile in the Sleat and Torridon groups, Scotland

“…Most of these sequences were deposited at considerable distance from the Grenville Orogen, implying their detritus was transported across Laurentia by continental-scale river systems (Rainbird et al, 1992(Rainbird et al, , 1997(Rainbird et al, , 2012. Similarly, remnants of more distal deposits, sourced from the Grenville Orogen occur in the southern United States (e.g., Mulder et al, 2017). These distal sequences were not deposited in foreland basins sensu stricto, that is basins in which accommodation space is primarily created by the load of the adjacent mountain belt (e.g., Beaumont, 1981;Jordan, 1995).…”

“…The basin fill, deposited between 1130-1035 Ma, consists of fluviatile siltstone and conglomerate and is deformed into late Grenvillian, km-scale recumbent folds (Soegaard and Callahan, 1994;Grimes and Mosher, 2003;Mulder et al, 2017). Hoffman, 1988;Buchan et al, 2000;Rivers et al, 2012).…”

From Breakup of Nuna to Assembly of Rodinia: A Link Between the Chinese Central Tianshan Block and Fennoscandia

“…Comparison of detrital zircon ages of metasedimentary rocks with similar depositional age in the Chinese CTB and Yili Block (this study; Huang et al, ), North Australia, West Australia, and South Australia (Smiths et al, , and references therein), West Laurentia (Hadlari et al, ; Howard et al, ; Lane et al, ; Lane & Geherls, ; Leslie, ; Mulder et al, , ; Spencer et al, ; Stewart et al, ; Tomas et al, ), and Fennoscandia (Bingen et al, ; Pulsipher & Dehler, ).…”

“…It is thus suggested that the Cathaysia Block was not adjacent to the CTB. Among the main blocks worldwide, the Western Laurentia displays an age peak at 1.4–1.5 Ga, close to that of the CTB (Figures a and e; Hadlari et al, ; Howard et al, ; Lane & Geherls, ; Lane et al, ; Leslie, ; Mulder et al, , ; Spencer et al, ; Stewart et al, ; Tomas et al, ). However, ca.…”

Neoproterozoic sedimentation and tectonics of the Laurentian midcontinent: Detrital zircon provenance of the Jacobsville Sandstone, Lake Superior Basin, USA and Canada

“…We find that the Jacobsville's zircon age distribution differs from that observed elsewhere for sedimentary rocks in North America's interior derived from the Grenville orogeny, such as Middle Run and equivalent sandstones in Ohio and Kentucky (Baranoski, Dean, Wicks, & Brown, 2009; Santos et al., 2002), in the Amundsen and Mackenzie basins of northwest Canada (Rainbird et al., 2017), and in the Hazel Formation of Texas (Spencer, Prave, Cawood, & Roberts, 2014). The Jacobsville has a relatively small percentage of zircons from the Ottawa (1,090–1,030 Ma) phase, but a larger percentage of Shawinigan (1,200–1,140 Ma), like rocks from southwestern Laurentia (Mulder et al., 2017) and Kentucky (Moecher, Bowersox, & Hickman, 2018), and perhaps the Middle Run. In contrast, there is a large Ottawa peak and a smaller Shawinigan peak for rocks in the Amundsen and Mackenzie basins of northwest Canada.…”