Key points are not available for this paper at this time.
Regional lithostratigraphic correlation of early Neoproterozoic Sequence B on the northwest margin of Laurentia includes a 0. 5-2 km-thick, laterally continuous, quartzarenite marker of mainly fluvial origin. Concordant U-Pb ages of 54 single detrital zircons from five regionally dispersed samples cluster in the Archean (2. 8-2. 6 Ga), Paleoproterozoic (2. 0-1. 9 Ga), and Mesoproterozoic (1. 6-1. 0 Ga). The vast majority (85%) of the zircons are of Mesoproterozoic age, with a high proportion clustering between 1. 25-1. 0 Ga, closely matching the age of synorogenic intrusions in the Grenville Province of North America. A 100 3 4 Ma zircon from the Pinguicula group in the eastern Ogilvie Mountains provides a maximum age for the quartzarenite marker. Sm-Nd isotopic data from intercalated mudrocks indicate a major contribution from sources with relatively juvenile model ages (T₃₌ = 1. 54-1. 74 Ga), consistent with the provenance indicated by the detrital zircons. The isotopic data support both regional lithostratigraphic correlations and the existence of a braided river system of pan-continental proportions that may have emanated from sources along the entire 5000 + km length of the Grenville orogenic front. Proximal parts of this river system may be preserved in a foreland basin setting in the subsurface of the midcontinental USA and perhaps in a thick molassic sequence in central-eastern Greenland.
Rainbird et al. (Wed,) studied this question.