INTEGRATING SPATIAL AND TEMPORAL VARIABILITY IN DETRITAL ZIRCON PROVENANCE STUDIES; A CASE STUDY FROM THE INTERIORLY-DRAINED MESOPROTEROZOIC BELT BASIN

The Belt Supergroup is a succession more than fifteen km. thick of slightly metamorphosed, mostly sedimentary rocks without an unconformity or incised marine sequence boundary. Instead it is a fluvial and lacustrine unit, which, based on stratigraphy and petrology, received sediments from west, south, and east sides of the basin (present coordinates). As lacustrine sediments filled the internally drained basin, base level of the flat lake floors and the surrounding gently sloping terrestrial surfaces rose, limiting incision. Formations deposited across these surfaces were broad and extensive.

Using multi-dimensional scaling, we statistically cataloged detrital zircon dates from 72 samples throughout the Belt basin in order to substantiate spatial and temporal trends in sedimentary provenances within Belt formations. Detrital zircon signatures are characterized by variable mixing between end member age populations and are largely controlled by geographic and stratigraphic position. Detrital zircon signatures within Belt formations change laterally, and within 180 km loose their distinctive character, indicating mixing of source terrains and limited transport distances. These results show that in the Belt basin, statistically defined detrital zircon populations cannot be used to correlate formations lithostratigraphically or chronostratigrphically beyond distances of ~200 km. This study highlights the importance of quantifying spatial variability in detrital zircon provenance and correlation studies of formations in internally drained sedimentary basins.