Evaluation of the approximate magnitude of the gross discrepancy between the volume of sediment produced on the hinterland and the volume deposited in the basin, over long time and length scales, is required to make source-to-sink sediment mass-balance calculations more accurate so that multiple sources for a single widespread stratigraphic unit, or bypass of the unit, might be more easily detected. This paper outlines a method to characterize the sources of sediments, or provenance lithotypes, according to their relative ability to produce dissolved ions, clay minerals, and unaltered residue at different levels of weathering. Estimating the relative proportion of the hinterland that is dissolved supports mass-balance analysis comparing hinterland denudation with basinal deposition, whereas estimating the relative proportion of clay (both original clay, eroded from mudstone, for example, as well as newly created clay produced by weathering of feldspar) supports potential identification of multiple sediment sources. The method is illustrated with a practical example from the Bohemian Massif and documented with an Excel workbook. This is a mineralogical approach based on mineral inventories of weathering profiles. Even if the prediction is necessarily uncertain because the mineralogical representation of the PLs are gross abstractions, the modelled transformation processes are crude cartoons, and the extent of transformation under different environmental conditions is wild speculation based on sparse examples, quantitative provenance analysis will be more accurate and more precise than it would be if dissolution and alteration were not explicitly accounted. There is ample opportunity for the community to improve the procedure!

The oldest recognized proxies for low atmospheric oxygen are massive iron-rich deposits. Following the rise of oxygen ~2.4 billion years ago, massive iron formations largely disappear from the geologic record, only to reappear in a pulse ~1.88 Ga, which has been attributed to passive margin transgressions, changing ocean chemistry triggered by intense volcanism, or lowered atmospheric oxygen levels. The North American Gogebic Range has exposures of both volcanics and iron formation, providing an ideal field locality to interrogate the relationship between the lithologies and investigate triggers for this pulse of iron formation. To determine the environmental context and key factors driving post-GOE iron formation deposition, we made detailed observations of the stratigraphy and facies relationships and present updated mapping relationshipsof the Gogebic Range Ironwood Iron Formation and the Emperor Volcanics. This work expands existing mine datasets and logs to constrain variations in stratigraphy. Our results are the first to quantitatively constrain thickness variations along the entire Gogebic range and tie them to syn-sedimentary faulting along listric normal faults and half grabens. Furthermore, our datasets suggest that initiation of major local volcanism does not coincide with iron formation deposition, thus, local intense volcanism cannot be invoked as a causal trigger. Finally, the possibility of iron formation deposition in a shallow water environment suggests that the post-GOE iron formation pulse may not reflect global marine transgressions, but instead a chemocline shallowing due to decreased atmospheric oxygen.