Provenance of bauxite and clay deposits in the Carboniferous Benxi Formation, Western Henan, China: Constraints from U–Pb geochronology and regional geology

Abstract

The bauxite and clay deposits of Western Henan, located in the southern part of the North China Craton (NCC), are rich reserves of bauxite ore, and the provenance of this bauxite has received much attention. In this study, X‐ray diffraction and detrital zircon U–Pb dating (using laser ablation–inductively coupled plasma–mass spectrometry) were applied to determine the source(s) of the bauxite in the Carboniferous Benxi Formation. Our data, combined with regional geological and geochemical observations, suggest that detrital zircons from the deposits with ages of ca. 457 Ma were derived mainly from Caledonian intermediate–acidic granitic rocks of the North Qinling Orogenic Belt (NQOB). Zircon grains with Precambrian ages of 2,713 to 549 Ma may have been derived from metamorphic rocks within the NQOB. The Benxi Formation bauxite in this area lacks late Palaeozoic zircons, which may be related to its location, as it is proximal to the NQOB but far from sources of late Palaeozoic zircons in the Inner Mongolia Uplift.