Geochemistry of the Bhor Saidan alluvial plains in Haryana state of north India: Implications for catchment weathering, provenance, and tectonic setting

The present study attempts to ascertain the sediment provenance of around 6.5-m thick palaeochannel sediment exposed in the vicinity of the Ghaggar–Hakra river system of the alluvial plains of the Haryana state of India. The major element geochemistry indicates that the sediments are arkosic in nature, dominated by quartz, K-feldspar, micas, plagioclase, and clay minerals (chlorite, illite, and a very less amount of montmorillonite). The CIA (chemical index of alteration) values ranged between 63 and 77, indicating moderate degrees of chemical weathering. REE plots show that the Eu anomaly is negative for average Bhor Saidan samples similar to PAAS and UCC, suggesting that they could have been deposited in the foreland basin after being originally produced from differentiated silicic and/or recycled sedimentary sources; nonetheless, a little positive Eu anomaly in the chondrite normalised plot is the result of feldspar and arkosic nature of sediments indicating higher levels of physical over the chemical weathering. Mostly the samples are from Siwaliks. Optically stimulated luminescence (OSL) dating suggests that the sediments are ~11 ka old. Further, the palaeochannel is being incised ~3.3 ka and younger sediments are stratigraphically deposited at lower levels. The discriminant function plots (Roser and Korsch 1988) of sediment samples exhibited that they were deposited in a passive margin setting and came from the interior of cratons or a quartzose sedimentary orogenic terrain. The present work done on the geochemistry of the sediments of a palaeochannel present in the alluvial plains will work as a dot on the map to connect the history of the river drainage system of the area in future studies.