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A new luminescence erosion meter has huge potential for inferring erosion rates on sub-millennial scales for both steady and transient states of erosion, which is not currently possible with any existing techniques capable of measuring erosion. This study applies new rock luminescence techniques to a well-constrained scenario provided by the Beinn Alligin rock avalanche, NW Scotland. Boulders in this deposit are lithologically consistent and have known cosmogenic nuclide ages and independently derived Holocene erosion rates. We find that luminescence-derived exposure ages for the Beinn Alligin rock avalanche were an order of magnitude younger than existing cosmogenic nuclide exposure ages, suggestive of high erosion rates (as supported by field evidence of quartz grain protrusions on the rock surfaces). Erosion rates determined by luminescence were consistent with independently derived rates measured from boulder edge roundness. Inversion modelling indicates a transient state of erosion reflecting the stochastic nature of erosional processes over the last ~ 4:5 kyr in the wet, temperate climate of NW Scotland. Erosion was likely modulated by known fluctuations in moisture availability and to a lesser extent temperature, which controlled the extent of chemical weathering of these highly lithified rocks prior to erosion. The use of a multi-elevated temperature, post-infrared, infra-red stimulated luminescence (MET-pIRIR) protocol (50, 150 and 225 °C) was advantageous as it identified samples with complexities that would not have been observed using only the standard infra-red stimulated luminescence (IRSL) signal measured at 50 °C, such as that introduced by within-sample variability (e.g. surficial coatings). This study demonstrates that the luminescence erosion meter can infer accurate erosion rates on sub-millennial scales and identify transient states of erosion (i.e. stochastic processes) in agreement with independently derived erosion rates for the same deposit. [ABSTRACT FROM AUTHOR]

Landscape at active mountain fronts such as the Himalayas results from climate and/or tectonic interactions. Thus, they are important geomorphic archives that preserve information about such changes/activities in the past. These are a combination of crustal movement and erosion or deposition by surface processes. The Main Frontal Thrust (MFT), which marks the southern end of the Himalayas, has been considered the most active fault in the past. Thus, the landscape in the foothills preserves the signature of deformation events and, at the same time, also records changes in the monsoonal rainfall, controlled by glacial and interglacial events. The present study attempts to understand the evolution of alluvial fan deposits in the Assam- Bhutan Himalayan foothills of the Kokrajhar district of North-East India. The study mainly focuses on the uplifted 30 km long fluvial deposition from the Pinkhua Khola River in the west and Leu Pani in the east. The study is critical because it will help understand the southward propagation of the Himalayan fold and thrust belt. The initiation of the faulting events is marked by the clay layers, which were dated using OSL; the dating of clay layers from the hanging wall of three blocks suggests that the FTB was activated at ~76 ka and experienced three other phases of deformation at ~45 ka, ~27 ka and 12 ka, respectively. [ABSTRACT FROM AUTHOR]