Textural and mineralogical characterization of moraine from the Galongla Glacier: Insights into climate-driven glacial degradation in Southeast Tibet

Glacial ablation is often considered a key indicator of global climate change. The world's greatest concentration of glaciers at mid- and low-latitudes is found in Southeast Tibet, where glaciers often deteriorate more quickly. The Galongla Glacier, sometimes referred to as the 24K Glacier, is a prime representative of debris-covered glacial deterioration. Over the past 23 years (from 2000 to 2022), the degraded area has reached 14.21%. This increased rate of degradation is directly linked to the high extensive formation of moraines on the surface of the 24K glacier (47%). Previous research focused on the reduction in glacier snow cover caused by increased moisture and rising temperatures, while there have been few studies on the products of glacial degradation. We have systematically examined the textural characteristics and genesis of moraines, aiming to provide a direct indicator for understanding the degradation mechanisms of such climate-driven glaciers in the southeast Tibetan Plateau. This study analyzes the composition, mineral components, particle morphology, and microstructure of the moraines from the 24K Glacier, and examines the textural and mineralogical features, elucidating the inherent connection between glacier decline and moraine development. The sediments were found to be mainly gravel, with relatively small amounts of sand and fine particles, which are attributed to abrasion during rapid degradation processes. The moraines consist mainly of metamorphic quartz sandstone and mylonite components, and it can be reflected from the rock microfiche that the debris experienced intense toughness fracture during the glacial movement. The morphology of moraine particles exhibits elongated, flattened shapes, along with blocky and flaky structures. These observations indicate that the moraines in this area have been significantly abraded by recession decline of glacial ice. It is currently undergoing severe hydro-chemical alteration in the longterm warm and humid climate, exhibiting distinct glacial sedimentary characteristics.