Fjord network in Namibia: A snapshot into the dynamics of the late Paleozoic glaciation

Fjords are glacially carved estuaries that profoundly influence ice-sheet stability by draining and ablating ice. Although abundant on modern high-latitude continental shelves, fjord-network morphologies have never been identified in Earth’s pre-Cenozoic glacial epochs, hindering our ability to constrain ancient ice-sheet dynamics. We show that U-shaped valleys in northwestern Namibia cut during the late Paleozoic ice age (LPIA, ca. 300 Ma), Earth’s penultimate icehouse, represent intact fjord-network morphologies. This preserved glacial morphology and its sedimentary fill permit a reconstruction of paleo-ice thicknesses, glacial dynamics, and resulting glacio-isostatic adjustment. Glaciation in this region was initially characterized by an acme phase, which saw an extensive ice sheet (1.7 km thick) covering the region, followed by a waning phase characterized by 100-m-thick, topographically constrained outlet glaciers that shrank, leading to glacial demise. Our findings demonstrate that both a large ice sheet and highland glaciers existed over northwestern Namibia at different times during the LPIA. The fjords likely played a pivotal role in glacier dynamics and climate regulation, serving as hotspots for organic carbon sequestration. Aside from the present-day arid climate, northwestern Namibia exhibits a geomorphology virtually unchanged since the LPIA, permitting unique insight into this icehouse.

Climatic Anomalies and Glacial Dynamics in the Himalayan Region Northern Pakistan: A Spatio-Statistical Approach

Glaciers are always climate-sensitive and affected by minor changes in temperature and other climatic elements. Past studies on the northern mountain ranges of Pakistan reveal changes in climatic patterns in and around these ranges. In this study, an attempt is made to explore and assess the temporal and spatial fluctuations occurring in the ice cover of the Himalayan Region of Pakistan as a result of changes in climatic pattern. Satellite imageries and meteorological data were used to explore the dynamics of both the ice cover and climatic elements. Remote Sensing and Geographical Information System were used to detect changes in snow cover both spatially and temporally. Various statistical techniques, mainly Mann Kendall Trend Test and Sen’s Slope Estimator, were used to analyze the temporal trend of climatic elements. Moreover, correlation and regression analysis were applied to establish the relationship between climate and ice cover. Analysis of the data reveals that the temporal trend in ice cover is not monotonic as there is glacial advancement in certain years while retreating in others. Moreover, it was found out that climatic elements such as temperature and precipitation have recorded changes during the past few decades.

High-Resolution Monitoring of Glacier Mass Balance and Dynamics with Unmanned Aerial Vehicles on the Ningchan No. 1 Glacier in the Qilian Mountains, China

Glaciers located in the Qilian Mountains are rapidly retreating and thinning due to climate change. The current understanding of small glacier mass balance changes under a changing climate is limited by the scarcity of in situ measurements in both time and space as well as the resolution of remote sensing products. Unmanned aerial vehicles (UAVs) provide an unparalleled opportunity to track the spatiotemporal variations in glacier extent at a high resolution and the changing glacier morphological features related to glacial dynamics. Five measurements were performed on the Ningchan No. 1 (NC01) glacier in the Qilian Mountains between 18 August 2017 and 13 August 2020. The glacier changes displayed in the digital orthophoto maps (DOMs) and digital surface models (DSMs) show a 7.4 ± 0.1 m a−1 retreat of the terminus of NC01, a mass balance of −1.22 ± 0.1 m w.e. a−1 from 2017 to 2020, and a maximum surface velocity of 3.2 ± 0.47 m from 18 August 2017 to 26 August 2018, which clearly show consistency with stake measurements. The surface elevation change was influenced by the combined effects of air temperature, altitude, slope, and surface velocity. This research demonstrates that UAV photogrammetry can greatly improve the temporal and spatial resolution of glaciological research.

Testing Hypotheses About Glacial Dynamics Using a Statistical Model of Paleo-Climate

We test hypotheses about glacial dynamics by evaluating the ability of a linear statistical model to simulate climate during the previous ~800,000 years. During this period, the linear model simulates the timing and magnitude of glacial cycles, including the saw-tooth pattern in which ice accumulates gradually and ablates rapidly, without falsely simulating an interglacial after each peak in obliquity. Conversely, the linear model fails to simulate experimental observations that are created by a nonlinear data generating process. Together, these (in)abilities suggest that nonlinearities, threshold effects, bifurcations, and/or phase-specific governing equations do not play a critical role in glacial cycles during the late Pleistocene. Furthermore, the model’s accuracy throughout the sample period suggests that changes in orbital geometry create the Mid-Brunhes event.

Late Quaternary evolution of the sedimentary environment in Modrejce near Most na Soči (Soča Valley, Julian Alps)

Geomorphological and geological mapping have long been used to study the glacial history of the Slovenian Alps, but many uncertainties remain regarding the time and extent of Pleistocene glaciations there. Glacial landforms and undisturbed glacial deposits are rare in the areas of the former glacier terminus, especially in the Soča Valley, where large discrepancies in the interpretation of the extent of the former Soča Glacier have been reported. Early studies proved inconclusive as to whether one or two glaciations extended into the Soča Valley as far as Most na Soči. In order to answer this question, the Quaternary sedimentary succession and landforms in the Modrejce Valley near Most na Soči were investigated. New geological and geomorphological field data allow the interpretation of the sedimentary environment and the stratigraphic relationships between different units. In response to glacial dynamics, the sedimentation developed from glaciofluvial and glaciolacustrine to fully glacial environments, followed by slope deposition. At higher altitudes lateral moraines are preserved, while the staircase-like slope below has been carved into older glacial, glaciofluvial and glaciolacustrine deposits by glacial and post-glacial processes, including fluvial erosion and slope dynamics. We conclude that the succession studied here was deposited over the course of two different glacial advances – LGM and pre-LGM. Our study thus suggests that the Soča Glacier extended as far as the area of Most na Soči twice over the course of the late Quaternary.