Avoiding, reducing, and reversing land degradation and restoring degraded land is an urgent priority to protect the biodiversity and ecosystem services that are vital to life on Earth. To halt and reverse the current trends in land degradation, there is an immediate need to enhance national capacities to undertake quantitative assessments and mapping of their degraded lands, as required by the Sustainable Development Goals (SDGs), in particular, the SDG indicator 15.3.1 ("proportion of land that is degraded over total land area"). Earth Observations (EO) can play an important role both for generating this indicator as well as complementing or enhancing national official data sources. Implementations like Trends.Earth to monitor land degradation in accordance with the SDG15.3.1 rely on default datasets of coarse spatial resolution provided by MODIS or AVHRR. Consequently, there is a need to develop methodologies to benefit from medium to high-resolution satellite EO data (e.g. Landsat or Sentinels). In response to this issue, this paper presents an initial overview of an innovative approach to monitor land degradation at the national scale in compliance with the SDG15.3.1 indicator using Landsat observations using a data cube but further work is required to improve the calculation of the three sub-indicators.

Assessment of sediment redistribution by end-Ordovician ice sheets is crucial for the reconstruction of Lower Paleozoic source-to-sink patterns. Focussing on the ice-distal, deepwater Tazekka depocenter (Moroccan Meseta), we thus performed a provenance study that combined whole-rock geochemistry, petrography and insights from highresolution detrital zircon ages. The results show that the glacigenic sediments are compositionally-mineralogically and geochemically-more mature than preglacial strata. This observation points to a preferential cannibalization of the "great Lower Paleozoic quartz-rich sandstone sheet", with a limited input of first-cycle, far-travelled clastic sediments. Differentiation of glacial units is not straightforward, yet the glaciation acme is typified by a highly mature sedimentary source and an age spectrum lacking Mesoproterozoic zircon grains, both features strongly indicating derivation from the Cambrian-Lower Ordovician cover of the Tuareg Shield. More regional sources are expressed during the earlier glaciation stages, during which lowstand remobilisations unrelated to subglacial erosion are also suspected. Subordinate but notable late Tonian (∼ 0.8 Ga) and latest Stenian to early Tonian (∼1 Ga) zircon populations are also evidenced in Morocco, which may have implications for future paleogeographic reconstructions.

The deep Middle Pleistocene subglacial incisions of the Southern North Sea (SNS) are commonly infilled by northward gently dipping clinoforms oriented toward the former ice-sheet core. We have focused on the terminal sector of the largest tunnel valley (TV) of the SNS and offer the first high-resolution reconstruction of the geomorphology and stratigraphy of the infill of the glacial incision, as well as the detailed geomorphology of the incision to better understand the genetic mechanisms of these uncommon but peculiar large-scale (up to 13 km in length) bedforms. For this study, high-resolution 3D seismic data, the grain-size distribution from ditch cutting samples, and the gamma-ray wireline log of borehole K14-12 are used. The TV formed in the subglacial environment by steady state flows in a time-transgressive fashion. Meltwater flow transports the eroded material southward and eventually deposits it at the ice-sheet margin, in the lightly grounded ice-sheet environment where the adverse slope forces the flow to wane. The process results in an elongated ice-margin fan made of clinoforms, whose grain-size distribution fines progressively southward, in the downstream direction. The formation and filling of the TV occurred during the retreat of the ice-sheet margin and cyclic fluctuations of the meltwater mass flow rate, which affected the internal stratigraphy and created an undulated top of the clinoforms’ unit. Sparsely distributed, horizontally layered units interpreted as distal proglacial lacustrine deposits filled depressions on the top of the clinoforms-bearing unit. The sequence was then sealed by a chaotic seismic-stratigraphic unit that probably belongs to postglacial times. The ice-sheet-oriented clinoforms were thus formed by sustained meltwater flow resulting from large-size Scandinavian and British convergent ice sheet flows in the freshwater environment of SNS developed between the complex ice margins and the topographic highs inherited from continental Europe.

12The Pleistocene sediment infill of elongated glacial incisions of the Southern North Sea (SNS) 13 often is referred to as tunnel valleys (TV). Its depositional environment is not yet fully understood and 14 present study addresses this challenge from a perspective of clay mineral transformation (illite to I-S) 15reported from the largest Elsterian TV of SNS. Material acquired from the K14-12 borehole in the 16 Dutch offshore was analyzed by X-ray diffraction, electron microscopy, electron microprobe analyses, 17and laser particle-size analysis. Illite and illite-smectite appeared as dominant clays along with minor 18 amounts of kaolinite, kaolinite-smectite, and chlorite. Highest amount of I-S is recognized in TV main 19 portion, while in pre-glacial and uppermost deposits I-S is less abundant. The XRD peak fitting and 20 deconvolution suggest I-S consists of several intermediates -ordered (well-crystallized illite + R3 I-S) 21and disordered (R0 I-S + R0 I-SS). Given the average particle sizes (> 2 µm) and Kübler index values 22 (0.415-0.341°Δ2θ), illite as well as chlorite and kaolinite were interpreted as detrital. On the basis of I-23 S distinctive distribution, grain sizes, and compositional variations its formation by way of early 24 diagenetic in-situ smectitization of illite under a cold climate is proposed. The process operated via a 25 series of mixed-layer intermediates derived from an illite component being progressively converted to 26 low-charged smectite. The reaction is marked by a significant net loss of K and Al with replacement 27 by Si in a tetrahedral coordination. Layer charge imbalance is accommodated by Fe 3+ and Mg entering 28 an octahedral layer, whereas Ca partly fills the interlayer sites. Smectitization rates were controlled by 29 illite grain sizes. The results of this study strongly support the existence of an ice-marginal fresh water 30 depositional environment at the glacial maximum in SNS in which early diagenesis at low 31 temperatures resulted in incomplete illite conversion into smectite. 32This is a 'pre-publication' version of an accepted article for Clays and Clay Minerals. This version may be subject to change during the production process.The DOI given, which may be used for citation purposes, though which will not be active until the version of record is published, is

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