Navarro, Gonzalo; Yáñez San Francisco, Eduardo; Robson, Benjamin A; Schaffer, Nicole; Castro-Cancino, Benjamín; Fernández, Alfonso; Valois, Rémi; MacDonell, Shelley: Rock glacier inventory for Estero Derecho nature reserve, semiarid Andes of Chile (30°S) [dataset]. PANGAEA, https://doi.pangaea.de/10.1594/PANGAEA.987674 (dataset in review)

The dataset is a rock glacier inventory of the Estero Derecho nature reserve, a headwater sub-catchment of the Elqui River basin, in the semiarid Chilean Andes (30°S). The inventory has been compiled followed the guidelines proposed by the Rock Glacier Kinematics and Inventory (RGIK) Standing Committee of the International Permafrost Assocciation on mapping rock glaciers. It contains the boundaries of the landforms, their geometric information, and kinematic data. Remote sensing data adpoted to produce this dataset includes optical images (ESRI basemap imagery: Vivir with 0.6 m resolution from 23 March 2023, and Google Earth Pro images) and Interferometric Syntethic Apertura Radar (InSAR) images (Sentinel-1). The kinematic data has been quantified from Sentine-1 data during September 2018 and Febraury 2024. An extended glacial (moraines) and periglacial landform inventory is presented, to complete the geomorphological mapping of the basin and to provide geomorphological context for the distribution and evolution of rock glaciers.

The Primary Markers file contains the identification of landforms indicating if they correspond to rock glacier or not: Landforms were identified as being "rock glaciers" if they presented the following morphologies: a talus front and a continuity to lateral margins, and optionally ridge-and-furrow surface topography (RGIK, 2023). "Uncertain rock glaciers" were identified when there was an obvious front but no obvious lateral margins or a chaotic topography without clear creeping morphology. "Not a rock glacier" landforms were also marked to indicate: i) landforms that look similar to rock glaciers but are not (e.g., rock outcrops, talus scree, gelifluction lobes) ; ii) landforms recognised as rock glaciers in previous inventories that do not meet the RGIK (2023) criteria; and iii) areas delineated as rock glaciers in the Chilean public national glacier inventory (DGA, 2022) which correspond to the rooting zone or an exaggerated lateral extension, both of which are excluded from the rock glacier delineation following RGIK (2023). An attribute table is filled for each RG or URG, which includes the identification, location, geomorphological connections, completeness and activity classification.

Initially, rock glaciers were divided into five activity (velocity) classes: active; active uncertain; transitional; relict uncertain or relict, based on their geomorphological activity indicators (i.e., steepness of the front, freshly exposed material, and surface expressions of flow). Specifically, according to the RGIK (2023) guidelnes: i) active uncertain which indicates that the landform is not in a relict state but there was insufficient evidence to distinguish between active and transitional; and ii) relict uncertain which, similarly, indicates it is not active but it is not possible to differentiate between transitional and relict states. In a second step, InSAR-derived multiannual unwrapped interferograms were used to define semi-quantitative velocity classes and the kinematic attribute for each landform.

Comparing the initial geomorphological categorisation, the InSAR analysis confirmed the activity class of 62 (63%) rock glacier units, while at the same time it suggests the need to reclassify 37 (37%) landforms. Specifically, 33 (77%) of those initially interpreted as intact do not exhibit detectable movement (<cm a-1) and four (7%) relict rock glaciers show movement.

Landforms identified as RG and URG were delineated with extended (including external parts such as front and lateral margins) and restricted (excluding external parts) outlines, following RGIK (2023). Rock glacier polygons are contained in the RGUOutline files, which associated attribute table includes the reliability of the delineation, area and completion details metadata.

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Additionally, the dataset includes a moraine (moraine_inventory_ED) inventory, including three categories:

- Dump morain: Accumulation of glacial debris marking former glacier locations. They form where debris is delivered to an ice margin and accumulates along the side or in front of the glacier to form a ridge. [Bennett and Glasser (2009); Hagg (2022)]

- Ablation moraine: Glacial deposit formed by the accumulation of debris released through ablation over stagnant, ice-cored glacier margins, where supraglacial debris insulates the ice. Its characteristic hummocky morphology—irregular mounds and enclosed hollows—results from uneven melt-out of debris-covered ice. [Bennett and Glasser (2009)]

- Ground moraine: Subglacial deposit of till, laid down beneath a glacier as it flows or retreats. It usually lies as a relatively thin layer on the subsurface and can be flat to undulating or hilly. The moraine material can be formed as lodgement till or subglacial melt-out till. [Hagg (2022)]

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An extended periglacial inventory is also presented in periglacial_inventory_ED. This identification differentiates landforms defined as rock glaciers under the RGIK inventory framework according to traditional periglacial geomorphology criteria, including morphology, size, and topographic setting:

- Rock glacier (sensu stricto): Tongue or lobate-shaped ice-containing landforms of debris, generated by the former or current creep of frozen ground, detectable by particular morphology such as front, lateral margins and, usually, ridge and furrow surface topography. They are often considered as the most evident geomorphological expression of creeping permafrost. [Barsch (1996); RGIK (2023a)];

- Protalus rampart: Ramp of debris formed at the downslope margin of steep slopes as consequence of cumulative deformation by long-term creep of ice/debris mixtures under periglacial conditions. They are considered to represent proto or embryonic rock glaciers. [Berthling (2011); Scapozza et al. (2011)];

- Protalus lobe: Lobes, usually tongue-shaped, originated at the foot of a slope by the stacking of gelifluction taluses. They are wider than they are long, and, usually, present flow structures characterised by ridges and furrows transversal to the flow direction and usually terminate in steep slope margins. They are usually referred to as lobate-rock glaciers. [García et al. (2017b); Harrison et al. (2008)];

- Gelifluction lobe: Lobes formed by the slow downslope flow of unfrozen soils on a frozen substrate, due to freeze–thaw action. [García et al. (2017b); Ballantyne (2018)].