PRESENT-DAY GULLY ACTIVITY (DARK FLOWS AND BLOCK MOVEMENTS) IN SISYPHI CAVI, MARS
Résumé
Introduction: We present the final results of our study regarding contemporary gully activity in the Sisyphi Cavi region on Mars [1]. We choose this specific region due to a high number of active gullied slopes [2, 3], as well as a former detailed study of ongoing activity of one specific gully [2]. Our study is mainly based on multi-temporal HiRISE (n = 212) and CTX (n = 382) imagery. In addition, we used HRSC, THEMIS-IR, CaSSIS, MOLA DTM, and TES datasets for our intensive survey of all gullies in the Sisyphi Cavi region. Study region: The study region (340° to 10° E and 66° to 76°S) comprises the complete Sisyphi Cavi region, an area with numerous polar pits up to ~1000 m deep [2] (Fig. 1). It is proposed that the south polar pitted terrains (including Sisyphi Cavi) were formed by collapse induced by basal melting of volatile-rich surface layers [4]. The complete study region is covered in a decimeter thick seasonal CO2 slab ice during winter with extensive surface defrosting during mid-spring and summer [2]. The steep slopes of the numerous pits host fresh-looking gullies, some with ongoing present-day activity [1-3]. Methods: We mapped and measured the orientation of all gullies (n = 17,760, based on the identification of a clearly visible alcove) in Sisyphi Cavi based on CTX images. We used multi-temporal HiRISE imagery for detailed analyses of active gullies.
Origine : Fichiers produits par l'(les) auteur(s)