Microstructures within a modern debris flow deposit derived from Quaternary glacial diamicton—a comparative micromorphological study

Depositional environment of the glacigenic deposits from the Holy Cross Mountains (Poland) – interpretation based on macro- and microstructure analyses

“…Turbate struc tures are found in clayey de pos its of de bris flow. For ma tion of these struc tures in such de pos its is ex plained by mix ing dur ing flow trans port (Lachniet et al, 2001;Men zies and Zaniewski, 2003;Phillips, 2006). How ever, it can not be excluded that the de posit is a till formed in a submarginal en vi ronment, un der sea son ally chang ing cli mate con di tions.…”

“…The pro cess of mar ble-bed for ma tion de stroys turbate and lin ear struc tures by break ing them apart, when shear is the dom i nant de form ing fac tor, and wa ter pres sures are not high (Kilfeather et al, 2008). Mar ble-bed struc ture is also de scribed and even con sidered as di ag nos tic for de bris flow de pos its (Men zies and Zaniewski, 2003). Crushed grains are also found in both de bris flow de pos its (e.g., Bertran and Texier, 1999) and subglacial till.…”

“…The in ves ti ga tions con cern mostly the re la tion ship be tween ma trix and skel e ton grains, and al low the in fer ence about rhe ol ogy of de pos its -based on the descrip tion of de for ma tions (duc tile, brit tle and com plex) as well as micro struc tures formed by pore-wa ter. The re sults of sub sequent in ves ti ga tions in di cate that not in di vid ual micro struc tures are di ag nos tic but rather their co in ci dence in sep a rate till types (Hiemstra and Rijsdijk, 2003;Men zies and Zaniewski, 2003;Phillips, 2006;Van der Meer et al, 2011). Mod ern re search on the subglacial till micromorphology mostly aims to de ter mine ice dy nam ics (e.g., Hiemstra and Van der Meer, 1997;Menzies, 2000;Ev ans and Hiemstra, 2005).…”

“…Kilfeather et al, 2008). Do mains, peb bles and ro tational struc tures are fre quent in de bris flow de pos its (Lachniet et al, 2001;Men zies and Zaniewski, 2003;Phillips, 2006). The lack of plas mic fab ric pat tern may be the re sult of rel a tively low-stress depositional con di tions.…”

“…The lack of plas mic fab ric pat tern may be the re sult of rel a tively low-stress depositional con di tions. Silasepic and argillasepic plas mic fab ric can be found in flow tills (Van der Meer, 1997;Men zies and Zaniewski, 2003). De po si tion from wa ter-sat urated flow is also in di cated by the lack of de for ma tion (re lated to the flow de vel op ment) in the un der ly ing de pos its (cf.…”