The relation between optical bleaching and sedimentological features of fluvial deposits in the Toruń Basin (Poland)

Abstract

Dis tri bu tions of equiv a lent doses (D E ) ob tained by the Sin gle Aliquot Re gen er a tive-dose (SAR) OSL method ap plied for large aliquots of coarse quartz grains ex tracted from flu vial sed i ments are pre sented and ana lysed with re spect to a flu vial palaeoenvironment. The Nowe D¹bie and £ochowo flu vial suc ces sion from the west ern part of Toruñ Ba sin (east ern part of Noteae-Warta streamway, Toruñ-Eberswalde ice-mar ginal val ley) was ana lysed. The flu vial depositional con di tions con trolling the ex tent of day light bleach ing are re con structed by sedimentological stud ies. The re la tion be tween the amount of bleach ing and sedimentological prop er ties of flu vial de pos its in di cate that rip ple cross-lam i nated sands that ac cu mu lated on the floodplain and hor i zon tally-bed ded sands de pos ited in shal low chan nels are more ap pro pri ate for OSL dat ing than sands de rived from the deep chan nel. Along with lu mi nes cence re sults ob tained for the river de pos its, data mea sured from an ancient pot tery sam ple, en sur ing com plete re set of the OSL sig nal, are pre sented, com pared to and dis cussed. On this base the poorly bleached sed i ment sam ples are iden ti fied and an ad just ment fac tor is in tro duced for cor rect ing their OSL dat ing re sults in or der to avoid age in ver sion. The ap pli ca tion of the ad just ment fac tor is found to min i mize over es ti ma tion of OSL ages of sed i ments.Key words: OSL age in ver sion, quartz, op ti cal bleach ing, sand-bed braided river, ice-mar ginal streamway/val ley.

The north-eastern aeolian ‘European Sand Belt’ as potential record of environmental changes: A case study from Eastern Latvia and Southern Estonia

“…Experimental studies indicate that well-bleached sediments (good bleaching is a prerequisite for luminescence dating) in water flow conditions are found in (1) the lower part of the lower flow regime in an overbank subenvironment, and (2) sheet-like flow with the upper plane bed in a channel environment (Weckwerth et al, 2012). The primary massive sand (Sm) with an alternating sequences of normal grading in the Mustjõgi 1 profile originates from small pulsatory discharges of sediments and very likely records channel environments (cf.…”

Luminescence as a Sediment Tracer and Provenance Tool

“…Most research into bleaching has focused on river systems, but bleaching varies greatly by geomorphic environment (Alexanderson, ; Jaiswal et al, ; Przegiętka et al, ; Schielein & Lomax, ; Weckwerth et al, ). For a given luminescence signal (OSL or IRSL), aeolian sediments often show lower residual doses (remnant luminescence) than other types of sediment (Buylaert et al, ; Singarayer et al, ).…”

Morphology and surficial sediments of the Waldemar River confined outwash fan (Kaffiøyra, Svalbard)

“…4). Similar processes can influence the results of luminescence dating of alluvial deposits due to poor quartz-grain bleaching (Weckwerth et al 2011(Weckwerth et al , 2013. The rate of sediments transport and deposition is directly related to the slope variations, and the three zones of the analyzed confined fan were thus distinguished in terms of slope changes, which are fundamental for controlling sedimentary processes.…”