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Luminescence dating of Romanian loess using feldspars

Stefan Vasiliniuc UGent (2011)
abstract
This work investigates the potential of optically and infrared stimulated luminescence signals (OSL and IRSL, respectively) from polymineral silt-sized grains to establish sedimentation chronologies for Romanian loess. The incentive for the study was the observation that various grain sizes of quartz yielded significantly different OSL ages, a behaviour that remains to be understood; feldspar also has the potential to date older deposits. The samples used in this study were taken from the loess/palaeosol sequence near Mircea Vodă, and all luminescence measurements were made using a single-aliquot regenerative-dose (SAR) protocol. A conventional approach, in which stimulation with IR was at 50°C and the detection window in the blue, was found to be compromised by thermal instability of the signals and/or initial sensitivity changes. A double-SAR approach – involving successive stimulation of the polymineral fine grains with IR and blue light, and detection of the resulting IRSL and post-IR OSL signals in the UV – was also tested. Although both signals exhibited significantly different fading rates, the corrected ages are mutually consistent and in agreement with OSL ages for purified silt-sized quartz. This indicates that it may not be necessary to isolate pure quartz to obtain reliable ages for Romanian loess. Owing to the limitations of the fading-correction method, however, the approach is limited to samples from the last glacial period. Finally, a post-IR IRSL protocol was tested, in which a first stimulation at 50°C was followed by a second stimulation at 225°C, and detection was in the blue. The post-IR IR225 signal appears not to suffer from anomalous fading, and yields ages entirely consistent with both OSL ages for silt-sized quartz and independent age control over four interglacial/glacial cycles. The overall conclusion is that post-IR IR dating of polymineral fine grains is very promising. The obtained age results urge the long-established chronostratigraphical framework for Romanian loess to be revised; the two uppermost well-developped palaeosols can no longer be thought of as interstadial soils that developed during the Last Glacial, but have formed during MIS 5 and MIS7, respectively.
Please use this url to cite or link to this publication:
author
promoter
Constantin Cosma, UGent and UGent
organization
year
type
dissertation (monograph)
subject
pages
145 pages
publisher
Babeş-Bolyai University ; Ghent University. Faculty of Sciences
place of publication
Cluj-Napoca, Romania ; Ghent, Belgium
defense location
Cluj-Napoca (Romania) : Universitatea Babeş-Bolyai (Amfiteatrul Iustinian Petrescu)
defense date
2011-10-05 11:00
language
English
UGent publication?
yes
classification
D1
additional info
dissertation consists of copyrighted material
copyright statement
I have transferred the copyright for this publication to the publisher
id
2075642
handle
http://hdl.handle.net/1854/LU-2075642
date created
2012-03-28 08:53:50
date last changed
2012-03-28 09:08:10
@phdthesis{2075642,
  abstract     = {This work investigates the potential of optically and infrared stimulated luminescence signals (OSL and IRSL, respectively) from polymineral silt-sized grains to establish sedimentation chronologies for Romanian loess. The incentive for the study was the observation that various grain sizes of quartz yielded significantly different OSL ages, a behaviour that remains to be understood; feldspar also has the potential to date older deposits.
The samples used in this study were taken from the loess/palaeosol sequence near Mircea Vod\u{a}, and all luminescence measurements were made using a single-aliquot regenerative-dose (SAR) protocol. A conventional approach, in which stimulation with IR was at 50{\textdegree}C and the detection window in the blue, was found to be compromised by thermal instability of the signals and/or initial sensitivity changes. A double-SAR approach -- involving successive stimulation of the polymineral fine grains with IR and blue light, and detection of the resulting IRSL and post-IR OSL signals in the UV -- was also tested. Although both signals exhibited significantly different fading rates, the corrected ages are mutually consistent and in agreement with OSL ages for purified silt-sized quartz. This indicates that it may not be necessary to isolate pure quartz to obtain reliable ages for Romanian loess. Owing to the limitations of the fading-correction method, however, the approach is limited to samples from the last glacial period. Finally, a post-IR IRSL protocol was tested, in which a first stimulation at 50{\textdegree}C was followed by a second stimulation at 225{\textdegree}C, and detection was in the blue. The post-IR IR225 signal appears not to suffer from anomalous fading, and yields ages entirely consistent with both OSL ages for silt-sized quartz and independent age control over four interglacial/glacial cycles.
The overall conclusion is that post-IR IR dating of polymineral fine grains is very promising. The obtained age results urge the long-established chronostratigraphical framework for Romanian loess to be revised; the two uppermost well-developped palaeosols can no longer be thought of as interstadial soils that developed during the Last Glacial, but have formed during MIS 5 and MIS7, respectively.},
  author       = {Vasiliniuc, Stefan},
  language     = {eng},
  pages        = {145},
  publisher    = {Babe\c{s}-Bolyai University ; Ghent University. Faculty of Sciences},
  school       = {Ghent University},
  title        = {Luminescence dating of Romanian loess using feldspars},
  year         = {2011},
}

Chicago
Vasiliniuc, Stefan. 2011. “Luminescence Dating of Romanian Loess Using Feldspars”. Cluj-Napoca, Romania ; Ghent, Belgium: Babeş-Bolyai University ; Ghent University. Faculty of Sciences.
APA
Vasiliniuc, S. (2011). Luminescence dating of Romanian loess using feldspars. Babeş-Bolyai University ; Ghent University. Faculty of Sciences, Cluj-Napoca, Romania ; Ghent, Belgium.
Vancouver
1.
Vasiliniuc S. Luminescence dating of Romanian loess using feldspars. [Cluj-Napoca, Romania ; Ghent, Belgium]: Babeş-Bolyai University ; Ghent University. Faculty of Sciences; 2011.
MLA
Vasiliniuc, Stefan. “Luminescence Dating of Romanian Loess Using Feldspars.” 2011 : n. pag. Print.