Thermoluminescence of feldspar as a multi-thermochronometer to constrain the temporal variation of rock exhumation in the recent past

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Serval ID
serval:BIB_7BD63BD1140F
Type
Article: article from journal or magazin.
Collection
Publications
Institution
Title
Thermoluminescence of feldspar as a multi-thermochronometer to constrain the temporal variation of rock exhumation in the recent past
Journal
Earth and Planetary Science Letters
Author(s)
Biswas R.H., Herman F., King G.E., Braun J.
ISSN
0012-821X
Publication state
Published
Issued date
08/2018
Peer-reviewed
Oui
Volume
495
Pages
56-68
Language
english
Abstract
Natural thermoluminescence (TL) in rocks reflects a dynamic equilibrium between radiation-induced TL growth and decay via thermal and athermal pathways. When rocks exhume through Earth's crust and cool from high to low temperature, this equilibrium level increases as the temperature dependent thermal decay decreases. This phenomenon can be exploited to extract thermal histories of rocks. The main advantage of TL is that a single TL glow curve has a wide range of thermal stabilities (lifetime <ka to Ba), and hence can provide multiple constraints on thermal histories. Here we constrain the distribution of kinetic parameters of TL in feldspar using a glow curve deconvolution method and fitting infinitesimal sub-peaks using a general order kinetic model. Each peak corresponds to a different but closely located energy level E. Forward modeling is applied for different time-temperature histories to estimate the sensitivity and limitation of each signal for different cooling rates. The results show that it is possible to constrain thermal histories between ∼30 °C and ∼80 °C. The results also illustrate that shallower traps, i.e. with lower activation energies, can be exploited to constrain lower cooling histories >100 °C/Ma, whereas deeper traps, i.e. with higher activation energies, provide constraints on thermal histories for higher cooling rates (>300 °C/Ma). Finally, we show how the path of rock exhumation (i.e., depth vs. time) can be constrained using an inverse approach. The newly developed methodology is applied to rapidly cooled samples from the Namche Barwa massif, eastern Himalaya to suggest a trend in exhumation rate with time that follows an inverse correlation with global temperature and glaciers equilibrium altitude line (ELA).
Keywords
TL of feldspar, TL-thermochronology, multi-thermochronometer, rock exhumation, Namche Barwa
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Create date
14/08/2018 6:37
Last modification date
24/12/2022 6:44
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