scholarly journals The closure temperature(s) of zircon Raman dating

2020 ◽  
Author(s):  
Birk Härtel ◽  
Raymond Jonckheere ◽  
Bastian Wauschkuhn ◽  
Lothar Ratschbacher
Keyword(s):  
Activation Energy ◽  
Kinetic Models ◽  
Damage Accumulation ◽  
Isothermal Annealing ◽  
External Rotation ◽  
Raman Band ◽  
Closure Temperature ◽  
Distributed Activation Energy Model ◽  
Geological Evidence ◽  
Annealing Experiments

Abstract. We conducted isochronal and isothermal annealing experiments on radiation-damaged zircons between 500 and 1000 °C for durations between ten minutes and five days. We measured the widths (Γ) and positions (ω) of the internal ν1(SiO4), ν2(SiO4), ν3(SiO4), and external rotation Raman bands at ~ 974, 438, 1008, and 356 cm−1. We fitted a Johnson-Mehl-Avrami-Kolmogorov and a distributed activation energy model to the fractional annealing data, calculated from the widths of the ν2(SiO4), ν3(SiO4), and external rotation bands. From the kinetic models, we determined closure temperatures Tc for damage accumulation for each Raman band. Tc range from 330 to 370 °C for the internal ν2(SiO4) and ν3(SiO4) bands; the external rotation band is more sensitive to thermal annealing (Tc ~ 260 to 310 °C). Our estimates are in general agreement with previous ones, but more geological evidence is needed to validate the results. The Tc difference for the different Raman bands offers the prospect of a multi-closure-temperature zircon Raman thermochronometer.

scholarly journals The closure temperature(s) of zircon Raman dating

Geochronology ◽  
2021 ◽  
Vol 3 (1) ◽  
pp. 259-272
Author(s):  
Birk Härtel ◽  
Raymond Jonckheere ◽  
Bastian Wauschkuhn ◽  
Lothar Ratschbacher
Keyword(s):  
Damage Accumulation ◽  
Isothermal Annealing ◽  
External Rotation ◽  
Raman Band ◽  
Closure Temperature ◽  
Irradiation Damage ◽  
Distributed Activation Energy Model ◽  
Geological Evidence ◽  
Annealing Step ◽  
Annealing Experiments

Abstract. Zircon Raman dating based on irradiation damage is a debated concept but not an established geo-/thermochronological method. One issue is the temperature range of radiation-damage annealing over geological timescales. We conducted isochronal and isothermal annealing experiments on radiation-damaged zircons between 500 and 1000 ∘C for durations between 10 min and 5 d to describe the annealing kinetics. We measured the widths (Γ) and positions (ω) of the ν1(SiO4), ν2(SiO4), and ν3(SiO4) internal Raman bands, and the external rotation Raman band at ∼974, 438, 1008, and 356 cm−1 after each annealing step. We fitted a Johnson–Mehl–Avrami–Kolmogorov and a distributed activation energy model to the fractional annealing data, calculated from the widths of the ν2(SiO4), ν3(SiO4), and external rotation bands. From the kinetic models, we determined closure temperatures Tc for damage accumulation for each Raman band. Tc ranges from 330 to 370 ∘C for the internal ν2(SiO4) and ν3(SiO4) bands; the external rotation band is more sensitive to thermal annealing (Tc∼260 to 310 ∘C). Our estimates are in general agreement with previous ones, but more geological evidence is needed to validate the results. The Tc difference for the different Raman bands offers the prospect of a multi-closure-temperature zircon Raman thermochronometer.

scholarly journals Kinetic Modeling of CO2 and H2O Gasification Reactions for Metallurgical Coke Using a Distributed Activation Energy Model

ACS Omega ◽  
2021 ◽  
Vol 6 (17) ◽  
pp. 11436-11446
Author(s):  
Yui Numazawa ◽  
Yuki Hara ◽  
Yoshiya Matsukawa ◽  
Yohsuke Matsushita ◽  
Hideyuki Aoki ◽  
...  
Keyword(s):  
Activation Energy ◽  
Kinetic Modeling ◽  
Energy Model ◽  
Metallurgical Coke ◽  
Distributed Activation Energy Model

Kinetic analysis of biomass pyrolysis using a double distributed activation energy model

2015 ◽  
Vol 121 (3) ◽  
pp. 1403-1410 ◽  
Author(s):  
Benedetta de Caprariis ◽  
Maria Laura Santarelli ◽  
Marco Scarsella ◽  
Carlos Herce ◽  
Nicola Verdone ◽  
...  
Keyword(s):  
Activation Energy ◽  
Kinetic Analysis ◽  
Energy Model ◽  
Biomass Pyrolysis ◽  
Distributed Activation Energy Model

scholarly journals Глубокие центры радиационных дефектов в монокристаллах CdZnTe, созданные потоком быстрых нейтронов

2018 ◽  
Vol 52 (3) ◽  
pp. 322 ◽  
Author(s):  
С.В. Пляцко ◽  
Л.В. Рашковецкий
Keyword(s):  
Activation Energy ◽  
Neutron Flux ◽  
Fast Neutron ◽  
Single Crystals ◽  
Isothermal Annealing ◽  
Fast Neutron Flux ◽  
Photoluminescence Properties ◽  
Radiation Induced ◽  
Induced Defects

AbstractThe effect of a fast neutron flux (Φ = 10^14–10^15 cm^–2) on the electrical and photoluminescence properties of p -CdZnTe single crystals is studied. Isothermal annealing is performed ( T = 400–500 K), and the activation energy of the dissociation of radiation-induced defects is determined at E _D ≈ 0.75 eV.

scholarly journals Thermogravimetric and Kinetic Analyses of Oil Palm Empty Fruit Bunch (OPEFB) Pellets Using the Distributed Activation Energy Model

2016 ◽  
Vol 27 (3) ◽  
pp. 67-83 ◽  
Author(s):  
Bemgba Bevan Nyakuma ◽  
◽  
Arshad Ahmad ◽  
Anwar Johari ◽  
Tuan Amran Tuan Abdullah ◽  
...  
Keyword(s):  
Activation Energy ◽  
Oil Palm ◽  
Energy Model ◽  
Empty Fruit Bunch ◽  
Distributed Activation Energy Model

Thermal Decomposition Kinetics of RDX with Distributed Activation Energy Model

2013 ◽  
Vol 641-642 ◽  
pp. 144-147 ◽  
Author(s):  
Ming Hua Chen ◽  
Tao Zhang ◽  
Wen Ping Chang ◽  
Xiao Biao Jia
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Energy Model ◽  
Decomposition Kinetics ◽  
Thermal Decomposition Kinetics ◽  
Distributed Activation Energy Model ◽  
Thermogravimetric Analyzer ◽  
Decomposition Stage ◽  
Decomposition Processes ◽  
Kinetics Of

The thermal decomposition kinetics of RDX at different rates was studied by thermogravimetric analyzer(TG) and the activation energy of RDX was calculated by distributed activation energy model. It is shown that the thermal decomposition processes of RDX were divided into three stages according to the TG curves, they are molten stage, thermal decomposition stage and eng stage. The activation energies of RDX are all between 124.34 and 181.48KJ•mol-1 in the thermal decomposition stage of non-monotonously increasing. The activation energy of RDX is 139.98 KJ•mol-1 in the molten stage, and the thermal decomposition stage is167.24KJ•mol-1.

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