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Anderson, L.*; Bartz, M.*; King, G.*; Fox, M.*; Herman, F.*; Stalder, N.*; Biswas, R.*; 末岡 茂; 塚本 すみ子*; Ahadi, F.*; et al.
no journal, ,
Optically stimulated luminescence (OSL) and electron spin resonance (ESR) thermochronometry have the potential to resolve continuous erosion histories from rapidly eroding settings. These thermochronometers are viable over the past few hundred thousand to a million years. These time periods are defined by persistent oscillations between warm and cold states. During the Quaternary, fundamental questions about the relationship between climate and erosion remain unanswered. With further development, the OSL and ESR thermochronometers could answer these questions. To realize this potential new strategies are required to invert low-temperature thermal histories for erosion rates. Here, we explore the use of PeCUBE (Braun, 2003), a three-dimensional finite-element model that simulates heat conduction and advection in the upper crust. As a training dataset we use cooling histories derived from eight samples from the Tateyama region in the Hida Mountains of Japan. The flexibility of PeCUBE allows us to quantify the role of time varying surface temperatures between glacial and interglacial periods. In high-relief settings the three-dimensionality of the topography, for example between valleys and ridges, can substantially perturb rock temperatures. PeCUBE allows us to quantify and remove these confounding topographic effects. We additionally explore the role of changing topographic relief on time varying thermal fields and erosion rates. Lastly, we explore a generous range of model parameters to quantify the sensitivity and robustness of our inversions.
Bartz, M.*; King, G.*; Anderson, L.*; Herman, F.*; 末岡 茂; 塚本 すみ子*; Ahadi, F.*; Gautheron, C.*; Delpech, G.*; Schwarz, S.*; et al.
no journal, ,
Electron spin resonance (ESR) thermochronometry has the potential to resolve continuous erosion histories from rapidly eroding settings over 10
time scales. These time periods are defined by persistent oscillations between warm and cold states. However, questions about the relationship between climate and erosion remain unanswered. We further develop ESR thermochronometry of quartz (Al and Ti centres) to answer these questions in the Tateyama region in the Hida Mountains of Japan. In the result, the Al and Ti centres in quartz can successfully be inverted to unravel rock cooling histories. As future work, all ESR signals will be converted together with OSL data, providing further constraints on their thermal histories.
Bartz, M.*; King, G.*; Anderson, L.*; Herman, F.*; 末岡 茂; 塚本 すみ子*; 田上 高広*
no journal, ,
捕獲電子を用いた熱年代手法に基づいて、日本アルプス飛騨山脈の岩石試料を対象に冷却史の解明を試みた。
Bartz, M.*; King, G. E.*; Anderson, L.*; Herman, F.*; 末岡 茂; 塚本 すみ子*; 田上 高広*
no journal, ,
The Japanese Alps uplifted throughout the Quaternary and reached elevations of up to 3,000 m. However, understanding the interaction between rates of Earth surface processes, tectonics and climate is challenging, partly due to the difficulties of measuring changes in the rates of Earth surface processes at the timescale of glacial-interglacial cycles. In particular, the youth of the Japanese Alps has made measurement of their exhumation histories complicated. Here we investigate the potential of ultra-low temperature thermochronometers based on the luminescence and electron spin resonance (ESR) of feldspar and quartz minerals respectively for understanding changes in exhumation rates. We focus on Tateyama (Hida range), which was glaciated during the late Quaternary period. In total, eight samples were analysed by luminescence and ESR thermochronometry. While most luminescence signals have already reached their upper dating limit, ESR signals give insights into Pleistocene exhumation rates. We measured the ESR dose response and thermal decay properties of all samples, specifically targeting the Al and Ti centres. In general, thermal stability is higher for the Ti signals, resulting in ESR ages of between 0.5-0.9 Ma, although some signals are close to or above the upper dating limit of the Ti centre. In contrast, the Al signal still grows with time and is suitable for determining finite exhumation rates. Initial inversions reveal rock cooling rates on the order of 80 deg. C/Ma, which can be inverted to preliminarily rates of rock exhumation of <3 mm/a within the past 1 Ma. In the next step, we will relate these rates to the climatic (glacial) and tectonic history of the Tateyama region.