Singularity analysis of global zircon U-Pb age series and implication of continental crust evolution |
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| Institution: | 1. School of Geography, Geology & Environment, Kingston University, Penrhyn Road, Kingston upon Thames KT1 2EE, UK;2. Camborne School of Mines, University of Exeter, Cornwall Campus, Penryn, Cornwall TR10 9FE, UK;3. Department of Mineralogy, Natural History Museum, Cromwell Road, London SW7 5BD, UK;4. Department of Earth and Planetary Sciences, Birkbeck College, Gower Street, London WC1E 7HX, UK;1. Department of Earth and Planetary Sciences, Macquarie University, Sydney, NSW 2109, Australia;2. Laboratorie de Géologie de Lyon, Ecole Normale Supérieure de Lyon, Université Claude Bernard Lyon 1, CNRS UMR 5276, 46 Allée d''Italie, 69007 Lyon, France;3. School of Earth and Environmental Sciences, University of Adelaide, Adelaide, SA 5000, Australia;1. Research Center for Astronomy and Geosciences, Geobiomineralization and Astrobiological Research Group, Institute for Geology and Geochemistry, Hungarian Academy of Sciences, Budaörsi út. 45, 1112 Budapest, Hungary;2. Eszterházy Károly College, Dept. of Natural Geography and Geoinformatics, Leányka str. 6, 3300 Eger, Hungary;3. Szeged University, Dept. of Mineralogy, Geochemistry and Petrology, Egyetem str. 2-6, 6702 Szeged, Hungary;4. Institute for Nuclear Research, Hungarian Academy of Sciences, Bem tér 18/c, H-4026 Debrecen, Hungary;5. Mangán Ltd, Külterület 1, Úrkút 8409, Hungary;6. Department of Geological Sciences, University of Colorado, 2200 Colorado Avenue, UCB 399, Boulder, CO 80309-0399, USA;1. Department of Geological Sciences, University of Florida, 241 Williamson Hall, Gainesville, FL 32611, USA;2. School of Earth Sciences and Resources, China University of Geosciences Beijing, Beijing 100083, PR China;3. Department of Earth Sciences, The University of Adelaide, Adelaide, SA 5005, Australia;4. Department of Earth System Sciences, Yonsei University, Seoul 03722, Republic of Korea;1. Key Laboratory of Mineral Resources, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China;2. CAS Center for Excellence in Tibetan Plateau Earth Sciences, Beijing 100101, China;3. Key Laboratory of Continental Collision and Plateau Uplift, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100085, China;4. John de Laeter Center for Isotope Research, TIGeR, Applied Geology, Curtin University, Perth, WA 6945, Australia;5. University of Chinese Academy of Sciences, Beijing 100049, China |
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| Abstract: | Recently compiled global databases of igneous and detrital zircon U-Pb ages have been integrated with other types of isotope data (e.g., neodymium, hafnium, and oxygen) to characterize the episodic growth of the continental crust and the development of supercontinents. However, to what extent do the age peaks reflect the rate of continent crust growth or the differential preservation due to supercontinent settings is a long-standing question. Instead of analyzing amplitudes and periodicity of the age series, here, the analysis focuses on shapes of the individual age peaks described by a power law model for measuring the scale invariant fractality and singularity of time-series records. The results indicate that zircon age distributions around peaks follow power law distribution, regardless of the bin-size used to measure the age distribution. Based on the commonly accepted mechanisms (phase transition, self-organized criticality and multiplicative cascade processes) for generation of power law distributions one can relate the nonlinearity of the age peaks to short spurts of accelerated magmatic activities due to “avalanches” (superplumes, slab breakoff etc.) occurred during episodic convection of the mantle. The exponents of the power law age distributions estimated from the age peaks can be used as an index to quantify the intensity of a singularity. The values of exponents calculated at all major age peaks from five global databases exhibit an episodic nature, with a mean duration of approximately 600–800 Myr. Both intensity of the zircon episodes and their duration for the interval from 3 Ga to 0.5 Ga depict a descending trend, which may signify mantle cooling. |
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