On application of fractal magnetization in Curie depth estimation from magnetic anomalies
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As an independent geothermal proxy, the Curie-point depth has important geodynamic implications, but its estimation from magnetic anomalies requires an understanding of the spatial correlation of source magnetization, mathematically characterized by a fractal exponent. In this paper, we show that fractal exponent and Curie depth are so strongly inter-connected that attempts to simultaneous or iterative estimation of both of them often turn out to be futile. In cases of true large Curie depths, the iterative “de-fractal” method has a tendency of overcorrecting fractal exponents and thereby producing erroneously small Curie depths and smearing out true geological trends. While true fractal exponent can no way be constant over a large area, a regionally fixed fractal exponent is better than any mathematical treatments that are beyond the limit of data resolution and the underlying physics.
KeywordsCurie depth Geothermal structure Heat flow Fractal magnetization Magnetic anomalies Inversion North America
This study is funded by National Natural Science Foundation of China (Grant Nos. 41776057, 41761134051, 41704086 and 91858213). Data mapping is supported by GMT (Wessel and Smith 1995). We thank anonymous reviewers for their critical but positive suggestions.
- Bryan TS (2008) The geysers of Yellowstone. University Press of Colorado, Niwot, pp 1–456Google Scholar
- Kucks RP, Hill PL, Ponce DA (2006) Nevada magnetic and gravity maps and data: a website for the distribution of data, U.S. geological survey data series, 234. https://pubs.usgs.gov/ds/2006/234. Accessed Aug 2017
- Li C-F, Wang J (2018) Thermal structures of the Pacific lithosphere from magnetic anomaly inversion. Earth Planet Phys 2:52–66Google Scholar
- Maus S, Gordan D, Fairhead D (1997) Curie-temperature depth estimation using a self-similar magnetization model. Geophys J Int 129:163–168. https://doi.org/10.1111/j.1365-246X.1997.tb00945.x CrossRefGoogle Scholar
- Maus S, Barckhausen U, Berkenbosch H, Bournas N, Brozena J, Childers V, Dostaler F, Fairhead JD, Finn C, von Frese RRB, Gaina C, Golynsky S, Kucks R, Luhr H, Milligan P, Mogren S, Müller D, Olesen O, Pilkington M, Saltus R, Schreckenberger B, Thébault E, Caratori Tontini F (2009G) EMAG2: a 2-arc-minute resolution earth magnetic anomaly grid compiled from satellite, airborne and marine magnetic measurements. Geochem Geophys Geosyst 10:Q08005. https://doi.org/10.1029/2009GC002471 CrossRefGoogle Scholar
- North American Magnetic Anomaly Group (NAMAG) (2002) Digital data grids for the magnetic anomaly map of North America, U.S. geological survey open file rep. 02–414. https://pubs.usgs.gov/of/2002/ofr-02-414/. Accessed Aug 2017
- Wang J, Li CF, Lei JS, Zhang GW (2016) Relationship between seismicity and crustal thermal structure in North China. Acta Seismol Sin 38(4):618–631Google Scholar