Analytical signals estimated from total field magnetic anomalies in eastern China and adjacent seas are found to be more accurate in detecting locations, depths, and boundaries of magmatic bodies than original magnetic anomalies. The depth distributions of magmatic sources differ significantly between different tectonic blocks. The North China Craton shows high analytical signal amplitudes and large lateral extensions, but the detected magmatic sources are mostly deeply buried at depths up to 10 km or larger. This indicates strong magmatic activities in the lower to middle crust of the craton from tectonic reactivation. Due to tectonic uplifting and magmatic intrusions, the Sulu-Dabie Orogen has mainly shallowly buried magmatic bodies with depths smaller than 5 km. The Yangtze Block shows predominantly deeply buried magmatic sources, but unlike North China Craton, the magmatic activities in the Yangtze Block appear to be very weak and the calculated analytical signal amplitudes there are very small. The Cathaysia Block and its offshore northeastward extension is dominated by relatively isolated and shallow magmatic bodies (mostly <5 km) that are mainly caused by the subduction of the Paleo-Pacific Plate in the late Mesozoic. Depths of magmatic sources in the East China Sea correlate well with basement uplifts and depressions caused by Cenozoic continental margin rifting. The Ryukyu Archipelago corresponds with a very quiet magnetic zone and shows deeply buried magmatic sources, and these observations support the reasoning that the Ryukyu Archipelago itself is not the volcanic arc from the subduction of the Philippine Sea Plate but is composed of accretionary materials and/or continental blocks separated from the Eurasian Plate by opening of the Okinawa Trough. The true volcanic arc is represented by a volcanic belt slightly to the west of the Ryukyu Archipelago.
张少武, 李春峰. 磁异常三维解析信号所揭示的中国东部及邻近海域岩浆岩特征[J]. 物探与化探, 2011, 35(3): 290-297.
ZHANG Shao-Wu, LI Chun-feng. MAGNETIC ACTIVITIES IN EASTERN CHINA AND ADJACENT SEAS REVEALED BY 3D ANALYTIC SIGNALS OF MAGNETIC DATA. Geophysical and Geochemical Exploration, 2011, 35(3): 290-297.
[3] Li C F, Chen B, Zhou Z. Deep crustal structures of eastern China and adjacent seas revealed by magnetic data [J].Sci in China :D,2009,52(7):984-993.
[4] Li C F, Zhou Z, Li J, et al. Magnetic zoning and seismic structure of the South China Sea ocean basin [J]. Mar Geophys Res,2008,29(4):223-238.
[5] Geological Survey of Japan and Coordinating Committee for Coastal and Offshore Geoscience Programmes in East and Southeast Asia (CCOP). Magnetic Anomaly Map of East Asia 1∶4 000 000 CD-ROM version, Digital Geoscience Map 2.CCOP,1996:(P-1).
[6] Ville J, Theorie et applications de la notion de signal analytique [M].Cables.Transmissions:2A,1948:61-74.
[7] Nabighian M N. The analytic signal of two-dimensional magnetic bodies with polygonal cross-section:Its properties and use for automated anomaly interpretation [J]. Geophysics, 1972, 37: 507-517.
[8] Nabighian M N. Additional comments on the analytic signal of two dimensional magnetic bodies with polygonal cross-section [J]. Geophysics, 1974, 39: 85~92.
[9] Nabighian M N. Toward a 3-dimensional automatic interpretation of potential-field data via generalized hilbert-transforms-fundamental relations [J]. Geophysics, 1984, 49: 780~786.
[10] Roest W R, Verhoef J, Pilkington M. Magnetic interpretation using the 3-D analytic signal [J]. Geophysics. 1992, 57: 116~125.
[11] Pilkington M, Keating P. The relationship between local wavenumber and analytic signal in magnetic interpretation [J]. Geophysics. 2006, 71(1): 1-3.
[12] Roest W R, Pilkington M. Identifying remanent magnetization effects in magnetic data [J]. Geophysics. 1993, 58(5): 653-659.
[13] Debeglia N, Corpel J. Automatic 3-D interpretation of potential field data using analytic signal derivatives [J]. Geophysics. 1997, 62(1): 87-96.
[14] Li X. Understanding 3D analytic signal amplitude [J]. Geophysics, 2006, 71: 13-16.
[15] Briggs I C. Machine contouring using minimum curvature [J]. Geophysics, 1974, 39: 39-48.
[16] Clement B M. Dependence of the duration of geomagnetic polarity reversals on site latitude [J]. Nature, 2004, 428: 637-640.
[17] Jackson A. Still Poles Apart on Reversals? [J].Nature , 1992, 358: 194-195.
[18] Glatzmaier G A, Coe R S. Magnetic polarity reversals in the core [M].Gerald Schubert.Treatise on Geophysics:8, Elsevier Science,2007:283-297.
[19] Blakely R J, Simpson R W. Approximating edges of source bodies from magnetic or gravity anomalies [J]. Geophysics,1986, 51(7): 1494-1498.
[23] Li C F,Zhou Z,Ge H,et al. Correlations between erosions and relative uplifts from the central inversion zone of the Xihu Depression [J].East China Sea Basin Terres Atmos Ocean Sci, 2007, 18:757-776.
[24] Li C F,Zhou Z,Ge H,et al. Rifting process of the Xihu Depression, East China Sea Basin [J].Tectonophysics, 2009, 472: 135-147.
[26] Lee G H, Kwon Y I, Yoon C S, et al. Igneous complexes in the eastern Northern South Yellow Sea Basin and their implications for hydrocarbon systems [J]. Marine and Petroleum Geology, 2006, 23(6): 631-645.