Gondwana Research 22 (2012) 1047–1059

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Lateral variation of the strength of lithosphere across the eastern North China Craton:New constraints on lithospheric disruption

Zhongjie Zhang a,⁎, Jing Wu a, Yangfan Deng b, Jiwen Teng a, Xi Zhang a, Yun Chen a, Giuliano Panza c,d,e

a State Key of Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, 100029, Chinab Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, 510640, Chinac Department of Mathematics and Geosciences, University of Trieste, Via Weiss, I-34127 Trieste, Italyd International Centre for Theoretical Physics, SAND group, I-34151 Trieste, Italye Institute of Geophysics, China Earthquake Administration, Beijing, 100080, China

⁎ Corresponding author.E-mail addresses: zhangzj@mail.iggcas.ac.cn (Z. Zhan

1342-937X/$ – see front matter © 2012 International Adoi:10.1016/j.gr.2012.03.006

a b s t r a c t

a r t i c l e i n f o

Article history:Received 22 November 2011Received in revised form 5 March 2012Accepted 6 March 2012Available online 6 April 2012

Handling Editor: A. Aitken

Keywords:Lithospheric strengthArchean North China CratonDelaminationUnderplatingThermal erosion

The structure and rheology of the lithosphere can provide constraints on our understanding of thegeodynamic processes in the Earth's interior. The lateral heterogeneity of the strength and rheologicalstructure of the lithosphere are closely correlated with the lateral variation in the thickness of theseismogenic layer. It is still unclear how geodynamic process(es) are linked with this lateral variation in thegeophysical properties of the lithosphere. In order to understand the possible links between geodynamicalprocess and lateral variation of lithosphere strength, we compiled crustal velocity and density structure, theelastic thickness of the lithosphere, and the temperature field, and then construct a northeast–southwesttransect of the lithosphere across the eastern part of the North China Craton (NCC) with an overall length of1660 km. Along the lithosphere-scale transect, we observe that (a) a thinner (80–120 km) Archeanlithosphere at the North China Plain (NCP), (b) a lateral variation of the seismogenic brittle layer, which isabout 15 km thick beneath the Qinling-Dabie orogenic belt (QDOB) and the Yanshan orogenic belt (YSOB),and about 25 km thick under the NCP. Together, these characteristics represent an excellent illustration of thescale of geodynamic processes necessary to accommodate lateral variations in lithospheric strength and thecontribution of these to the mechanism of disruption of the Archean NCC. The thick seismogenic layerbeneath the NCP can be formed due to: (1) deeper fault penetration beneath the NCP than beneath the QDOBand the YSOB; (2) the thick brittle layer is preserved after delamination of the lower part of the thickenedcrust; (3) thickening by changes to brittleness of the brittle/ductile transition layer (BDTL). With constraintsof above mentioned geophysical properties of the lithosphere, we propose that (1) only the first and thirdprocesses can successfully explain the lateral variation of the thickness of the seismogenic layer across theeastern part of the NCC, and (2) the extensional tectonics and thermal erosion (notwithstanding thedelamination of the lithosphere) play their significant roles in the disruption of the NCC.

© 2012 International Association for Gondwana Research. Published by Elsevier B.V. All rights reserved.

1. Introduction

It is the strength and rheology of the lithosphere that controls itsdeformation; hence, a proper understanding of these properties isessential if the consequences of any such deformation are to bepredicted (Watts and Burov, 2003; Brandmayr et al., 2010). Threemodels are commonly used to describe the rheological structure of thelithosphere: (1) the jelly sandwich (JS)model, which is characterised bya weak middle and lower crust sandwiched between a strong uppercrust and a strong lithospheric mantle (Goetze and Evans, 1979; Braceand Kohlstedt, 1980;Molnar and Chen, 1983), (2) the crème brulée (CB)model, in which the strength of the continental lithosphere lies entirelywithin the crust, because the uppermost part of the upper mantle is

g), panza@units.it (G. Panza).

ssociation for Gondwana Research.

significantlyweaker as a result of its high temperature and the presenceof fluids (Jackson, 2002; Burov and Watts, 2006; Frezzotti et al., 2009),and (3) the banana split (Brudy et al., 1997), in which there is aconcentration of weakness within the major fault zones that aredistributed throughout the entire depth of the lithosphere.

Each of these models has been used to describe the rheologicalstructure of the lithosphere and its characteristic deformation(Urgmann and Dresen, 2008). The validity of each may be assessedin terms of the distributions of the focal depths of the earthquakesand the effective variation in elastic thickness that occurs in anyparticular continent (Maggi et al., 2000). Numerous studies haveshown that, in different parts of the world, shallow seismic activity isconcentrated in different ranges of depth. Molnar and Chen (1983)found that earthquakes that occur on continents are confined to theupper part of the crust, whose brittle nature ensures that earthquakesare relatively common here. Foster and Jackson (1998) provided

Published by Elsevier B.V. All rights reserved.

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evidence that in East Africa, India, and Himalayas, earthquakes occurthroughout the entire crust, although no deeper than the Moho. Weherein describe a remarkable lateral variation in the thickness of theseismogenic layer through the analysis of both seismic activity andthe release of seismic energy along a 1660 km long northeast–southwest transect across the eastern part of Archean North ChinaCraton (NCC) (Fig. 1), where a considerable degree of lithosphericremoval is evident. Through the joint analysis of density, seismicvelocity and temperature, we herein provide data that couldcontribute to our understanding of the relationship existing betweenthe geodynamic process of lithospheric removal and the lateralvariation of lithospheric strength in the NCC.

2. Tectonic properties of the Archean North China Craton

Generally speaking, Archean cratons are characterised by a cold,thick, structurally complex lithosphere, whose density is balanced bytheir refractory composition that gives rise to their chemicalbuoyancy. The lack of any high elevations or free-air gravityanomalies over cratons suggests that, provided the density of themantle is laterally homogeneous, they are in isostatic equilibriumand have a density profile similar to that of off-craton regions. Thepresence of thick, refractory and anhydrous peridotite residues

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Fig. 1. The brown line is the boundary of the North China Craton (NCC), which is further suEastern Block (EB) by two black lines (Zhao et al., 2010). Inset map shows geographic posiwhite and the boundaries of political provinces are shown by continuous black lines; P1, PChina Craton (NCC) (Li and Mooney, 1998; Zhang et al., 2011b) and the rectangle delimits

beneath Archean crustal regions is widely held to be responsible forthe inherent stability of Archean cratons (Durrheim and Mooney,1994; Griffin and O'Reilly, 2003). The Archean NCC is one of the oldestin existence (about 3800 Ma, Fan and Menzies, 1992), and it hasendured the collision/convergence with the Yangtze plate to form theQDOB at its southern boundary (Li et al., 1993, 2007; Zhao and Zhou,2009), and with the Paleo-Asian oceanic plate to form the YSOBtopography to the north (Zhai et al., 2007; Diwu et al., 2011; Genget al., 2012; Zhai and Santosh, 2011) (top panel of Fig. 2).

The Archean NCC is characterised by a thick, diamond-bearinglithospheric keel, and behaved as a stable lithospheric blockthroughout the Proterozoic and Palaeozoic (Albee and Cullins,1975; Li et al., 1996; Kusky et al., 2003; Rogers and Santosh, 2004).During the Mesozoic, the eastern part of the NCC experienced theeffects of tectonic activity, as evidenced by voluminous magmatismand widespread deformation (Liu et al., 1992; Xu et al., 1998; Wuet al., 2003, 2005; Zhang et al., 2003; Zhao et al., 2003, 2010; Huangand Zhao, 2004; Zhai et al., 2007; Xu et al., 2008; Kusky, 2011; Menget al., 2011). At present, the NCC is affected by the removal of a layerof lithospheric material 80-100 km thick (Menzies et al., 1993; Fanet al., 2000; Chen et al., 2008), and the lithosphere of the easternportion of the NCC can now be classified as transitional (Zhang et al.,2003; Menzies et al., 2007; Wang et al., 2009; Zhang et al., 2009a,

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bdivided into three parts: Western Block (WB), Trans-North China Orogen (TNCO) andtion of the NCC in China continent (Zhang et al., 2011b). The fault belts are outlined in2, P3 (violet lines) identify three wide-angle seismic profiles carried out in the Norththe study area featured with our 1660 km lithosphere-scale transect.

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2009b). Mantle xenoliths carried by Cenozoic basalts have arelatively fertile bulk composition, not been depleted by meltextraction (Menzies et al., 1993; Griffin et al., 1998, 1999; Xu et al.,1998; Zheng et al., 2001, 2006; Wu et al., 2003; Xu et al., 2004; Lee,2006).

The disruption of the lithosphere of the NCC has attractedparticular attention (Zhai et al., 2007; Zhao et al., 2007; Santoshet al., 2010), because it is currently the only location at which anArchean craton is known to have developed a continental root in theArchean, and has subsequently lost half of that root in more recenttectonic activity. In general, the lithosphere can be thinned bydelamination, thermal erosion (from bottom to top) and decompres-sion (from top to bottom). The lithospheric removal of the mantle,and its transitional properties (from continental to oceanic), may beattributed either to lithospheric delamination (Wu et al., 2003; Gaoet al., 2004), or to thermal erosion (Zheng et al., 2003), or to both ofthese mechanisms (Zhu and Zheng, 2009). Although the evidence forongoing tectonic activity in this Archean craton may be seen clearly inthe strong earthquakes of 1966 (Ms 6.8 Xingtai), 1976 (Ms 7.8Tangshan) and 1998 (Ms 6.2 Zhangjiakou), the actual response of thecrust to lithospheric disruption is still unclear (Zhang et al., 2011a).

In order to contribute to the understanding of the ongoingtectonic processes involved, we assembled the results obtained fromthree north–south trending wide-angle seismic profiles, and fromsome other geophysical experiments, conducted on a 1660 km longnortheast–southwest transect across the eastern part of the NCC.Together with the study of the distribution of seismicity within thelithosphere, these data provide an excellent resource useful tounderstand the rheological structure of the lithosphere and itspotential links with the geodynamic processes that are responsiblefor the lithospheric disruption.

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Fig. 2. (a) Top: Topography along the 1660 km long northeast–southwest transect across thecrustal velocity structures are compiled by interpreting the results from three wide-angle sdepth obtained from gravity inversion① (Yuan, 1996); geothermal inversion② (Zang et al.,al., 2006); and MT ⑤ (Wei et al., 2006). XMOB: Xinjiang-Mengulia Orogenic Belt. The lirepresents the depth to which the cumulative seismic release energy reaches 80% of the tota41°N may well be due to the inadequacy of the Vp-transformed density used to construct talong the transects. SL indicates the seismogenic layer (within which 80% of the seismic endiscontinuity. The thin black line marks the depth separating SL and NSL in the crust. (d(e) Distribution of log N versus h. The numbers in each cell show the value of the max(f) Distribution of log E/min(log E) versus h (see Panza and Raykova, 2008 for more details)the QDOB and YSOB, and at about 30 km under the NCP. The yellow line shows the depth aused to separate the SL from the NSL.

3. Crustal velocity structure and lithospheric thickness along thenortheast–southwest transect

3.1. Crustal structure

In view of the sequence of disastrous earthquakes that occurred inNorth China in the last few decades (see Section 2), since severalyears there is a great interest for the crustal structure of the NCC. Thishas led to a number of wide-angle seismic experiments, including theLeting-Zhangjiakou profiling in 1976 (Zeng et al., 1988). The highconcentration of wide-angle seismic profiles (Chinese StateSeismological Bureau (CSB) and Deep Exploration Group (DEG),1986; Li and Mooney, 1998; Zhang et al., 2011a) provides thenecessary background for the proper understanding of the crustalstructure and the lithospheric evolution of the craton. In the easternpart of the NCC, there are three wide-angle seismic profiles. All ofthem approximately follow a north–south axis, namely (1) theYichuan-Shiyan (Cao et al., 1994) and Anxin-Kuangchen profiles(Zhang et al., 2011b) (Profile 1 in Fig. 1), (2) the Zhengzhou-Jinanprofile (Zhang et al., 1994) (Profile 2 in Fig. 1), and (3) the Cangzhou-Zuoqi profile (Ma, 1989) (Profile 3 in Fig. 1). According to the existinginterpretations of these three profiles, the crust may be divided intoupper, middle and lower. Profile 1 extends across the YSOB, whichforms the northern margin of the NCC (Cao et al., 1994), and wherethe crustal thickness varies between 30 and 35 km. The P-wavevelocity (Vp) varies from 5.8 to 6.2 km/s in the upper crust (at depthsranging from 0 to about 15 km), from 6.1 to 6.3 km/s in the middlecrust (from the bottom of the upper crust to a depth of about 26 km),and from 6.5 to 6.9 km/s in the lower crust (down to a depth of about35 km). Profile 2 is located in the centre of the eastern part of the NCC(Zhang et al., 1994). Along this profile, the thickness of the crust

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NCC. (b) Geophysical structure along the lithosphere-scale transect across the NCC. Theeismic profiles (Li and Mooney, 1998; Zhang et al., 2011b). Lithosphere bottom (LAB)2002); receiver function imaging③ (Chen, 2010); surface wave tomography④ (Zhu etne that separates the seismogenic layer (SL) from the non-seismogenic layer (NSL)l energy in the crust. The large lithospheric thickness inverted from the gravity data athe initial model in a tectonically active area. (c) Distribution of earthquakes (red dots)ergy is released) and NSL indicates the BDTL, the layer between the SL and the Moho) Distribution of log E/Emax versus h (see Brandmayr et al., 2010 for more details).imum of each histogram when the earthquakes are sorted in 4 km depth intervals.. The distribution of seismicity with depth clearly tends to zero at about 10 km beneatht which the release of the 80% of the seismic energy is reached and it is conventionally

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1050 Z. Zhang et al. / Gondwana Research 22 (2012) 1047–1059

reduces to about 30–33 km, with a P-wave velocity that variesbetween 5.8 and 6.4 km/s in the upper crust (down to a depth ofabout 17 km), between 6.4 and 6.5 km/s in the middle crust (to adepth of about 25 km), and between 6.5 and 7.4 km/s in the lowercrust (down to the Moho at a depth of about 33 km). Profile 3 crossesthe QDOB (Ma, 1989). The thickness of the crust is relatively constant(30–33 km), with a Vp between 6.0 and 6.25 km/s in the upper crust(to a depth of about 17 km), between 6.1 and 6.4 km/s in the middlecrust (to a depth of about 25 km), and between 6.25 and 7.3 km/s inthe lower crust (to a depth of about 33 km).

Fig. 2 shows the crustal velocity, which was obtained by inter-preting and combining the results of the three wide-angle seismicprofiles described above, throughout the lithosphere-scale transectused in the present study, which cuts across the eastern part of theNCC. The crustal thickness is fairly constant at around 33–35 km,although small undulations occur in the Moho between the QDOBand the central part of the North China Plain (NCP; see Fig. 2). Thethickness increases gradually as the profile passes beneath theYSOB.

3.2. Lithospheric thickness

Numerous studies of the lithosphere have provided evidence of itsvariation in thickness within the NCC, based on results obtained fromsurface wave tomography (Zhu et al., 2002, 2006), gravity inversion(Fang, 1999), receiver function imaging (Chen et al., 2008, 2010),thermal inversion (Zang et al., 2002), and magneto telluric (MT)measurements (Wei et al., 2006). These results are summarised inFig. 2b. Along the transect, the lithospheric thickness varies between70 and 140 km, according to the results of the inverted data obtainedfrom surface wave dispersion tomography (Zhu, et al., 2006) andtraveltime tomography (Huang and Zhao, 2004). This finding iswithin the range of 70–130 km determined by geothermal modelling(Zang et al., 2002), within the range of 80–130 km determined usinggravity inversion (Fang, 1999), and within the range of 70–110 kmdetermined using receiver function imaging (Chen et al., 2010). Theuse of MT imaging yields a rather different range from 55 to 80 km(Wei et al., 2006), which instead of being seen to be an indication ofthe top of asthenosphere, has instead been interpreted as signaling

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the presence of magma or partial melting of the lithosphere at thesedepths (Zhang et al., 2011b). This finding is probably connected withthe occurrence of a double lithosphere, but the deeper of the two iseither not generally seen in the images or it is poorly resolved by theMT data (Adam and Panza, 1989). The presence of such a layer mayprovide evidence of the residual inland propagation of the Yellow searifting, caused by the back arc of the subduction that extends fromJapan to Taiwan (Zhai et al., 2007). A common characteristic of all theconceptual models described above (Fan and Menzies, 1992; Xu,2001; Gao et al., 2004; Xu et al., 2004, 2008; Wu et al., 2005; Zhenget al., 2006; Fan et al., 2007; Zhu and Zheng, 2009; Zhang et al., 2011a,2011b, 2011c, 2011d) is the pronounced lithospheric removal that, incomparison with other parts of the profile, is particularly evidentbeneath the central segment of the lithosphere-scale transect acrossthe eastern part of the NCC.We herein focus on the lateral variation ofthe lithospheric thickness as determined by surface wave tomogra-phy, which is consistent with the results of gravity inversion.

In general, the lithospheric thinning beneath the northern part ofthe NCC is more pronounced than it is beneath its southern part.Tectonic processes such as lithospheric delamination (Gao et al.,2004; Wu et al., 2005), thermal erosion of the lithospheric keel(Zheng et al., 2006; Xu et al., 2008), and the northward subduction ofthe Yangtze and the southward subduction of the Paleo-AsianOceanic plate (Fan et al., 2007; Zhai et al., 2007; Zhang et al., 2011a,2011b, 2011c, 2011d), could all be responsible for the thinning of thelithosphere of the NCC. The greater thickness of the lithosphere to thesouth could be an effect of the Himalayan orogeny (Fan and Menzies,1992; Liu et al., 2004), and the thinning of the lithosphere to thenorth could be correlated with the formation of Pacific back arcs (Zhuand Zheng, 2009).

4. Seismic activity and lithospheric rheology alongthe northeast–southwest transect

Whether or not the lithosphere of the NCC is disrupted as aconsequence of the delamination of the lithospheric root or as a resultof thermal removal, it is necessary to consider the flux of material inthe deeper crust, which may be inferred from the rheologicalstructure of the lithosphere. The construction of a rheological profilerequires the knowledge of several parameters, like strain rate andtectonic style, that are not generally available. In response to thelithospheric disruption of the Archean NCC, the lower crust there ischaracterized by a relatively high heat flow and the consequentattenuation of its brittleness, results in a relatively low release ofseismic energy. The rheological properties of the lower crust may bequantified using the scheme proposed by Panza and Raykova (2008),i.e., considering the distribution of the depth of the hypocentres (N)and the seismic energy released, E, as a proxy for the rheology,keeping in mind that lack of seismicity does not necessarily implythat the lithosphere is locally more rigid (it may indicate, for example,that there is not active tectonics or that the strain rate is locallylower). All the seismic events reported during the period 1980–2010in the Catalogue of the China Earthquake Network Centre (CENC)were considered in a total of 12 contiguous cells, each 1° by 1° in size(Fig. 2a), along the northeast–southwest transect across the NCC. Thenational seismic network commonly uses the Geiger method (Geiger,1912) to locate the events, while the hypo2000 (Klein, 2002) andhypoDD (Waldhauser and Ellsworth, 2000) codes are used by theprovincial seismic networks. The precision of the location of seismicevents is commonly scaled either as level A (having an uncertaintyof focal depth Δ≤5 km), B (5bΔ≤15 km), C (15bΔ≤30 km), orD(Δ>30 km). We herein limit our analysis to events of level A.

Fig. 2 shows the distribution of earthquake's depth (h) (Fig. 2c),log E/Emax versus h (Fig. 2d), log N versus h (Fig. 2e) and logE/min(logE) versus h (Fig. 2f), for each of the 12 cells along the transect.Seismic energy (E) is computed from the magnitude of an earthquake

(Ms) using the relationship logE=11.8+1.5 Ms (Panza and Raykova,2008; Zhang et al., 2011c; Wu and Zhang, 2012). A synoptic rep-resentation of themechanical properties of the uppermost 60 km of thelithosphere, together with the seismicity, is shown in Fig. 2c, d, e, f. Boththe number of earthquakes (N) and the energy released (E) areparticularly high in the zone 35°–40°N, which is located in the centre ofthe NCC, and point to a concentration of seismic activity beneath theNCP, in the central part of the transect. The QDOB and the YSOB arerelatively less seismically active, and the hypocentres there are muchshallower than they are in the NCP.

The assumption of a classic Coulomb/Byerlee (brittle/ductile)transition is valid beneath the QDOB and the YSOB, where therheological and mechanical properties of the rocks follow Sibson'slaw in the upper crust and a power law creep in the lower crust(Sibson, 1977). The release of earthquake energy is thus concentratedin the upper crust (b15 km) in the QDOB and the YSOB, whereasbeneath the NCP, the release of energy takes place throughout thecrust. In recognition of the depth uncertainty of earthquake location,we take the line which separates the seismogenic layer with 80% oftotal release of earthquake energy. In this way, the thickness ofseismogenic layer is about 15 km beneath the QDOB and the YSOB,and about 25 km beneath NCP.

5. Crustal density structure along the transect

The Bouguer gravity anomaly (Yuan, 1996) varies along thetransect from −100 to −20 mGal beneath the southern part of theprofile, then it rises to between −20 and 20 mGal between km 500and km 1100 (upper panel, Fig. 3). It is relatively constant at around0 mGal from km 1200 to the northern end of the northeast–southwest transect. The variation of the Bouguer gravity anomalysuggests a strong lateral variation in the density of the crust and evenof the lithospheric mantle. In order to obtain the crustal densitymodel by (linear) inversion, the initial density model was obtained byconverting the P-wave velocities into densities using the linearvelocity–density relationship ρ=a+bVp, where a=0.0546 g/cm3,and b=0.3601 g.s/km.cm3 (Christensen and Mooney, 1995, Table 7).The distribution of crustal density that was obtained after inversion isshown in Fig. 4. The difference between the gravity anomalycalculated from our final model and the observed gravity anomaly isless than 5 mGal (lower panel of Fig. 4). Above the crystallinebasement, the density is about 2.4 g/cm3. In the seismogenic layer itvaries in the range 2.7–2.8 g/cm3. In the nonseismogenic layer it isabout 3.0 g/cm3. In the lithospheric mantle it is 3.3 g/cm3. Wepostulate the existence of a zone of low density (3.2 g/cm3) beneaththe central segment of the northeast–southwest transect, in order tofit the observed Bouguer anomaly (Fig. 4) within the parameterisa-tion used herein. The small-scale residual Bouguer gravity anomalies(b5 mGal) (lower panel in Fig. 4) may be attributed to local, shallowgravity anomaly bodies or faults, and are not discussed further.

6. Temperature distribution within the lithosphere

The pattern of heat flow in the NCC has received considerableattention over the last 20 years (Chen, 1988; Hu et al., 2001; Wang,2001; Zang et al., 2002). Along the southwest–northeast transect, themeasured surface heat flow varies between 55 and 70 mW/m2 (upperpanel in Fig. 4). A slightly higher heat flow (65–70 mW/m2) has beenobserved in the NCP (the central part of the profile). The temperaturefield was calculated down to a depth of 55 km along the profile using afinite element model (lower panel, Fig. 4), by making use of a two-dimensional numerical solution of the steady-state heat conductionequation. The solution was constrained by surface and basal heat flow,and assumed a temperature-dependent thermal conductivity (Cermakand Bodri, 1986) and heat production (Rybach and Buntebarth, 1984;Cermak and Rybach, 1989) in the continental crust.

Fig. 3. Average seismic P-wave velocity in the seismogenic layer (BL, brittle portion ofthe crust) and nonseismogenic layer (DL, ductile portion of the crust) along the1660 km transect across the NCC.

1052 Z. Zhang et al. / Gondwana Research 22 (2012) 1047–1059

Given the uncertainties associated with the measurements ofsurface heat flow, the uncertainties of the calculated temperaturefield are generally estimated to be about 15% (Pasquale et al., 1990).In the upper crust, the temperature field is correlated with theregional variation in surface heat flow, whereas in the lower crust it isthe mantle heat flow that controls the temperature field. Thetemperatures at the Moho vary from 500 to 600 °C beneath the

Fig. 4. Upper panel: observed Bouguer gravity anomaly along the transect together with thepart of the upper mantle; central panel: density structure of the crust and uppermost part

QDOB at the southern end of the southwest–northeast transect (fromkm 0 to km 450) to a local maximum of about 630 °C beneath thecentral segment under the NCP. Beneath the YSOB (from km 1000 tokm 1600), the temperature at the Moho varies between 500 and600 °C. Obviously, the temperature structure is consistent with thelateral variation of lithosphere's thickness: the temperature is higherbeneath the NCP where the thinning of lithosphere is remarkable.

7. Discussion

7.1. Lateral variation in lithospheric strength across the eastern NCC

7.1.1. Seismogenic layerWe defined the NS lateral variation of the lithospheric properties

(Fig. 1) by combining (a) a compilation of the crustal velocity modelsderived from dense wide-angle seismic profiling (Chinese StateSeismological Bureau (CSB) and Deep Exploration Group (DEG),1986; Li and Mooney, 1998; Zhang et al., 2011b), (b) the lithosphericthickness as determined from teleseismic receiver function imaging(Chen et al., 2008, 2010) and surface wave tomography (Zhu et al.,2006), (c) the crustal density structure (extended to the uppermostpart of the upper mantle) from the inversion of the gravity anomaliesmodel (Yuan, 1996), and (d) an indicator of the lithospheric rheologyafforded by the distribution of the hypocentres and by the re-lationship between the seismic energy released and the depth (Panzaand Raykova, 2008). Four major characteristics can be seen along thetransect: (1) the crustal thickness is relatively constant at around40 km; (2) the lithosphere becomes noticeably thinner, being about80 km beneath the central segment compared with a thickness of

calculated anomaly of the model of the final crust and of the density of the uppermostof the upper mantle along the transect; lower panel: residual gravity anomalies.

1053Z. Zhang et al. / Gondwana Research 22 (2012) 1047–1059

about 140 km under the southern segment and the northern margin;(3) a classic Coulomb/Byerlee (brittle/ductile) transition law is validbeneath the southern and the northern segments of the transect,where the rheological and mechanical properties of the rocks followSibson's (1977) law in the upper crust and a power law creep in thelower crust; and (4) the earthquake energy is distributed throughoutthe whole crust beneath the central portion of the transect. Thesecharacteristics are inconsistent with the general observation that theruptures and earthquakes seen in many stable continental regions areconfined within the upper one third (0–10 km) and/or the lower onethird (20–35 km) of the crust, while the middle crust (10–20 km)tends to be aseismic (Klose and Seeber, 2007), and it is usuallyconsidered the brittle–ductile transition layer (BDTL) (Brown andRushmer, 2006). In the profile described herein, the earthquakes aredistributed within the middle part of the crust, and even within thewhole crust beneath the central part of the transect (Fig. 2c).

The variation in the distribution of hypocentres and the structure ofthe lithospheric rheology are usually attributed to a number of factors,including the intracrustal boundaries, differences in the frictional andrheological properties, the heat flow, the strain rates, and the tectonicforces (Klose and Seeber, 2007). The lateral variation of the thickness ofthe seismogenic layer described herein may be explained by assumingthat (a) the intracontinental deformation is focused within a relativelythin and hot (and therefore weak) lithosphere, while the interior of thecraton is strong enough to inhibit tectonism, and (b) the differences inlithospheric rigidity, structure, and composition between the stablecratons and the sites of intracontinental deformation are not transient,and may in some cases (e.g. Australia) be preserved for at least 500 Ma(Pe´rez-Gussinye´ et al., 2007). However, the remarkably thin (about80 km) lithosphere (which corresponds to the thermal removal of alayer of lithospheric mantle material 80–120 km thick) beneath theinterior of the NCC demonstrates that the Archean craton is not stable

Fig. 5. Upper panel: observed heat flow data along the transect; central panel: values calcucolumns are chosen in the calculation of lithosphere strengths beneath QDOB, the NCPdistributions within the three blocks (a), (b) and (c) of the geothermal model.

and that the rigidity of the lithosphere has not been well preservedover time. The thick seismogenic layer beneath theNCP could be due to:(1) the deeper penetration of faults beneath the NCP than beneaththe QDOB and the YSOB; (2) the delamination of the lower part ofthe thickened crust, while the thick brittle layer is preserved; and(3) changes in the brittleness of the 15–25 km thick brittle/ductiletransition layer (BDTL).

7.1.2. Rheological yield stress envelopeThere has been much debate recently concerning the long-term

strength of continental lithosphere. In one model, dubbed jellysandwich (JS), the strength resides in the crust and mantle, while inanother, dubbed creme brulee (CB), the mantle is weak and thestrength is limited to the crust. In order to evaluate the applicabilityof these two models to the eastern NCC, we consider three sites(dark triangles in Fig. 6b) beneath QDOB, the YSOB and the NCP,respectively. At these sites we calculate the rheological yield stressenvelope considering crustal density structure (Fig. 5) and temper-ature distribution (Fig. 4). In the calculation of lithosphere strength tothe depth of 55 km (Fig. 6c), the brittle regime for most rocks can beadequately described by a linear frictional failure criterion (Sibson,1977):

σ1−σ3 ¼ γρgz 1−δð Þ ð1Þ

Where, σ1 and σ3 are maximum and minimum principal stresses,respectively; γ is a parameter depending on the type of faulting, withvalues of 3, 1.2 and 0.75 for thrust, stike-slip and normal faulting,respectively; ρ is material density; g is the acceleration of gravity; z isdepth and δ is the pore fluid factor (ratio of pore fluid pressure tooverburden pressure). The most uncertain parameter is the pore fluidpressure. In the absence of information on it, we assume that the pore

lated from the final model of temperature distribution (Wang, 2001); the translucentand the YSOB, respectively, shown in Fig. 6b–d. Lower panel: temperature–depth

Fig. 6. Rheological yield stress envelopes (YSE) for (a) the craton JS (top of Fig. 6a), JS (center, Fig. 6a) and the CB (bottom, Fig. 6a) (Burov, 2011); (b) the QDOB; (c) the NCP and(d) the YSOB. Where, the YSEs for the QDOB, the NCP and the YSOB correspond to strain rate of 10−14, 10−15, 10−16 s−1, respectively.

1054 Z. Zhang et al. / Gondwana Research 22 (2012) 1047–1059

fluid pressure is hydrostatic and take a typical value of δ=0.4. Sincelithospheric density is inhomogeneous, Eq. (1) can be rewritten as

σ1−σ3 ¼ γg 1−δð Þ∫z0ρ zð Þdz ð2Þ

In the ductile regime, rocks deforms in a manner of power-lawdislocation creep (Ranalli, 1995). The experimentally determinedflow law for most crustal and upper mantle rocks results in a creepstrength given by (Kirby, 1983):

σ1−σ3 ¼ εA

� �1=nexp

QnRT

� �ð3Þ

Where, ε is strain rate; A is power-law stress constant; n is power-law exponent; Q is activation energy; R is gas constant and T isabsolute temperature. The values of the parameters used in thecalculation are given in Table 1. Fig. 6 displays the rheological yieldstress envelopes obtained for the strain rate of 10−14, 10−15,10−16 s−1, respectively, beneath the QDOB, the NCP and the YSOB.Our calculation results in Fig. 6 support the conclusion that the higherthe strain rate is, the larger the differential stress required in Eq. (3)(Burov, 2011).

From the rheological yield stress envelopes (YSEs), shown in Fig. 6,we can find the different patterns of the structure of lithosphererheology beneath the QDOB, the NCP and the YSOB. All these YSEs showstrong upper mantle, especially beneath the QDOB and the YSOB,contrary to the CB model where the upper mantle is weak. Thedifference between the YSEs, in themiddle and lower crust of YSOB andQDOB, may reflect the differences between the Yangtze and thesouthern NCC continent–continent collision at the southern margin ofNCC, and the ocean–continent collision between the Paleo Asia Oceanplate and the northern margin of the NCC. From Fig. 6, we can see thatthe YSE beneath the QDOB is consistent with the JS model, where thetopmost upper mantle is very strong, but the middle/lower crust isweak (or wet). The YSE beneath the YSOB suggests the presence of a

Table 1Parameters used in calculation of yield strength envelope (YSE).

Composition Pre-exponentialstress constant,A (MPa−ns−1)

Power lexpone

Upper crust Wet quartzite 3.2×10−4 2.3Lower crust Dry diabase 2.0×10−4 3.4Lithosphere mantle Dry olivine 1.0×104 3.0

stronger (or dryer) middle/lower crust compared to the QDOB one. TheYSE beneath the NCP looks to be close to the craton JS model. In anutshell, the JS model is suitable in North China Craton, even thoughthere are still differences among theQDOB, theNCP and theYSOB,whilethe CB model is valid in other tectonic regions, such as the continentalshield in North India (Jackson, 2002). Furthermore the YSE beneath theQDOB indicates the presence of a brittle upper crust and of a strongupper mantle. The YSE pattern is consistent with two peaks in theearthquake distribution versus depth (Molnar and Chen, 1983) whilethe earthquakes occur only in the topmost 10 km of the crust. In ourcalculation of YSEs for the QDOB, the NCP and the YSOB, the mantle isconsidered to be dry. If a wet upper mantle is considered in thecalculation for the specific tectonic unit, upper mantle will be weak andCB model will be suitable for this tectonic unit. The pertinence of the JSand CB models is strongly dependent upon the amount of fluid in theupper mantle, about which we do not have strong constraints from thecurrent geophysical experiments (Teng et al., 1982, 1985, 2008, 2010;Chinese State Seismological Bureau (CSB) and Deep Exploration Group(DEG), 1986; Li and Mooney, 1998; Bai et al., 2007; Chen et al., 2008,2010; Zhu and Zheng, 2009; Tian et al., 2011; Ai and Shen, 2011; Zhanget al., 2000, 2011a, 2011b). Anyhow, the results both of seismogeniclayer and the rheological yield stress envelopes illuminate the lateralvariation of lithosphere rheology strength across the eastern NCC.

7.2. Origin of the thick seismogenic layer beneath the NCP: deeper faultpenetration, conservation or thickening?

The deepening of the earthquake foci from about 15 km in thenorthern and southern segments to about 25 km in the centralsection may be seen clearly. Accordingly, the lithosphere is only about80 km thick in the central segment compared with a thickness ofabout 120–150 km in the northern and southern sections (Fig. 2). Athick seismogenic layer is found in the NCP where the lithosphere ismuch thinner, while a relatively thin seismogenic layer characterisesthe two orogenic belts (QDOB, YSOB) at the southern and northern

awnt, n

Activation energy,Q (KJ mol−1)

Reference

154 Kirby and Kronenberg, 1987260 Kirby, 1983; Burov, 2007520 Chopra and Paterson, 1984; Burov, 2007

1055Z. Zhang et al. / Gondwana Research 22 (2012) 1047–1059

margins of the NCC. The complex lithospheric structure seen through-out the study area may well result from the complex geodynamics ofits past. Nevertheless, given our hypothesis that the lithosphericstructure and rheology were initially relatively laterally homoge-neous, our observations provide the opportunity to perform a re-construction of (a) the possible tectonic processes responsible ofthe lateral transition to the two different rheological structures, and(b) the contribution of these processes to the disruption of thelithosphere of the NCC.

We focus on the thickening of the seismogenic layer beneath theNCP in relation to the observed behaviour at the two orogenic belts atits southern and northern margins. The thickness of the seismogeniclayer in the NCP (25 km) may be explained by either (1) deeper faultpenetration beneath NCP than beneath the QDOB and the YSOB, or(2) the conservation of the old thick brittle upper crust, or (3) thethickening of the brittle layer, or (4) both (2) and (3), due to someparticular tectonic process, such as the local weakening of the BDTLand the subsequent concentration of stress in the stronger elasticcrust, around and above the zone of decreased strength (Fig. 7). Sucha mechanism has been used to interpret some intraplate seismiczones in southeastern Tennessee (Long and Zelt, 1991), as well as thelocal thermal softening beneath the NCP caused by the underplatingof the lower crust (Brown and Rushmer, 2006).

7.2.1. Deeper fault penetration?As a rule, the occurrence of earthquakes is closely related to

faulting, even if there are some differences between intra-continentalfaulting and that seen at subduction margins. The thick seismogeniclayer beneath the NCP (Fig. 2a) may be explained by deeper faultpenetration beneath the NCP than beneath the QDOB and the YSOB(Fig. 7). Along the transect from the southwest to the northeast, thereare a number of faults as observed from surface geological mapping(Zhang et al., 1983; Ye et al., 1985; Chen and Nabelek, 1988), such asthe northern and southern marginal faults beneath Heifei basin, theQDOB, the southern and northern faults of the NCP, Zhangjiakou-Beijing-Bohai basin fault beneath the YSOB (Fig. 7). The positions ofthese faults correspond to the relatively higher residual Bouguergravity anomalies as shown in the bottom panel of Fig. 4. Thesedimentary thickness is about 3–4 km beneath the Heifei basin inthe QDOB, 8–10 km beneath the NCP and 2–3 km beneath the YSOB(as shown by the crustal density model of Fig. 4). The variation of thesedimentary cover has a pattern, which is consistent with that of thethickness of the seismogenic layer. The lateral variation in thethickness of the seismogenic layer may be attributed to the changein depth of the fault penetration across the eastern part of the NCC.Fluid pressurisation in the deep parts of these faults beneath theNCP leads to seismicity in the middle crust (and forms the thick

Fig. 7. Cartoon to display the lateral variation of lithosphere strength across the eastern NCCmay be attributed to the thickening of the seismogenic layer.

seismogenic layer there) (Touret, 1985; Suzuki and Adachi, 1992;Kinny et al., 2004).

7.2.2. Conservation of the thick seismogenic layer?If the approximately 25 km thick seismogenic layer is due to the

conservation of the brittle upper crust of the NCP, the thickness of theentire crust should exceed the 35 km revealed by wide-angle seismicprofiling (Fig. 2). The results of recent tectonic, stratigraphic, petrolog-ical and geochemical analyses demonstrate that a plateau with a hightopography and a crustal thickness greater than 50 km existed in theNCC (Zhang et al., 2001, 2007). Evidence of the formation andsubsequent disappearance of this plateau is supplied by the presenceof adakite-like rocks (Zhang et al., 2001, 2007; Zhai et al., 2007). Foundin eastern parts of China, these are the product of the partial melting ofintermediate-to-mafic granulites in the deep lower crust at hightemperatures and pressures (Wu and Sun, 1999; Zhang et al., 2001).Recently published data have shown that adakite ranges in age from170 to 120 Ma, which implies that the East China Plateau (ECP)appeared before 170 Ma, probably reached its maturity during the lateJurassic and disappeared during the middle Cretaceous (120 Ma). Dataobtained from tectonics, stratigraphy and volcanic rocks in the northernmargin of the NCC (western Liaoning, northwestern Liaoning, andnorthern Hebei) indicate that the plateau experienced compression anduplift during the Jurassic, after which a background regime of extensionoccurred during the early Cretaceous (from 127 Ma) (Zhang et al., 2001,2007).

Our northeast–southwest transect reveals that the non seismo-genic layer (the residual old lower crust) is very thin (about 5 km). Atleast 15 km of the lower crust must therefore have been lost duringthe collapse of the Mesozoic NCP, because beneath the plateau, thepresent-day crustal thickness is only about 35 km, rather than>50 km, as we would expect it to be. The possible mechanisms forthe disruption of the 15 km thick lower crust beneath the NCP duringthe middle Cretaceous probably all include the delamination of thelower crust (Gao et al., 2004; Wu et al., 2005, 2006; Zhu and Zheng,2009). The NCC collided with the Yangtze plate to its south, and withthe Paleo-Asian Oceanic plate to its north. These collisions thickenedthe NCC crust and led to the formation of the plateau beneath the NCC(Zhang et al., 2001, 2007), which collapsed after the delamination ofthe eclogised lower crust, as it has been proposed by a number ofChinese tectonicists and geochemists (Wu et al., 1999, 2003, 2005,2006; Gao et al., 2004; Zhang et al., 2001, 2007). The high velocityanomalies (beneath a depth of 200 km) obtained from travel timetomography (Huang and Zhao, 2004) may be interpreted as anindicator of this delaminated lower crust or lithospheric mantle.Some geochemical studies proposed that underplating of the lowercrust should take place beneath the NCC (Zhang et al., 2010, 2011a,2011b, 2011c, 2011d). The observed average P-wave velocity that

. Where, the deeper penetration of faults beneath the NCP, or the softening of the BDTL

1056 Z. Zhang et al. / Gondwana Research 22 (2012) 1047–1059

ranges from 6.9 to 7.1 km/s (Fig. 3), and the relatively higher density(Fig. 4), high temperature (Fig. 5) of the nonseismogenic layer be-neath the NCP may represent geophysical signatures of the under-plating of the lower crust that followed its delamination.

7.2.3. Thickening of the seismogenic layer?Another possible explanation for the existence of the thick

seismogenic layer beneath the NCP is that the brittle (seismogenic)layer has been thickened by some particular tectonic process, such asthe underplating of the lower crust, accompanied by an alteration ofthe lithospheric mantle from the collision of NCC with Yangtze plateand Paleo-Asian Ocean plate, evidenced by systematic geochemicalstudies (Zhang et al., 2010, 2011a, 2011b, 2011c, 2011d; Santosh etal., 2012). This implies that part (or all) of the BDTL (themiddle crust)has been transformed into a brittle layer. Some experiments on brittleand ductile strength (Kohlstedt et al., 1995) demonstrated that themiddle crustal (BDTL) deforming beam can be strain-hardened byupright folding and through the development of vertical foliation.

The underplating of the lower crust implies a high P-wave velocityand density at the bottom of the crust, as recognised in extensionaland compressional regions, such as the Baikal rift (Thybo and Nielsen,2009) and the northern margin of South China Sea (Zhang et al.,2009a, 2009b). Fig. 3 shows the average P-wave velocity in theseismogenic layer and in the nonseismogenic layer along thenortheast–southwest transect. For the seismogenic layer, the averageP-wave velocity and the density are about 6.3–6.4 km/s and 2.8 g/cm3

beneath the NCP, and 6.1–6.2 km/s and 2.7 g/cm3, beneath the QDOBand the YSOB. For the nonseismogenic layer, the P-wave velocity anddensity are about 6.3–6.5 km/s (Fig. 5) and 2.9 g/cm3 beneath theQDOB and the YSOB, and about 6.9–7.1 km/s and 3.0–3.1 g/cm3

beneath the NCP. The lateral variation in P-wave velocity and densityis consistent with the lateral variation in elastic thickness, which isabout 15 km beneath the QDOB and the YSOB (Wang, 2001) andabout 25 km beneath the NCP (Wang and Xu, 1996).

Based on the experimental study of the BDTL by Kohlstedt et al.(1995), underplating of the lower crust can thermally soften theductile component (or harden the brittle component) of the BDTL inthe overlying wet felsic crust. Beneath the NCP, this is evidenced bythe P-wave velocity value of 6.3–6.5 km/s in the middle crust (Fig. 2),consistent with the global average given by Christensen and Mooney(1995). The lower P-wave velocity (Fig. 3) and density (Fig. 4) of thecrust, and the thinner seismogenic layer beneath the QDOB and theYSOB with respect to the NCP, may be a result of the strain softeningof the crust. This in turn can be produced by the elevated pressures offluid or magma around the zones of melt transfer (in the underplatedlower crust; Long and Zelt, 1991; Pili et al., 1999; Brown andRushmer, 2006). In this way, the lateral variation in the thickness ofthe seismogenic layer (Fig. 2c, d, e, f), the P-wave velocity (Fig. 3), andthe density of the crust (Fig. 4) from the NCP southwards to theQDOB, and northwards to the YSOB, probably reflect the variation instrength of the BDTL (middle crust), due to thermal and strainsoftening, respectively. The density at the top of the upper mantle isabout 0.1 g/cm3 lower than it is in the neighbouring regions (Fig. 4).This reduced density suggests significant amount of melt extractionfrom the upper mantle beneath the NCP. The positive temperatureanomaly of about 100 °C in both the lower and upper mantle beneaththe NCP (Fig. 5) and the amount of melt extraction from the uppermantle may provide the conditions necessary for thermal softening inthe lower crust beneath the NCP. Keeping in mind that both the highseismic P-wave velocity of 6.9–7.1 km/s, and the density of 3.0–3.1 g/cm3 in the crustal bottom layer beneath the NCP may be explainedsatisfactorily in terms of the underplating of the lower crust, wecontend that the lateral transition in lithospheric strength beneaththe NCC derives from (a) the thermal softening of the ductilecomponent in the BDTL beneath the NCP and (b) the strain softeningbeneath the two margins (to the north and south) of the NCC,

respectively, together with the significant alteration of the underlyinglithospheric mantle.

8. Conclusions

A lithosphere-scale transect across the eastern part of the NCC hasbeen constructed, using data on crustal velocity, density, tempera-ture, distribution of seismic energy, and lithospheric thickness, as acontribution to the understanding of the disruption mechanism of theArchean NCC. There is a clear north–south variation in the thicknessof the seismogenic layer, from about 25 km under the NCP to about15 km under the southern and the northern margins of the NCC. Inaddition, the crustal P-wave velocity and density are both higherbeneath the NCP than at the two margins of the NCC. This may be thegeophysical signature of syn-collisional channel flow and exhumation(Trap et al., 2011); accordingly, the temperature is about 100 °Chigher and the lithosphere is about 30 km thinner beneath the NCPthan it is at either margins along the lithosphere-scale transect.

We propose three possible interpretations for this lateral variationin lithospheric strength in the NCC, by paying special attention tosome features of the thick seismogenic layer beneath the NCP: (1) thedeeper penetration of faults beneath the NCP than beneath the QDOBand the YSOB; (2) the conservation of a thick brittle (seismogenic)layer and of a thin layer with a high density and a high P-wavevelocity that may suggest the underplating of the lower crust, afterthe exceptional (and probably complete) delamination of the lowercrust in the eastern plateau, brought about by the collision betweenthe NCC and the Yangtze and the Paleo-Asian Oceanic plates; (3) thethickening of the seismogenic layer beneath the NCP through theunderplating of the lower crust, which has changed the BDTL into abrittle layer, as a result of the thermal softening of the ductilestrength of the BDTL, while the strain softening of the (middle)crustal BDTL confines the occurrence of earthquakes in the uppercrust beneath the QDOB and the YSOB. In the last two cases, asignificant alteration of the underlying lithospheric mantle may beexpected, the characteristics of which may help to determine whichof the two models is correct. This question forms the focus of ongoingstudies. In our present understanding, the first and the thirdinterpretations provide a reasonable explanation of the observedlateral variation of the seismogenic layer across the eastern part of theNCC, while the second is unable to do so (the brittle layer should bethicker beneath the QDOB and the YSOB, where the lithosphericthinning is weak, than beneath the NCP, where the lithosphericthinning is strong). As a consequence, there is no direct and strongsupport for lithospheric delamination as an explanation of thedisruption of the Archean NCC. If the first interpretation of the lateralvariation of the thickness of the seismogenic layer across the easternpart of the NCC is correct, then the extensional tectonics of thelithosphere could either play an active role in the disruption of thelithosphere of the NCC or could be a consequence of it. If the thirdinterpretation is correct, thermal–mechanical–chemical erosion couldbe an important mechanism in the disruption of the Archean NCClithosphere. We cannot exclude the possibility that lithosphericdelamination has played an important role in the disruption of theArchean NCC as we cannot distinguish the passive or active role ofextensional tectonics in the lithospheric disruption.

Acknowledgements

The study was supported financially by the Chinese Academy ofScience (KZCX2-YW-132) and the National Nature Science Foundationof China (90914012, 41074033, 40830315, and 40874041), theImportant National Science and Technology Specific Projects(2008ZX05008-006). The partial support of the Italian PRIN is alsoacknowledged. We are most grateful to all those people andinstitutions that provided data on, and interpretations of,

1057Z. Zhang et al. / Gondwana Research 22 (2012) 1047–1059

geophysical experiments in the research area. We also appreciatethe constructive suggestions on the interpretation of geodynamicprocesses made by Santosh M., Aitken A., two anonymous reviewers,Zhu R., Wu F., Zhang F.Q. and Zhang H.

References

Adam, A., Panza, G.F., 1989. A critical review of the magetotelluric information on theupper mantle. Acta Geodesy Geophysics Hungary 24 (3–4), 395–415.

Ai, Y.S., Shen, Z.Y., 2011. Crust and upper mantle structure beneath Bohai Sea infreedfrom receiver function study. Earthquake Science 24, 35–43.

Albee, H.F., Cullins, H.L., 1975. Geologic map of the Alpine Quadrangle, BonnevilleCounty, Idaho, and Lincoln County Wyoming. United States Geological SurveyGeologic Quadrangle Map GQ-1259, scale 1:24,000.

Bai, Z.M., Zhang, Z.J., Wang, Y.H., 2007. Crustal structure across the Dabie-Sulu orogenicbelt revealed by seismic velocity profiles. Journal of Geophysics and Engineering.4 (4), 436–442.

Brace, W., Kohlstedt, D., 1980. Limits on lithospheric stress imposed by laboratoryexperiments. Journal of Geophysics Research 85 (B11), 6248–6252.

Brandmayr, E., Raykova, R., Zuri, M., Romanelli, F., Doglioni, C., Panza, G.F., 2010. Thelithosphere in Italy: structure and seismicity, In: Beltrando, M., Mattei, A.M.,Conticelli, S., Doglioni, C. (Eds.), The Geology of Italy, Electronic Edition. Journal ofthe Virtual Explorer1441-8142, vol. 36, p. 1.

Brown, M., Rushmer, 2006. Evolution and differentiation of the continental crust.Cambridge University Press.

Brudy, M., Zoback, M.D., Fuchs, K., Rummel, F., Baumgartner, J., 1997. Estimation of thecomplete stress tensor to 8 km depth in the KTB scientific drill holes: implicationsfor crustal strength. Journal of Geophysics Research 102, 18453–18476.

Burov, E.B., 2007. Plate rheology and mechanics. In: Schubert, G., Watts, A.B. (Eds.), Crustand Lithosphere Dynamics, 6. Elsevier. ISBN: 978-0-444-51928-3, p. TOGP00102.99-152, 611 pp.

Burov, E.B., 2011. Rheology and strength of the lithosphere. Marine and PetroleumGeology 28, 1402–1443.

Burov, E.B., Watts, A.B., 2006. The long-term strength of continental lithosphere: “jellysandwich” or “crème brulee”? GSA Today 12, 4–10.

Cao, J.M., Zhu, J.S., Wu, D.C., 1994. Velocity structure of the crust in eastern Qinlingmountain. Journal of Chengdu Institute of Technology 21 (01), 11–17 (in Chinese).

Cermak, V., Bodri, L., 1986. Two-dimensional temperature modeling along five East-European geotraverses. Journal of Geodynamics 5, 133–163.

Cermak, V., Rybach, L., 1989. Vertical distribution of heat production in the continentalcrust. Tectonophysics 159, 217–230.

Chen, M.X. (Ed.), 1988. Geothermics of North China. Science Press, Beijing.Chen, L., 2010. Concordant structural variations from the surface to the base of the

upper mantle in the North China Craton and its tectonic implications. Lithos 120,96–125.

Chen, W.P., Nabelek, J., 1988. Seismological strike–slip faulting and the development ofnorth China basin. Tectonics 7, 975–989.

Chen, L., Tao, W., Zhao, L., 2008. Distinct lateral variation of lithospheric thickness inthe Northeastern North China Craton. Earth Planetary Science Letters 267, 56–68.

Chen, L., Wei, Z.G., Wang, T., 2010. Significant structural variations in the central andwestern North China Craton and its implications for the craton destruction. EarthScience Frontiers 17 (1), 212–228 (in Chinese).

Chinese State Seismological Bureau (CSB), Deep Exploration Group (DEG), 1986.Results of Geophysical inverstigation in China. Crust and upper mantle. ChineseSeismological Press, Beijing.

Chopra, P.N., Paterson, M.S., 1984. The role of water in the deformation of dunite.Journal of Geophysical Research 89, 7861–7876.

Christensen, N.I., Mooney, W.D., 1995. Seismic velocity structure and composition ofthe continental crust: a global view. Journal of Geophysics Research 100,9761–9788.

Diwu, C.R., Sun, Y., Guo, A.L., Wang, H.L., Liu, X.M., 2011. Crustal growth in the NorthChina Craton at ~ 2.5 Ga: Evidence from in situ zircon U–Pb ages, Hf isotopes andwhole-rock geochemistry of the Dengfeng complex. Gondwana Research 20 (1),149–170.

Durrheim, R.J., Mooney, W.D., 1994. Evolution of the Precambrian lithosphere,seismological and geochemical constraints. Journal Geophysics Research 99 (15),359.

Fan, W., Menzies, M.A., 1992. Destruction of aged lower lithosphere and accretion ofasthenosphere mantle beneath eastern China. Geotectonics 16, 171–180.

Fan, W.M., Zhang, H.F., Baker, J., Davis, K.E., Mason, P.R.D., Menzies, M.A., 2000. On andoff the North China craton: where is the Archean keel? Journal of Petrology 41,933–950.

Fan, W.M., Guo, F., Wang, Y.J., Zhang, H.F., 2007. Late Mesozoic mafic magmatism fromthe North China Block: constraints on chemical and isotopic heterogeneity ofthe subcontinental lithospheric mantle. From In: Zhai, M.G., Windley, B.F., Kusky,T.M., Meng, Q.R. (Eds.), Mesozoic Sub-continental lithospheric thinning undereastern Asia: Geological Society, London, Special Publications, 280, pp. 77–100.doi:10.1144/SP280.40305-8719/07.

Fang, J., 1999. Global crustal and lithospheric thickness inversed by using satellitegravity data. Crustal Deformation and Earthquake 19 (1), 26–31 (in Chinese withEnglish abstract).

Foster, A.N., Jackson, J.A., 1998. Source parameters of large African earthquakes,implications for crustal rheology and regional kinematics. Geophysical JournalInternational 134 (2), 422–448.

Frezzotti, M.L., Peccerillo, A., Panza, G.F., 2009. Carbonate metasomatism and CO2

lithosphere–asthenosphere degassing beneath the Western Mediterranean: anintegrated model arising from petrological and geophysical data. Chemical Geology262, 108–120.

Gao, S., Rudnick, R., Yuan, H.L., 2004. Recycling lower continental crust in the NorthChina craton. Nature 432, 892–897.

Geiger, L., 1912. Probability method for the determination of earthquake epicentresfrom arrival time only. Bulletin Stain Louis University 8, 60–71.

Geng, Y.S., Du, L.L., Ren, L.D., 2012. Growth and reworking of the early Precambriancontinental crust in the North China Craton: Constraints from zircon Hf isotopes.Gondwana Research 21 (2–3), 517–529. doi:10.1016/j.gr.2011.07.006.

Goetze, C., Evans, B., 1979. Stress and temperature in the bending lithosphere asconstrainted by experimental rock mechanics. Geophysical Journal of RoyalAstronautic Society 59, 463–478.

Griffin, W., O'Reilly, S., 2003. The origin and evolution of Archean lithospheric mantle.Precambrian Research 127 (1–3), 19–41.

Griffin, W.L., Zhang, A.D., O'Reilly, S.Y., Ryan, C.G., 1998. Phanerozoic evolution of thelithosphere beneath the Sino-Korean Craton. In: Flower, M., Chung, S.L., Lo, C.H.,Lee, T.Y. (Eds.), Mantle dynamics and plate interactions in East Asia: AmericanGeophysical Union, Geodynamics Series, 100, pp. 107–126.

Griffin, W.L., O'Reilly, S.Y., Ryan, C.G., 1999. The composition and origin of sub-continental mantle. In: Fei, Y., Bertka, M., Mysen, B.O. (Eds.), Mantle petrology:field observations and high-pressure experimentation: a tribute to France R. (Joe)Boyd: Geochemical Society, Special Publications, 1, pp. 13–46.

Hu, S.B., Wang, J.Y., He, L.J., 2001. Compilation of heat flow data in the China continentalarea (3nd edition). Chinese Journal of Geophysics 44 (5), 610–626.

Huang, J., Zhao, D., 2004. Crustal heterogeneity and seismotectonics of the regionaround Beijing, China. Tectonophysics 385 (1–4), 159–180.

Jackson, J., 2002. Strength of the continental lithosphere: time to abandon the jellysandwich? GSA Today 12, 4–9.

Kinny, P.D., Collins, A.S., Razakamanana, T., 2004. Provenance hints and age constraintsof metasedimentary gneisses of Southern Madagascar from SHRIMP U-Pb zircondata. In: Chetty, T.R.K., Bhaskar Rao, Y.J. (Eds.), International FieldWorkshop on theSouthern Granulite Terrane. National Geophysical Research Institute, Hyderabad,India, pp. 97–98.

Kirby, S.H., 1983. Rheology of the lithosphere. Reviews of Geophysics and Space Physics21, 1458–1487.

Kirby, S.H., Kronenberg, 1987. Rheology of the lithosphere: selected topics. Review ofGeophysics 25, 1219–1244.

Klein, W., 2002. User's guide to hypoinverse-2000, a fortran program to solve forearthquake locations and magnitudes. U.S. Geological Survey, open file report02-171.

Klose, C.D., Seeber, L., 2007. Shallow seismicity in stable continental regions.Seismological Research Letters 78 (5), 554–562.

Kohlstedt, D.L., Evans, B., Maxwell, S.J., 1995. Strength of the lithosphere: constraintsimposed by laboratory experiment. Journal of Geophysical Research 100 (17),587–602.

Kusky, T.M., 2011. Geophysical and geological tests of tectonic models of the NorthChina Craton. Gondwana Research 20 (1), 26–35.

Kusky, T.M., Stern, R.J., Tucker, R.D., 2003. Evolution of East African and related orogensand the assembly of Gondwana. Precambrian Research 123, 81–85.

Lee, C.T., 2006. Geochemical/petrologic constraints on the origin of cratonic mantle.AGU Monographs 164, 89–114.

Li, S.L., Mooney, W.D., 1998. Crustal structure of China from deep seismic soundingprofiles. Tectonophysics 288, 105–113.

Li, S.G., Xiao, Y.L., Liou, D.L., 1993. Collision of the North China and Yangtze Blocks andformation of coesite-bearing eclogites-timing and processes. Chemical Geology109, 89–111.

Li, Z.X., Metcalfe, I., Powell, C.M., 1996. Breakup of Rodinia and Gondwanaland andAssembly of Asia: Australian Journal of Earth Sciences, 43.

Li, S.Z., Kusky, T.M., Wang, L., Zhang, G.W., Lai, S.C., Liu, X.C., Dong, S.W., Zhao, G.C.,2007. Collision leading to multiple-stage large-scale extrusion in the Qinlingorogen: Insights from the Mianlue suture. Gondwana Research 12 (1–2), 121–143.

Liu, D.Y., Nutman, A.P., Compston, W., Wu, J.S., Shen, Q.H., 1992. Remnants of 3800 Macrust in the Chinese part of the Sino-Korean craton. Geology 20, 339–342.

Liu, M., Cui, X., Liu, F., 2004. Cenozoic rifting and volcanism in eastern China a mantledynamic link to the Indo-Asian collision. Tectonophysics 393, 29–42.

Long, L.T., Zelt, K.H., 1991. A local weakening of the brittle- ductile transition canexplain some intraplate seismic zones. Tectonophysics 186, l75–l92.

Ma, X.Y., 1989. Lithospheric Dynamics Atlas of China. China Cartographic PublishingHouse, Beijing. (in Chinese).

Maggi, A., Jackson, J.A., McKenzie, D.P., Priestley, K., 2000. Earthquake focal depths,effective elastic thickness, and the strength of the continental lithosphere. Geology28, 495–498.

Meng, Q.R., Wei, H.H., Qu, Y.Q., Ma, S.X., 2011. Stratigraphic and sedimentary records ofthe rift to drift evolution of the northern North China Craton at the Paleo- tomesoproterozoic transition. Gondwana Research 20, 205–218.

Menzies, M.A., Fan, W.M., Zhang, M., 1993. Paleozoic and Cenozoiclithosprobes and theloss of >120km of Archean lithosphere, Sino-Korean Craton, China. In: Prichard,H.M., Alabaster, T., Harris, N.B.W., Neary, C.R. (Eds.), Magmatic Processes and PlateTectonics: Geological Society London, Special Publications, 76, pp. 71–78.

Menzies, M.A., Xu, Y.G., Zhang, H.F., Fan, W.M., 2007. Integration of geology,geophysics and geochemistry: a key to understanding the North China Craton.Lithos 96, 1–21.

Molnar, P., Chen, W.P., 1983. Focal depths and fault plane solutions of earthquakesunder the Tibetan plateau. Journal of Geophysical Research 88 (B2), 1180–1196.

1058 Z. Zhang et al. / Gondwana Research 22 (2012) 1047–1059

Panza, G.F., Raykova, R.B., 2008. Structure and rheology of lithosphere in Italy andsurrounding. Terra Nova 20 (3), 194–199.

Pasquale, V., Cabella, C., Verdoya, M., 1990. Deep temperatures and lithosphericthickness along the European geotraverse. Tectonophysics 176, 1–11.

Pe´rez-Gussinye´, M., Lowry, A.R., Watts, A.B., 2007. Effective elastic thickness of SouthAmerica and its implications for intracontinental deformation. GeochemistryGeophysics Geosystem 8, Q05009. doi:10.1029/2006GC001511.

Pili, E., Sheppard, S.M.F., Lardeaux, J.M., 1999. Fluid-rock interaction in the granulites ofMadagascar and lithospheric transfer of fluids. Gondwana Research 2, 341–350.

Ranalli, G., 1995. Rheology of the Earth. Chapman and Hall, London.Rogers, J.J.W., Santosh, M., 2004. Continents and Supercontinents. Oxford University

Press, New York.Rybach, L., Buntebarth, G., 1984. The variation of heat generation, density and seismic

velocity with rock type in the continental lithosphere. Tectonophysics 103 (1–4),335–344.

Santosh, M., Zhao, D.P., Kusky, T., 2010. Mantle dynamics of the Paleoproterozoic NorthChina Craton: a perspective based on seismic tomography. Journal of Geodynamics49 (1), 39–53.

Santosh, M., Liu, S.J., Tsunogae, T., Li, J.H., 2012. Paleoproterozoic ultrahigh-temperaturegranulites in the North China Craton: implications for tectonic models on extremecrustal metamorphism. Precambrian Research. doi:10.1016/j.precamres.2011.05.003.

Sibson, R.H., 1977. Fault rocks and fault mechanisms. Journal of the Geological Society133, 191–213.

Suzuki, K., Adachi, M., 1992. Middle Precambrian detrital monazite and zircon from Hidagneiss in Oki-Dogo island, Japan: their origin and implications for the correlation ofbasement gneiss of Southwest Japan and Korea. Tectonophysics 235, 277–292.

Teng, J.W., Wei, S.Y., Li, K.S., Chao, Z.X., 1982. Structure of upper mantle and lowvelocity layer of the mantle under Hsingtai earthquake region on the North ChinaPlain. Acta Geophysical Sinica 25 (1), 58–69.

Teng, J.W., Sun, K.Z., Xiong, S.B., Yao, H., Yin, Z.X., Cheng, L.F., Xue, C.S., Tian, D.S., Hao,T.Y., Lai, M.H., Wu, M.C., 1985. Explosion seismological study for velocitydistribution and structure of the crust and upper mantle from Maanshan toQidong of the Southern parts of China. Acta Geophysica Sinica 28 (2), 155–169.

Teng, J.W., Wang, F.Y., Zhao, W.Z., Zhao, J.R., Li, M., Tian, X.B., Yan, Y.F., Zhang, Y.Q.,Zhang, C.K., Duan, Y.H., Yang, Z.X., Xu, C.F., 2008. Velocity distribution of uppercrust, undulation of sedimentary formation and crystalline basement beneath theOrdos basin in North China. Chinese Journal of Geophysics-Chinese Edition 51 (6),1753–1766.

Teng, J.W., Wang, F.Y., Zhao, W.Z., Zhang, Y.Q., Zhang, X.K., Yan, Y.F., Zhao, J.R., Li, M.,Yang, H., Zhang, H.S., Ruan, X.M., 2010. Velocity structure of layered block and deepdynamic process in the lithosphere beneath the Yinshan orogenic belt and OrdosBasin. Chinese Journal of Geophysics-Chinese Edition 53 (1), 67–85.

Thybo, H., Nielsen, C.A., 2009. Magma-compensated crustal thinning in continental riftzones. Nature 457 (7231), 873–876.

Tian, X.B., Teng, J.W., Zhang, H.S., Zhang, Z.J., Zhang, Y.Q., Yang, H., Zhang, K.K., 2011.Structure of crust and upper mantle beneath the Ordos Block and the YinshanMountains revealed by receiver function analysis. Physics of the Earth andPlanetary Interiors 184 (3–4), 186–193.

Touret, J.L.R., 1985. Fluid regime in southern Norway, the record of fluid inclusions. In:Tobi, A.C., Touret, J.L.R. (Eds.), The Deep Proterozoic Crust in the North AtlanticProvinces. Reidel, Dordrecht, pp. 517–549.

Trap, Pierre, Faure, Michel, Lin, Wei, Augier, Romain, Fouassier, Antoine, 2011. Syn-collisional channel flow and exhumation of Paleoproterozoic high pressure rocksin the Trans-North China Orogen: the critical role of partial-melting and orogenicbending. Gondwana Research 20, 498–515.

Urgmann, R.B., Dresen, Georg, 2008. Rheology of the lower crust and upper mantle:evidence from rock mechanics, geodesy, and field observations. Annual Review ofEarth Planetary Science 36, 531–567.

Waldhauser, F., Ellsworth, W.L., 2000. A double-difference earthquake locationalgorithm: method and application to the northern Hayward Fault California.Bulletin of Seismology Society of America 90, 1353–1368.

Wang, Y., 2001. Heat flow pattern and lateral variations of lithosphere strength inChina mainland: constraints on active deformation. Physics Earth PlanetaryInterior 126, 121–146.

Wang, Y., Xu, H., 1996. The variations of lithospheric flexural strength and isostaticcompensation mechanisms beneath the continent of China and vicinity. ChineseJournal of Geophysics 39, 105–113 (Suppl.).

Wang, Y.J., Zhang, Y.Z., Zhao, G.C., Fan, W.M., Xiao, X.P., Zhang, F.F., Zhang, A.M., 2009.Zircon U–Pb geochronological and geochemical constraints on the petrogenesis ofthe Taishan sanukitoids (Shandong): Implications for Neoarchean subduction inthe Eastern Block, North China Craton. Precambrian Research 174 (3–4), 273–286.

Watts, A.B., Burov, E.B., 2003. Lithospheric strength and its relationship to the elasticand seismogenic layer thickness. Earth Planetary Science Letter 213, 113–131.

Wei, W.B., Jin, S., Ye, G.F., 2006. MT sounding and lithosphere thickness in North China.Geology in China 33 (2), 762–772 (in Chinese).

Wu, F.Y., Sun, D.Y., 1999. Mesozoic magmatism and Lithosphere thinning in EasternChina. Bulletin of Changchun University of Science and Technology 29, 313–318(in Chinese with English abstract).

Wu, J., Zhang, Z., 2012. Spatial distribution of seismic layer, crustal thickness, and Vp/Vsratio in the Permian Emeishan Mantle Plume region. Gondwana Research.doi:10.1016/j.gr.2011.10.007.

Wu, F.Y., Walker, R.J., Ren, X.W., Sun, D.Y., Zhou, X.H., 2003. Osmium isotopic constraintson the age of lithospheric mantle beneath northeastern China. Chemical Geology196, 107–129.

Wu, F.Y., Zhao, G.C., Wilde, S.A., Sun, D.Y., 2005. Nd Isotopic constraints on the crustalformation of the North China Craton. Journal of Asian Earth Sciences 24, 523–545.

Wu, F.Y., Walker, R.J., Yang, Y.H., Yuan, H.L., Yang, J.H., 2006. The chemical–temporalevolution of lithospheric mantle underlying the North China Craton. Geochemicaet Cosmochimica Acta 70, 5013–5034.

Xu, Y.G., 2001. Thermo-tectonic destruction of the Archean lithospheric keel beneaththe Sino-Korean Craton in China: evidence, timing and mechanism. Physics andChemistry of the Earth (A) 26, 747–757.

Xu, X.S., O'Reilly, S.Y., Griffin, W.L., Zhou, X.M., 1998. The nature of the Cenozoiclithosphere at Hushan, central eastern China. In: Flower, M., Ching, S.L., Lo, C.H.,Lee, T.Y. (Eds.), Mantle Dynamics and Plate Interactions in East Asia: AGUGeodynamics Series, 27, pp. 167–196.

Xu, Y.G., Ma, J.L., Huang, X.L., Iizuka, Y., Chung, S.L., Wang, Y.B., Wu, X.Y., 2004. EarlyCretaceous gabbroic complex from Yinan, Shandong Province: petrogenesis andmantle domains beneath the North China Craton. International Journal of EarthScience 93, 1025–1041.

Xu, Y.G., Blusztajn, J., Ma, J.L., Suzuki, K., Liu, J.F., Hart, S.R., 2008. Late Archean to EarlyProterozoic lithospheric mantle beneath the western North China craton: Sr-Nd-Osisotopes of peridotite xenoliths from Yangyuan and Fansi. Lithos 102, 25–42.

Ye, H., Shedlock, K.M., Hellinger, S.J., 1985. The north China basin: an example of aCenozoic rifted intraplate basin. Tectonics 4, 153–169.

Chief compilerYuan, X.C., 1996. Geophysical Atlas of China. Geological PublishingHouse, Beijing. (in Chinese).

Zang, S.X., Liu, Y.G., Ning, J.Y., 2002. Thermal structure of the lithosphere in NorthChina. Chinese Journal of Geophysics 45 (1), 56–66 (in Chinese).

Zeng, R.S., Lu, H.X., Ding, Z.F., 1988. Seismic refraction and reflection profilings acrossTangshan epicentral region and their implication to seismogenic processes. ActaSeismologica Sinica 31 (4), 383–398.

Zhai, M.G., Santosh, M., 2011. The early Precambrian odyssey of the North ChinaCraton: a synoptic overview. Gondwana Research 20 (1), 6–25.

Mesozoic Sub-continental lithospheric thinning under eastern Asia. In: Zhai, M.G.,Windley, B.F., Kusky, T.M., Meng, Q.R. (Eds.), Geological Society, London, SpecialPublications.

Zhang, W.Y., Zhang, K., Zhao, Y.G., 1983. The Mesozoic and Cenozoic geotectoniccharacteristics and dynamical model of the lithosphere in North China faultblockregion. Acta Geology Sinica 57 (1), 33–42 (in Chinese with English abstract).

Zhang, C.K., Zhao, J.R., Ren, Q.F., 1994. Study on crust and upper mantle structure innorth Henan and its surroundings. Seismology and Geology 16 (3), 243–253 (inChinese).

Zhang, Z.J., Li, Y.K., Lu, D.Y., Teng, J.W., Wang, G.J., 2000. Velocity and anisotropystructure of the crust in the Dabieshan orogenic belt from wide-angle seismic data.Physics of the Earth and Planetary Interiors 122 (1–2), 115–131.

Zhang, Q., Wang, Y., Wang, Y.L., 2001. Preliminary study on the components of thelower crust in east China plateau during Yanshanian Period: constraints onSr and Nd isotopic compositions of adakite-like rocks. Acta Petrologica Sinica 17(4), 505–513.

Zhang, H.F., Sun, M., Zhou, X., Zhou, M., Fan, W., Zheng, J., 2003. Secular evolution of thelithosphere beneath the eastern North China Craton: evidence from Mesozoicbasalts and high-Mg andesites. Geochimica et Cosmochimica Acta 67, 4373–4387.

Zhang, Q., Jin, W.J., Wang, Y.L., Li, C.D., Jia, X.Q., 2007. Discussion of north boundary ofthe East China Plateau during late Mesozoic Era. Acta Petrologica Sinica 23 (4),689–700.

Zhang, H.F., Goldstein, S.L., Zhou, X.H., Sun, M., Cai, Y., 2009a. Comprehensiverefertilization of lithospheric mantle beneath the North China Craton: further Os-Sr-Nd isotopic constraints. Journal of Geological Society London 166, 249–259.

Zhang, Z.J., Liu, Y.F., Zhang, S.F., Zhang, G.C., 2009b. Crustal P-wave velocity structureand layering beneath Zhujiangkou-Qiongdongnan basin, the northern continentalmargin of South China Sea. Chinese Journal of Geophysics 52 (10), 2461–2471(in Chinese).

Zhang, H.F., Zhou, M.F., Sun, M., Zhou, X.H., 2010. The origin of Mengyin and Fuxiandiamondiferous kimberlites from the North China Craton: implication for Palaeozoicsubducted oceanic slab-mantle interaction. Journal of Asian Earth Sciences 37,425–437.

Zhang, J., Zhang, H.F., Kita, N., Shimoda, G., Morishita, Y., Ying, J.F., Tang, Y.J., 2011a.Secular evolution of the lithospheric mantle beneath the eastern North Chinacraton: evidence from peridotitic xenoliths from Late Cretaceous mafic rocks inthe Jiaodong region, east-central China. International Geology Review 53,182–211.

Zhang, Z.J., Chen, Q.F., Bai, Z.M., Chen, Y., Badal, J., 2011b. Crustal structure andextensional deformation in the thinned North China lithosphere. Tectonophysics508, 62–72.

Zhang, Z.J., Yang, L.Q., Teng, J.W., Badal, J., 2011c. Overview of the earth crust underChina. Earth Science Reviews 104 (1–3), 143–166.

Zhang, Z.J., Klemperer, S.L., Bai, Z.M., Chen, Y., Teng, J.W., 2011d. Crustal structure of thePaleozoic Kunlun orogeny from an active-source seismic profile between Mobaand Guide in East Tibet, China. Gondwana Research 19 (4), 994–1007.

Zhao, T.P., Zhou, M.F., 2009. Geochemical constraints on the tectonic setting ofPaleoproterozoic A-type granites in the southern margin of the North China Craton.Journal of Asian Earth Sciences 36 (2–3), 183–195.

Zhao, G.C., Sun, M., Wilde, S.A., Li, S.Z., 2003. Assembly, Accretion and Breakup of thePaleo-Mesoproterozoic Columbia Supercontinent: records in the North China Craton.Gondwana Research 6 (3), 417–434.

Zhao, D.P., Muruyama, S., Omori, S., 2007. Mantle dynamics of western Pacific to EastAisa: new insight from seismic tomography and mineral physics. GondwanaResearch 11, 120–131.

Zhao, G.C., Wilde, S.A., Guo, J.H., Cawood, P.A., Sun, M., Li, X.P., 2010. Single zircongrains record two Paleoproterozoic collisional events in the North China Craton.Precambrian Research 177 (3–4), 266–276.

1059Z. Zhang et al. / Gondwana Research 22 (2012) 1047–1059

Zheng, J.P., O'Reilly, S.Y., Griffin, W.L., Lu, F.X., Zhang, M., Pearson, N.J., 2001. Relictrefractory mantle beneath the eastern North China block: significance for lithosphereevolution. Lithos 57, 43–66.

Zheng, J.P., Sun, M., Lu, F.X., Pearson, N., 2003. Mesozoic lower crust xenoliths and theirsignificance in lithospheric evolution beneath the Sino-Korean Craton. Tectonophysics361, 37–60.

Zheng, J.P., Griffin, W.L., O'Reilly, S.Y., 2006. Mineral chemistry of garnet peridotites fromPaleozoic, Mesozoic and Cenozoic lithosphere: constraints on mantle evolutionbeneath Eastern China. Journal of Petrology 47, 2233–2256.

Zhu, R.X., Zheng, T.Y., 2009. Destruction geodynamics and Paleoproterozoic platetectonics of the North China Craton. Chinese Science Bulletin 54 (14),1950–1961.

Zhu, J., Cao, J., Cai, X., Yan, Z., Cao, X., 2002. High resolution surface wave tomography inEast Asia and West Pacific marginal seas. Chinese Journal of Geophysics 45 (5),679–698.

Zhu, J.S., Cai, X.L., Cao, J.M., 2006. Lithospheric structure and geodynamics in China andits adjacent areas. Geology in China 33 (4), 793–803 (in Chinese).