Motion of Nubia relative to Antarctica since 11 Ma: Implications for Nubia-Somalia, Pacific–North America, and India-Eurasia motion

Royer, Jean‐Yves; Gordon, Richard G.; Horner-Johnson, B. C.

doi:10.1130/g22463.1

Cited by 42 publications

(37 citation statements)

References 17 publications

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“…In contrast to Figure 7, the velocities over SOM are estimated relative to the Nubian plate. Prawirodirdjo and Bock, 2004;McCaffrey, 2005;Calais et al, 2006b;Royer et al, 2006;Socquet et al, 2006;HornerJohnson et al, 2007]. For the pairs NAM-PAC, NAZ-SAM, NUB-SOM, and EUR-IND, most GPS estimates of the pole position agree with the geologic pole at a 95% confidence level.…”

Section: Relative Plate Rotation Vectorsmentioning

confidence: 87%

Current global plate kinematics from GPS (1995–2007) with the plate‐consistent reference frame

Коган¹,

Steblov²

2008

J. Geophys. Res.

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[1] We present the vectors of rotation of 10 major lithospheric plates, estimated from continuous GPS observations at 192 globally distributed stations; 71 stations were selected as representing stable plate regions. All days for the period 1995.0-2007.0 were included in the analysis. In contrast to previous GPS plate models, our model is independent of international terrestrial reference frames (ITRF). The origin of our plate-consistent reference frame is the center of plate rotation (CP) rather than the center of mass of the entire Earth's system (CM) as in recent versions of ITRF. We estimate plate rotations and CP by minimizing the misfit between the horizontal velocities predicted by the plate model and the observed GPS velocities. If any version of ITRF is used as the reference frame, the drift of the ITRF origin relative to CP cannot be neglected in estimation of plate rotation vectors and plate-residual station velocities. The model of the plate kinematics presented here addresses the problem debated since the beginning of the space geodesy: how big are disagreements between the current plate motions and the motions averaged over several million years? We compare the vectors of relative plate rotations estimated here with the published vectors from GPS and geologic models. We also discuss the integrity of individual plates as exhibited by plate-residual station velocities. For seven largest plates, the RMS value of plate-residual station velocities in stable plate interiors is 0.5-0.9 mm/a; this value is an upper bound on deviation of real plates from infinite stiffness.

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Section: Relative Plate Rotation Vectorsmentioning

confidence: 87%

Current global plate kinematics from GPS (1995–2007) with the plate‐consistent reference frame

Коган¹,

Steblov²

2008

J. Geophys. Res.

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“…While there is much higher resolution data available for part of the latter plate circuit, there is also considerable uncertainty in terms of constraints as to the magnitude of crustal extension in the East-African Rift System. For example our investigation of the various reconstructions that rotate India relative to Somalia (e.g., Chu and Gordon, 1999;Horner-Johnson et al, 2007;Lemaux et al, 2002;Royer et al, 2006) highlighted that there was contradiction between what these models proposed for the timing and geometry of crustal extension in the East-African Rift System (11-0 Ma), compared to field observations that suggest crustal extension began at ∼32 Ma (Joffe and Garfunkel, 1987). This discrepancy indicates that the problem in the India-Somalia plate circuit cannot simply be resolved, e.g., by changing the age of the 11 Ma Euler pole to 32 Ma.…”

Section: Towards An Integrated Modelmentioning

confidence: 99%

The collision of India with Asia

White

Lister

2012

Journal of Geodynamics

112

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a b s t r a c tWe review the relative motion of India and Asia for the last 100 million years and present a revised reconstruction for the India-Antarctica-Africa-North America-Eurasia plate circuit based on published motion histories. Deformation of these continental masses during this time introduces uncertainties, as does error in oceanic isochron age and location. Neglecting these factors, the data ipso facto allow the inference that the motion of India relative to Eurasia was distinctly episodic. Although motion is likely to have varied more smoothly than these results would allow, the geological record also suggests a sequence of distinct episodes, at about the same times. Hence we suggest that no single event should be regarded as the collision of India with Asia. The deceleration of the Indian plate commencing at ∼65 Ma is matched by an equally significant prior acceleration and this aspect must be taken into account in geodynamic scenarios proposed to explain the collision of India with Asia.

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“…Kendall et al, 2005;2006;Bastow et al, 2010) show that the MER is one of the most anisotropic regions worldwide, with SKS splitting delay times as high as~3 s. Intriguingly, the change in orientation of fast SKS waves from the plateau regions to the MER mirrors a shift from N130°E-directed extension to N110°E-directed extension at~2 Ma, when crustal strain localized towards the volcanically active Wonji Fault Belt (WFB) (e.g. Wolfenden et al, 2004), though recent studies have questioned such polyphase deformation (Corti, 2008) based upon revised kinematic models for Nubia-Somalia plate motion (Royer et al, 2006). Study of seismic anisotropy via combined analysis of body and surface waves shows that elongate melt inclusions (dikes and veins) characterise the Ethiopian lithosphere from~20 km to at least 50 km depth beneath the MER (Bastow et al, 2010).…”

Section: Geophysical Evidence Of Mer Developmentmentioning

confidence: 99%

Insights into extensional processes during magma assisted rifting: Evidence from aligned scoria cones

Rooney

Bastow

Keir

2011

Journal of Volcanology and Geothermal Research

125

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Mechanical and magmatic processes exert first-order control on the architecture and evolution of rifts. As a continental rift develops towards a new oceanic spreading centre, extension that is initially accommodated in a broad zone of faulting and ductile stretching must transition towards a narrow zone of focused magmatic intrusion. The Main Ethiopian Rift (MER), part of the East African Rift System, is an ideal location to study this transition because it captures rifting processes during continental breakup. In this contribution we synthesise geochemical data from scoria cones in the Wonji Fault Belt (WFB) and Silti-Debre Zeyit Fault Zone (SDFZ) in the MER to provide new constraints on the development of mantle melting columns and magmatic plumbing systems since the onset of rifting. We utilize the extensive geophysical and geochemical databases, collected in the Ethiopian Rift, to show that geochemical evidence of heterogeneity in the depth of the mantle melting column which produced Quaternary rift basalts correlates with lithospheric structure. When combined with existing observations of asymmetry across the rift in terms of depth of melting column and magmatic plumbing systems, it is evident that the mechanical structure of the rift, defined during the initial stages of breakup, has played a dominant role in the initial development of magma assisted rifting in the MER. Surface structures and crustal-scale geophysical studies have suggested the WFB is analogous to a sea-floor spreading centre. However, the geochemical characteristics of rift basalts are consistent with mantle tomography that shows no evidence beneath the MER for passive magmatic upwelling beneath discrete rift segments as is observed in the ocean basins. Collectively, the Ethiopian data show that the distribution of mantle melts during the initiation of magma assisted rifting is fundamentally influenced by lithospheric structures formed during earlier syn-rift stretching.

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Motion of Nubia relative to Antarctica since 11 Ma: Implications for Nubia-Somalia, Pacific–North America, and India-Eurasia motion

Cited by 42 publications

References 17 publications

Current global plate kinematics from GPS (1995–2007) with the plate‐consistent reference frame

Current global plate kinematics from GPS (1995–2007) with the plate‐consistent reference frame

The collision of India with Asia

Insights into extensional processes during magma assisted rifting: Evidence from aligned scoria cones

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