A complex 660 km discontinuity beneath northeast China

Ai, Yinshuang; Zheng, Tianyu; Xu, Weiwei; He, Yumei; Dong, Deping

doi:10.1016/s0012-821x(03)00266-8

Cited by 154 publications

(103 citation statements)

References 24 publications

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“…2(a)) and consistent with those of Li et al (2000). The complicated structure of '660' beneath MDJ has been suggested previously but interpreted differently (Niu and Kawakatsu, 1996;Lebedev et al, 2002;Ai et al, 2003). Our results also show several weak peaks near a depth of 660 km, but as our data is based on the stacking of ORFs from all directions, we were unable to discriminate between the different models.…”

Section: Resultssupporting

confidence: 87%

“…on the depth of the mantle discontinuities beneath China (Niu and Kawakatsu, 1998;Yang and Zhou, 2001), on the lithospheric and upper mantle structure of southern Tibet (Yuan et al, 1997), and on a complex structure of the upper mantle discontinuities beneath northeastern China (Niu and Kawakatsu, 1996;Lebedev et al, 2002;Ai et al, 2003). Although important results have been obtained from such studies, resolution of the topography of upper mantle discontinuities can be improved by making use recent observation data.…”

Section: Introductionmentioning

confidence: 99%

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Mapping the upper mantle discontinuities beneath China with teleseismic receiver functions

2008

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We used teleseismic body waves recorded at stations of the Chinese Center of Digital Seismic Network to map the upper mantle discontinuities beneath continental China. The CRUST2.0 and an S-tomography model beneath each station were combined with the one-dimensional tracing method to convert time series of radial receiver functions to depth series. Clear signatures corresponding to the 410-and 660-km discontinuities ('410' and '660') are visible at almost all of the stations. The average S velocity contrast of '410' beneath the study area is close to the global average, but that for '660' is smaller than the global average. The average depth of '410' is 413 km, and the peak-to-peak topography is about 36 km, with regional depressions that correlate with the Datong quaternary volcano in northern China. The '660' topography exhibits a peak-to-peak variation of about 43 km, and its average depth is 669 km; the depressions of the '660' in northeastern, southeastern and northern China are well correlated with the past subduction around the Pacific Ocean and Philippine Sea. The width of the transition zone is also increased in the region with the deeper '660'. Our results would appear to indicate that there may be a low-velocity layer below a depth of approximately 600 km that may be the accumulated garnetite layer of an ancient crust above the '660'.

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Section: Resultssupporting

confidence: 87%

Section: Introductionmentioning

confidence: 99%

Mapping the upper mantle discontinuities beneath China with teleseismic receiver functions

2008

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“…By definition, the ETF incorporates all time shifts, phase rotations and amplitude changes associated with the modal summation process. We use a Wiener deconvolution approach to obtain the ETF, similar in principle to methods used in some surface-wave dispersion studies [e.g., Taylor and Toksöz, 1982] and receiver-function analyses [e.g., Ai et al, 2003].…”

Section: Smks Waves and Empirical Transfer Function Methodsmentioning

confidence: 99%

Empirical transfer functions: Application to determination of outermost core velocity structure using SmKS phases

Alexandrakis

Eaton

2007

Geophysical Research Letters

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[1] SmKS waves provide good resolution of outer-core velocity structure, but are affected by heterogeneity in the D 00 region. We have developed an Empirical Transfer Function (ETF) technique that transforms a reference pulse (here, SmKS) into a target waveform (SKKS) by: (1) timewindowing the respective pulses, (2) applying Wiener deconvolution, and (3) convolving the output with a Gaussian waveform. Common source and path effects are implicitly removed by this process. We combine ETFs from 446 broadband seismograms to produce a global stack, from which S3KS-SKKS differential time can be measured accurately. As a result of stacking, the scatter in our measurements (0.43 s) is much less than the 1.29 s scatter in previous compilations. Although our data do not uniquely constrain outermost core velocities, we show that the fit of most standard models can be improved by perturbing the outermost core velocity. Our best-fitting model is formed using IASP91 with PREM-like velocity at the top of the core. Citation: Alexandrakis, C., and D. W. Eaton (2007), Empirical transfer functions: Application to determination of outermost core velocity structure using SmKS phases, Geophys.

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“…Sometimes in mantle convection models, the bottom-heavy prohibition is obviated by assuming that the solid rock mantle behaves as an ideal gas, adiabatic without viscous losses. But the mantle is not without viscous losses, as indicated by earthquakes at depths as great as 660 km (Ai et al 2003). Moreover, the Rayleigh Number, derived for a non-compressed thin film (Rayleigh 1916), has been misapplied to wrongly justify physically impossible mantle convection.…”

Section: What's Wrong With This Picture?mentioning

confidence: 99%

New concept on the origin of petroleum and natural gas deposits

Herndon¹

2016

J Petrol Explor Prod Technol

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The scientific basis that underlies the geology of petroleum and natural gas deposit origination has for the past five decades been based upon plate tectonics theory. However, plate tectonics theory depends critically upon physically impossible mantle convection. I have disclosed a new indivisible geoscience paradigm, called whole-Earth decompression dynamics, that begins with and is the consequence of our planet's early formation as a Jupiter-like gas giant and which permits deduction of: (1) earth's internal composition and highly reduced oxidation state; (2) core formation without whole-planet melting; (3) powerful new internal energy sources, protoplanetary energy of compression and 'georeactor' nuclear fission energy; (4) mechanism for heat emplacement at the base of the crust; (5) georeactor geomagnetic field generation; (6) decompression-driven geodynamics that accounts for the myriad of observations attributed to plate tectonics without requiring physically impossible mantle convection; and (7) a mechanism for fold-mountain formation that does not necessarily require plate collision. Here, I describe from that new framework the scientific basis that underlies a new concept for the geological origin of petroleum and natural gas deposits.

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A complex 660 km discontinuity beneath northeast China

Cited by 154 publications

References 24 publications

Mapping the upper mantle discontinuities beneath China with teleseismic receiver functions

Mapping the upper mantle discontinuities beneath China with teleseismic receiver functions

Empirical transfer functions: Application to determination of outermost core velocity structure using SmKS phases

New concept on the origin of petroleum and natural gas deposits

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