Structure of crust and upper mantle beneath the Ordos Block and the Yinshan Mountains revealed by receiver function analysis

Abstract The Crust and lithosphere Investigation of the Easternmost expression of the Laramide Orogeny was a two-year deployment of 24 broadband, compact posthole seismometers in a linear array across the eastern half of the Wyoming craton. The experiment was designed to image the crust and upper mantle of the region to better understand the evolution of the cratonic lithosphere. In this article, we describe the motivation and objectives of the experiment; summarize the station design and installation; provide a detailed accounting of data completeness and quality, including issues related to sensor orientation and ambient noise; and show examples of collected waveform data from a local earthquake, a local mine blast, and a teleseismic event. We observe a range of seasonal variations in the long-period noise on the horizontal components (15–20 dB) at some stations that likely reflect the range of soil types across the experiment. In addition, coal mining in the Powder River basin creates high levels of short-period noise at some stations. Preliminary results from Ps receiver function analysis, shear-wave splitting analysis, and averaged P-wave delay times are also included in this report, as is a brief description of education and outreach activities completed during the experiment.

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Structure of the crust and upper mantle of the Great Slave Lake shear zone, northwestern Canada, from teleseismic analysis and gravity modelling

Canadian Journal of Earth Sciences ◽

10.1139/e03-038 ◽

2003 ◽

Vol 40 (9) ◽

pp. 1203-1218 ◽

Cited By ~ 17

Author(s):

David W Eaton ◽

Jacqueline Hope

Keyword(s):

Shear Zone ◽

Upper Mantle ◽

Receiver Function ◽

Function Analysis ◽

Crustal Material ◽

S Wave ◽

Crust And Upper Mantle ◽

Fast Axis ◽

Great Slave Lake ◽

Basic Features

The Great Slave Lake shear zone (GSLsz) exposes lower crustal rocks analogous to deep-seated segments of modern strike-slip fault zones, such as the San Andreas fault. Extending for 1300 km beneath the Western Canada Sedimentary Basin to the southern margin of the Slave Province, the GSLsz produces one of the most prominent linear magnetic anomalies in Canada. From May to October 1999, 13 three-component portable broadband seismograph stations were deployed in a 150-km profile across a buried segment of the shear zone to investigate its lithospheric structure. Splitting analysis of core-refracted teleseismic shear waves reveals an average fast-polarization direction (N49°E ± 19°) that is approximately parallel to the shear zone. Individual stations near the axis of the shear zone show more northerly splitting directions, which we attribute to interference between regional anisotropy in the upper mantle (fast axis ~N60°E) and crustal anisotropy within the shear zone (fast axis ~N30°E). At the location of our profile, the shear zone is characterized by a 10-mGal axial gravity high with a wavelength of 30 km, superimposed on a longer wavelength 12-mGal low. This gravity signature is consistent with the basic features of the crustal model derived from receiver-function analysis: a Moho that dips inward toward the shear-zone axis and a mid-crustal zone with high S-wave velocity (ΔVs = 0.6 ± 0.2 km/s). The axial gravity high may be related to uplift of deeper crustal material within the shear zone, or protolith-dependent compositional differences between the shear zone and surrounding wall rocks.

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Teleseismic studies of the lithosphere below the Abitibi-Grenville Lithoprobe transect

Canadian Journal of Earth Sciences ◽

10.1139/e98-088 ◽

2000 ◽

Vol 37 (2-3) ◽

pp. 415-426 ◽

Cited By ~ 21

Author(s):

Stéphane Rondenay ◽

Michael G Bostock ◽

Thomas M Hearn ◽

Donald J White ◽

Hua Wu ◽

...

Keyword(s):

Upper Mantle ◽

Seismic Anisotropy ◽

Receiver Function ◽

Function Analysis ◽

Geophysical Methods ◽

Azimuthal Anisotropy ◽

Crust And Upper Mantle ◽

Traveltime Inversion ◽

Velocity Models ◽

Geophysical Surveys

In the past decade, the Abitibi-Grenville Lithoprobe transect has been the site of numerous geological and geophysical surveys oriented towards understanding the lithospheric evolution of the southeastern Superior and adjoining Grenville provinces. Among the different geophysical methods that have been employed, earthquake seismology provides the widest range of information on the deep structures of the upper mantle. This paper presents a review of studies, both complete and ongoing, involving teleseismic datasets that were collected in 1994 and 1996 along the transect. A complete shear-wave splitting analysis has been performed on the 1994 dataset as part of a comparative study on electrical and seismic anisotropies. Results suggest a correlation between the two anisotropies (supported by xenolith data) and favour a lithospheric origin for the seismic anisotropy. The two anisotropies are believed to represent the fossilized remnants of Archean strain fields in the lithospheric roots of the Canadian Shield. Preliminary splitting results for the 1996 experiment suggest that the S-wave azimuthal anisotropy may be depth dependent and laterally varying. Ongoing receiver function analysis and traveltime inversion studies provide velocity models of the crust and upper mantle beneath the study area. Preliminary receiver function results reveal the presence of an S-velocity increase at ~90-100 km depth which appears to be laterally continuous over 200 km. Traveltime inversion models indicate the presence of an elongate, low-velocity anomaly beneath the southern portion of the 1996 array which strikes obliquely to major geological structures at the surface (e.g., Grenville Front). Preliminary interpretation relates this anomaly to the same process (e.g., fixed mantle plume, continental rifting) responsible for the emplacement of the Monteregian Hills igneous province.

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Structure of the oceanic lithosphere and upper mantle north of the Gloria Fault in the eastern mid-Atlantic by receiver function analysis

Journal of Geophysical Research Solid Earth ◽

10.1002/2016jb013582 ◽

2017 ◽

Vol 122 (10) ◽

pp. 7927-7950 ◽

Cited By ~ 10

Author(s):

Katrin Hannemann ◽

Frank Krüger ◽

Torsten Dahm ◽

Dietrich Lange

Keyword(s):

Upper Mantle ◽

Receiver Function ◽

Function Analysis ◽

Oceanic Lithosphere ◽

Receiver Function Analysis

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Preliminary results from teleseismic tomography of the upper mantle beneath northern Borneo

10.5194/egusphere-egu2020-4148 ◽

2020 ◽

Author(s):

Simone Pilia ◽

Nick Rawlinson ◽

Felix Tongkul ◽

Amy Gilligan ◽

Dave Cornwell

Keyword(s):

Upper Mantle ◽

Receiver Function ◽

Function Analysis ◽

P Wave ◽

The West ◽

Tomographic Images ◽

Teleseismic Tomography ◽

North East ◽

Receiver Function Analysis ◽

Entire Network

We present preliminary P-wave tomographic images of the upper mantle beneath northern Borneo (Sabah) using teleseismic earthquake data. Sabah underwent diachronous double-polarity subduction, one dipping to the southeast (terminated in the early Miocene) and the other to the northwest (terminated 5-6 Ma). With the goal of better understanding post-subduction processes in Sabah, 24 permanent seismic stations of MetMalaysia were augmented by the deployment of 46 temporary stations of the nBOSS network, which ran from March 2018 to January 2020. Relative P-wave traveltime residuals from nearly a thousand teleseismic events have been extracted from the continuous records using an adaptive stacking technique, which uses the coherency of global phases across the entire network. Using a grid-based eikonal solver and a subspace inversion technique implemented in FMTOMO, relative arrival time residuals are mapped as 3-D P-wave perturbations.The most intriguing feature of the final tomographic model is a north-east trending lithospheric structure running across northern Borneo and separating relatively low to high wavespeeds to the west and east, respectively. This structure possibly indicates the suture between pre-Cenozoic lithosphere to the east and the Cenozoic accreted material to the west.Results from receiver function analysis (i.e., crustal thickness) and crustal velocities from ambient noise tomography will be in the future incorporated in the tomographic inversion in order to obtain an integrated view of the crust-mantle system beneath Sabah.

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