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Seismological constraints on the crustal structures generated by continental rejuvenation in northeastern China.

Zheng TY, He YM, Yang JH, Zhao L - Sci Rep (2015)

Bottom Line: Here, we present a seismic image across the North China Craton (NCC) and Central Asian Orogenic Belt (CAOB) using a velocity structure imaging technique for receiver functions from a dense array.The crustal evolution of the eastern NCC was delineated during the Mesozoic by a dominant low seismic wave velocity with velocity inversion, a relatively shallow Moho discontinuity, and a Moho offset beneath the Tanlu Fault Zone.The fossil structural fabric of the convergent boundary in the eastern CAOB indicates that the back-arc action of the Paleo-Pacific Plate subduction did not reach the hinterland of Asia.

View Article: PubMed Central - PubMed

Affiliation: Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, 100029, China.

ABSTRACT
Crustal rejuvenation is a key process that has shaped the characteristics of current continental structures and components in tectonic active continental regions. Geological and geochemical observations have provided insights into crustal rejuvenation, although the crustal structural fabrics have not been well constrained. Here, we present a seismic image across the North China Craton (NCC) and Central Asian Orogenic Belt (CAOB) using a velocity structure imaging technique for receiver functions from a dense array. The crustal evolution of the eastern NCC was delineated during the Mesozoic by a dominant low seismic wave velocity with velocity inversion, a relatively shallow Moho discontinuity, and a Moho offset beneath the Tanlu Fault Zone. The imaged structures and geochemical evidence, including changes in the components and ages of continental crusts and significant continental crustal growth during the Mesozoic, provide insight into the rejuvenation processes of the evolving crust in the eastern NCC caused by structural, magmatic and metamorphic processes in an extensional setting. The fossil structural fabric of the convergent boundary in the eastern CAOB indicates that the back-arc action of the Paleo-Pacific Plate subduction did not reach the hinterland of Asia.

No MeSH data available.


Related in: MedlinePlus

(a) Major tectonic units along with the location of the NCISP-6 profile. (b) The cross section of the shear-wave velocity structure beneath the NCISP-6 profile. The color lines mark the velocity discontinuities, and the dark line represents the boundary between C1 and C2. (c) Schematic illustration of the crustal rejuvenation by structural, magmatic and metamorphic processes in an extensional setting observed in the NCISP-6 profile.
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f3: (a) Major tectonic units along with the location of the NCISP-6 profile. (b) The cross section of the shear-wave velocity structure beneath the NCISP-6 profile. The color lines mark the velocity discontinuities, and the dark line represents the boundary between C1 and C2. (c) Schematic illustration of the crustal rejuvenation by structural, magmatic and metamorphic processes in an extensional setting observed in the NCISP-6 profile.

Mentions: The diffused and weakened PpPs phases from the Moho at certain stations (see Fig. S2 in the Supplementary material) indicated that the Moho interface beneath the NCISP-6 is not always a sharp velocity discontinuity and presents gradual transitions in seismic velocity23, with the shear-wave velocity (VS) of 3.9 km/s of the lower crust increasing gradually to 4.2 km/s. We defined the depth of the lower boundary of the transition zone as the depth of the Moho. The crustal thickness (Moho depth) shows a good agreement with results of the previous Donggou-Dongwuqi Geoscience Transect24 (Fig. S5 in the Supplementary material), which very closely parallels the NCISP-6 profile and shows a thin crust with an approximate thickness of 31–35 km in the southeast that increases to an approximate thickness of 38–41 km in the northwest. The velocity image of the NCISP-6 profile shows four significant features (Figs 2c and 3b): (1) crustal structures characterized by dominant low-velocity zones and a velocity inversion in the southeast; (2) large-scale dipping strata in the northwest; (3) offset of the Moho beneath stations 17–19; and (4) well-partitioned matching of the crustal structures with surficial geologic observations (Fig. 3a,b).


Seismological constraints on the crustal structures generated by continental rejuvenation in northeastern China.

Zheng TY, He YM, Yang JH, Zhao L - Sci Rep (2015)

(a) Major tectonic units along with the location of the NCISP-6 profile. (b) The cross section of the shear-wave velocity structure beneath the NCISP-6 profile. The color lines mark the velocity discontinuities, and the dark line represents the boundary between C1 and C2. (c) Schematic illustration of the crustal rejuvenation by structural, magmatic and metamorphic processes in an extensional setting observed in the NCISP-6 profile.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4595743&req=5

f3: (a) Major tectonic units along with the location of the NCISP-6 profile. (b) The cross section of the shear-wave velocity structure beneath the NCISP-6 profile. The color lines mark the velocity discontinuities, and the dark line represents the boundary between C1 and C2. (c) Schematic illustration of the crustal rejuvenation by structural, magmatic and metamorphic processes in an extensional setting observed in the NCISP-6 profile.
Mentions: The diffused and weakened PpPs phases from the Moho at certain stations (see Fig. S2 in the Supplementary material) indicated that the Moho interface beneath the NCISP-6 is not always a sharp velocity discontinuity and presents gradual transitions in seismic velocity23, with the shear-wave velocity (VS) of 3.9 km/s of the lower crust increasing gradually to 4.2 km/s. We defined the depth of the lower boundary of the transition zone as the depth of the Moho. The crustal thickness (Moho depth) shows a good agreement with results of the previous Donggou-Dongwuqi Geoscience Transect24 (Fig. S5 in the Supplementary material), which very closely parallels the NCISP-6 profile and shows a thin crust with an approximate thickness of 31–35 km in the southeast that increases to an approximate thickness of 38–41 km in the northwest. The velocity image of the NCISP-6 profile shows four significant features (Figs 2c and 3b): (1) crustal structures characterized by dominant low-velocity zones and a velocity inversion in the southeast; (2) large-scale dipping strata in the northwest; (3) offset of the Moho beneath stations 17–19; and (4) well-partitioned matching of the crustal structures with surficial geologic observations (Fig. 3a,b).

Bottom Line: Here, we present a seismic image across the North China Craton (NCC) and Central Asian Orogenic Belt (CAOB) using a velocity structure imaging technique for receiver functions from a dense array.The crustal evolution of the eastern NCC was delineated during the Mesozoic by a dominant low seismic wave velocity with velocity inversion, a relatively shallow Moho discontinuity, and a Moho offset beneath the Tanlu Fault Zone.The fossil structural fabric of the convergent boundary in the eastern CAOB indicates that the back-arc action of the Paleo-Pacific Plate subduction did not reach the hinterland of Asia.

View Article: PubMed Central - PubMed

Affiliation: Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, 100029, China.

ABSTRACT
Crustal rejuvenation is a key process that has shaped the characteristics of current continental structures and components in tectonic active continental regions. Geological and geochemical observations have provided insights into crustal rejuvenation, although the crustal structural fabrics have not been well constrained. Here, we present a seismic image across the North China Craton (NCC) and Central Asian Orogenic Belt (CAOB) using a velocity structure imaging technique for receiver functions from a dense array. The crustal evolution of the eastern NCC was delineated during the Mesozoic by a dominant low seismic wave velocity with velocity inversion, a relatively shallow Moho discontinuity, and a Moho offset beneath the Tanlu Fault Zone. The imaged structures and geochemical evidence, including changes in the components and ages of continental crusts and significant continental crustal growth during the Mesozoic, provide insight into the rejuvenation processes of the evolving crust in the eastern NCC caused by structural, magmatic and metamorphic processes in an extensional setting. The fossil structural fabric of the convergent boundary in the eastern CAOB indicates that the back-arc action of the Paleo-Pacific Plate subduction did not reach the hinterland of Asia.

No MeSH data available.


Related in: MedlinePlus