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| Titel |
The Taili-Yiwulüshan metamorphic core complex corridor: Diachronous exhumation and relationships to the adjacent basins based on new 40Ar/39Ar and (U-Th-Sm)/He mineral ages |
| VerfasserIn |
Chenyue Liang, Franz Neubauer, Yongjiang Liu, Johann Genser, István Dunkl, Bianca Heberer, Wei Jin, Zuoxun Zeng, Weimin Li, Quanbo Wen, Jing Li |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250105224
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| Publikation (Nr.) |
 EGU/EGU2015-4694.pdf |
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| Zusammenfassung |
| The Xingcheng-Taili ductile shear zone (western Liaoning Province in China) formed during
latest Jurassic to Early Cretaceous crustal extension of the eastern North China craton, and
exhumed low to medium metamorphic grade Archean, Upper Triassic and Upper Jurassic
granitic rocks. The Mesozoic Yiwulüshan metamorphic core complex (Yiwulüshan MCC) is
dominated by a NNE–SSW elongated dome with a left-lateral shear zone, which is located in
the northeastern part of Xingcheng-Taili ductile shear zone, and combine as Taili-Yiwulüshan
metamorphic core complex corridor. To the east, it is bounded by the NNE-trending
Cretaceous to Eocene Liaohe basin (the northern extension of the Bohai Bay basin), and
to the west by the Cretaceous-aged Fuxin–Yixian basin, which could potentially
interpreted as supra-detachment basins. Here, we present results from a multi-method
thermochronological study and coupled with structural investigations and sections of adjacent
supra-detachment basins, which constrain the timing of regional deformation as
well as the cooling history and exhumation processes of the low- to middle-grade
metamorphic complex in the Taili-Yiwulüshan MCC corridor, in order to understand the
mode of lithospheric scale reactivation, extension and thinning of the North China
craton.
The new40Ar/39Ar muscovite, biotite, K-feldspar and (U-Th)/He apatite ages
from granitic rocks help constrain the thermal evolution during its exhumation. The
thermochronologic studies have shown at least three stages of exhumation and cooling from
late Jurassic to Eocene in Xingcheng-Taili shear zone should be distinguished, e.g., ~
150–130 Ma, 130–115 Ma and 115–52 Ma, respectively. Diachronous onset and subsequent
parallel cooling and exhumation characterize the early thermal history. The Yiwulüshan
MCC has a similar exhumation history from 135 to 97 Ma with a similar cooling
history.
The development of Taili-Yiwulüshan MCC corridor is associated with synkinematic
emplacement, exhumation, and volcanic-clastic deposition in the supra-detachment basins.
Initiation of the unroofing history resulted from ductile left-lateral shearing since latest
Jurassic times. Diachronous onset and subsequent cooling and exhumation characterize the
early thermal history. The second and third stages of cooling started lasted until the recently
active faulting. Start form the Early Cretaceous the detachment shear zone truncating by the
later brittle normal fault. The (U-Th)/He age of 52.3 ± 4.7 Ma indicating final Eocene
exhumation of the Taili area is consistent with normal faulting in the Bohai basin area in the
east.
Based on the present results and published information, that Cretaceous WNW-ESE
extensional deformation and lithosphere thinning in the Taili-Yiwulüshan corridor and
throughout the eastern North China craton, the synchroneity of cooling and exhumation of
metamorphic core complexes, the formation of supra-detachment basins, and regional
alkaline igneous activity reflects Early Cretaceous regional extensional tectonics , possibly
resulting from roll-back of the subducted Pacific plate beneath North China Craton. |
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