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The crustal structure of south central Mongolia using receiver functions
Author(s) -
He Jing,
Wu Qingju,
Sandvol Eric,
Ni James,
Gallegos Andrea,
Gao Mengtan,
Ulziibat Munkhuu,
Demberel Sodnomsambuu
Publication year - 2016
Publication title -
tectonics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.465
H-Index - 134
eISSN - 1944-9194
pISSN - 0278-7407
DOI - 10.1002/2015tc004027
Subject(s) - geology , crust , bouguer anomaly , receiver function , seismology , tectonics , upper crust , fault (geology) , gravity anomaly , lithosphere , geophysics , paleontology , oil field
The crustal thickness H and average crustal velocity ratio k (Vp/Vs) beneath south central Mongolia are investigated using the H‐k stacking method based on teleseismic radial receiver functions. Our primary results reveal that the local crustal thickness varies from 38 to 46 km with an average value of 43 km. Thicker crust is found beneath the western Hentey Mountains, while thinner crust is located in the southern area of the Zuunbayan fault zone. The Bouguer gravity anomalies exhibit a strong correlation with the overall crustal thickness pattern throughout most of our study regime. Moreover, a new approach which integrates the Bouguer anomaly gradient and the receiver function‐derived crustal thickness is adopted to calculate the density of the lower crust underneath central Mongolia. Fairly dense lower crust of approximately 3000 kg/m 3 is found in the Middle Gobi Desert. The measured crustal Vp/Vs ratio ranges from 1.68 to 1.83 with an average value of 1.74. Low Vp/Vs ratio is found beneath the western Hentey Mountains. In general, low Vp/Vs ratios correlate well with regions of quartz‐rich crust and high heat flow. High Vp/Vs ratios occur in the Middle Gobi volcanic regions and the Mesozoic Southern Gobi Basin.