Thermal Structure of Lithosphere in North China

Abstract

The thermal structures of lithosphere in North China(105°E – 124°E, 30°N – 41°N) were calculated using two kinds of average heat flow on 1° × 1° Latitude‐Longitude grid combining with four heat production models which were obtained from observed heat production and from the inversion of Curie depth distribution. By comparison and analysing the thermal structures obtained from different models, the most reasonable model was obtained. The temperature at Moho‐discontinuity is about from 450°C to 750°C. The thickness of thermal lithophere is from 60km to 180km. It is found that big fault systems are related to thiner part of the lithosphere and the earthquakes of MS >6.5 occurred near the area of thiner part of the lithosphere and the area in which the temperature of the Moho‐discontinuity is higher.

Crust and Lithospheric Structure - Global Crustal Structure

“…1.11.4.6 Surface Geology, Exposed Deep Crustal Sections, Xenoliths, and Geochemical Data Surface geology, exposed deep crustal sections, xenolith samples, and geochemical data all provide direct observations of the Zang et al 2002 composition and physical properties of the crust. The composition of the upper continental crust is, by definition, evident in global geologic maps, which are dominated by felsic intrusive rocks and low-grade metamorphic rocks, particularly shales and sandstones (Clarke, 1889;Clarke and Washinton, 1924;Taylor and McLennan, 1992).…”

Thermal structure about southwest sub-basin of South China Sea

“…Firstly, thermal conductivities in this paper are not accordant with the reality. In this paper we suppose the conductivity of each layer is constant, but the value is usually changing with temperature, pressure or different mineral composition (Liu et al, 2003;Wang et al, 1996;Zang et al, 2002b;Ou et al, 2006). According to formula (2), the conductivity can affect the heat flow.…”

Three-dimensional thermal structure of the Chinese continental crust and upper mantle

“…The heat productivities of sediments and the upper crust are taken from Wang [3] ; for the middle crust, the heat productivities are set as 0.4 μWm −3 [3,26] , which is the maximum value used by Artemieva and Mooney [1] ; for the heat productivities of the lower crust and upper mantle, we again follow Artemieva and Mooney [1] by setting them as 0.1 and 0.01 μWm −3 , respectively. Considering that both temperature and pressure have an obvious influence on conductivities of the upper crust [27] , the conductivities are estimated from a relation [3,24] of conductivity (Wm −1 K −1 ) with depth (D, in km) and temperature (℃): 3.0×(1+0.0015D)/(1+0.0015T). Finally, we use constant conductivities for the other layers: 2.5 Wm -1 K −1 [3] for sediments; 2.25 Wm −1 K −1 for the middle crust, which is the average of the values used by Artemieva and Mooney [1] ; and 2.0 and 4.0 Wm −1 K −1 for the lower crust and upper mantle respectively, also from Artemieva and Mooney [1] .…”

“…Many geothermal scientists [3,24,28,[32][33][34] have studied the craton's thermal structure, but with the steady-state thermal conduction assumption. Based on systematic studies of the average heat productivities of different cratonic rocks and different formations in the North China craton, Chi and Yan [28] calculated the thermal structure of the craton lithosphere.…”

“…Instead, we estimate the crustal temperatures by solving the steady-state thermal conduction equation with the boundary conditions of the surface temperatures and the upper-mantle temperatures estimated above from seismic velocities. The steady-state thermal conduction equation [24] can be written as…”