Traditionally the Chinese South Tianshan has been regarded as a late Paleozoic orogenic belt. However, little is known about
the early Paleozoic tectonic architecture of the region. This paper presents the first evidence of Cambrian–Ordovician MORB-type
basalts and adakitic diorites on the southern margin of the Yili plate in China. Basalts from Xiate in southwestern Tianshan
show a typical transitional (T-) MORB and ferrobasalt composition, which indicate a formation at a propagating spreading ridge.
The basalts give a weighted mean 206Pb/238U crystallization age of 516.3 ± 7.4 Ma by SHRIMP U–Pb zircon dating and have experienced contact metamorphism due to the
intrusion of a dioritic pluton. The dioritic pluton has a weighted mean 206Pb/238U crystallization age of 470 ± 12 Ma and geochemical characteristics resembling that of adakitic rocks. The pluton is considered
to have been formed by partial melting of garnet amphibolites from thickened lower crust in arc or continental collision settings.
The basalts and diorites are considered to outline the eastern extension of the early Paleozoic suture zone, the Nikolaev
Line, which stretches east–west for hundreds of kilometers between the Northern Tianshan and Central Tianshan terranes of
Kyrgyzstan. Our findings substantiate that the Yili and Central Tianshan plates were separated by the early Paleozoic Terskey
ocean. The Terskey ocean probably closed during the early stage of the late Ordovician (Lomize et al. in Geotectonics 31(6):463–482,
1997), resulting in the final amalgamation of the Yili and Central Tianshan plates. Consequently, an early Paleozoic suture zone
is documented in the Chinese Tianshan region, which is most likely represented by the North Nalati fault. 相似文献
We develop a new numerical model based on a precise integration method to investigate the coupled thermo-mechanical performance of layered transversely isotropic media around a cylindrical/tubular heat source. To obtain the relational matrices of the extended precise integration method, we first convert the governing equations of the problem into ordinary differential matrix equations through the Laplace–Hankel transform. Then, the cylindrical heat source is divided into a series of plane heat sources, and the plane temperature load term is added to the state vector between layer elements. By combining the layer elements, we build a layered transversely isotropic numerical model containing a cylindrical heat source in the transformed domain. Finally, we solve the model in the transformed domain and obtain the solution of the problem in the real domain through the Laplace–Hankel transform inversion. The accuracy of this method is verified by comparing the solutions with the results of the analytical method and the finite element method. Then, we study the influence of the anisotropy of thermal parameters, the embedded depth, the length/radius ratio, the type of heat source and the stratification of the medium on the thermo-mechanical coupled performance.
This paper summarizes the main flash flood early-warning systems of America, Europe, Japan, and Taiwan China and discusses their advantages and disadvantages. The latest development in flash flood prevention is also presented. China’s flash flood prevention system involves three stages. Herein, the warning methods and achievements in the first two stages are introduced in detail. Based on the worldwide experience of flash flood early-warning systems, the general research idea of the third stage is proposed from the viewpoint of requirements for flash flood prevention and construction progress of the next stage in China. Real-time dynamic warning systems can be applied to the early-warning platform at four levels (central level, provincial level, municipal level, and county level) . Through this, soil moisture, peak flow, and water level can be calculated in real-time using distributed hydrological models, and then flash flood warning indexes can be computed based on defined thresholds of runoff and water level. A compound warning index (CWI) can be applied to regions where rainfall and water level are measured by simple equipment. In this manner, flash-flood-related factors such as rainfall intensity and antecedent and cumulative rainfall depths can be determined using the CWI method. The proposed methodology for the third stage could support flash flood prevention measures in the 13th 5-Year Plan for Economic and Social Development of the People’s Republic of China (2016–2020). The research achievements will serve as a guidance for flash flood monitoring and warning as well as flood warning in medium and small rivers. 相似文献