The Dasanjiang basin group in Northeast China contains more than ten Mesozoic–Cenozoic sedimentary basins. Much evidence shows that they were a unified large-scale depression lacustrine basin in the Early Cretaceous; however, destruction processes and mechanisms after the formation of the unified lacustrine basin are some of the key issues restricting basic research and oil and gas exploration in the Dasanjiang area. In this study, we carried out low-temperature thermochronology and thermal history inversion on samples from the main basins in the Dasanjiang area to finely restore the destruction process of the unified basin. The results show that since the Early Cretaceous, the Dasanjiang area has experienced three major positive tectonic inversions: 100 Ma~90 Ma, 73 Ma~40 Ma, and 23 Ma~5 Ma. The unified basin was destroyed by compression and uplift and gradually disintegrated. The basin gradually changed from initial unified evolution to differential evolution and finally formed the isolated appearance of each basin. The aforementioned three-stage positive tectonic inversion time limits basically corresponded to the changing periods in the movement direction, subduction angle, and movement speed of the paleo–Pacific Ocean plate. It is believed that the movement and reorganization events of the plates on the Pacific side dominated the formation, destruction, and disintegration of the Dasanjiang prototype basin, which was the main dynamic mechanism of the tectonic evolution of the Mesozoic and Cenozoic basins in the study area and Northeast China.
Intelligent diagnosis method has become a new focus for researchers, which can get rid of the dependence of diagnostic experience and prior knowledge. However, in practical application, to deal with the new fault type of mechanical equipment, the number of fault labels of the diagnosis model needs to be increased. We must retrain the whole training model, which is a time-consuming process. To solve this problem, higher requirements are put forward for the generalization ability and universality of the algorithm. In view of the feature extraction advantages of cross-sparse filtering (Cr-SF), which can be regarded as an unsupervised minimum entropy learning method using the maximization of the proxy of sparsity, this paper proposed a parallel network based on Cr-SF. The feature extraction process of each sample is independent, and the feature extraction and classifier training process are separated. Therefore, the most prominent advantage of the proposed method is that when a new fault occurs, it only needs to extract the feature of the new fault separately and then input it to the classifier at the last layer for training. The experimental results show that the proposed method can obtain high accuracy and stability and can significantly improve the adaptability of intelligent fault diagnosis in practical application.
The Lower Cambrian Xiaoerbulake Formation consist of thick dolostones which are high-quality hydrocarbon reservoir in the western Tarim Basin, but the origin of dolomite is still controversial, which lead to poor understanding to the origin of reservoir beds. By using the latest core data of Well XKD-1, we analyzed the petrology and geochemistry of the formation in order to clarify the genesis of dolomite. The geochemical analysis includes Sr, C, and O isotopes, and in-situ minor element and rare Earth element measurements for different types of dolomites by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). Four types of lithofacies are recognized in the Xiaoerbulake Formation based on different textures, which are laminated dolostone, thrombolite dolostone, bacteria-bonded dolostone, and grain dolostone. Two types of dolomites can be separated which are matrix dolomite (MD) and cement dolomite (CD). MD is the primary type of laminated and bacteria-bonded dolostone, and CD was developed mainly in grain dolostone and thrombolite dolostone. The δ13C and δ18O indicate that the grain dolostone and thrombolite dolostone have undergone more intensive diagenetic modification. On the contrary, the diagenetic modification of laminated and bacteria-bonded dolostone are relatively weak, which implies that the dolomitization of the latter two lithofacies occurs before burial stage. The 87Sr/86Sr ratio indicates that the corresponding fluid for dolomitization was seawater or marine-origin fluids. The MD was formed in the near-surface stage via the penecontemporaneous dolomitization of seawater or hyper-saline seawater. The dolomitization of CD occurred in the burial environment with the porosity was filled by marine-origin fluid, indicating a seepage-reflux dolomitization process. Both types of dolomites are partially affected by hydrothermal activities.
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