The formation of the Yellow River involved the draining of a series of ancestral local lakes along their course, substantially changing the regional, geomorphic, and paleoenvironmental evolution. However, the evolution of the Weihe-Sanmenxia Basin section of the Yellow River remains indistinct as previous studies regard the Weihe and Sanmenxia Basin as one integral basin of the Late Cenozoic. Here, we present the detrital zircon age spectra from the Pliocene-Pleistocene Sanmen Formation to clarify the drainage system evolution of the two basins since the Late Pliocene. The results reveal that these two basins belonged to different drainage systems in the Late Pliocene because no sediments from the marginal mountains of the Weihe Basin accumulated in the Sanmenxia Basin. At 2.8/2.6 Ma, the currents presented at the edge of the basins and transported the sediment of east Hua Mountain into the Sanmenxia Basin, where it was deposited. This integration likely leads to a mismatch between the deposition and regional paleoclimate in previous studies. At ∼1.0 Ma, the Sanmenxia Gorge was traversed and the Yellow River finally formed, depositing Jinshaan Gorge sediment into the Sanmenxia Basin and lower reaches of the Yellow River.
To solve the problems of underwater image color deviation, low contrast, and blurred details, an algorithm based on color correction and detail enhancement is proposed. First, the improved nonlocal means denoising algorithm is used to denoise the underwater image. The combination of Gaussian weighted spatial distance and Gaussian weighted Euclidean distance is used as the index of nonlocal means denoising algorithm to measure the similarity of structural blocks. The improved algorithm can retain more edge features and texture information while maintaining noise reduction ability. Then, the improved U-Net is used for color correction. Introducing residual structure and attention mechanism into U-Net can effectively enhance feature extraction ability and prevent network degradation. Finally, a sharpening algorithm based on maximum a posteriori is proposed to enhance the image after color correction, which can increase the detailed information of the image without expanding the noise. The experimental results show that the proposed algorithm has a remarkable effect on underwater image enhancement.
As the last area with unknown oil exploration potential, Zealandia has attracted the attention of petroleum scientists. Under the constraint of the known rift distribution, the gravity and magnetic anomaly data are utilized to predict the distribution of rift basins, and the balanced cross-section technique and basin simulation technique are utilized to analyze the development of the rift basins and hydrocarbon generation history of source rocks for the hydrate prospect prediction of the rift basins of northwest Zealandia. The time of rifting in Zealandia varies greatly from place to place, and it has experienced extensive rifts, migrated to the east of the Lord Howe Ridge, migrated to the west of the Lord Howe Ridge, migrated to the west of the Dampier Ridge, and finally migrated to both sides of the Lord Howe Ridge and then experienced multiple stages of compression transformation and deep burial transformation. The Upper Cretaceous coal source rock in the rift Ⅱ stage has entered the wet gas generation stage in the deep part of the rift or deeper rift on the eastern side of the Lord Howe Ridge, and the coal-generated wet gas may migrate along the fault and form a gas hydrate in the shallow seabed stable zone.
The premise to discuss the evolution of an orogenic belt is to understand the origins and tectonic affinities of various blocks that constitute the orogen. The Baoshan Block in the SE Tibetan Plateau is an ultimate window to observe the orogenic evolution, but its origin and eastern boundary remains debated. In this contribution, we report new detrital zircon U–Pb ages and Hf isotopic data from the Cambrian Baoshan Formation in the middle–western part of the Baoshan Block. Detrital zircon ages range from the Archean to Early Palaeozoic, with age peaks at ~2.5, ~0.95, and ~0.55 Ga. Zircon ε Hf (t) values exhibit a wide range from negative to positive for each of the three major age groups, indicating diverse magma sources. The eastern boundary for the Baoshan Block should be extended from the Kejie‐Nandinghe Fault to the Changning‐Menglian suture belt, based on not only comparisons of Early Palaeozoic magmatism, sedimentary facies, and provenances for the Palaeozoic strata that developed on both sides of the Kejie‐Nandinghe Fault but also on the regional tectonic framework correlation. The Baoshan Block should be along the Indian margin as the Qiangtang, Tengchong, and Simao‐Indochina blocks in Early Palaeozoic according to the provenance analyses.
ABSTRACT The Tobago Basin, which is located offshore northern Venezuela with a southern margin close to Trinidad and Tobago, has an area of approximately 59,600 km 2 . The Tobago Basin has relatively favourable hydrocarbon prospects, and to date, exploration work has mainly concentrated on small areas of the southwestern portion of the basin. To conduct a comprehensive study of the structural framework of the basin and the characteristics of the basement in order to identify prospective zones for hydrocarbon exploration, shipborne‐measured and satellite‐measured gravity data, shipborne‐measured magnetic data, and aeromagnetic survey data were analysed. A regularisation filtering method was used to separate and obtain regional and residual gravity and magnetic anomalies. Directional gradients of gravity and magnetic anomalies and the total horizontal gradient and vertical second derivative of gravity anomalies were employed to extract information about fault structures. Regression analysis methods were used to determine the basement depth. The geological significance of the gravity and magnetic fields was examined, the structural framework of the basin was assessed, the basement depth was estimated, and favourable hydrocarbon exploration prospects within the basin were identified. The results show that the Tobago Basin contains complex structures consisting mainly of two groups of faults trending in northeasterly and northwesterly directions and that the major northeasterly trending faults control the main structural configuration and depositional system within the basin. The basement of the Tobago Basin has deep rises and falls. It can be divided into the following four secondary tectonic units: the western sub‐basin, the central uplift area, the southern sub‐basin, and the northeastern sub‐basin. The central uplift area and northeastern sub‐basin are most likely to have developed hydrocarbon accumulations and should be targeted for further exploration.
Using citric acid instead of ammonia water as the complexing agent, an NCM622 cathode material with excellent electrochemical performance can be prepared by a hydroxide coprecipitation method which is environmentally friendly.
'/%3e%3cuse xlink:href='%23a' transform='rotate(23.036 .093 25.536)'/%3e%3cuse xlink:href='%23a' transform='rotate(45.87 1.273 16.18)'/%3e%3cuse xlink:href='%23a' transform='rotate(69.945 .996 12.078)'/%3e%3cuse xlink:href='%23a' transform='rotate(20.66 -19.689 31.932)'/%3e%3c/svg%3e)