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Object detection has made tremendous progress in natural images over the last decade. However, the results are hardly satisfactory when the natural image object detection algorithm is directly applied to satellite images. This is due to the intrinsic differences in the scale and orientation of objects generated by the bird’s-eye perspective of satellite photographs. Moreover, the background of satellite images is complex and the object area is small; as a result, small objects tend to be missing due to the challenge of feature extraction. Dense objects overlap and occlusion also affects the detection performance. Although the self-attention mechanism was introduced to detect small objects, the computational complexity increased with the image’s resolution. We modified the general one-stage detector YOLOv5 to adapt the satellite images to resolve the above problems. First, new feature fusion layers and a prediction head are added from the shallow layer for small object detection for the first time because it can maximally preserve the feature information. Second, the original convolutional prediction heads are replaced with Swin Transformer Prediction Heads (SPHs) for the first time. SPH represents an advanced self-attention mechanism whose shifted window design can reduce the computational complexity to linearity. Finally, Normalization-based Attention Modules (NAMs) are integrated into YOLOv5 to improve attention performance in a normalized way. The improved YOLOv5 is termed SPH-YOLOv5. It is evaluated on the NWPU-VHR10 dataset and DOTA dataset, which are widely used for satellite image object detection evaluations. Compared with the basal YOLOv5, SPH-YOLOv5 improves the mean Average Precision (mAP) by 0.071 on the DOTA dataset.

Single zircon LA-ICP-MS U-Pb dating and lithogeochemical studies have been performed on the Xianggou monzonitic granitic porphyry outcropped in the Ma'anqiao gold deposit. A weighted average U-Pb age of 242.0±0.8 Ma for Xianggou monzonitic porphyry has been obtained. This corresponds with the conclusions of previous studies indicating a syn-orogenic age (242±21 Ma) of the Qinling Orogenic Belt, suggesting that the formation of the Xianggou granite should be associated with the collisional event of the North China Plate and the Yangtze Plate in the Indosinian period. The Xianggou granite is characterized by the high silicon and alkali of high K calc-alkaline series granites. It is rich in Al (Al 2 O 3 =14.49%-15.61%) and Sr (457.10-630.82 ppm), poor in Y (<16 ppm) and HREE (Yb<0.45 ppm), and exhibits high ratios of Sr/Y (76.24-97.34) and (La/Yb) N (29.65-46.10), as well as strongly fractionated REE patterns. These geochemical characteristics suggest the Xianggou granite can be classified as C-type adakitic rock. The initial Sr isotope ratios for the Xianggou granite vary from 0.70642 to 0.70668, ε Nd (t) values from −4.54 to −3.98, and T DM values from 1152 Ma to 1220 Ma. The low ε Nd (t) and I Sr and high T DM values, as well as Na 2 O/K 2 O ratios of the Xianggou granite are close to 1 (Na 2 O/K 2 O=0.95-1.10), indicating that it is not an I-type adakite formed by partial melting of the subducting oceanic crust, nor adakitic rock formed by melting of the underplated basaltic lower crust, but the product of partial melting of the nonunderplated basaltic thickened lower crust. Zircons from the Xianggou pluton have a homogeneous Hf isotopic composition with negative ε Hf (t) values (between −9.7 and −5.9, with an average of −6.9), indicating that the rock-forming materials were mostly extracted from the ancient crust, not from the depleted mantle. The Xianggou monzonitic granitic porphyry is rich in LILE and LREE and depleted in HSFE, HREE and Y; the composition of trace element and REE are similar to those of the syn-collisional granites. The geological and geochemical characteristics of the Xianggou granite reveal that it was a product of partial melting of the basaltic rocks from the thickened lower crust, triggered by continental collision, which occurred in the geodynamic background of continental-continental collision and shearing within the crust. The Xianggou granite was intruded in the compressive orogenic environment 242 Ma ago, but the gold mineralization occurred in the transitional environment of compression to extension around 170 Ma ago, lagging behind the intrusive age of the Xianggou granite by about 70 Ma. Meanwhile, the distribution of trace elements and REEs of the Xianggou monzonitic granitic porphyry is distinct from that of ores, suggesting the absence of direct genetic relationship between the Xianggou granite and gold mineralization. In contrast, the relatively high ore-forming elemental content of the Xianggou monzonitic granitic porphyry is due to the rock having experienced Au-bearing hy...

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