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The Neoproterozoic Jiangnan orogenic belt delineates the suture zone between the Cathaysia and Yangtze blocks of the South China Craton. The western part of the belt, in the Longsheng region, consists of a disrupted mafic-ultramafic assemblage of pillow basalt, gabbro, diabase, and peridotite along with siliceous marble, ophicalcite, and jasper mixed with basalt. Significant talc deposits occur on the margins of the ultramafic bodies as well as in the transition zone between marble and basalt. Primary rock relations are largely overprinted by pervasive shearing, resulting in disruption of the assemblage into series of discontinuous blocks within a phyllite matrix. West-dipping thrust faults mark the eastern contact of blocks, and the overall succession has the appearance of a tectonic melange. U-Pb zircon age data from the gabbros and diabases yield crystallization ages of 867 ± 10, 863 ± 8, and 869 ± 9 Ma, with positive εHf(τ) values. The gabbro, basalt, serpentinite, and some talc samples display minor light rare earth element-enriched patterns with obvious depletion of Nb and Ta, indicating a subduction-related setting. The tuffaceous phyllite shows similar geochemical features. A few mafic rocks and the altered ultramafic rocks display mid-ocean ridge basalt (MORB) affinity. Overall lithostratigraphic relationships, age data, and geochemical signatures suggest a forearc setting that was imbricated and disrupted within an accretionary prism environment to form an ophiolitic melange. The pillow basalt, red jasper, and MORB-type mafic-ultramafic rocks within the melange occur as exotic blocks derived from the subducting oceanic plate, whereas the arc-type mafic rocks occur as autochthonous blocks, which are all exposed in a matrix of sandy and tuffaceous phyllite.

In order to better constrain the specific depositional age and provenance of the Danzhou Group and understand the geological evolution of the Jiangnan Orogenic Belt, we conducted a combined U-Pb and Hf-isotope analysis of detrital zircons from the Gongdong and Hetong formations of the Danzhou Group in the Longsheng area of the Western Jiangnan Orogenic Belt. Detrital zircons from the Gongdong Formation yield three age populations of 2658–2517 Ma, 2427–1678 Ma and 891–781 Ma, and the youngest ages suggest that the sedimentation began after ca. 783 Ma. U-Pb ages of detrital zircons from the Hetong Formation yield major populations at 2769–2502 Ma, 2492–2100 Ma, and 991–731 Ma, and the youngest ages redefine the maximum depositional age of this unit is 760 Ma, much younger than previously considered. Thus, the upper part of the Hetong Formation in the Longsheng area is newly subdivided into the Sanmenjie Formation, which is characterized by a large amount of 765–761 Ma volcanic rocks. The dominant 991–731 Ma detrital zircons for all samples were likely sourced from the Neoproterozoic igneous rocks of the southeast margin of the Yangtze Block. The subordinate 2494–1678 Ma detrital zircons were probably sourced from the Cathaysia Block. Minor amounts of 2769–2502 Ma detrital zircons may have been sourced from the Yangtze Block. Detrital zircons from the Gongdong Formation have mainly negative εHf (t) values (−1.1 to 21.8, 90%), suggesting that the detritus of the Gongdong Formation is dominated by the recycling of old crustal materials. The εHf (t) values of detrital zircons from the Hetong Formation have a large spread of −22.2 to +9.7, indicating that the source material of the Hetong Formation includes both the juvenile crustal materials and the recycled ancient crustal materials. The above age populations and Hf isotopic characteristics are consistent with the magmatic rocks in the Jiangnan Orogenic Belt and the Southeast Yangtze Block. Taking into account the lithostratigraphic features, provenances, and depositional ages, the Danzhou Group in the Western Jiangnan Orogenic Belt was deposited in a back-arc basin.

The Jiangnan Orogen, located at the southeastern margin of the Yangtze Block, South China, records the complete history of assembly and evolution between the Yangtze and Cathaysia blocks. Neoproterozoic sedimentary sequences are widespread in the Jiangnan Orogen, with a regional angular unconformity separating the Sibao and Danzhou groups. U-Pb geochronology and Lu-Hf isotope analyses were carried out on detrital zircons across this unconformity and also the associated granites in the western Jiangnan Orogen in this study. Our new results, combined with previous data, indicate that the Sibao and Danzhou groups were deposited at 860-832 and 803-764 Ma, respectively. Thus, this unconformity was constrained to be 832-803 Ma. Detrital zircons from the Sibao and Danzhou groups have generally similar age populations, with three major peaks at 2000-1550, 1000-880, and 850-830 (760) Ma and one minor at 2600-2400 Ma. The most important generation of juvenile crust appears to have occurred at 2600-2400 Ma. Both recycling of ancient crustal materials and addition of juvenile mantle components took place in the time intervals of 2000-1550 and 1000-880 Ma. Detrital zircons in the age population of 850-830 (760) Ma were probably derived from proximal magmatic rocks in the western Jiangnan Orogen, reflecting fast erosion of newly formed igneous rocks. The Sibao and equivalents were deformed and intruded by granites posterior to the deposition of the Sibao and equivalent sequences after 832 Ma but before deposition of the Danzhou and equivalent units before 803 Ma. The pre-Danzhou deformation marked a collision along the southeast margin of the Yangtze Craton. The regional angular unconformity sealed the Jiangnan Orogeny, and thus the collision between the Yangtze and Cathaysia blocks was during 832-803 Ma. The Danzhou and equivalent units unconformably overlying the Sibao Group record the onset of rifting along the southeastern Yangtze margin beginning around 803 Ma.

Background Danzhou chicken (DZC) is a native chicken breed endemic to Hainan Island, which is renowned for its superior meat quality and strong disease resistance. Prolonged geographical isolation, coupled with natural and artificial selection events in response to the tropical environment, has significantly transformed the behavior, appearance, and economically important traits of DZC. However, the relatively small size of its conservation population has impeded research on the genetic mechanisms of specific traits and population genetics, exerting an adverse influence on resource conservation and commercial development. This study aims to investigate the formation mechanisms of environmental adaptability through a scanning analysis of population selection in DZC. Results The results of ROH (runs of homozygosity) analysis revealed a total of 59,217 ROH segments among 200 individuals, with short ROH segments constituting approximately 96% of the total count. The F ROH method determined an average inbreeding coefficient of 0.068, indicating a low level of inbreeding in the DZC population. Furthermore, by employing the Wenchang chicken (WCC) population as a control group and utilizing within-group and between-group selection scan methods, we identified the genomic selection characteristics of the DZC population. Through multi-method analysis, a total of 160 potential candidate genes, including IL1RAPL1 , RBFOX1 , VSTM2A , CADM2 , ANO5 , PHF14 , and BCO2 , were identified. Gene annotation revealed the potential impacts of these genes on behavioral traits, immunity, neural development processes, lipid regulation, reproduction, and growth development. Conclusion In summary, we used whole-genome resequencing data combined with SNPs detection data from other local varieties and four selection signal analysis methods to explore selection signatures. These discoveries contribute to the identification of genes associated with phenotypic traits in the DZC population and enhance our understanding of the biological processes underlying strong and sustained selective influences in populations. These findings provide crucial insights for conserving DZC genetic resources as well as driving advancements in breeding innovation and genetic improvement.