Geochemistry of Mesoproterozoic Volcanic Rocks in the Western Kunlun Mountains: Evidence for Plate Tectonic Evolution

Mesoproterozoic volcanic rocks occurring in the north of the western Kunlun Mountains can be divided into two groups. The first group (north belt) is an reversely-evolved bimodal series. Petrochemistry shows that the alkalinity of the rocks decreases from early to late: alkaline→calc-alkaline→tholeiite, and geochemistry proves that the volcanic rocks were formed in rifting tectonic systems. The sedimentary facies shows characteristics of back-arc basins. The second (south belt) group, which occurs to the south of Yutian-Minfeng-Cele, is composed of calc-alkaline island arc (basaltic) andesite and minor rhyolite. The space distribution, age and geochemistry of the two volcanite groups indicate that they were formed in a back-arc basin (the first group) and an island arc (the second group) respectively and indicate the plate evolution during the Mesoproterozoic. The orogeny took place at -1.05 Ga, which was coeval with the Grenville orogeny. This study has provided important geological data for exploring the position of the Paleo-Tarim plate in the Rodinia super-continent.

切开复位内固定治疗前臂双极骨折脱位

目的探讨切开复位内固定治疗前臂双极骨折脱位的疗效。方法2014年6月—2019年3月,收治14例前臂双极骨折脱位患者。男9例,女5例;年龄19~52岁,平均34.9岁。致伤原因:高处坠落伤8例,交通事故伤4例,运动伤1例,机器绞伤1例。受伤至入院时间2~48 h,平均16.6 h。均为闭合性损伤。尺、桡骨骨折均切开复位内固定,上、下尺桡关节根据稳定程度选择修补环状韧带、外侧副韧带或者TightRope带袢钢板固定。术后石膏固定3周后,指导患者开始功能锻炼。记录骨折愈合时间,腕、肘关节稳定性及活动度、前臂旋转功能恢复情况。末次随访时,采用Anderson等的前臂功能评分标准评价疗效。结果术后切口均Ⅰ期愈合。14例均获随访,随访时间12~36个月,平均24.8个月。X线片复查显示骨折均愈合,愈合时间12~18周,平均14.9周。上、下尺桡关节稳定性均可。末次随访时,肘关节屈伸活动度为65°~160°,平均124.6°;腕关节屈伸活动度为115°~165°,平均155.0°;前臂旋转活动度为65°~165°,平均154.6°。根据Anderson等的前臂功能评分标准评价:优8例,良5例,不满意1例。结论前臂双极骨折脱位需选择个体化治疗方案,重点是恢复尺、桡骨解剖结构及坚强内固定,稳定上、下尺桡关节,术后尽早进行功能锻炼,才能获得满意的临床疗效。