New morphologic information permits systematic revision of trilobites from the Middle Ordovician Klimoli Formation of the Zhuozishan area, Ordos Basin, Inner Mongolia. The new assemblage is composed of 10 species of t...New morphologic information permits systematic revision of trilobites from the Middle Ordovician Klimoli Formation of the Zhuozishan area, Ordos Basin, Inner Mongolia. The new assemblage is composed of 10 species of the Raphiophoridae, Nileidae, Asaphidae, and Telephinidae.？ An asaphid, aff. Mioptychopyge lashachungensis （previously Paraptychopyge lashachungensis） displays an intermediate morphology between the Chinese nobiliasaphine genera Mioptychopyge and Zhenganites. The pygidial doublure is regarded as the most significant character to differentiate Symphysurus klimoliensis （previously Nileus klimoliensis） of the Nileidae from such closely allied taxa as Poronileus. A nileid, cf. Peraspis kujandensis displays typical nileid morphology, unlike the type species, Peraspis lineolata, which might turn out to be an asaphid. Ampyx gongwusuensis sp. nov. of the Raphiophoridae is the first record of the genus in the Zhuozishan area and reveals morphologic details that might be employed to resolve Ampyx taxonomy in China. Morphologic differences between A. gongwusuensis and Abulbaspis ordosensis might represent a case of sexual dimorphism.展开更多
分水岭是水系演化中的动态因素,通过连续或不连续的水系袭夺而发生迁移,从而导致水系重组。传统的对水系演化的研究主要集中单个河流袭夺事件,而新提出的利用分水岭两侧chi(χ)值差异来描述分水岭的动态迁移过程,能够解释大尺度的河流...分水岭是水系演化中的动态因素,通过连续或不连续的水系袭夺而发生迁移,从而导致水系重组。传统的对水系演化的研究主要集中单个河流袭夺事件,而新提出的利用分水岭两侧chi(χ)值差异来描述分水岭的动态迁移过程,能够解释大尺度的河流袭夺事件,描述水系的整体演化过程。文章基于12.5 m DEM数据提取了鄂尔多斯西北缘桌子山地区的chi(χ)值揭示其空间分布具有东高西低的特点,反映桌子山的分水岭处于向东迁移过程。综合分析进一步揭示,在桌子山东西两侧的构造升降和降水条件都无明显差异的条件下,岩性抗侵蚀能力差异是控制桌子山分水岭向东迁移的主要因素,当抗侵蚀能力更强的寒武系、奥陶系灰岩位于背斜西翼,而中元古宙长城系(Pt)沉积碎屑岩位于其下部时,背斜西翼的河流具有更强的侵蚀能力,西翼河流可能会穿过背斜核部,从而侧向袭夺东侧的河流。展开更多
基金financially supported by a grant from the Basic Research Project(GP2016-013)of KIGAM to S.-B.Leethe Korea Research Foundation(Grant No.KRFR1A4007-2010-0011026)to D.-C.Lee
文摘New morphologic information permits systematic revision of trilobites from the Middle Ordovician Klimoli Formation of the Zhuozishan area, Ordos Basin, Inner Mongolia. The new assemblage is composed of 10 species of the Raphiophoridae, Nileidae, Asaphidae, and Telephinidae.？ An asaphid, aff. Mioptychopyge lashachungensis （previously Paraptychopyge lashachungensis） displays an intermediate morphology between the Chinese nobiliasaphine genera Mioptychopyge and Zhenganites. The pygidial doublure is regarded as the most significant character to differentiate Symphysurus klimoliensis （previously Nileus klimoliensis） of the Nileidae from such closely allied taxa as Poronileus. A nileid, cf. Peraspis kujandensis displays typical nileid morphology, unlike the type species, Peraspis lineolata, which might turn out to be an asaphid. Ampyx gongwusuensis sp. nov. of the Raphiophoridae is the first record of the genus in the Zhuozishan area and reveals morphologic details that might be employed to resolve Ampyx taxonomy in China. Morphologic differences between A. gongwusuensis and Abulbaspis ordosensis might represent a case of sexual dimorphism.
文摘分水岭是水系演化中的动态因素,通过连续或不连续的水系袭夺而发生迁移,从而导致水系重组。传统的对水系演化的研究主要集中单个河流袭夺事件,而新提出的利用分水岭两侧chi(χ)值差异来描述分水岭的动态迁移过程,能够解释大尺度的河流袭夺事件,描述水系的整体演化过程。文章基于12.5 m DEM数据提取了鄂尔多斯西北缘桌子山地区的chi(χ)值揭示其空间分布具有东高西低的特点,反映桌子山的分水岭处于向东迁移过程。综合分析进一步揭示,在桌子山东西两侧的构造升降和降水条件都无明显差异的条件下,岩性抗侵蚀能力差异是控制桌子山分水岭向东迁移的主要因素,当抗侵蚀能力更强的寒武系、奥陶系灰岩位于背斜西翼,而中元古宙长城系(Pt)沉积碎屑岩位于其下部时,背斜西翼的河流具有更强的侵蚀能力,西翼河流可能会穿过背斜核部,从而侧向袭夺东侧的河流。
