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构造地貌学重点关注构造和地表过程对于地形地貌演化的差异化作用,构造活动速率则是评估这种影响的一个重要指标。利用河流阶地数据计算河流下切速率从而约束构造抬升速率是常用的方法,但由于阶地成因复杂,这一方法具有不确定性。对于山前河流地貌序列,基于背斜段与未变形段的阶地拔河高度差以及阶地面形成年龄,计算得到的河流下切速率可在一定程度上消除气候等因素的影响,因此可用于估算背斜自阶地形成以来的平均抬升速率。基于该方法,本文通过研究天山北麓乌鲁木齐河、塔西河、玛纳斯河、金钩河、安集海河及奎屯河等河流在背斜段发育的主要阶地,分析了背斜抬升速率及其时空特征。天山北麓发育3排逆断裂一背斜带,结果表明位于第Ⅱ排逆断裂一背斜带的吐谷鲁背斜自约13ka以来的抬升速率为3.52mm/a,同时期霍尔果斯背斜构造抬升速率为4.8mm/a,玛纳斯背斜东端的抬升速率相对较小,为<2ram/a;第Ⅲ排构造带中的独山子背斜全新世抬升速率仅为1.2~1.9mm/a。这可能表明,自山前向盆地方向晚第四纪背斜抬升速率大致呈减小趋势,与背斜地壳缩短量的空间分布规律基本一致。更多的阶地年龄数据有助于更好地揭示天山北麓晚第四纪背斜构造活动特征。
Tectonic geomorphology focuses on the differential effects of tectonics and surface processes on the evolution of topography and geomorphology, and tectonic activity rates are an important indicator of this effect. It is a common method to use the terrace data to calculate the rate of river undercutting and constrain the rate of tectonic uplift. However, this method is uncertain due to the complicated formation of terrace. For the sequence of piedmont rivers, based on the altitude difference between terraced troughs of the anticlinal sections and the undeformed sections and the formation age of the terrains, the calculated river subduction rate can eliminate the influence of climate and other factors to a certain extent, so it can be used to estimate the anticline The average rate of ascent since the terrace formed. Based on this method, by studying the main terraces developed in the anticline, such as the Urumqi River, the Tashi River, the Manas River, the Jinhuan River, the Anjihai River and the Kuitun River in the northern foot of the Tianshan Mountains, Space-time features. The results show that the Tugulu anticline located in the anticlinal zone of the second row of reverse faults has a 3.52 mm / a rise rate since about 13 ka, and the same period of Horgos The uplift rate of anticline is 4.8mm / a, and the uplift rate of Manas anticline is relatively less than 2ram / a. The Holocene uplifting rate of the Dushanzi anticline in the third row of structural belt is only 1.2-1.9 mm / a. This may indicate that the late Quaternary anticline uplift from the piedmont to the basin direction generally shows a decreasing trend, which is basically consistent with the spatial distribution of the anticline crustal shortening. More terraces and age data help to better reveal the northern foot of Tianshan Late Quaternary anticline tectonic activity characteristics.