摘要
在哀牢山-红河剪切带的元阳到者龙的6个不同地点,对18个变质岩样品进行系统分析钾长石的^(40)Ar-^(39)Ar年龄。发现用MDD模式得到的18条冷却曲线(温度范围在400-150℃之间)均存在一次(或两次)快速冷却过程(冷却速度>100°C/Ma),这种快速冷却(抬升)过程不仅反映了该剪切带在大约25-17Ma时,韧性走滑作用结束和正断作用的开始,而且它的起始时间还有自东南向西北逐渐变新的趋势。利用6个不同地点快速冷却(抬升)的起始时间与相对距离作图时,得到了较好的线性函数关系(斜率为34mm/a)。并对这种函数关系进行了两种可能的构造解释。
The Ailao Mountains-Red River shear zone is located in southern Yunnan province. To better understand the nature and timing of this zone, 40Ar/39Ar age spectrum analyses were undertaken on 18 K-feldspars samples from six sites. Interpretation of the analytical results using the MDD model (multiple-diffusion domain model) yields 18 cooling curves in the temperature range of 400-150℃. All these curves have one (or two) rapid cooling process (with a cooling rate>100℃/Ma). The rapid cooling (uplift) event not only reflects the termination of ductile deformation and beginning of normal faulting along the shear zone at about 25 - 17 Ma B. P. but also shows that its starting time had a northwestward-younging trend. When plotted as a function of the distance along the range, the starting time of rapid cooling (uplift) at the six site decreases linearly at a slope of 34mm/a. Two different tectonic interpretations may possibly accounts for this good linear functional relationship.
出处
《地质论评》
CAS
CSCD
北大核心
1996年第5期385-390,共6页
Geological Review
关键词
哀牢山-红河
剪切带
构造抬升
时间序列
中新世
Ailao Mountains-Red River shear zone, Multiple-Diffusion Domain modle, tectonic uplift
