中文摘要：

采用激光40Ar/39Ar阶段加热分析技术,对采自新疆东部吐哈地区红山铜金矿床氧化带中风化矿物——两种不同相的黄钾铁矾分别进行重现性测试,获得可靠的年龄,年龄分别为7.5和8.0 Ma,结果再次证明黄钾铁矾适用于40Ar/39Ar法测年.根据矿床沿同一剖面不同位置样品的年龄,显示表生硫酸盐矿物从上到下生成年代逐渐变新,记录了在中中新世到早上新世风化前锋的向下扩展,计算得到该地区晚中新世以来风化前锋的平均拓展速率约为2.92 m/Ma.

英文摘要：

Two jarosite samples with visually distinct phases collected from the oxidation zone of the Hongshan Cu-Au deposit in the TuHa Basin are dated by laser ^40Ar/^39Ar incremental heating analysis. To test the age reproducibility of each sample, two aliquots are dated. The results indicate that the dates obtained are reproducible, yielding ages of 7.5 and 8.0 Ma, confirming the suitability of supergene jarosite to ^40Ar/^39Ar geochronology. Combined with published ages, the obtained ^40Ar/^39Ar ages decrease from the top to the bottom of the profile, which records the arrival of a weathering front at that depth, yielding a weathering front propagation rate of 2.92 m/Ma.