Quaternary sediments of the Haji Arab River catchment located in Qazvin Plain, northwestern Iran, were studied in terms of sedimentology and geochemistry to determine the sedimentary environment and rock weathering. Discrimination diagrams show that the source rock of these sediments is granite and their tectonic setting is the active continental margin. These rocks show a negative Eu anomaly and a high ratio of light rare earth elements to heavy rare earth elements, suggesting that these sediments are originated due to the weathering of felsic rocks. Regarding the descending trend of chemical index of weathering, chemical index of alteration values, and the increase in coarse-grained particles, it was concluded that the sediments from the depth of 6 to 2.6 m formed under arid and high-energy conditions; however, this trend for sediments from 2.6 m depth to surface changes slightly toward semi-humid up to semiarid climate. Hence, it can be stated that the conditions of sedimentation environments in the Haji Arab basin are not constant at least in the Upper Holocene (Schmidt et al. in Holocene, 2011. https://doi.org/10.1177/0959683610385961) and this has led to changes in river sedimentation. These results indicate the changes in river regime conditions probably because of the changes in weather conditions during the Quaternary.

从沉积学和地球化学方面研究了位于伊朗西北部加兹温平原的哈吉阿拉伯河流域的第四纪沉积物，以确定沉积环境和岩石风化。判别图表明，这些沉积物的烃源岩为花岗岩，构造环境为活动大陆边缘。这些岩石显示出负 Eu 异常和高比例的轻稀土元素与重稀土元素，表明这些沉积物是由于长英质岩石的风化作用而形成的。从化学风化指数、化学蚀变指数值和粗粒增加的趋势来看，6~2.6 m深度的沉积物是在干旱高能条件下形成的；然而，从 2 开始的沉积物的这种趋势。到地表 6 m 的深度向半湿润至半干旱气候略有变化。因此，可以说哈吉阿拉伯盆地的沉积环境条件至少在全新世上层不是恒定的（Schmidt et al. in Holocene, 2011. https://doi.org/10.1177/0959683610385961），而这导致了河流沉积的变化。这些结果表明河流状况的变化可能是由于第四纪天气条件的变化。