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The variability and dynamics of the Asian monsoon (AM, hereafter indicates both of the summer and winter monsoons.) at orbital and millennial timescales has attracted wide interest. Chinese loess deposits, covering an area of ~500 × 103 km2 and with a thickness of several tens to more than three hundred meters, is an ideal continental archive to reconstruct AM variations during the Quaternary epoch. Over the past thirty years, since the earliest paper published in an international journal that linked the Asian monsoon and Chinese loess deposits, many studies have been undertaken focusing on this research topic. These results have greatly deepened our understanding of the variations of the AM climate and their driving mechanisms during the past ~2.6 Myr. In this paper, we emphasize recent progress on the AM variability and dynamics revealed by Chinese loess records; in particular, we discuss the reliability and precision of the timescale and the monsoon proxy indicators for the loess-paleosol sequences, which are two fundamental aspects for understanding AM behavior. We analyze what we know and discuss what we do not know about the AM. We refine the timescale for the typical loess-paleosol sequence in the central Chinese Loess Plateau (CLP), which can be used as a new timescale to study palaeoclimate and palaeoenvironmental changes in the monsoonal Asia. We conclude that low-latitude insolation changes induced by precession, and global ice volume, temperature at high-latitudes, as well as sea-level changes forced variations of the AM at orbital time scales. High-latitude cooling events and low-latitude hydroclimate process at millennial time scales, such as climate changes associated with Heinrich events and Dansgaard-Oeschger cycles in Northern Atlantic and Greenland, have also modulated AM variability. We suggest that high-latitude forcing of AM variations occurs through ocean and atmospheric circulation linkages, although the roles of atmospheric CO 2 , ocean and vegetation feedbacks need further investigation. In future study, high-resolution independent dating, novel proxy indices and transient numerical simulations are still basic tools to understand the loess deposition and AM variations that require considerably more work. Issues such as reliable spatial comparison and regional linkages of records (dependent on precise and accurate numerical chronologies), and quantitative reconstruction of the AM variations, should be given priority in the study the past climate change in Asia, and low-latitude hydroclimate process. [ABSTRACT FROM AUTHOR]

The magnetic susceptibility of the loess-paleosol sequence is considered a significant indicator for recording paleoclimate, and the relationship is different between magnetic susceptibility and climate variation in diverse regions. A deep analysis of the composition, content, and evolution mechanism of magnetic minerals is helpful to enhance our understanding of magnetic signals in different regions. This paper presents a systematic study of environmental magnetism and geochemical elements in the loess-paleosol sequence of the Attock (ATT) area in the Peshawar Basin, northern Pakistan, exploring the significance and limitation of magnetic susceptibility as a proxy index of paleoclimate and the variation mechanism of magnetic susceptibility. The results showed that: 1) the ATT section had a magnetic mineral composition similar to that of the Chinese Loess Plateau; however, the contents of different minerals were distinguishable. The loess layer contained a specific amount of magnetite and maghemite and a handful of goethite and hematite. Additionally, the content of soft magnetic minerals was relatively higher than that of paleosol; the paleosol contained maghemite and nearly no magnetite. Furthermore, it contained more hematite and goethite, and the hard magnetic and paramagnetic minerals were dominant; 2) the effective humidity of the pedogenic environment in the ATT section fluctuated around the magnetic susceptibility wetting critical value F (B–C region), resulting in a poor relationship between magnetic susceptibility and climate; 3) Rb/Sr, K/Na, the coefficient of eluviation, and the content of <2 μm particles were well correlated with the stratum and can be used as paleoclimatic variation indicators in this area. Understanding the B–C region is helpful to comprehend the complex relationship between magnetic signals and climate in some areas and better interpret the environmental information carried by magnetic signals. [ABSTRACT FROM AUTHOR]