"成都粘土"由Thorp和Dye于1936年命名,用以指示分布在四川盆地西部、西北部丘陵及高阶地上的含钙质结核粘土。Thorp和Dye并提出,"成都粘土"可能是遭受风化的风尘堆积。在四川盆地西北部,发育完整的第四纪粘土剖面,自上而下可分为三层:"成都粘土"、褐色粘土及网纹红土。在Thorp和Dye之后的70多年间,"成都粘土"成为土壤学家、地理学家和地质学家所共同关注的研究对象。但是,"成都粘土"的成因、物源、时代及其古环境意义,以及"成都粘土"与青藏高原黄土、黄土高原黄土的关系是一个长期争论的、有待解决的科学问题。"成都粘土"作为可能的风成堆积,针对其的研究,对认识和了解地质时期,尤其是冰期和冰消期四川盆地西部及其周边地区风向、大气环流格局及强度,以及风尘源区的植被覆盖及干旱化等古环境变化是十分有意义的。此外,"成都粘土"及其下伏的褐色粘土和网纹红土是著名的超固结性、胀缩性和裂隙性粘土,对于这一特殊土体的研究亦具有重要的理论和实践意义。为此,就有关成都粘土的研究历史进行了回顾,并对今后的研究工作提出如下建议:1.深入调查成都粘土的分布范围及其地貌分布特征;2.开展成都粘土的精细年代学研究并建立标准剖面;3.褐色粘土和网纹红土的成因及物源的深入研究;4.确认"成都粘土"、褐色粘土及网纹红土三者间的关系及可能存在的沉积间断;5.阐明"成都粘土"与川西高原黄土、黄土高原黄土之间的物源关系;6.重建"成都粘土"的风尘传输过程及机制;7.探索各层粘土的成因及后期风化改造对其超固结性、胀缩性和裂隙性发育的影响。
The Chengdu Clay(Chengtu Clay) was named by Thorp and Dye in 1936.The Chengdu Clay is defined as a type of brownish yellow sticky and plastic clay which contains lime concretions overlying the hills and higher terraces in the northwest Sichuan Basin(Szechwan Basin).Thorp and Dye also proposed that the Chengdu Clay is likely a weathered aeolian deposit.The developed Quaternary clayey strata in the northwestern Sichuan Basin can be divided into three units from top to bottom:Chengdu Clay(upper horizon),brown clay( middle horizon) and reticulate-mottled red clay(lower horizon).Within the 70 years after Thorp and Dye,a number of pedologists,geographers and geologists focused on the study of the Chengdu Clay.But,the origin,provenance,age and climatic links of the Chengdu Clay,and the relationship among the Chengdu Clay,loess on the Tibetan Plateau,and loess on the Chinese Loess Plateau are still debatable.The Chengdu Clay as a possible aeolian deposit can provide valuable information about past climate and vegetation,especially information about past wind direction,intensity of atmospheric circulation,source-area aridity and plant cover.In addition,the Chengdu Clay and underlying brown clay and red clay are characterized by overconsolidated,expansive and fissured features.Therefore,the study of these particular clays has theoretical and practical significance.The history of the study for the Chengdu Clay was reviewed in this paper.In addition,a number of research questions for future work have been raised.They involve the following issues:1.further investigation of geomorphological distribution of Chengdu Clay; 2.high-resolution geochronological study of Chengdu Clay and establishment of key profile; 3.origin of brown clay and reticulatemottled red clay; 4.relationship and possible sedimentary hiatus among the Chengdu Clay,brown clay and reticulate-mottled red clay; 5.original relationship among the Chengdu Clay,loess on the eastern Tibetan Plateau,and loess on the Chinese Loess Plateau; 6.the