Origin and evolution of modern loess science-1824 to 1964

Loess is the most important aeolian deposit of the Quaternary and plays an important role in explorations of the evolution of paleoclimate and paleoenvironment. In recent years, historians of science have been working on how loess research originated, developed, and was promoted in Europe in the early 19th century. The Chinese community has a clear history of the loess research from the late 20th century. However, it remains unclear when and how modern loess studies were communicated between western and eastern academic societies and who contributed to the development and dissemination of modem loess knowledge, especially from the western to the eastern societies. Based on books, essays, memoirs, travel notes, published letters, and other types of records from geologists, such as K. Leonhard (1779-1862), C. Lyell (1797-1875), and R. Pumpelly (1837-1923), the present study clarifies the way and process by which loess research originated from the Rhine valley and spread to Britain onto the United States and, in particular, China. It was discovered that loess was formally defined in 1824 in the Rhine valley. In the 1830s, L. Homer (1785-1864) and Lyell introduced loess research from the Rhine valley to Britain. At the same time, Lyell put forward the theory of the fluvial origin of loess and verified his theory by expanding study areas to the United States. In 1866, Pumpelly, the first foreign geologist investigating Chinese loess, put forward lacustrine formation of loess. Pumpelly's hypothesis was soon argued against in 1870 by F. von Richthofen (1833-1905), who thought loess was formed via an aeolian mode based on a wide investigation in the Loess Plateau of China. Although the above main hypotheses originated based on investigations of Chinese loess, they were not disseminated to China and received by Chinese scholars in a timely manner, and the local loess research in China launched almost 130 years later by the stimulation from work by scholars of the Soviet Union.