Abstract: 【Objective】 Using the data obtained from the LGT soil profile, this paper attempts to illustrate soil-forming process of modern soil in the Guanzhong areas and its micromorphological features. 【Method】 Micromorphology was observed under a petrographic microscope, and its image was quantitatively measured by LEICAL Qwin software. 【Result】Micromorphological observations of the thin sections show that the minerals assemblage of different horizons very similar, which is mainly composed of Q and Pl. However, there are obvious differences in C/F15?m ratio, mineral content, and coarse features. Pedofeatures mainly consist of clay, calcite, and amorphous Fe. Ap horizon is characterized by abundant needleshaped secondary-calcite, secondary-clay, and earthworm fecal pellet. BC horizon is characterized by the secondary-calcite of large quantity with various shapes. Bt1 and Bt2 horizons are characterized by abundant clay hyopcoatings and a small quantity of secondary-calcite. 【Conclusion】All the results of this research suggest that Earth-cumulic Orthic Anthrosols consist of both the upper Ap horizon, which cause loessal dung and eolian dust deposition, and cultivation occurs simultaneously during the process of Ap horizon-formation, and the lower BC horizon, which is aeolian sedimentary at the time of relative aridity during late Holocene.

Key words: Micromorphology, Palaeo-cultivated soil, Modern soil, Guanzhong areas