大箐梁子剖面位于四川省西昌市东南17公里的分水岭地带，由下部的巨砾层与上部的细砾-砂-粘土韵律层所组成。出露较好，曾广为新生代地质研究者所注意。曾忻耕(1 965) 将剖面上部的韵律层同昔格达组对比，时代定为上新世。第四纪冰川考察队(1977) 亦认为这套“厚55 米”的韵律层与昔格达组底部属同期沉积，其下伏“紫灰色泥砾”是早更新世第一冰期(又称安宁冰期)遗迹的主要代表山。一些文献资料据此进一步推导，西昌盆地与大箐梁子分水高地之间的千米高差，代表了昔格达组沉积之后新构造运动的强度。1980~1983 年，笔者细测了该剖面，从岩石地层、生物地层、气候地层、年代地层学的角度进行了综合研究，结果表明该剖面属上更新统;鉴于该剖面是川西南地区第四纪地层中少见的完整剖面之一，将剖面上部韵律层称为大菁梁子组，剖面下部巨砾层与第四纪冰川考察队建立的西溪冰破层对比。1986 ~ 1987 年笔者对该剖面作了进一步的研究，澄清了大菁梁子组上覆层的时代及其间的关系，本文是前后二次研究资料的汇总。

Daqingliangzi section includes the lower moraines (130m thick) of Xiqi Ice Age (the early stage of Late Pleistocene). the upper Daqingliangzi formation (95.7m thick )and also the overlying formation of Lower Holoccne Series of Tongziling formation (2.5m thick). The most important part of this section is the Daqingliangzi formation.

Daqingliangzi formation is a set of multi - rhythmic laycrs mainly consists of coarse debris. The sediments which consist of the gravel layer of the lower part and finc sand, silt and clay of the upper part .can be divided into 8 layers. The upper part of cach layer CNo.2 - No.7 )contain many carbonization herbosa remains and carbonization timber fragment; the upper part of each layer (No.3 - No.7)contain several layers of lignite. Being reflected by the spore pollen assemblages. the vegetation can be classified inTo evergreen broad-leaved forest. evergreen borad-leaved and deciduous broad • leaved mixed forest .deciduous broad-leaved and coniferous mixed forest. but among them evergreen broad-leaved forest is dominant.The research indicates that Daqingliangzi formation is characterized by fluvial deposits alternated with lacustrine deposits under a wet and hot climate condition. The CU ages of carbonization woods which are collected from No.2, No.4 and No,6 layer are respectively indicated of more than 40000 years. 40000±2000 years and 34870±1500 years BP. .

The ancient environment analysis indicates that the area round Daqingliangzi had experienced the palaeo-erosional stage (pre-Late Pleistocene). glacial erosional stage (early stage of Late Pleistocene). river • lake • marsh pile up stage (middle stage of Late Pleistocene)and modern erosional stage (no moer than32000 years B P • ).  aqingliangzi water parting is based on a urstromtal which formed in early-middle stage of Late Pleistocene and connected with Qionghai basin , and then formed by the uplifting here relative to the Qionghai basin. since 32000 years I3P.. During this period. the relative dislocation between Daqingliangzi and Qionghai basin is about 500-700m. The uplifting and deformation (fracture and inclination)of Daqingliangzi Formation confirmed that during the late stage of Late Pleistocene. the intensive movement of Zemuhe faules and the regional dislocation of fault block had obviously strengthened. The uplifting of Daqingliangzi and the settling of Qionghai basin. the intensve movent of Zemuhe faules and the large scale of quick uplifiting probably have some connections, and mark the appearance of a regional tectonism. Since the late stage of the Late Pleistocene, the important variatiom of nature environment which had occured at the Dapingliangzi area, is mainly resulted from the tectonism.