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地处华南之粤东北丘陵区的蕉岭红土属粉砂质粘土,形成于末次间冰期。红土的细粘粒含量为12.15%～24.64%(平均值18.46%)、Mz为5.91Φ～7.53Φ(6.72Φ)、概率累积曲线和频率曲线分别呈现以“四段式”和“三峰式”构型;主元素氧化物以SiO2、Al2O3、TFe2O3为主,含量依次为50.10%～53.14%(51.36%)、23.07%～24.44%(24.00%)、10.18%～11.40%(10.77%),其它如CaO、Na2O、MgO、K2O的含量均小于1%。这一趋向于细粉砂分布的粒度特征和脱硅富铝化的化学元素特征说明红土形成于较强的风化—淋溶作用下,硅铝系数(3.49～3.86,平均为3.64)指示多数层位属次强度富铝化。其气候环境,以<2μm和<1μm颗粒的含量、硅铝系数、CIA值为指标,与我国的南亚热带—北热带一些地点的现代赤红土和砖红土作一详细对比后认为蕉岭红土发育在湿热于现今南亚热带,相似于热带北缘的气候环境之下。这一看法与前人有关同期“大熊猫—剑齿象动物群”指示的古生态的研究结果相吻合。由此表明,末次间冰期的粤东北甚至整个华南地区可能都处在类似现今热带北缘的气候环境之下,其时的热带—亚热带界线向北推移了至少3个纬度。
Jiaoling laterite, located in the hilly area of northeast Guangdong, is a silty clay, formed in the last interglacial period. The clay content of laterite is 12.15% ~ 24.64% (average 18.46%), and Mz is 5.91Φ ~ 7.53Φ (6.72Φ). The cumulative probability curve and frequency curve of the clay show " The main elemental oxides were mainly SiO2, Al2O3 and TFe2O3 with the order of 50.10% ~ 53.14% (51.36%), 23.07% ~ 24.44% (24.00%), 10.18% ~ 11.40% (10.77% %), Others such as CaO, Na2O, MgO, K2O content of less than 1%. The characterization of the fine-grained sand distribution and the characteristics of the desilication-alu-sizing chemical elements suggest that the laterite formation was under strong weathering-leaching. The Si-Al coefficient (3.49-3.86, 3.64 on average) indicates that most of the layers Secondary intensity is aluminum-rich. Its climatic and environmental conditions, with the content of <2μm and <1μm particles, Si-Al coefficient and CIA value as indicators, are compared with modern laterite and brick laterite in some locations in the south subtropics and north tropical of China, In the hot and humid climate in today’s southern subtropics, similar to the tropical northern edge of the climate. This view is in line with previous studies on the paleoecology of the giant panda - Stegodon fauna. This indicates that the last interglacial period in northeast Guangdong and even the whole of South China may be in a climate similar to the present tropical North Rim, when the tropical-subtropical boundary shifted northward by at least 3 latitudes.