论文部分内容阅读
长江三角洲地区晚第四纪古土壤形成于25～12kaBP,古土壤中反映暖湿气候的扇型、方型、长方型与反映冷干气候的棒型、帽型、尖型植物硅酸体含量比值A,自下向上总体变小,表明气候由暖湿向冷干转变,A值并未指示气候转暖,推断末次冰盛期之后海侵速度较快.古土壤发育过程受海侵、海退的显著控制,呈明显阶段性:(i)沉积与成土交替作用时期,自末次冰盛期海退开始,至海面接近最低时止;(ii)暴露成土期,至末次冰盛期过后古土壤被海水淹没时止;(iii)淹埋期,古土壤被海相沉积物覆盖,经受早期成岩改造.
Palaeozoic of the late Quaternary in the Yangtze River delta formed in 25 ~ 12kaBP, ancient soil reflect the warm and humid climate sector, square, rectangular and cold and dry climate reflect the rod, hat, pointed plant silicate The content ratio A decreases from bottom to top, indicating that the climate changes from warm to damp to dry and cold, while A does not indicate warming of the climate, and infers that the transgression rate is faster after the last ice age.The paleosols development process is affected by transgression, The significant control over the retreat was marked in phases: (i) the period of alternation between sedimentation and soil formation, beginning from the regression of the last ice age and ending at a time when the sea surface is at a minimum; (ii) When the ancient soil was submerged by the seawater after the expiration of the period; (iii) In the submerged period, the paleosol was covered by marine sediments and subjected to the early diagenetic transformation.