松辽平原典型黑土区不同土壤结构的古气候背景与黑土成因机制

Paleoclimate background and genetic mechanisms of different soil structures in typical black soil areas of Songliao Plain

黑土成因机制研究是理解黑土形成演化过程的基础,更是加强黑土地保护和可持续利用的关键。以松辽平原典型黑土区吉林梨树县LZK-4钻孔为研究对象,基于粘土矿物学、元素地球化学、^(14)C、光释光测年等手段,重建了梨树县晚更新世中期以来的古气候演化序列,揭示不同土壤类型的古气候背景,解析了典型黑土的气候成因机制。结果表明:①研究区典型黑土形成于晚全新世,底界年龄为2452 cal.a BP;②LZK-4钻孔揭示了黑土层—灰白色粘土层—褐黄色粘土层的垂向结构,气候总体变化趋势由温湿向干冷转化;③研究区典型黑土主要形成于晚全新世寒冷干旱的气候条件。本研究有助于理解松辽平原梨树地区典型黑土的形成演化过程,为黑土资源的开发、利用和保护提供科学依据。

The study of the genetic mechanisms of black soil is fundamental to understanding its formation and evolution,and is crucial for enhancing the protection and sustainable use of black soil.Focusing on the LZK-4 borehole in Lishu County,a representative black soil region of the Songliao Plain,paleoclimate sequences since the mid—late Pleistocene were reconstructed using clay mineralogy,elemental geochemistry,^(14)C dating,and optically stimulated luminescence dating.This revealed the paleoclimatic contexts of various soil types and elucidated the climatic causes behind the formation of typical black soil.The findings indicated:①The typical black soil in the study area originated during the Late Holocene,with a bottom age of 2452 cal.a BP;②LZK-4 drilling unveiled a vertical structure of a black soil layer,followed by a grey-white clay layer,and then a brown-yellow clay layer,reflecting an overall trend in climate from warmth and humidity to dryness and coldness;③The typical black soil in the study area primarily formed under cold and arid conditions during the Late Holocene.This research contributes to understanding the formation and evolution of black soil in the Lishu region of the Songliao Plain,thereby providing a scientific foundation for the development,utilization,and protection of black soil resources.