松嫩平原北部全新世黑土剖面孢粉组合及其对环境演化的制约

    Palynological assemblages of Holocene typical black soil profile from northern Songnen Plain and its restricts to environmental evolution

    • 摘要: 古气候和古环境演化是研究黑土形成演化最关键的问题之一。重建古植被、古气候、古环境,预测黑土区气候环境的演变已成为黑土地研究的热点。在松嫩平原北部克山县典型黑土剖面中采集到15件孢粉样品进行孢粉学研究,并对部分相同层位土壤样品中总有机碳进行了AMS14C测年。系统分析、鉴定和研究表明,克山县黑土剖面自下而上可划分为3个孢粉组合,下部孢粉组合以Planted Poaceae-Echinate Asteraceae-Tamarix-Polypodiaceae为代表,中部孢粉组合以Tamarix-Chenopodium-Polypodiaceae-Echinate Asteraceae为代表,上部孢粉组合以Pinus-Chenopodium为代表。综合第四纪地质地貌、孢粉、AMS14C、元素地球化学分析认为,典型黑土主要形成于中全新世7500 a B.P.以来的大暖期,形成于松嫩平原温暖半湿润的气候环境,植被为以草本灌木为主的草原植被。新构造运动是控制典型黑土区自然环境演变的主要内动力,晚更新世黄土状亚粘土为克山县典型黑土的成土母质,黑土发育过程即为成土母质黑化的过程。

       

      Abstract: Paleoclimate and paleoenvironmental evolution is one of the most critical issues in the study of the formation and evolution of black soil.Reconstruction of paleo-vegetation, paleo-climate and paleo-environment, and prediction of the evolution of the climate and environment in the black soil area have become hot spots in black soil research.Fifteen sporopollen samples were collected from a typical black soil profile in the Keshan County of the northern Songnen Plain for pollen research, and total organic carbon in some soil samples from the same stratum was AMS14C dating.Systematic analysis, identification, and research have shown that three sporo-pollen assemblages from bottom to top were developed in the black soil profile of Keshan County.The lower pollen assemblage is represented by Planted Poaceae-Echinate Asteraceae-Tamarix-Polypodiaceae, the middle pollen assemblage is represented by Tamarix-Chenopodium-Polypodiaceae-Echinate Asteraceae, and the upper pollen assemblage is represented by Pinus-Chenopodium.Comprehensive Quaternary geology and geomorphology, pollen, AMS14C, and element geochemistry analysis all suggest that the typical black soil was mainly formed in the Great Warm Period since the 7500 a B.P.of the Middle Holocene.Which formed in the warm and semi-humid climate of the Songnen Plain, the vegetation is mainly grassland vegetation with herbaceous shrubs.Neotectonic movement is the main internal driving force that controls the evolution of the natural environment in the typical black soil area.The Late Pleistocene yellow clay is the parent material of the typical black soil in the Keshan black soil area, and the development process of the black soil is the process of of soil blackening.

       

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