古地理学报
古地理學報
고지이학보
Journal of Palaeogeography
2015年
5期
699-708
,共10页
凌超豪%龙进%贾玉连%洪君%徐传奇%王鹏岭
凌超豪%龍進%賈玉連%洪君%徐傳奇%王鵬嶺
릉초호%룡진%가옥련%홍군%서전기%왕붕령
赣北%鄱阳湖地区%第四纪%常量元素%古气候演变
贛北%鄱暘湖地區%第四紀%常量元素%古氣候縯變
공북%파양호지구%제사기%상량원소%고기후연변
northern Jiangxi Province%Poyang Lake region%Quaternary%major element%palaeo_climatic evolution
赣北鄱阳湖地区土塘剖面发育第四纪红土,自下而上可分为强网纹红土层、弱网纹红土层、微网纹红土层、均质红土层和下蜀黄土层。基于常量元素、粒度分析数据以及前人年代框架,初探土塘剖面化学风化特征及其古气候意义。(1)土塘剖面粒度组分均一,常量元素含量相近,风化淋溶强烈。(2)土塘剖面各地层间化学风化强度存在差异:下蜀黄土层为初期的去 Na、Ca 阶段;均质红土层为中期的去 K 阶段;微网纹红土层由去 K 阶段向去 Si 阶段过渡;网纹红土层已完全进入晚期去 Si 阶段。剖面常量元素的相对迁移能力为:Na2 O>MnO2>CaO>P 2 O5>MgO>K2 O>SiO2>Al2 O3>TiO2>Fe 2 O3。(3)中更新世以来赣北鄱阳湖地区气候总体上由暖湿趋于干冷,期间伴随多个明显的干湿旋回佐证强烈的淋溶与干湿交替作用是网纹红土发育的重要驱动因子。
贛北鄱暘湖地區土塘剖麵髮育第四紀紅土,自下而上可分為彊網紋紅土層、弱網紋紅土層、微網紋紅土層、均質紅土層和下蜀黃土層。基于常量元素、粒度分析數據以及前人年代框架,初探土塘剖麵化學風化特徵及其古氣候意義。(1)土塘剖麵粒度組分均一,常量元素含量相近,風化淋溶彊烈。(2)土塘剖麵各地層間化學風化彊度存在差異:下蜀黃土層為初期的去 Na、Ca 階段;均質紅土層為中期的去 K 階段;微網紋紅土層由去 K 階段嚮去 Si 階段過渡;網紋紅土層已完全進入晚期去 Si 階段。剖麵常量元素的相對遷移能力為:Na2 O>MnO2>CaO>P 2 O5>MgO>K2 O>SiO2>Al2 O3>TiO2>Fe 2 O3。(3)中更新世以來贛北鄱暘湖地區氣候總體上由暖濕趨于榦冷,期間伴隨多箇明顯的榦濕鏇迴佐證彊烈的淋溶與榦濕交替作用是網紋紅土髮育的重要驅動因子。
공북파양호지구토당부면발육제사기홍토,자하이상가분위강망문홍토층、약망문홍토층、미망문홍토층、균질홍토층화하촉황토층。기우상량원소、립도분석수거이급전인년대광가,초탐토당부면화학풍화특정급기고기후의의。(1)토당부면립도조분균일,상량원소함량상근,풍화림용강렬。(2)토당부면각지층간화학풍화강도존재차이:하촉황토층위초기적거 Na、Ca 계단;균질홍토층위중기적거 K 계단;미망문홍토층유거 K 계단향거 Si 계단과도;망문홍토층이완전진입만기거 Si 계단。부면상량원소적상대천이능력위:Na2 O>MnO2>CaO>P 2 O5>MgO>K2 O>SiO2>Al2 O3>TiO2>Fe 2 O3。(3)중경신세이래공북파양호지구기후총체상유난습추우간랭,기간반수다개명현적간습선회좌증강렬적림용여간습교체작용시망문홍토발육적중요구동인자。
The Quaternary laterite was developed in the Tutang section in Poyang Lake region, northern Jiangxi Province,and it was divided into four layers from bottom to top,including the highly de_veloped vermicular laterite layer,the weakly developed vermicular laterite layer,the very weakly devel_oped vermicular laterite layer,the homogenous laterite layer and the Xiashu loess layer.The geochemical characteristics and palaeoclimate of Tutang section was analyzed based on the major element,grain size and chronological data from former researchers,and the conclusions were drawn as follows:(1 ) All lay_ers of Tutang section are quite coincident in particle size and geochemical characteristics,and they all ex_perienced an intense chemical weathering process.(2) As for the degree of weathering,the Xiashu loess is in the primary stage by leaching Ca and Na;the homogenous laterite almost reaches the secondary stage by leaching K;the very weakly developed vermicular laterite almost finishes the secondary stage by leac_hing K,and begins to leach Si;the vermicular laterite has been in the late stage by leaching Si.In terms of migration ability,the major elements are ranked as follows:Na2 O>MnO2 >CaO>P 2 O5 >MgO>K2 O>SiO2>Al2 O3 >TiO2 >Fe 2 O3 .(3) The climate of the Poyang Lake region in northern Jiangxi Province since the Middle Pleistocene changed from warm_wet to cool_dry generally,and the alternate dry and wet fluctua_tions were oprious,which suggested that the strong eluviation and alternate dry and wet fluctuations are the important driving factors to form the vermicular laterite.