运用X射线衍射仪（XRD）、X射线荧光光谱仪（XRF）、电感耦合等离子体质谱仪（ICP-MS）以及Triton Plus质谱分析技术，对云南弥勒内陆盆地中新世褐煤中的矿物和元素组成以及锶同位素进行了分析，发现了在陆相煤盆地泥炭堆积过程中海水入侵的新证据。除了煤中高度富集的自生石膏的锶同位素比值87Sr/86Sr与同时期海水中的锶同位素比值一致以外，石膏和自生黄铁矿的赋存状态也表明泥炭在堆积过程中受到了海水输入的影响。指示沉积环境的敏感元素对Ca/Mg，Sr/Ba，Th/U，V/Ni的质量分数比，以及P2O5的质量分数、稀土元素La和Gd正异常、Y/Ho质量分数比变化特征，均表明海水的入侵，并且随着泥炭的堆积，海水的影响逐渐减弱，而淡水的影响和陆源碎屑的供给逐渐增强。在泥炭堆积期间，弥勒盆地处于多期活动阶段的断裂带变形区内，该盆地通过哀牢山—红河断裂与特提斯海相连接，为海水输入至陆地泥炭堆积地提供了通道；与此同时，哀牢山—红河断裂带北部区域抬升，使弥勒盆地泥炭堆积时受到的海水影响随之减小。

X-Ray Diffractometer (XRD),X-Ray Fluorescence Spectrometer (XRF),Inductively Coupled Plasma Mass Spectrometer (ICP-MS) and Thermal Ionization Mass Spectrometer (TI-MS) have been applied on the Miocene lignite of Mile Basin,Eastern Yunnan,for the geochemical,mineralogy and strontium isotope analysis,and new evidence for the seawater input during the peat accumulation process into the terrestrial coal basin have been identified. Besides the consistence of strontium isotope 87Sr/86 Sr of gypsum,which is abundant in the Mile coals,with the value of contemporary seawater,the occurrence modes of gypsum and authigenic pyrite in the coals also indicate the peat was influenced by seawater during its accumulation process. The ratios of sediment environment sensitive element Ca/Mg,Sr/Ba,Th/U and V/Ni,the percentage of P2O5,and the anomalous of rare earth element La and Gd,as well as the variety of Y/Ho along the seam profile,indicate the peat was suffering a decreasing seawater influence,while an increasing fresh water influence and supply of terrigenous debris with the peat accumulation. During the peat accumulation process,the Mile Basin which located in multiple-stage-active deformed zone,connected the Tethys with the Ailao Shan-Red River fault,providing an access for the transformation of seawater into the peat pile;meanwhile,the uplift of north area of the deformed zone,contributed to the decreasing influence of seawater on the peat during the Mile coal basin.

1 研究区地质背景

2 分析方法

3 结果

   3.1 原煤中的矿物组成

   3.2 元素地球化学特征

4 讨论：泥炭堆积受到海水影响的证据

   4.1 矿物学证据

   4.2 元素地球化学证据

   4.3 锶同位素证据

   4.4 研究区海水的输入机制

5 结论