【摘要】 云南腾冲地区晚白垩世（81 Ma）滇滩花岗岩具有类似于典型A型花岗岩的地球化学组成特征,如高K₂O+Na₂O（6.37%⁸.68%）和低Al₂O₃（最高为13.1%）、P₂O₅（<0.01%）含量,明显亏损Ba、Sr、Ti、Eu等元素;同时具有明显高的K₂O/Na₂O（除15DT-11为56.9,其余为1.51¹.58）、FeO/（FeO+MgO）（0.76⁰.90）和10000Ga/Al（3.26³.72）比值。另外,研究区A型花岗岩地球化学组成与实验岩石学研究结果相吻合,如具有较低的CaO（0.65%⁰.78%）、Al₂O₃（12.40%¹3.10%）和Mg O（0.11%⁰.32%）含量等。滇滩花岗岩上述地球化学组成特征,很可能暗示其为英云闪长质或花岗闪长质原岩部分熔融的产物。结合青藏高原南部和东南部广泛发育的晚白垩世岩浆作用及区域构造背景,滇滩A型花岗岩很可能为陆-陆板块碰撞后因伸展作用引起的地幔物质上涌增温导致地壳熔融产生的一期重要岩浆活动。更多还原

【Abstract】 The Late Cretaceous（81 Ma） Diantan granites, developed in the Tengchong area of the Yunnan Province, have some affinities with typical A-type granites, such as high K₂O + Na₂O concentration（6.37%–8.68%）, low Al₂O₃（< 13.1%） and P₂O₅（< 0.01%） concentrations, obvious depletions in Ba, Sr, Ti, Eu elements in multielement patterns normalized to primitive mantle plots, and high K₂O/Na₂O（except 15 DT-11 is 56.9, and the rest is 1.51–1.58）, FeO/（FeO + MgO）（0.76–0.90）, and 10000 Ga/Al（3.26–3.72） ratios. In addition, the major element contents of Diantan granites are similar to the experimental petrology results of previous researches. The geochemical characteristics of the Diantan granites suggest that they probably resulted from partial melting of tonalitic or granodioritic material. The Diantan A-type felsic magmatism, combined with the widespread Late Cretaceous magmatism that occurred in southern and southeastern Tibet, imply that the Late Cretaceous magmatism developed in an extension setting during continental-continental collision, which was triggered by the upwelling mantle material.更多还原