中文摘要：

TTG岩套是一类包含了三种岩性的岩石组合,即英云闪长岩（tonalite）—奥长花岗岩（trondhjemite）—花岗闪长岩（granodiorite）.TTG岩套的规模在太古宙最大,是早期陆壳的主体且在各地质历史时期均有发育.该岩石组合是岩石学定名,多数样品的地球化学特征相似：富Na,高Al2O3（平均＞15％）,低Mg、Ni、Cr,富集LREE、亏损HREE、高Sr、低Y、低Yb且无明显的负Eu异常.其微量元素特征与Adakite（高锶低钇中酸性岩,“埃达克岩”）类似.目前多数学者认同其为变玄武质岩石部分熔融后的熔体,主要争论在于其源岩的变质程度.笔者认为TTG岩套的源区不应局限于某个变质相,而是涵盖了较大的P-T范围.对于其形成环境的探讨,笔者认为应该以地球演化不同时期的地球动力学背景为前提,盲目地“将今论古”是不合理的.本文在总结前人研究成果的基础上提出3.8Ga之前的TTG岩套可能是在板块构造未启动的非俯冲条件下形成的;3.8 ～ 1.9Ga的TTG岩套产生在发育俯冲式板块构造且板块构造具有间歇式特点的背景下,此时可能既存在非俯冲环境下产出的TTG岩套也存在俯冲环境下产出的TTG岩套,而且其产出应该具有幕式特征;古元古代之后的TTG岩套可能无一例外均是俯冲板片熔融的产物.

英文摘要：

TTG suite is an assemblage of three kinds of lithologies, namely the abbreviation of tonalite—trondhjemite—granodiorite. Although the TTG suite exists through the Earth history, it reaches the maximum scale during the Archean, consisting of the major part of primitive continental crust. TTG suite is named after petrological characteristics and most of them have similar geochemical features, i.e. Na-rich, high-aluminum （mean 〉 15% ）, low in Mg, Ni and Cr, LREE-enriched while HREE-depleted, High-Sr, low in Y and Yb and no evident Eu negative anomaly, that are similar with Adakitcs in the chemical features of rare elements. Most scholars believe TTG melt is derived from partial melting of metabasahic protoliths while having little consensus on possible metamorphic phases of sources. Authors think it may not be constrained within a narrow range of P—T condition. As for the diagenetic environments, from the authors＂ humble opinion, it is more appropriate for us to take different geodynamic backgrounds throughout the Earth history into serious consideration thus obtaining relatively objective and trustworthy results. Therefore, the diagenetic environments of TTG before 3.8Ga might be related to non- subduction backgrounds; that of 3.8～1.9Ga might be related to multiple possibilities reflecting the episodic features of subduction ; that of 1.9Ga—present might be more reasonable related only to subduction.