Granitoids and Greenstone Belts of the Pietersburg Block—Witnesses of an Archaean Accretionary Orogen Along the Northern Edge of the Kaapvaal Craton
Granitoids and Greenstone Belts of the Pietersburg Block—Witnesses of an Archaean Accretionary Orogen Along the Northern Edge of the Kaapvaal Craton
复制标题
彼得斯堡地块的花岗岩和绿岩带——卡普瓦尔克拉通北缘太古宙增生造山带的见证
DOI：
--
复制
发表时间：
2019
期刊：
影响因子：
--
通讯作者：
Allan H Wilson
中科院分区：
文献类型：
--
作者：
O. Laurent;A. Zeh;G. Brandl;Adrien Vezinet;Allan H Wilson
Kaapvaal克拉通最北端的Pietersburg地块（PB）可划分为makhutsi - murchison South （MMS）、Groot Letaba-Duivelskloof （GDL）、Goudplaats-Hout River （GHR）和Southern Marginal Zone （SMZ）四个太古代灰色片麻岩单元。这些域受绿岩带（Pietersburg、Murchison、Rhenosterkoppies和Giyani）和主要剪切带的限制。这些岩性被基性层状岩体（Rooiwater杂岩）和大量的同-后构造花岗岩侵入，形成灰色片麻岩中的小体或大量的岩体/岩基。灰色片麻岩主要由中太古代（3.12 ~ 2.85 Ga）和古太古代（3.46 ~ 3.17 Ga） ttg组成，这些ttg是由变质玄武岩在bb0 ~ 45km深度熔融形成的。绿岩带由古太古代（3.46 ~ 3.20 Ga）基性变质玄武岩、变质岩（及侵入岩）和稀有的中太古代（2.95 ~ 2.84 Ga）长英质火山岩组成，与Murchison带3.05 ~ 2.92 Ga的BIF、燧石岩和硅质碎屑岩互插；Pietersburg和Giyani带2.88 ~ 2.80 Ga；Rhenosterkoppies带和SMZ为2.76 ~ 2.71 Ga。所有岩性均受绿片岩-上角闪岩相变质作用的影响，主要发生在中太古宙南北向挤压时期。2.97 ~ 2.96 Ga的Rooiwater杂岩和同时期Murchison带的长英质火山岩是由幔源岩浆分选作用形成的。PB花岗岩类包括2.84 ~ 2.75 Ga由TTGs（±沉积物）熔融形成的Bt-(Ms-)花岗岩，以及2.70 ~ 2.67 Ga由富集岩石圈地幔熔融和岩浆上升过程中与地壳相互作用形成的Hbl-Bt-(Cpx-)sanukitoids和Bt- ep - granite。在岛弧和（或）海洋高原环境中形成古太古代（3.46-3.18 Ga）微地质体后，PB的地球动力学演化特征为中-新太古代（3.15-2.65 Ga）长时间向南俯冲形成的增生造山带。中太古代演化始于3.15-2.97 Ga，沿原卡普瓦尔克拉通北缘形成弧后体系。随后，受古太古代微地体在2.97-2.84 Ga的对接控制，在安第斯型大陆边缘环境下（2.84-2.73 Ga）引起强烈的地壳改造，以及新太古代（2.73-2.65 Ga）与位于更北的地壳块体碰撞控制，可能是林波波河带中部的前体（> - 2.7 Ga）岩石。
The Pietersburg Block (PB), the northernmost terrane of the Kaapvaal Craton, can be subdivided into four Archaean grey gneiss units: Makhutswi-Murchison South (MMS), Groot Letaba-Duivelskloof (GDL), Goudplaats-Hout River (GHR) and Southern Marginal Zone (SMZ). These domains are limited by greenstone belts (Pietersburg, Murchison, Rhenosterkoppies and Giyani) and major shear zones. These lithologies were intruded by a mafic-layered intrusion (the Rooiwater Complex) and voluminous syn- to post-tectonic granitoids forming either small bodies in grey gneisses or voluminous plutons/batholiths. The grey gneisses are made up of Mesoarchaean (3.12–2.85 Ga) and seldom Palaeoarchaean (3.46–3.17 Ga) TTGs formed by melting of metabasaltic rocks at >45 km depth. The greenstone belts consist of Palaeoarchaean (3.46–3.20 Ga) mafic metabasalts, metakomatiites (and intrusive counterparts) and rare Mesoarchaean (2.95–2.84 Ga) felsic volcanics, intercalated with BIF, chert and siliciclastic rocks deposited at 3.05–2.92 Ga in the Murchison belt; 2.88–2.80 Ga in the Pietersburg and Giyani belts; and 2.76–2.71 Ga in the Rhenosterkoppies belt and SMZ. All lithologies were affected by greenschist—to upper amphibolite-facies metamorphism, mainly during Mesoarchaean N–S-directed compression. The 2.97–2.96 Ga Rooiwater Complex and coeval felsic volcanics of the Murchison belt formed through fractionation of mantle-derived magma. Granitoids of the PB include Bt-(Ms-) granites formed at 2.84–2.75 Ga by melting of TTGs (± sediments), and Hbl-Bt-(Cpx-)sanukitoids and Bt-Ep-granitoids at 2.70–2.67 Ga by melting of enriched lithospheric mantle and interactions with the crust during magma ascent. After formation of a Palaeoarchaean (3.46–3.18 Ga) micro-terrane(s) in an island arc and/or oceanic plateau setting, the geodynamic evolution of the PB features a Meso- to Neoarchaean (3.15–2.65 Ga) accretionary orogen formed during protracted southward subduction. The Mesoarchaean evolution began at 3.15–2.97 Ga with the formation of an arc/back-arc system along the northern margin of the proto-Kaapvaal Craton. Subsequently, it was controlled by the docking of the Palaeoarchaean micro-terrane at 2.97–2.84 Ga, causing intense crustal reworking in an Andean-type continental margin setting (2.84–2.73 Ga) and by Neoarchaean (2.73–2.65 Ga) continent-continent collision with a crustal block located farther North, possibly the precursor (>2.7 Ga) rocks of the Central Zone of the Limpopo Belt.
登录
查看更多内容
彼得堡绿岩带（南非）含金沉积物中碎屑锆石的 U-Pb 和 Hf 同位素记录——与 Witwatersrand 盆地是否有共同的来源？
影响因子：
3.8
作者：
Gerdes
通讯作者：
Gerdes
影响因子：
64.8
作者：
T. Næraa;A. Schersten;M. Rosing;A. Kemp;J. Hoffmann;T. Kokfelt;M. Whitehouse
通讯作者：
T. Næraa;A. Schersten;M. Rosing;A. Kemp;J. Hoffmann;T. Kokfelt;M. Whitehouse
南非默奇森绿岩带：具有对比变质条件的增生碎片
影响因子：
3.8
作者：
Poujol;Jaguin;Paquette. J.-L.
通讯作者：
Paquette. J.-L.
非洲最古老的锆石——它们的 UâPbâHfâO 同位素和微量元素系统学，以及对冥古宙到太古代壳幔演化的影响
影响因子：
3.8
作者：
Gerdes
通讯作者：
Gerdes
Kaapvaal 克拉通东北部 2 97 Gaâ 的新生地壳形成对太古代地体增生的影响以及彼得斯堡金的来源
影响因子：
3.8
作者：
Jaguin;Poujol;Boulvais;Hallot;Paquette
通讯作者：
Paquette