Structure and age of the northern Leeuwin Complex, Western Australia: constraints from field mapping and U-Pb isotopic analysis
Structure and age of the northern Leeuwin Complex, Western Australia: constraints from field mapping and U-Pb isotopic analysis
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DOI：
10.1046/j.1440-0952.2003.01014.x
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发表时间：
2003-08-01
影响因子：
1.2
通讯作者：
Collins, AS
中科院分区：
文献类型：
--
作者：
Collins, AS
位于澳大利亚西南部北方的列文杂岩中的岩石保存了证据，证明它们是在罗迪尼亚断裂和随后的冈瓦纳合并过程中形成的。利用高质量分辨率离子探针（SHRIMP）进行的详细野外测绘、构造调查和锆石U-Pb同位素分析表明：（1）粉红色花岗片麻岩和灰色花岗闪长片麻岩的原岩结晶时间约为750 Ma，与Rodinia西部的裂解时间相同;（2）麻粒岩相/上角闪岩相变质作用发生在早寒武世522.5Ma，类似于1亿年后，比以前的估计和相同的年龄估计的冈瓦纳最终合并;和（iii）三个主要阶段的韧性变形发生在此变质作用期间或之后，并代表了一个渐进的应变演化从近垂直缩短（D1）到近水平东西（D2），然后北-西北-南-东南（D3）收缩。
Rocks in the northern Leeuwin Complex of southwestern Australia preserve evidence of having formed during the breakup of Rodinia and the subsequent amalgamation of Gondwana. Detailed field mapping, structural investigation and U-Pb isotopic zircon analysis, using the Sensitive High-mass Resolution Ion Microprobe (SHRIMP), have revealed that: (i) protoliths of pink granite gneiss and grey granodiorite gneiss crystallised at ca 750 Ma, coeval with breakup of western Rodinia (ii) granulite/upper amphibolite facies metamorphism occurred at 522 5 Ma, in the Early Cambrian, similar to100 million years later than previous estimates and of identical age to estimates of the final amalgamation of Gondwana; and (iii) three major phases of ductile deformation occurred during or after this metamorphism and represent a progressive strain evolution from subvertical shortening (D1) to sub-horizontal east-west (D2) then north-northwest-south-southeast (D3) contraction.