Tectonic evolution and copper-gold metallogenesis of the Papua New Guinea and Solomon Islands region
Tectonic evolution and copper-gold metallogenesis of the Papua New Guinea and Solomon Islands region
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DOI：
10.1016/j.oregeorev.2018.11.007
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发表时间：
2019-01
影响因子：
3.3
通讯作者：
R. Holm;S. Tapster;H. Jelsma;G. Rosenbaum;D. Mark
中科院分区：
文献类型：
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作者：
R. Holm;S. Tapster;H. Jelsma;G. Rosenbaum;D. Mark
巴布亚新几内亚和所罗门群岛是与侵入有关的矿藏最有前景的地区之一。然而，由于该区域构造的复杂性和缺乏全面的区域地质数据集，成矿作用与区域尺度地球动力学框架之间的联系尚不清楚。本文综合了近年来对该区岩浆弧成岩作用和俯冲带历史的研究，结合与侵入有关的矿床的时空分布，提出了一个新的成矿模式，并提出了6个新的矿床年龄。在太平洋-澳大利亚板块交界处的会聚至少从45 Ma开始，通过美拉尼西亚海沟的俯冲作用以及与之相关的美拉尼西亚弧岩浆活动来适应。约26 Ma时，安通爪哇高原到达海沟，导致俯冲停止，随后在整个美拉尼西亚弧内形成了铜-金斑岩-浅成热液矿床(24-20 Ma)。晚渐新世-早中新世构造重组导致波克灵顿海槽开始俯冲，马拉穆尼弧岩浆作用开始。12 Ma时，澳大利亚大陆到达波克灵顿海槽，导致大陆碰撞和矿床形成(12~6 Ma)。这以新几内亚造山带的铜金斑岩矿床和巴布亚半岛的浅成热液金矿系统为代表。从6 Ma开始，与先前的波克灵顿海槽俯冲有关的巴布亚新几内亚地壳拆沉导致绝热地幔熔融，从6 Ma开始在巴布亚褶皱冲断带和巴布亚半岛内侵位了不同的铜、金斑岩和浅成热液矿床。约10 Ma在新不列颠和圣克里斯托巴尔海沟的俯冲导致构造复杂性的升级和巴布亚新几内亚东部和所罗门群岛微板块构造的开始。这反映在最近到现代的弧形背景下形成了多样化和离散的成矿地球动力学环境，主要与上板块的缩短和伸展以及与俯冲板块内构造的空间关系有关。
Papua New Guinea and the Solomon Islands are in one of the most prospective regions for intrusion-related mineral deposits. However, because of the tectonic complexity of the region and the lack of comprehensive regional geological datasets, the link between mineralization and the regional-scale geodynamic framework has not been understood. Here we present a new model for the metallogenesis of the region based on a synthesis of recent studies on the petrogenesis of magmatic arcs and the history of subduction zones throughout the region, combined with the spatio-temporal distribution of intrusion-related mineral deposits, and six new deposit ages. Convergence at the Pacific-Australia plate boundary was accommodated, from at least 45 Ma, by subduction at the Melanesian trench, with related Melanesian arc magmatism. The arrival of the Ontong Java Plateau at the trench at ca. 26 Ma resulted in cessation of subduction, immediately followed by formation of Cu-Au porphyry-epithermal deposits (at 24–20 Ma) throughout the Melanesian arc. Late Oligocene to early Miocene tectonic reorganization led to initiation of subduction at the Pocklington trough, and onset of magmatism in the Maramuni arc. The arrival of the Australian continent at the Pocklington trough by 12 Ma resulted in continental collision and ore deposit formation (from 12 to 6 Ma). This is represented by Cu-Au porphyry deposits in the New Guinea Orogen, and epithermal Au systems in the Papuan Peninsula. From 6 Ma, crustal delamination in Papua New Guinea, related to the prior Pocklington trough subduction resulted in adiabatic mantle melting with emplacement of diverse Cu and Au porphyry and epithermal deposits within the Papuan Fold and Thrust Belt and Papuan Peninsula from 6 Ma to the present day. Subduction at the New Britain and San Cristobal trenches from ca. 10 Ma resulted in an escalation in tectonic complexity and the onset of microplate tectonics in eastern Papua New Guinea and the Solomon Islands. This is reflected in the formation of diverse and discrete geodynamic settings for mineralization within the recent to modern arc setting, primarily related to upper plate shortening and extension and the spatial relationship to structures within the subducting slab.