دانلود رایگان ترجمه مقاله کانسارهای طلا – نقره اپی ترمال Hauraki Goldfield، نیوزلند – Geoscienceworld 2011
دانلود رایگان مقاله انگلیسی + خرید ترجمه فارسی | |
عنوان فارسی مقاله: |
کانسارهای طلا – نقره اپی ترمال Hauraki Goldfield، نیوزلند: معرفی |
عنوان انگلیسی مقاله: |
Epithermal Gold-Silver Deposits of the Hauraki Goldfield, New Zealand: An Introduction |
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مشخصات مقاله انگلیسی (PDF) | |
سال انتشار | ۲۰۱۱ |
تعداد صفحات مقاله انگلیسی | ۵ صفحه با فرمت pdf |
رشته های مرتبط با این مقاله | زمین شناسی |
گرایش های مرتبط با این مقاله | سنگ شناسی |
چاپ شده در مجله (ژورنال) | زمین شناسی اقتصادی – Economic Geology |
رفرنس | دارد ✓ |
کد محصول | F1133 |
نشریه | Geoscienceworld |
مشخصات و وضعیت ترجمه فارسی این مقاله | |
وضعیت ترجمه | انجام شده و آماده دانلود |
تعداد صفحات ترجمه تایپ شده با فرمت ورد با قابلیت ویرایش | ۴ صفحه با فونت ۱۴ B Nazanin |
ترجمه عناوین تصاویر | ترجمه نشده است ☓ |
ترجمه متون داخل تصاویر | ترجمه نشده است ☓ |
درج تصاویر در فایل ترجمه | درج شده است ✓ |
کیفیت ترجمه | کیفیت ترجمه این مقاله خوب میباشد |
توضیحات | تا نصف مقاله ترجمه شده است. |
فهرست مطالب |
زمین شناسی و کانسارهای معدنی منطقه Hauraki Goldfield
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بخشی از ترجمه |
چکیده |
بخشی از مقاله انگلیسی |
Geology and Mineral Deposits of the Hauraki Goldfield The five papers that follow describe diverse aspects of epithermal gold-silver deposits and genetically related hydrothermal systems in the Hauraki goldfield on the Coromandel peninsula of the North Island of New Zealand (Fig. 1). The Hauraki goldfield contains more than 50 Miocene and Pliocene epithermal Au-Ag deposits and several porphyry Cu-Au-Mo occurrences in a 200-km-long by 40-km-wide north-south–trending belt (Fig. 1C; Christie et al., 2007). Production from these deposits between 1862 and 2009 totaled approx. 335,000 kg (10.8 Moz) of Au and 1.6 million kg (51.4 Moz) of Ag (Mauk et al., 2011). The epithermal deposits are related to subaerial hydrothermal systems hosted in rocks of the early Miocene to late Pliocene (~18–۱٫۹ Ma) Coromandel volcanic zone (Skinner, 1986). Placer gold was first discovered near Coromandel township in 1852, but because of the small size of these placers, little mining activity occurred until the discovery of Au-bearing quartz veins in 1861 at the site of the Kapanga mine (Fig. 1C). Prospecting elsewhere on the Coromandel peninsula resulted in the opening of mines at Thames in 1865, Karangahake in 1875, and Waihi (Martha) in 1878. The major period of gold mining ended with the closure of the underground Martha mine at Waihi in 1952. Total production during this period was more than 250,000 kg (8.0 Moz) of Au and 1,100,000 kg (35.3 Moz) of Ag (Christie et al., 2007). Higher gold prices in the 1980s led to renewed exploration, and the recent phase of gold mining began in 1988 with opening of the Martha openpit mine at Waihi. This was followed by a combined open-pit and underground operation at Golden Cross from 1991 to 1998 and discovery of the Favona deposit, 1.5 km from the Martha open pit, which opened as an underground mine in 2006. Mining continues today at the Martha mine, and the Trio deposit, which lies between the Martha and Favona mines, is being developed through underground workings extending from the Favona mine. The Martha mine is by far the largest producer in the Hauraki goldfield, with total production through 2009 of ~220,000 kg (7.1 Moz) of Au and 1,430,000 kg (46 Moz) of Ag (Newmont Waihi Gold Limited, 2010), which accounts for approximately 66 percent of the total Au and 89 percent of the total Ag production of the Hauraki goldfield. Other major past producers were the Thames, Golden Cross, and Karangahake mines. The Coromandel peninsula is composed of Miocene and Pliocene subaerial volcanic rocks and volcaniclastic deposits of the Coromandel volcanic zone that unconformably overlie Late Jurassic graywacke and argillite basement (Fig. 1C; Skinner, 1986; Christie et al., 2007). Rocks of the Coromandel volcanic zone merge with and are overlain by Quaternary volcanic deposits of the Taupo volcanic zone at the southern end of the Coromandel peninsula. The Coromandel volcanic zone is a subduction-related magmatic arc whose eruptive products are medium-K and calc-alkaline with compositions that range from basaltic andesite to rhyolite. The main ore hosts are basaltic andesite, andesite, and dacite units in the 18 to 2.5 Ma Coromandel Group (Booden et al., 2011). The exact origin of the Coromandel volcanic zone is controversial. Mauk et al. (2011) summarize available evidence and interpretations and suggest that the Coromandel volcanic zone represents products of both the Northland and Colville arcs and that reorganization of these arcs may have occurred at about 10 Ma, just prior to a shift from andesite-dacite to bimodal andesite-rhyolite volcanism in the Coromandel volcanic zone. The active Taupo volcanic zone is at the southwest end of the Tonga-Kermadec-Taupo volcanic zone arc (Fig. 1B). The Coromandel volcanic zone is cut by north-northwest– and north-northeast– to east-northeast–striking faults (Fig. 1C). Most northeast- and east-northeast–striking faults are downthrown to the south, thereby lowering the Jurassic basement to the south, thickening the volcanic sequence toward the Taupo volcanic zone, and tilting these volcanic rocks gently eastward. Several major structural corridors cross the peninsula and may reflect major basement structures (Fig. 1D). Morrell et al. (2011) describe geophysical features in the Waihi-Waitekauri area in the central part of the KarangahakeOhui structural trend that may have localized numerous late Miocene hydrothermal systems.. |