Fail asli (3,623 × 2,557 piksel, saiz fail: 4.2 MB, jenis MIME: image/jpeg)
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Ringkasan
| Keterangan |
Banded iron formation from the Precambrian of Wyoming, USA. (~10.9 cm across at its widest) Banded iron formations, or BIFs, are unusual, dense sedimentary rocks consisting of alternating layers of iron-rich oxides and iron-rich silicates. Most BIFs are Proterozoic in age (although some are Late Archean), and do not form today - they're “extinct”! Many specific varieties of iron formation are known, and some are given special rock names. For example, jaspilite is an attractive reddish & silvery gray banded rock consisting of hematite, red chert (“jasper”), and specular hematite or magnetite. Because of their age, most BIFs have been around long enough to have been subjected to one or more orogenic (mountain-building) events. As such, most BIFs are folded and/or metamorphosed to varying degrees. BIFs are known from around the world, but some of the most famous & extensive BIF deposits are found in the vicinity of North America’s Lake Superior Basin. Many BIFs have economic concentrations of iron and are mined. BIFs are the most important variety of iron ore on Earth. Some iron mines in west-central Wyoming exploit BIFs in the Goldman Meadows Formation, a Mesoarchean unit exposed in the Wind River Range. These rocks have been multiply metamorphosed during the Precambrian. The result of this metamorphism is highly contorted folding and fracturing. The rock shown above is a folded quartz-hematite-limonite meta-BIF. Stratigraphy: iron formation member (probably the upper iron formation member) of the Goldman Meadows Formation, upper Mesoarchean, 2.87 Ga (metamorphosed in the Archean at 2.8 Ga and in the Mesoproterozoic at 1.4 Ga) Geologic context: northwestern flank of the South Pass Greenstone Belt, southern Wind River Range Locality: Atlantic City Iron Mine (open-pit mine; sample possibly collected from tailings piles around the now-flooded pit) (E1/2 of section 26, T30N, R100W, Miners Delight 7.5' USGS topographic quadrangle), South Pass-Atlantic City Mining District, along Rt. 28, southwestern side of South Pass, north of Atlantic City, southwestern Fremont County, west-central Wyoming, USA (mine is at 42° 32' 45" North latitude, 108° 44' 33" West longitude) |
| Tarikh | |
| Sumber | Banded iron formation (Goldman Meadows Formation, Mesoarchean; Atlantic City Iron Mine, South Pass, Wyoming, USA) 2 |
| Pengarang | James St. John |
Perlesenan
- Anda bebas:
- untuk berkongsi – untuk menyalin, mengedar dan memindah hasil kerja
- untuk mencampur semula – untuk menyesuaikan karya
- Di bawah syarat berikut:
- pengiktirafan – Anda mesti memberi penghargaan yang berpatutan, bekalkan pautan ke lesen, dan tunjukkan jika perubahan telah dibuat. Anda boleh lakukannya dalam sebarang cara yang munasabah, tetapi bukan dalam sebarang cara yang mencadangkan pemberi lesen mengendors anda atau penggunaan anda.
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This image was originally posted to Flickr by James St. John at https://flickr.com/photos/47445767@N05/30749219994 (archive). It was reviewed on 10 Oktober 2019 by FlickreviewR 2 and was confirmed to be licensed under the terms of the cc-by-2.0. |
Sejarah fail
Klik pada tarikh/waktu untuk melihat rupa fail tersebut pada waktu itu.
| Tarikh/Waktu | Gambar kenit | Ukuran | Pengguna | Komen | |
|---|---|---|---|---|---|
| semasa | 00:37, 10 Oktober 2019 | | 3,623 × 2,557 (4.2 MB) | Ser Amantio di Nicolao | Transferred from Flickr via #flickr2commons |
Penggunaan fail
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Penggunaan fail sejagat
Fail ini digunakan oleh wiki-wiki lain yang berikut:
- Penggunaan di en.wikipedia.org
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