| 词条 | Spruce Pine Mining District |
| 释义 |
The Spruce Pine Mining District is a swath of the valley of the North Toe River in the Blue Ridge Mountains of northwestern North Carolina that is home to one of the richest deposits of gems and minerals in the world.{{cn|date=August 2011}} Mined for its mica, kaolin, quartz and feldspar, the district provides much of the raw materials used in plumbing fixtures.{{citation needed|date=December 2012}} Spruce Pine district is one of the largest suppliers of high-purity quartz, which is used in the manufacture of silicon chips.[1] The district is named after the town of Spruce Pine, which is located in the middle of the region and is the hub of major mining activity there. The district is approximately {{convert|25|mi|km}} long and {{convert|5|mi|km}} wide. GeologyThe pegmatites intruded into the Ashe Formation. The pegmatites and country rock are part of the Spruce Pine thrust block, the highest thrust sheet of the Blue Ridge belt, the latter being part of the Tugaloo Terrane which was accreted to North America during the Taconic Orogeny.[2] References1. ^{{cite web | last =Nelson | first =Sue | title =Silicon Valley's secret recipe | work =BBC News - Radio 4 | publisher =BBC | date =2 August 2009 | url =http://news.bbc.co.uk/2/hi/technology/8178580.stm | accessdate =2009-08-03 }} 2. ^{{cite journal|last=Swanson|first=S.E.|author2=Veal, W.B. |url=http://www.jgeosci.org/content/jgeosci.062_2010_1_swanson.pdf|title=Mineralogy and petrogenesis of pegmatites in the Spruce Pine District, North Carolina, USA|journal=Journal of Geosciences|date=2010|pages=27–42|doi=10.3190/jgeosci.062}} External links
2 : Mining in North Carolina|Blue Ridge Mountains |
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