登录注册
主页关于 MindatMindat手册Mindat的历史版权Who We Are联系我们于 Mindat.org刊登广告
捐赠给 MindatCorporate Sponsorship赞助板页已赞助的板页在 Mindat刊登 广告的广告商于 Mindat.org刊登广告
Learning CenterWhat is a mineral?The most common minerals on earthInformation for EducatorsMindat ArticlesThe Elements书籍及杂志
搜索矿物的性质搜索矿物的化学Advanced Locality Search随意显示任何一 种矿物Random Locality使用minID搜索邻近产地Search Articles搜索词汇表更多搜索选项
搜索:
矿物名称:
地区产地名称:
关键字:
 
Mindat手册添加新照片Rate Photos产区编辑报告Coordinate Completion Report添加词汇表项目
Mining Companies统计会员列表Mineral Museums矿物展及活动The Mindat目录表设备设置
照片搜索Photo Galleries今天最新的照片昨天最新的照片用户照片相集过去每日精选照片相集Mineral Photography

Webster-Addie ultramafic ring dike, Webster-Balsam, Jackson Co., North Carolina, USA

This page is currently not sponsored. Click here to sponsor this page.
 
Location is approximate, estimate based on other nearby localities.
 
Latitude & Longitude (WGS84): 35° North , 83° West (est.)
Margin of Error:~9km


The Webster-Addie ultramafic body, one of the many alpine ultramafic bodies in the Appalachian belt (Larrabee, 1966), is located in the northwestern part of Jackson County, North Carolina near the town of Sylva. It is elliptical in shape (about 10 km long and 5 km wide), dips outward, and varies in outcrop width from a few meters to about 600 m.

Clinopyroxene-rich rocks, chiefly metawebsterite and olivine metaclinopyroxenite, are an important constituent of the Webster-Addie ultramafic complex, but are rare elsewhere in Blue Ridge metaultramafic bodies. They occur as layers and lenses in metadunite, ranging in thickness from a few millimeters to tens of meters. Compositional and structural (layering) characteristics are similar to, and suggest derivation from, the ultramafic cumulate portion of an ophiolite. Metamorphism of the clinopyroxene-rich rocks has produced the assemblage clinopyroxene (Cpx) + orthopyroxene (Opx) + olivine + calcic amphibole + Al-rich spinel, characteristic of the amphibolite-granulite facies transition. The absence of anthophyllite in associated metadunites indicates that pressure during metamorphism was at least 11 kb. A major feature of the metamorphism at Webster-Addie is the growth of calcic amphibole at the expense of pyroxene. Initially, this produced an aluminous hornblende, edenite. Later, edenite was, in part, retrograde metamorphosed to tremolite, resulting in composite crystals with edenite cores mantled by tremolite. Depending on the extent to which pyroxene was replaced by calcic amphibole, rocks grade from pyroxene-rich with minor amphibole to nearly pure amphibole rocks. Calcic amphiboles similar to those found replacing pyroxene at Webster-Addie are a minor, but widespread, constituent in Blue Ridge metaultramafic bodies, and may reflect
origin from a Cpx-bearing protolith.(http://www.southeasterngeology.org/Warner47-3.pdf)

Mineral List


18 valid minerals.

The above list contains all mineral locality references listed on mindat.org. This does not claim to be a complete list. If you know of more minerals from this site, please register so you can add to our database. This locality information is for reference purposes only. You should never attempt to visit any sites listed in mindat.org without first ensuring that you have the permission of the land and/or mineral rights holders for access and that you are aware of all safety precautions necessary.

References

Miller III, Roswell (1953), The Webster-Addie Ultramafic Ring, Jackson County, North Carolina, and Secondary Alteration of Its Chromite, American Mineralogist: 38: 1134-1147.

Johnson, Alvin C. (1958), A Magnetometer Survey of the Webster-Addie Ultabasic Ring, Jackson County, North Carolina (reprint), University of Michigan, Ann Arbor, 12 pp.

Larrabee (1966).

Condie, Kent C. and Madison, James A. (1969), Compositional and Volume Changes Accompanying Progresive Serpentinization of Dunites from the Webster-Addie Ultramafic Body, North Carolina, The American Mineralogist: 54 (July-August).

Wilson, W.F and McKenzie, B.J. (1978), Mineral Collecting Sites in North Carolina, Information Circular 24.

Snyder, Daniel R. (2011), Olivine weathering textures in serpentinized dunite, Webster-Addie ultramafic body, North Carolina, ProQuest, UMI Dissertation Publishing (September 30, 2011), 204 pp. [Paperback]

External Links


 
矿物 and/or 产地  
版权所有© mindat.org1993年至2020年,除了规定的地方。 Mindat.org全赖于全球数千个以上成员和支持者们的参与。
隐私政策 - 条款和条款细则 - 联络我们 Current server date and time: 2020.1.19 07:24:00 Page generated: 2017.4.3 02:13:20
Go to top of page