登录注册
Quick Links : Mindat手册The Rock H. Currier Digital LibraryMindat Newsletter [Free Download]
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 ElementsThe Rock H. Currier Digital LibraryGeologic Time
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 MuseumsClubs & Organizations矿物展及活动The Mindat目录表设备设置The Mineral Quiz
照片搜索Photo GalleriesSearch by Color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Photography

Identity HelpLocality of columbite from Madagascar - Analalava vs. Tsaramanga

12th Jul 2012 01:25 UTCPavel Kartashov Manager

09401550016016767706553.jpg
I'd received crystaline cluster labeled as "Ferrocolumbite from Analalava district, Sofia region, Mahajanga pr., Madagascar".

00008250016016767711537.jpg

00186500016016767714979.jpg


But locality http://www.mindat.org/loc-157722.html don't contain any pagmatite minerals but only mineralized basaltic effusive rocks.

Fromother hand, here was uploaded photo very similar crystal - http://www.mindat.org/photo-149304.html


Other very similar crystals we see in classic pegmatite occurrence http://www.mindat.org/loc-27803.html

Compare my specimen with http://www.mindat.org/gallery.php?loc=27803&min=1112


I am confused...:-(:-S:-(


By the way my mineral in reality is Sc-bearing ferroan and titanoan Manganocolumbite. It contains inclusions of quartz, microcline, films of bastnasite-(La), pseudomorphoses of bismuthite after bismuthinite and overgrown by minute tetragonal prismes similar to xenotime.

12th Jul 2012 09:09 UTCKnut Edvard Larsen 🌟 Manager

The labelling of these as coming from Analalava District, Sofia Region are highly doubtful, i i would say a misnomer.

The geology of the Analalava District consist, as you say, only of cretaceous basaltic roks and jurassique-cretaceous and tertiary sedimentary layers. The columbites like these come from precambrian granite pegmatites (55o MA) from the socle of the Madagascar highland. There are so far as I know no granite pegmatites in the Analalava district,. and none marked on the geological maps of the area.


There is a granite pegmatite field with Beryl-Columbite subtype LCT pegmatites in the neighbour District of Analalava, in the Bealanana District , along the River Meavarano wich produced some columbite in the 1950s, but I have not seen these.


Your sample looks indeed very similar to samples from Tsaramanga. I have several in my collection, collected at the Tsaramanga pegmatite. Together with these I found also bismutite pseudomorphs after bismuthinite etc.


But , of course i can't say with a 100% certainty that your specimen is from Tsaramanga. It may come from another locality- but not Analalava District.

12th Jul 2012 09:54 UTCKnut Edvard Larsen 🌟 Manager

Message sent about http://www.mindat.org/photo-149304.html

10th Jan 2015 02:20 UTCPavel Kartashov Manager

Michel never answers messages and complaints.:-D But it looks like, that we both had the same source of material.
 
矿物 and/or 产地  
Mindat Discussions Facebook Logo Instagram Logo Discord Logo
版权所有© mindat.org1993年至2024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 - Report a bug/vulnerability Current server date and time: 2024.4.26 23:44:16
Go to top of page