首页   按字顺浏览 期刊浏览 卷期浏览 A palaeomagnetic study of Svecokarelian basic rocks from northern Sweden
A palaeomagnetic study of Svecokarelian basic rocks from northern Sweden

 

作者: Sten-ÅKe Elming,  

 

期刊: Geologiska Föreningen i Stockholm Förhandlingar  (Taylor Available online 1985)
卷期: Volume 107, issue 1  

页码: 17-35

 

ISSN:0016-786X

 

年代: 1985

 

DOI:10.1080/11035898509452608

 

出版商: Taylor & Francis Group

 

关键词: Svecokarelian;palaeomagnetism;AF-demagnetization;thermal-demagnetization;physical properties;mineralogy;basic rocks;Haparanda Suite;Notträsk;Sangis;Tärendö;Svappavaara;Vittangi;Dundret;north Sweden;N6550 N6740 E2035 E2330

 

数据来源: Taylor

 

摘要:

This palaeomagnetic investigation comprises basic rocks from six localities from the Svecokarelian zone in northern Sweden. Most of the pole positions in this study and other reported poles of Svecokarelian and post-Svecokarelian rocks fall within an approximately 12 degrees wide band running from east to west representing ages of magnetizations from 1880-1700 to ∼ 1530 Ma. Thermal demagnetizations of specimens of the probably oldest massifs indicate a possible backward continuation of the polar wandering path. Mineralogical studies of thin sections of the rocks show ore symplectites and myrmekitic textures indicating a slow rate of cooling at least at the end of the rock formation. Signs of metamorphism are demonstrated by the existence of secondary minerals, including magnetite, not related to late magmatic alterations. The distribution of site means as well as the change of directions of the remanence vectors during thermal demagnetization can be explained by a slow rate of cooling and where signs of metamorphism exist by partial remagnetization of the rock. This study has, apart from the palaeomagnetic results, demonstrated the difficulty of correlating radiometric ages with ages of magnetization.

 

点击下载:  PDF (1375KB)



返 回