Petrography, geochemistry and magnetic susceptibility of the Isortoq Fe-Ti-V deposit, Isortoq Giant Dykes, South Greenland
2
Citation
10
Reference
10
Related Paper
Citation Trend
Abstract:
The Isortoq Giant Dykes in the Proterozoic Gardar Province, South Greenland, include the Isortoq South giant dyke and the Isortoq North giant dyke. The fine-grained Fe-Ti-V deposit hosted by the Isortoq South giant dyke, referred to as the Isortoq Fe-Ti-V deposit, is considered a good test site for the use of magnetic susceptibility for the mapping of ore grades. Here, we test this and show that the Fe, Ti and V distribution is controlled by titanomagnetite disseminated throughout fine-grained troctolite. The deposit displays a clear correlation between magnetic susceptibility and Fe, Ti and V grades in bulk samples of consecutive 2 m sections from 11 drill cores, totalling 2671 m in length. We observe that Fe, Ti and V are almost entirely hosted in titanomagnetite, which controls the magnetic susceptibility. Field measurements of the magnetic susceptibility can thus be considered as a reliable exploration tool for this type of mineralisation. We further consider the origins of the deposit by reconnaissance petrography, mineral and bulk rock chemistry of the large mass of aphanitic Fe-rich troctolite in the Isortoq South giant dyke. We suggest that the deposit may represent the base of a basanitic to trachybasaltic magma chamber, in which Fe-rich immiscible melts accumulated, crystallised and fractionated. The processes suggested here may apply to other giant dykes and intrusions of the Gardar Province.The application of petrographic analysis to the problems of provenance attribution of ceramics made in the Islamic world is complicated by the presence of the highly quartzose ‘stonepaste’body. To facilitate the differentiation of different stonepaste groups, it has been necessary to develop specific criteria for distinguishing the characteristics of each centre, including the assessment of the degree of cloudiness of the quartz as rendered by fluid inclusions. This has enabled the successful application of petrographic analysis, and the solution of a number of provenance problems.
Cite
Citations (29)
Cite
Citations (0)
Biplot
Cite
Citations (13)
Abstract Differences in particle roundness and petrography have been studied in more than 250 gravel pits all over Gotland. The recording of petrographic properties was. however, restricted to the differences in the percentual representation of limestones, marlstone. Burgsvik sandstone, and the erratic, Precambrian elements. Gotland may be divided into distinct regions, according to the petrography of the gravels. The differences are interpreted as being due, to a certain extent, to the influence of various ice flows over the island, where the ice flows carried material of specific petrographic composition. The possibility of tracing the source formation of littoral accumulations by using petrographic analysis has been investigated. It is considered that such analyses alone are not sufficient to allow safe conclusions to be drawn.
Marl
Eemian
Cite
Citations (2)
Thrust fault
Cite
Citations (24)
Study of Indian refractory materials, under the petrographic microscope does not appear to have received sufficient attention. Petrographic data on Indian silica and magnesite bricks have been presented as also those on some foreign bricks for comparison. Correlated data like true density, thermal expansion, etc. have been included for a better appreciation of the petrographic data given.
Refractory (planetary science)
Cite
Citations (1)