Ilmenite,
magnetite,
titanomagnetite (Ti-bearing variety of magnetite)
apatite,
pyrrhotite,
pyrite,
chalcopyrite,
pentlandite,
chromite,
platinum-group minerals.
Best regards,
Guenter Grundmann
Dear Sir (Professor Dr. Guenter),
I am pleased to convey my respects to
you. Thanks for your immediate and informative response.
Sincerely yours
Sudip
Dear Dr. Saha:
The following heavy minerals can be used as diagnostic of the various “clans” of igneous rocks:
1. The (calc-alkali) gabbro clan:
Augite, diallag, hypersthene s.s.s., amphibole and hornblende s.s.s. (metabasic), clinozoisite-epidote s.s.s. (metabasic), Mg-enriched (metabasic) olivine (least resistant transparent HM under supergene conditions) , ilmenite, magnetite, titano-magnetite, titano-hematite, ulvöspinel, titanite (metabasic), pseudobrookite (altered), pseudorutile (altered), chromite (in placer Cr-placers), Cr-enriched rutile (metabasic), Mg-enriched spinel (mantle xenolites), pyrrhotite, pentlandite (least resistant opaque HM under supergene conditions), PGE (mineralized bridging the gap into PGM deposits and placer deposits).
Cu-Ni sulfides and -arsenides are only present in placer deposits proximal to the basic source rocks and uncommon to normal siliciclastic sediments at a distal position.
Rare constituents: corundum, sapphirine
2. The alkali-gabbro clan:
In addition to the HM of 1. Fe ore minerals, apatite, titanite, perovskite, aegirite, aegirite-augite, diopsidic augite, rare wollastonite, Cr diopside, Cr titanite,
See also for mineralized parts of sediments (placer-type) and basic intrusive source rocks
DILL H.G. , KHISHIGSUREN S., MAJIGSUREN Yo. BULGAMAA J., HONGOR O. and HOFMEISTER, W. (2004) The diamondiferous peridote (olivine)-garnet deposit Shavryn Tsaram, Central Mongolia, with special reference to its placer deposits.- Gemmologie, 53: 87-104.
DILL, H.G. (2007) Grain morphology of heavy minerals from marine and continental placer deposits, with special reference to Fe -Ti oxides.- Sedimentary Geology, 198: 1-27.
DILL, H.G. and KLOSA, D. (2011) Heavy-mineral-based provenance analysis of Mesozoic continental-marine sediments at the western edge of the Bohemian Massif, SE Germany:With special reference to Fe-Ti minerals and the crystal morphology of heavy minerals. - International Journal of Earth Sciences, 100: 1497-1513.
DILL, H.G., WEBER, B. and KLOSA, D. (2012) Crystal morphology and mineral chemistry of monazite–zircon mineral assemblages in continental placer deposits (SE Germany): Ore guide and provenance marker.- Journal of Geochemical Exploration, 112: 322-346.
DILL, H.G. (2018) Gems and Placers—A Genetic Relationship Par Excellence. Minerals 8/470: 1-43 (open access)
Available upon request on the RG server
Kind regards
H.G.Dill
Respected Sir (Professor Dr. Dill),
I am pleased to convey my respects to
you. I would like to convey my thanks to you for your immediate and informative answer. It will help me.
Thanking you Sir,
Sincerely yours,
Sudip Saha
Dear Dr. Saha
A late answer, I just wish to emphasize an important aspect when doing provenance analysis, the stability of minerals in sediments. It is important to consider the sedimentary environment in which the sediments are located, time and depth of burial. Placer deposits are just one sedimentary environment. Of the Mafic-Ultramafic minerals mentioned above, only one mineral can be considered stable in sediments: Cr-spinel (chromite). Apatite is stable in some, and unstable in other environments, it can also be generated in sedimentary environments. Magnetite is not necessarily from mafic intrusions etc. Unless your investigated samples are located in a modern, close to source setting, I advise taking the necessary time to consider it.
Trond
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