Magnetite geochemistry and iron isotope signature of
Magnetite is a common accessory mineral and an indicator to magma evolution and sulfide fractional crystallization in magmatic Ni Cu sulfide deposits. The Kalatongke magmatic sulfide deposit at the southern margin of the Central Asian Orogenic Belt is composed of 11 mafic intrusions.
Recent Advances in Magnetite Crystallization: …
Understanding the crystallization process of magnetite will improve the design and control of its prop... This review focuses on the magnetite crystallization …
Ilmenite composition in the Tellnes Fe–Ti deposit, SW …
Major and trace element XRF and in situ LA-ICP-MS analyses of ilmenite in the Tellnes ilmenite deposit, Rogaland Anorthosite Province, SW Norway, constrains a two stage fractional crystallization model of a ferrodioritic Fe-Ti-P rich melt. Stage 1 is characterized by ilmenite-plagioclase cumulates, partly stored in the lower part of the ore …
Identifying crystal accumulation and melt extraction during …
Ubiquitous silicic igneous rocks, such as rhyolite and granite, are major components of the continental crust. However, understanding the processes responsible for the generation of silicic magmas is challenging due to the difficulties in identifying complementary cumulate residues predicted by the fractional crystallization and elevated heat flow required for …
Release of gold-bearing fluids in convergent margin magmas
However, the onset of magnetite fractional crystallization and increased rate of total Fe and particularly Fe 3+ removal from the magma results in a shift in this redox exchange 29:
Formation of magnetite-(apatite) systems by crystallizing
Magnetite-(apatite) ore deposits are interpreted as being formed by the crystallization of iron-rich ultrabasic melts, dominantly generated by the interaction of silicate melts with oxidized P-F-SO4-bearing sedimentary rocks. This hypothesis is supported by geologic evidence, experimental studies, numerical modeling, stable and …
Evidence for iron-rich sulfate melt during magnetite
Injections of this melt form magnetite orebodies by crystallization of magnetite (mt; gray) and diopside (di; green). Fractional crystallization drives the melt …
Titanite geochemistry traces extreme differentiation of …
In highly peraluminous granites, the fractional crystallization of muscovite, biotite, amphibole and magnetite with a mineral/melt partition coefficient for Nb higher than that for Ta (D Nb /D Ta > 1) can lead to a significant decrease of the Nb/Ta ratio with enrichment in Ta relative to Nb in the residual melts (Fig. 3 c, Stepanov et al., 2014).
Magnetite Chemistry by LA-ICP-MS Records Sulfide Fractional
Mineralogical and chemical zonations observed in massive sulfide ores from Ni-Cu-platinum group element (PGE) deposits are commonly ascribed to the fractional crystallization of monosulfide solid solution (MSS) and intermediate solid solution (ISS) from sulfide liquid. Recent studies of classic examples of zoned orebodies at Sudbury and Voisey's Bay …
Integrating mineralogy, geochemistry and aeromagnetic …
Ilmenite and magnetite's association with primitive rocks, such as trocholite and pyroxene gabbro, indicate that fractional crystallization from Fe–Tirich parental magma had occurred 41,42.
Fractional Crystallization
Fractional crystallization is understood to be an important process for Earth's magmatic systems and appears to be important wherever molten magma cools slowly enough to …
Platinum-group element geochemistry of the Zhuqing Fe-Ti …
Hence, magnetite in the Zhuqing intrusions relatively concentrated Ir, Ru and Rh in preference to Pt and Pd. In addition, fractional crystallization of magnetite has contributed to the obviously different contents of Ir–Ru–Rh and Pt–Pd between the oxide-rich gabbros and the oxide-poor ones in the Zhuqing intrusions (Figs. 4 and 6).
The differentiation trend of the Skaergaard intrusion
These iron-rich magmas could lead to the generation of an iron oxide fraction (ore-bearing magma) through liquid immiscibility (Veksler et al., 2006) or produce magnetite ores by fractional ...
Fractional crystallization and magma mixing: evidence from …
The Zhoukoudian pluton in the North China craton is a circular granodiorite intrusion containing porphyritic diorite dykes (PDDs), porphyritic granodiorite dykes (PGDs) and abundant mafic microgranular enclaves (MMEs), which provide an excellent opportunity to study fractional crystallization and magma mixing. The PDDs and PGDs are located …
Styles of Fe–Ti–V ore deposits in the
However Ti-rich melts may reach ilmenite saturation before magnetite crystallization, even in oxidizing conditions, and in some cases may crystallize hemo-ilmenite without magnetite ... Fractional crystallization by in situ crystallization accompanied with crystal settling and accumulation of Fe–Ti oxide crystals was …
Trace element systematics of magnetite from alkaline mafic …
Therefore, the chemostratigraphic variations of magnetite in the intrusions were not caused by fractional crystallization. We suggest that the partitioning of compatible elements in magnetite is more likely controlled by in situ crystallization and compositional convection/diffusion in a magma chamber.
Magnetite layer formation in the Bushveld …
fractional crystallization of magnetite from a homogeneous body of melt containing 57 ppm Cr3,27, with f O2 between zero and one log unit below the quartz-fayalite …
Magnetite geochemistry and iron isotope signature …
Magnetite is a common accessory mineral and an indicator to magma evolution and sulfide fractional crystallization in magmatic Ni Cu sulfide deposits. …
Magnetite layer formation in the Bushveld Complex …
Previous models of in situ fractional magnetite crystallization require frequent ad hoc adjustments to the boundary conditions. An alternative model incorporating compositional convection...
In situ crystallization of non-cotectic and foliated …
Numerous studies have now highlighted the fact that simple fractional crystallization alone cannot explain the variation in Cr along vertical sections across magnetitite layers 7,13,34,41....
Magnetite layer formation in the Bushveld Complex of …
fractional crystallization of magnetite from a homogeneous body of melt containing 57 ppm Cr3,27, with f O2 between zero and one log unit below the quartz-fayalite-magnetite oxygen buffer (i.e.,
What Drives Iron Isotope Fractionation in Magma? | Science
Fractional crystallization of magnetite has the opposite effect, however . CREDIT: ADAPTED BY P. HUEY/ SCIENCE In addition, because olivine is the most abundant mineral in the upper mantle and is the major host for Fe, we can speculate that Fe-isotope fractionation during melting in the mantle must occur as well.
Fractional crystallization – major elements
Reverse modelling. For reverse modelling of fractional crystallization, the composition of the primitive magma is considered to be a mixture of differentiated magma and cumulus crystals. Numerical solution is provided, for instance, by …
Variation in trace element content of magnetite
It is well known that the composition of the sulfide liquid changes during fractional crystallization: ... Such compositional similarity can be explained by the crystallization of type 2 magnetite from the sulfide liquid pool that have been mingled with the downward percolated sulfide liquid. Accordingly, the downward percolation of sulfide ...
Formation of magnetite-(apatite) systems by …
When the iron-rich melt attains neutral buoyancy, fractional crystallization leads to melt immiscibility similar to that observed in industrial blast furnaces, which …
Zinc systematics quantify crustal thickness control on
Arguably, fractional crystallization ... The onset, in the most evolved stages of arc magmas, of crystallization of biotite and magnetite, plus other accessory mineral phases (e.g., ilmenite) for ...
Genesis of the Hujiazhuang apatite-rich carbonatite
Rather, they were generated through a fractional crystallization process: magnetite-calcite-apatite carbonatites are the early-stage crystallization products, whereas the calcite carbonatites represent the late-stage, highly evolved products. Although this complex was derived from a metasomatized mantle and experienced intensive …
Fractional Crystallization Link between Komatiites, Basalts, …
A Fractional Crystallization Link between Komatiites, Basalts, and Dunites of the Palaeoproterozoic Winnipegosis Komatiite Belt, Manitoba, Canada Pedro Waterton, Pedro Waterton ... where QFM is the quartz–fayalite–magnetite buffer. Winnipegosis basalts have low Mg# values that are not in equilibrium with mantle …
Fractional Crystallization
The fractional crystallization problem corresponds to the separation of sodium sulfate and magnesium sulfate from astrakanite (Na 2 SO 4.MgSO 4.4H 2 O). ... magnetite, and apatite. Late-stage carbonatite magmas may evolve to extremely sodic or ferroan compositions, and can crystallize important volumes of REE minerals such as monazite …
Magmatic karst reveals dynamics of crystallization and
During magnetite crystallization, such a boundary layer gradually increases in thickness and decreases in density until it obtains sufficient buoyancy to be released upwards into the main magma ...
