Rais Latypov

• PhD
• Professor (Full) at University of the Witwatersrand

A common feature of layered intrusions is the absence of the Upper Border Series (UBS)—a rock sequence that is expected to grow from the roof downwards in large basaltic magma chambers. This is surprising because magma cooling occurs predominantly through the roof of magma chambers. The lack of the UBS is thus indicative of some fundamental reason...

The Bushveld Complex in South Africa hosts the lion’s share of the world’s noble metal resources in platinum reefs – thin layers of silicate/chromite rocks containing platinum-rich sulphides. The reefs are widely attributed to multiple replenishments by ore-forming magmas that have been entering the evolving Bushveld chamber through numerous feeder...

Several recent petrogenetic models propose that layers of stratiform chromitites in the Bushveld Complex are produced by mechanical separation of chromite from co-existing silicate minerals (e.g., olivine, orthopyroxene, plagioclase) within crystal-rich slurries. One feature in common for the slurry models is that they imply that interstitial liqui...

Layered mafic intrusions commonly contain non-cotectic, foliated igneous rocks that are traditionally attributed to processes involving settling, transport, and redeposition of crystals. Here we examine the chemistry of magnetitite layers of the Bushveld Complex using a portable XRF spectrometer on drill core and dissolution ICP-MS analysis on pure...

The vertical growth rate of basaltic magma chambers remains largely unknown with available estimates being highly uncertain. Here, we propose a novel approach to address this issue using the classical Skaergaard intrusion that started crystallizing from all margins inward only after it had been completely filled with magma. Our numerical simulation...

Several recent studies have argued that large, long-lived and molten magma chambers may not occur in the shallow Earth’s crust. Here we present, however, field-based observations from the Bushveld Complex that provide evidence to the contrary. In the eastern part of the complex, the magmatic layering continuously drapes across a ~ 4-km-high sloping...

The Bushveld Complex in South Africa shows spectacular examples of regional and local magmatic erosion of the floor cumulates by new melt batches that replenished the evolving magma chamber. Field observations indicate that, at some stratigraphic levels, at least, 15-20 m of pre-existing floor cumulates, often nearly monomineralic in composition (e...

The magmatic stratigraphy of the Sudbury Igneous Complex (Canada) is thought to have resulted from closed-system differentiation of an initially homogeneous impact melt sheet. The topography of its upward-growing chamber floor is therefore thought to have been planar and subhorizontal. However, we report on the discovery of a large pothole-like dep...

The classical paradigm of the ‘big magma tank’ chambers in which the melt differentiates, is replenished, and occasionally feeds the overlying volcanos has recently been challenged on various grounds. An alternative school of thought is that such large, long-lived and largely molten magma chambers are transient to non-existent in Earth’s history. O...

Several recent studies have argued that large, long-lived and molten magma chambers 1–10 may not occur in the shallow Earth’s crust 11–23 . Here we present, however, field-based observations from the Bushveld Complex ²⁴ that provide evidence to the contrary. In the eastern part of the complex, the magmatic layering was found to continuously drape a...

The Upper Zone of the Bushveld Complex has long been known to have formed from a major influx of magma into the chamber that caused large-scale erosion of the chamber floor cumulates. The most dramatic manifestations of this process are two major gap areas (Northern and Southern) in the western Bushveld Complex in which the Upper Zone appears to ha...

The Critical Zone of the Bushveld Complex contains thick and laterally extensive Lower, Middle and Upper Group chromitite layers (LG, MG & UG, respectively), which are exposed within many open pit and underground mines. Using field observations from these exposures throughout the Eastern and Western Lobes of the Bushveld Complex, we describe here t...

A recent re-interpretation of the Bushveld Complex and other layered intrusions as stacks of randomly emplaced, amalgamated sills is mostly fuelled by finding of zircon ages that are not getting progressively younger from the base upwards, as expected from a classical model for the formation of layered intrusions. Rather, they display several rever...

The spatial association between Pt minerals, magmatic sulfides, and chromite has been investigated using microbeam X-ray fluorescence (XRF) element mapping and the Maia Mapper. This lab-based instrument combines the Maia parallel energy dispersive (ESD) detector array technology with a focused X-ray beam generated from a liquid metal source. It pro...

An emerging and increasingly pervasive school of thought is that large, long-lived and largely molten magma chambers are transient to non-existent in Earth’s history 1–13 . These ideas attempt to supplant the classical paradigm of the ‘big magma tank’ chambers in which the melt differentiates, is replenished, and occasionally feeds the overlying vo...

An understanding of magma chamber dynamics relies on answering three important yet highly controversial questions: where, why, and how magma chambers crystallize and differentiate. Here we report on a new natural phenomenon—the undercut-embayed chamber floor in the Bushveld Complex—which allows us to address these questions. The undercut-embayed fl...

Orthopyroxenite cumulates throughout the Critical Zone of the Bushveld Complex commonly contain prominent euhedral crystals of bottle-green augite, typically around 1 cm in size and surrounded by “haloes” of nearly pure plagioclase. On close examination, the augite grains can be seen to be oikocrysts, containing extensively resorbed chadacrysts of...

Basaltic magma chambers are best exemplified by layered intrusions – fossilized natural laboratories that historically constrain most fundamental principles of igneous petrology. Progressive fractional crystallization of basaltic melts in layered intrusions results in successive appearance of 5-10 liquidus minerals. Most minerals appear in the stra...

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Chemical differentiation of magma on Earth occurs through physical separation of liquids and crystals. The mechanisms of this separation still remain elusive due to the lack of information on solidification fronts in plutonic magmatic systems. Here, we present records of fossilized solidification fronts from massive magnetitites of the Bushveld Com...

Plutonic mafic complexes are composed of cumulates in which minerals mostly occur in cotectic proportions. This is consistent with a concept that basaltic magma chambers predominantly crystallize in situ from margins inward. However, cumulates with two (or more) minerals in proportions that are at odds with those expected from liquidus phase equili...

The formation of some Earth’s monomineralic igneous rocks appears to be prohibited by constraints imposed by liquidus phase-equilibria on evolution of mantle-derived magmas. Yet, these rocks exist as stratiform layers in many mafic-ultramafic intrusions. One conspicuous example is monomineralic anorthosites in the Bushveld Complex that occur as str...

We describe an impressive ~55 m high outcrop from the Pilanesberg Platinum Mine open pit, located in the North-Western Bushveld Complex. The outcrop exposes the complete two-dimensional structure of three Merensky Unit potholes that cut several metres down into the underlying footwall anorthosites. The transgressive field relationships are interpre...

Most of the world’s economically-viable platinum deposits occur as ‘reefs’ in layered intrusions – thin layers of silicate rocks that contain sulphides enriched in noble metals. There are two contrasting magmatic hypotheses for their formation. The first suggests accumulation through gravity-induced settling of crystals onto the magma chamber floor...

The Merensky Reef (MR) of the Bushveld Complex is known for containing the lion’s share of the world’s reserves of platinum group elements (PGE). It is commonly described as a single, relatively thin layer (or package) of chromite- and sulphide-bearing orthopyroxenite hosted by almost barren norite and/or anorthosite. Here, we present a drill-core...

Bolide impact is a ubiquitous geological process in the Solar System, which produced craters and basins filled with impact melt sheets on the terrestrial planets. However, it remains controversial whether these sheets were able to undergo large-scale igneous differentiation, or not. Here, we report on the discovery of large discrete bodies of melan...

Coarse-grained, discordant, mainly ultramafic, bodies cut the layered succession of the Bushveld Complex. Previous models have subdivided them into magnesian dunite, considered to have been emplaced upward, and more iron-rich wehrlite (± oxides), referred to as iron-rich ultramafic pegmatites (IRUP), emplaced downward. We have studied a number of t...

The Merensky Unit, Bushveld Complex, is commonly described using genetic terms such as "cyclic unit", typically without careful consideration of the connotations. We suggest that this contributes to the debate on processes forming the unit. This study integrates an extensive field study with detailed petrographic and textural analyses of the Merens...

Platinum-bearing chromitites in mafic-ultramafic intrusions such as the Bushveld Complex are key repositories of strategically important metals for human society. Basaltic melts saturated in chromite alone are crucial to their generation, but the origin of such melts is controversial. One concept holds that they are produced by processes operating...

The Bushveld Complex is traditionally interpreted as having formed from numerous magma pulses that successively replenished the evolving chamber and deposited crystals on a temporary floor, building the layered sequence from the base upwards. There are, however, several historic and recent attempts to question this view, with the suggestion that so...

The origin of chromitites in the Bushveld Complex has been attributed to two principal mechanisms: (1) gravity-controlled settling of chromite onto the chamber floor from magma that was saturated in chromite, either initially or owing to some internal process; or (2) gravity- and size-controlled separation of chromite from coexisting olivine and or...

This study evaluates combined U-Pb, Hf-Nd-Sr-Os radiogenic and Cu-S stable isotope data for the ultramafic-mafic intrusions of the Noril’sk and Taimyr Provinces to provide new insights on the timing and sources of materials involved in the generation of variously mineralized lithologies and associated Ni-Cu-PGE sulfide ores. New isotopic-geochemica...

Thick dolerite sills show a range of vertical geochemical variation trends attributable to various processes during slow crystallization. We have identified chemical parameters in a 169-m-thick sill from the Karoo igneous province in South Africa that define three different lower crossover levels (maximum or minimum concentrations) creating S-shape...

A central issue for understanding platinum group element (PGE) deposits in layered intrusions is whether they formed through gravitational settling or in situ deposition of sulphide-bearing cumulates on the chamber floor. A unique feature pertinent to this issue is the undercutting Merensky Reef (MR) of the Bushveld Complex, which is commonly assoc...

The UG-1 chromitite in the Bushveld Complex is a 1 metre thick massive layer overlain by orthopyroxenite (4 ‒ 9 m thick) and underlain by anorthosite (1.5 ‒ 2.0 m thick), which is strongly interleaved with numerous thin layers of UG-1 chromitite (mm to 10s of cm thick). The chromitite-bearing anorthosite is further underlain by mottled anorthosite,...

One of the most puzzling features of the UG1 chromitite layers in the famous exposures at Dwars River, Eastern Bushveld Complex, is the bifurcation, i.e. convergence and divergence of layers along strike that isolate lenses of anorthosite. The bifurcations have been variously interpreted as resulting from: (1) the intermittent accumulation of plagi...

Pothole structures in layered igneous complexes are where one of the horizons transgresses downwards into the underlying stratigraphy. They are best recognised in the Merensky Reef (MR) of the Bushveld Complex, where the potholes provide key insights into the processes through which the layering and the critical metals it hosts (PGE, Cr and V) deve...

Significant PGE and Cr mineralization occurs in a number of 2.44–2.50-Ga mafic layered intrusions located across the Karelian and Kola cratons. The intrusions have been interpreted to be related to mantle plume activity. Most of the intrusions have negative εNd values of about −1 to −2 and slightly radiogenic initial Sr isotope compositions of abou...

Potholes are spectacular 3D features that provide key insights into processes of igneous layering and concentration of economic elements (e.g. PGE, Cr & V). Despite detailed studies there is very little consensus as to how they formed and even less on predicting their spatial distribution. These studies have been based on typical geological techniq...

A central issue for understanding the platinum group element (PGE) deposits in layered intrusions is whether they formed through gravitational settling, or in situ deposition of sulphide-bearing cumulates on the chamber floor. A unique feature pertinent to this issue is the undercutting Merensky Reef (MR) of the Bushveld Complex, which is commonly...

Pothole structures in layered igneous complexes are where one of the horizons transgresses downwards into the underlying stratigraphy. They are best recognised in the Bushveld Complex, as the Merensky Reef is the type locality, and are also described from the Stillwater Complex. However, there is a widespread lack of recognition of pothole structur...

Pothole structures are formed where horizons cut downwards into the underlying stratigraphy. They notably occur in the Bushveld and Stillwater Complexes, where they greatly complicate extraction of the economic resources. However, there is a widespread lack of recognition of pothole structures in other layered intrusions, due to poor understanding...

We have recently discovered several chromitite dykes that cut a sequence of alternating layers of dunite and chromitite in the lower part of the Monchegorsk Layered Intrusion, Russia. The chromitite dykes are up to 18cm wide and several metres long, have sharp boundaries with the host dunite, are fine-grained and contain up to 80-85% chromite. The...

The Merensky Reef (MR) in the Bushveld Complex has been variously interpreted as resulting from: magma mixing followed by gravitational settling of chromite and/or sulphide onto the magma chamber floor; upward percolation of interstitial fluids from the solidifying underlying cumulates; a pressure-induced burst of crystallization of sulphide and ch...

Fractional crystallization of ponded basaltic magma results in rocks that become increasingly more evolved in composition inwards. However, almost all mafic sills and layered intrusions show basal reversals tens to hundreds of meters thick in which minerals and rocks become compositionally more primitive upwards. Two main types of basal reversals c...

The northeastward subduction of the Neo-Tethyan oceanic lithosphere beneath the Iranian block produced vast volcanic and plutonic rocks that now outcrop in central (Urumieh–Dokhtar magmatic assemblage) and north–northeastern Iran (Alborz Magmatic Belt), with peak magmatism occurring during the Eocene. The Karaj Dam basement sill (KDBS), situated in...

Marsh (Contrib Miner Petrol 166:665-690, 2013) again claims that crystal-free basalt magmas are unable to differentiate in crustal magma chambers and regards layered intrusions as primarily due to the repeated emplacement of crystal suspensions. He ignores an earlier critique of his unconventional inferences (Latypov, J Petrol 50:1047-1069, 2009) a...

Electronic Supplementary Appendix A: Geological background of the studied ore samples

This edited work contains the most recent advances related to the study of layered intrusions and cumulate rocks formation. The first part of this book presents reviews and new views of processes producing the textural, mineralogical and geochemical characteristics of layered igneous rocks. The second part summarizes progress in the study of select...

Magmatic rocks containing economic concentrations of iron, titanium, vanadium and phosphorous are commonly associated with massif-type anorthosites and related rocks. This rock association is part of the Anorthosite-Mangerite-Charnockite-(rapakivi-)Granite suites that are restricted to the Proterozoic. Understanding the geochemistry and emplacement...

We have discovered an adcumulate late-stage dyke in the Bayantsagaan layered intrusion. The 11-cm-thick dyke is composed of fresh troctolite with no signs of chilling against the host leucotroctolite. Texturally, both the dyke and its host are medium-grained plagioclase-olivine-magnetite cumulates. The dyke is however finer grained and contains les...

Combined Cu–S isotope data for Ni-Cu-PGE sufides from the economic deposits hosted in the Noril’sk-1, Talnakh and Kharaelakh intrusions, from the subeconomic deposits in the Chernogorsk, Zub-Marksheider, and Vologochan intrusions, and from the non-economic occurrences in the Nizhny Talnakh intrusion in the Noril’sk Province (Russia), and the J-M Re...

The study evaluates the usefulness of Nd-Sr-Hf-Cu-S isotope information, providing insights into origin of mafic-ultramafic intrusions and associated Ni-Cu-PGE sulfide ores of the Polar Siberia. New indicators for the economic potential of Ni-Cu-PGE sulfide deposits are suggested.

The Rum Layered Suite (NW Scotland) is generally regarded as one of a handful of classic examples of open-system layered mafic-ultramafic intrusions, or ‘fossilized’ basaltic magma chambers, world-wide. The eastern portion of the Rum intrusion is constructed of sixteen repeated, coupled, peridotite–troctolite units. Each major cyclic unit has been...

The current debate on the origin of platinum-group element (PGE) reefs in layered intrusions centres mostly on gravity settling of sulphide liquid from overlying magma versus its introduction with interstitial melt/fluids migrating upward from the underlying cumulate pile. Here, we show that PGE-rich chromitite seams of the Rum Eastern Layered Intr...

The origin of mafic and ultramafic sills exhibiting different whole-rock compositional profiles (e.g. I-, C-, D-, M- and S-shaped profiles) remains controversial. We have addressed this issue by revisiting three ~100 m-thick Siberian dolerite sills (Vavukansky, Kuz'movsky and Vilyuysky) that display remarkable internal differentiation. The Vavukans...

It is commonly expected that late-stage dykes in mafic layered intrusions must be strongly enriched in all incompatible components that are concentrated in the evolved residual melt. Our recent study of one late-stage dyke from the Bayantsagaan layered intrusion (Mongolia) has revealed, however, that this is not always the case. This 11 cm thick dy...

Stable isotope systematics of magmatic PGE-Cu-Ni sulphide ores of the Noril'sk Province: genetic constraints and implications for exploration

This study assesses Cu and S isotopic data for PGE-Cu-Ni sulphide deposits associated with the economic Noril’sk-1, Talnakh and Kharaelakh intrusions, the subeconomic Chernogorsk, Zub-Marksheider and Vologochan intrusions, and the non-economic Nizhny Talnakh intrusion within the Noril’sk Province (Russia). In terms of Cu-isotopes, the majority of...

We have undertaken for the first time the examination of the Cu isotope composition of primary high temperature Cu-Ni sulfde ores from world-class PGE-Cu-Ni sulfide deposits associated with the economic Talnakh and Kharaelakh intrusions and native copper ores from the Noril’sk Province (Russia). Copper isotope ratios are reported as δ65Cu‰=((65Cu/6...

Magma differentiation processes that take place in conduits delivering basaltic magmas to the Earth's surface are still poorly understood. To get new insights into this problem we have studied in detail the whole-rock geochemistry of a section across a dolerite dyke (21 m thick) and three sections across its narrow apophysis (69 cm, 29 cm and 17 cm...

The ~100 m thick marginal zone of the Fongen–Hyllingen Intrusion (FHI) consists of non-layered, highly iron-enriched ferrodiorites that are overlain by a ~ 6 km thick layered sequence of gabbroic to dioritic rocks of the Layered Series. From the base upwards the marginal zone becomes more primitive as exemplified by a significant increase in whole-...

The ~100 m thick marginal zone of the Fongen-Hyllingen Intrusion (FHI) consists of nonlayered, highly iron-enriched ferrodiorites that are overlain by a ~6 km thick layered sequence of gabbroic to dioritic rocks of the Layered Series. From the base upwards the marginal zone become more primitive as exemplified by a significant increase in whole-roc...

The relative roles of crystal settling and in situ crystallization in the formation of igneous bodies are still a subject of debate in igneous petrology. Both processes predict that minerals must become more evolved in composition inward. Our study of three dolerite sills from Siberia indicates, however, that this is not always the case. In particu...

Magma differentiation processes that operate in conduits delivering basaltic magmas towards the Earth's surface still remains poorly understood. To get insight into this problem we have studied whole-rock geochemistry and mineral composition of rock-forming minerals (plagioclase and clinopyroxene) in one section across a large dolerite dyke (21 m t...

RECEIVED FEBRUARY 10, 2011; ACCEPTED OCTOBER 7, 2011 ADVANCE ACCESS PUBLICATION DECEMBER 2, 2011 The $13 m thick marginal zone of the $3·5 km thick mafic Imandra Layered Intrusion (ILI) consists of fine-grained pigeonite gabbros that are chilled against the underlying host andesitic basalts but reveals a non-chilled, highly irregular upper contact...

Abstract. The ultramafic–mafic Noril'sk-type intrusions in the northern part of Siberia, in Russia, host some of the world's major economic platinum-group-element (PGE)–Cu–Ni sulfide deposits. We present the results of Re–Os and S isotope systematics of PGE–Cu–Ni sulfide ores associated with the economic Talnakh and Kharaelakh intrusions within the...

We have studied a single apothysis of a dolerite dyke that provides a novel insight into differentiation processes operating in basaltic magma conduits. The apothysis emanates from a large master dyke and gradually pinches out along a distance of about 11 m. Three continuous profiles across an apothysis (17 cm, 29 cm and 69 cm wide) were studied. C...

To gain insights into the long-standing problem of marginal reversals, we have studied in detail the similar to 200 m thick marginal zone of the similar to 3 km thick, mafic Koitelainen Layered Intrusion (KLI). This marginal zone consists of pigeonite gabbros that are chilled against gneisses of the underlying basement but reveals a non-chilled upp...

Small dykes are traditionally considered as rapidly quenched bodies that preserve information on the parental liquid composition. This is because a fast cooling regime in small dykes promotes magma quenching that impedes any cumulate growth processes. However, the assumption appears to be not universally valid. A 16 cm thick, fine-grained, dacitic...

A 140 cm thick dolerite dyke in the Vochelambina area of the Kola Peninsula, Russia, has an unexpected internal zonation that combines the features of both reverse and normal differentiation trends. From the margins inwards, the dyke exhibits a steady increase in normative An (100An/(An+Ab)), whole-rock Mg# (100 Mg/(Mg+Fetotal)), MgO and Cr and dec...

Many aspects of the origin of the Sudbury Igneous Complex (SIC) remain controversial despite a wealth of studies. There are strong arguments on both sides of the controversy regarding whether the SIC was produced from a single melt sheet of granodioritic composition or from a combination of compositionally different mafic and felsic magmas. We have...

The Sudbury Igneous Complex (SIC) is thought to have crystallized from an impact melt sheet which was superheated relative to its liquidus temperature by several hundred degrees and which retained its super-liquidus temperature for hundreds of thousands of years after impact. Such specific thermal conditions during the development of the SIC imply...

Three dolerite dykes (Small, 3.2 cm; Middle, 13.5 cm; Thick, 50 cm) from Torsholma Island, SW Finland, reveal distinctly different internal zonation that becomes more complicated with increasing thickness of the dykes. The Small Dyke shows a systematic inward increase in normative Pl (An+Ab+Or) and a decrease in normative An (100*An/(An+Ab)), whole...