Marlina Elburg

University of Johannesburg | uj · Department of Geology

Pleistocene (50 to 70 ka) aeolianite of the Isipingo Formation (Maputaland Group) at Cape Vidal, northern KwaZulu-Natal province, South Africa, contains a combination of three detrital zircon age fractions (A: 940 to 1150 Ma, B: 470 to 720 Ma, C: 230 to 280 Ma) that are also known from Holocene sediments in eastern South Africa, Mesozoic – Cenozoic...

The world-class deposits of the Kalahari Manganese Field (KMF) in South Africa constitute a key resource of manganese (Mn) ore for the global steel industry. Many aspects of the origin of high metal-grade ores in the northernmost KMF remain unresolved, especially with respect to the complex hydrothermal history of these ores and the source/s of flu...

The Palaeoproterozoic sandstones and quartzites of the Pretoria Group (Transvaal Supergroup) in the Transvaal Basin of South Africa are important markers for regional correlations and dating of events of global importance (e.g., the Great Oxidation Event). The succession has few independent age markers, and much of the discussion about the time of...

The new mineral pilanesbergite, with the ideal formula Na2Ca2FeTi2(Si2O7)2O2F2, was found in a nepheline syenite, locally known as green foyaite, from the Pilanesberg Complex located in the North West Province of South Africa. Pilanesbergite occurs in green foyaite in association, and partly intergrown, with aegirine. The two minerals share an asse...

The abstract discusses the geology of the Buem Structural Unit (BSU) in Ghana, which contains rocks similar to ophiolite sequences, typically found in oceanic crust. However, the BSU ophiolite complex is incomplete, lacking a sheeted dyke complex seen in classical ophiolites like those in Oman and Troodos. The BSU's rocks, including serpentinized p...

An extrusive rock unit in the Mesoproterozoic Pilanesberg alkaline complex that has been referred to as the “Beacon Heights Tinguaite” since the work of Shand (1928) has been reexamined in the field and studied by petrographic microscopy, scanning electron microscopy, and whole-rock major and trace element analysis. The new observations indicate th...

The Pan-African Damara Belt in southern Africa is a trench-trench-trench triple junctions orogen that formed at 590-470 Ma during the Gondwana Supercontinent assembly. The Damara Belt records up to granulite facies HTLP metamorphism in the core, upper plate of the orogen. However, the cause of this metamorphism is not well understood. To tackle thi...

An integrated approach embracing field studies, petrographic and geochemical investigations together with zircon U-Pb-Hf data was used to investigate the petrogenesis of potassic granite suites along the southern margin of the Zimbabwe Craton. Zircon U-Pb geochronology identifies age relationships, revealing coeval magmatism of the ca. 2 635 ± 5 to...

The Singhbhum Craton in India contains well-preserved Palaeoarchaean greenstone belts that rival their Australian and South African counterparts, but their stratigraphic make-up remains to be resolved. Here we provide new SHRIMP- and LA-ICP-MS-based U–Pb and Lu-Hf data on magmatic and detrital zircons from stratigraphically resolved samples of the...

So far, the nature and evolution of the lower crust under central Spain have been constrained mainly on the basis of a heterogeneous suite of granulite xenoliths from the Spanish Central System (SCS). In recent years, ultramafic volcanics from the Calatrava Volcanic Field (CVF) have also provided deep-seated crustal xenoliths which have not been st...

The Hokuroku region of north-eastern Japan is endowed with important volcanic-hosted massive sulphide Zn–Pb–Cu deposits, which are considered the archetype of Kuroko (black ore) deposits worldwide. The bimodal, felsic-dominated volcanic succession that hosts the ore was deposited in a continental rift formed during continental extension in the fina...

Elevated lead levels in scavenging raptors can originate from a variety of environmental and anthropogenic sources, including soil, water, mining activities and legacy lead from leaded fuel, but has mostly been attributed to fragments of lead-based ammunition embedded in the tissues of carcasses. To identify the origins of lead in the tissues of wh...

We present new field, petrological and geochemical data, combined with U-Pb zircon ages and Lu-Hf isotope compositions for the sandstones of the Neoproterozoic Buem structural unit (BSU) of the Dahomeyide belt, and whole-rock geochemical data of BSU shale to investigate their provenance and depositional setting. The BSU contains siliciclastic seque...

The age and properties of detrital zircon in a sediment reflect properties of the rocks in which the zircon crystallized, and not necessarily the immediate precursor of the host sediment. Where clastic sediments are recycled, these properties are preserved so that U‐Pb ages and Lu‐Hf data on zircon grains will no longer give information on the rout...

The Singhbhum Craton of East India has a remarkably well-preserved Archaean geological record that rivals those of the Kaapvaal and Pilbara cratons. Based on a critical literature review, and aided by new field and geochronological data, a consistent framework of craton evolution during the Archaean is proposed that aims to put to rest some of the...

Eight samples of prehnite from southern Africa were analysed for their major and trace element geochemistry to investigate the controls on their compositions. Variations in the major elements are limited (Fe3+-Al exchange, limited enrichment in Mn), and trace elements typically occur at levels <10 ppm, apart from Ga and sometimes Ti. The main contr...

The ~1 200 to 1 000 Ma Namaqua-Natal Metamorphic Province (NNMP) is part of a major orogenic belt in the west-central parts of South Africa and most likely formed during the convergence of the Laurentia and Kalahari cratons during the assembly of Rodinia. Controversy exists regarding the mode of formation of the Namaqua sector of the NNMP, with som...

The Neoproterozoic Pan-African Orogeny in the Adamawa-Yad´ e domain (AYD) of Cameroon is characterized by intense magmatism of metaluminous to weakly peraluminous I-type granites spatially associated with transcurrent shear zones. This domain provides a critical geological record that is important for unravelling the regional tectonic evolution and...

This work presents new major and trace element geochemical data and the first SmNd and LuHf isotopic data for the mafic suite of the Buem structural unit (BSU) in Ghana in order to infer its origin and geodynamic setting, relationship to the Pharusian suture zone and significance in the Dahomeyide belt. The BSU, which occurs about 50 km to the west...

Detrital zircon in six surface samples of sandstone and contact metamorphic quartzite of the Magaliesberg and Rayton formations of the Pretoria Group (depositional age c. 2.20–2.06 Ga) show a major age fraction at 2.35–2.20 Ga, and minor early Palaeoproterozoic – Neoarchaean fractions. Trace-element concentrations vary widely, with Ti, Y and light...

Gneiss domes cored by migmatites and granites represent the principal role of anatectic melts during the exhumation of high-grade metamorphic complexes. This study explores the exhumation history of a metapelitic granulite within the Ha-Tshanzi structure from the Central Zone of the Neoarchean-Paleoproterozoic Limpopo high-grade Complex, South Afri...

New ⁴⁰ Ar/ ³⁹ Ar data from dykes intruded into Sverdrupfjella and Ahlmanryggen, Dronning Maud Land, Antarctica, indicate that dyke emplacement commenced at ca. 207 Ma and lasted until ca. 178 Ma. Whereas the ages ascribed to the Karoo-age magmatism contributing to Gondwana breakup are typically inferred as being ca. 182 Ma, the data indicate that a...

The Kaapvaal Craton records a long Archaean to Phanerozoic history of intracratonic magmatism that reflects contrasting regimes of melt generation. The correct interpretation of this rich geological record relies critically on field evidence and ever refined chronological and isotopic data. Here, we present new U – Pb zircon, apatite and titanite a...

The Sveconorwegian orogen represents a branch of Grenville-age (~1250–950 Ma) orogenic belts that formed during the construction of the supercontinent Rodinia. This study traces the Sveconorwegian records from its type-area in the Baltic Shield of South Norway into basement windows underneath Caledonian nappes, by combining zircon U–Pb geochronolog...

The effects of the Sibumasu–Indochina Terranes collision created several kinds of mineral deposits in Thailand, which include porphyry–skarn copper–gold, epithermal gold and antimony, orogenic gold–antimony–tungsten and tin‐tungsten mineralization among others. The deposits show a distinct spatial zonal distribution and occur in specific tectonic t...

The Bushmanland Subprovince of the Mesoproterozoic Namaqua-Natal orogenic belt in southern Africa hosts numerous occurrences of monazite-magnetite-(biotite-apatite-sulfide)-bearing veins and granitoid dykes, including the Steenkampskraal vein system, which is one of the highest-grade REE-Th ore deposits in the world. Here, we provide whole-rock geo...

Interpretations of Rb–Sr and Sm–Nd data from the Grunehogna Granite demonstrate that anatexis of and mixing with Høgfonna Formation sedimentary rocks, caused by hot basic sills of ~1100 Ma Borgmassivet Suite, are consistent, with the granite εNdεSr100Ma data, partially overlapping Borgmassivet Suite data and are marginally displaced toward publishe...

Numerous Mesoproterozoic alkaline intrusions belonging to the Pilanesberg Alkaline Province are present within the Transvaal subbasin of the Kaapvaal craton. The Pilanesberg Complex is the best-known example; it represents one of the world's largest alkaline complexes, and is associated with NW-SE trending dyke swarm that extends from Botswana to t...

Previously dated zircon crystals from the Amalia-Kraaipan granite-greenstone belts and Makoppa Dome were analysed for their Lu-Hf isotopic characteristics to refine the geological evolution of these areas. Samples from the Makoppa Dome, belonging to the Pietersburg Block, largely fall within the epsilon Hf-age range for granitoids from the eastern...

A network of monazite-rich, coarse-grained veins and fine-grained veins permeating the mid-Proterozoic Concordia Granite in the Kliphoog area near Springbok, Namaqualand, North Cape Province, South Africa, are described with respect to their whole-rock chemistry, petrography, mineralogy, and mineral chemistry along with zircon and monazite geochron...

Ar/ ³⁹ Ar and U–Pb data from five structural domains constrain the late Neoproterozoic – early Palaeozoic tectonothermal history of the eastern part of the East African–Antarctic Orogen in Sør Rondane. A total of 27 new Ar/Ar ages span 570–474 Ma, roughly corresponding to the age range of three generations of syn- to post-tectonic granitoids. The a...

Dehydration of the subducting slab is a crucial process in the generation of hydrous convergent margin magmas, yet the exact processes of how and where the slab dehydrates and how these fluids are transported to the mantle wedge remain obscure. Strontium is a “fluid-mobile” element and as such well suited to investigate the source of slab-derived f...

Detrital zircon grains from three samples of sandstone from the Tswaane Formation of the Okwa Group of Botswana have been dated by U-Pb and analysed for Hf isotopes by multicollector LA-ICPMS. The detrital zircon age distribution pattern of the detrital zircons is dominated by a mid-Palaeoproterozoic age fraction (2 000 to 2 150 Ma) with minor late...

Detrital zircons in late Cretaceous – Palaeogene, calcareous sandstone and conglomerate deposited in continental basins on the southeastern African margin after the breakup of Gondwana have characteristic combinations of age and epsilon-Hf that indicate an origin by recycling of Palaeoproterozoic (Waterberg, Soutpansberg and Pretoria groups) and Ph...

Dronning Maud Land (DML) is a key area for the better understanding of the geotectonic history and amalgamation processes of the southern part of Gondwana. Here, we present comprehensive new zircon U–Pb–Hf–O, whole-rock Sm–Nd isotopic and geochemical data for late Neoproterozoic-Cambrian igneous rocks along a profile from central to eastern DML, wh...

This study focusses on the Grenville-age Maud Belt in Dronning Maud Land (DML), East Antarctica, which was located at the margin of the Proto-Kalahari Craton during the assembly of Rodinia. We present new U–Pb zircon ages and Hf–O isotope analyses of mafic and granitic gneisses exposed in the Orvin-Wohlthat Mountains and Gjelsvikfjella, central DML...

The Delamerian Orogen formed at the final stages of assembly of the Gondwana supercontinent. This system marks the initiation of subduction of the Pacific oceanic lithosphere along a prior rifted and extended passive margin. This paper explores the magmatic consequences following the early Cambrian initiation at the palaeo-Pacific margin in South A...

The Neoarchean to Paleoproterozoic (ca. 2.65 – 2.06 Ga) Transvaal Supergroup of the Kaapvaal Craton is dominated by clastic and chemical sedimentary rocks, with few strata-bound igneous units. Two ca. 2.2 Ga igneous units in its upper part (Pretoria Group), the Machadodorp Member of the Silverton Formation and the Mashishing dyke swarm, have so far...

Pliocene (Phase 1) deposits from the volcanic centres of Aegina and Poros (western Aegean Arc) consist of andesitic-dacitic lava flows and domes with mafic enclaves, whereas basaltic-andesitic and rhyolitic lava flows were emplaced during the early Pleistocene Phase 2 and its precursor activity. Fifty-nine new whole rock analyses of lavas and encla...

A network of monazite-rich, coarse-grained veins and fine-grained veins permeating the mid-Proterozoic Concordia Granite in the Kliphoog area near Springbok, Namaqualand, North Cape Province, South Africa, are described with respect to their whole-rock chemistry, petrography, mineralogy, andmineral chemistry along with zircon and monazite geochrono...

Late Tonian (ca. 785–760 Ma) granodioritic to granitic orthogneisses of the Schirmacher Oasis region in Dronning Maud Land (DML), East Antarctica, are interpreted as recording an active continental margin setting at the periphery of Kalahari and Rodinia. The rocks probably represent exposures of a significant tectonic province hidden beneath the ic...

The Buem Structural Unit (BSU) occurs about 50 km west of the high-pressure (HP) rocks of the Pharusian suture zone (PSZ) of the Dahomeyide Orogen, West Africa. Shale and sandstone intercalations form the base of the BSU, followed by serpentinised peridotite, gabbro, massive and pillow basalts (fragment of oceanic crust), jasper/chert, and limeston...

We present a study of carbonate-bearing polyphase inclusions in garnets from leucocratic granitoids intruding metapelitic granulites of the Southern Marginal Zone (SMZ) of the Neoarchean Limpopo high-grade complex, South Africa, during the post-peak stage (2710–2650 Ma; U-Pb ages for zircons and monazites). Ternary feldspar thermometry suggests tha...

The distribution pattern of U-Pb ages of detrital zircon in a sedimentary rock is commonly assumed to reflect the ages of igneous or metamorphic processes in rocks that have contributed material to the sedimentary basin (i.e. the protosources), directly or through recycling of older sedimentary rocks. If the Pb isotopic composition of detrital zirc...

Laser-ablation ICPMS U-Pb and Lu-Hf isotope data on detrital zircon in sandstone from the Palaeoproterozoic Waterberg Group in the Waterberg and Nylstroom basins of northeastern South Africa contain a dominant Palaeoproterozoic (2000-2100 Ma) age fraction and minor Archaean zircon. Zircon in the 2200-2350 Ma age range is very scarce. There are no s...

Rare element pegmatites of the Li-Cs-Ta (LCT) family have a major economic potential for Li and Ta, but the reasons behind their rare metal enrichment remain unclear. The parental peraluminous magma of these pegmatites can be highly enriched in fluxing elements, such as B, P, F and Li, which has the effect to reduce the viscosity and solidus of the...

New Sr-Nd-Hf-Pb isotope data for volcanic rocks from the peninsula of Methana (South Aegean Active Volcanic Arc, Greece) show a wide variation, and more ‘enriched’ isotopic signatures (e.g. elevated ⁸⁷Sr/⁸⁶Sr at 0.705–0.709) than those of other active Aegean volcanic centres, all located on thinner crust. The data set is best explained by polybaric...

Globular structures in volcanic and hypabyssal rocks called varioles (or spherulites) have been described from a wide variety of places and rock types including komatiites, basalts, dacites, rhyolites as well as alkaline dykes, but the processes leading to their formation are still debated. Here, we present a field, petrological and geochemical stu...

The ∼2.23 Ga Hekpoort Formation (Transvaal sub-basin) and the ∼2.43 Ga Ongeluk Formation (Griqualand West sub-basin) represent voluminous Paleoproterozoic igneous events on the Kaapvaal craton of South Africa that predate the emplacement of the ∼2.055 Ga Bushveld Complex, and probably covered most of the craton at the time of their extrusion. In th...

We present new U-Pb and Hf zircon isotope data on a suite of granitoids from a hitherto unstudied area of the Palaeoproterozoic Lupa terrane of the Ubendian belt in SW Tanzania. The major part of the area comprises a sequence of upper amphibolite grade paragneisses and migmatites. Subsequently, the field relations show a complex history of granitoi...

Different types of peralkaline nepheline syenite in the Pilanesberg Alkaline Complex show contrasting Zr- and Ti-bearing mineral assemblages: In some members of the green foyaite suite, eudialyte is the dominant Zr mineral, as is common in many other agpaitic nepheline syenites. Eudialyte has formed together with aegirine ± arfvedsonite, alkali fel...

Neoproterozoic sedimentary rocks in the Gariep, Saldania and Damara Belts and the Nama Group of South Africa and Namibia, which were deposited between ca. 750 Ma and ca. 550 Ma, have detrital zircon distribution patterns dominated by four major age fractions: A: ≤ 750 Ma, epsilon-Hf = −32 to +13, B: 950 to ca. 1100 Ma, epsilon-Hf = −25 to +11, C: c...

Evidence is presented for the localized melting of cordierite-orthopyroxene-biotite metapelites within the Petronella shear zone in the Southern Marginal Zone of the Limpopo Belt of Southern Africa. This process is expressed by the formation of centimetre-scale, K-feldspar-rich, garnet- orthopyroxene-bearing leucosome patches. Structural data indic...

We have traced the particle path of high-pressure metasedimentary rocks on Elba Island, Northern Apennines, with the help of a U-Pb-Hf detrital zircon study. One quarter of the analysed zircons are surprisingly young, 41-30 Ma, with a main age peak at ca. 32 Ma, indicating an unexpected early Oligocene maximum deposition age. These Oligocene ages w...

We present the first in-situ Sr isotopic and mineral geochemical results for plagioclase in mafic to ultramafic rocks of the Waterberg Project of the far northern Bushveld Complex. Initial strontium isotopic compositions of plagioclase are dominantly in the range of 87Sr/86Sri (Sri) 0.7065 to 0.7075, differing from the rest of the Northern Lobe, wh...

To investigate their genesis and relations with their host rocks, we study igneous microgranular enclaves (IMEs) in the c. 370 Ma, post-orogenic, high-level, felsic plutons and volcanic rocks of Central Victoria, Australia. The IMEs are thermally quenched magma globules but are not autoliths, and they do not form mixing series with their host magma...

The Kaapvaal Craton, along with the Pilbara Craton (Western Australia), are the only two areas on Earth with a record of relatively pristine 3.6-2.5 Ga crust. Yet, such crust continuously evolved up to our days by numerous episodes of erosion, sedimentation, and magmatic additions. This study focuses on the geochemical evolution and geodynamic situ...

In the Kaapvaal craton of southern Africa, as well as other Archaean cratons worldwide, the progression from dominant tonalite-trondhjemite-granodiorite (TTG) to granite-monzogranite-syenogranite (GMS) rock types is interpreted to reflect progressive reworking and differentiation of the continental crust. Here we re-evaluate the early Archaean evol...

The development of fast and reliable instrumental methods for U-Pb dating and Lu-Hf isotope analysis of zircon has caused detrital zircon to become a popular provenance indicator for clastic sediments and an important tool in basin analysis. In parallel with the increasing ease of access to data, advanced methods of data interpretation have been de...

We have targeted the southern side of the Dronning Maud Land (DML) Mountains in search of moraine material that might reveal the geology in the ice-covered region of the East Antarctic polar plateau. Nine samples of unconsolidated moraine material, carried by the northward flowing East Antarctic Ice Sheet to the southern side of the DML escarpment,...

The Pilanesberg Complex (South Africa) is one of the world's largest but least studied alkaline complexes. It consists of trachytes, phonolites, syenites and nepheline syenites (foyaites) and the preservation of the volcanic carapace makes it unique among the larger alkaline complexes. The intrusive history of the Pilanesberg Complex shows similari...

The Mesoproterozoic Pilanesberg Complex, South Africa, is built up by several distinct, ring-shaped intrusions of syenite and peralkaline nepheline syenite. A mildly peralkaline ((Na + K)/Al = 1.04-1.09), medium-to coarse grained nepheline syenite makes up the outermost ring in the southwestern part of the complex (“Matooster type white foyaite”)....

Using chemical evidence, particularly the variations between titanium and iron + magnesium, we demonstrate that the petrogenetic processes that operated within Central Victorian granitic host magmas and their igneous microgranular enclave suites are dissimilar. Chemical variations within the granitic series result from a variety of what might be ca...

The Neoproterozoic to Cambrian Selwyn Block in Central Victoria forms the mainly unexposed basement to the Paleozoic metasediments, granitic rocks and felsic volcanic complexes of the Melbourne Zone of the Lachlan Orogen. The Late Devonian felsic rocks are largely products of partial melting of the Selwyn Block, and their chemistry implies that the...

U–Pb and Lu-Hf data are routinely used to trace detrital zircon in clastic sediments to their original source in crystalline bedrock (the protosource), to map out paths of sediment transport, and characterize large-scale processes of crustal evolution. For such data to have a provenance significance, a simple transport route from the protosource in...

New U-Pb zircon ages for the younger phase of magmatism in the Sør Rondane Mountains (East Antarctica) are combined with published igneous and metamorphic zircon ages and show evidence for at least four thermal pulses: at 650–600 Ma, 580–550 Ma, ca. 530 Ma, and a magmatic tail between 510 and 500 Ma. No igneous U-Pb ages younger than 500 Ma have be...

Three distinct types of granitoids, and intrusive contacts between them, are exposed in the central White Mfolozi Inlier, northern KwaZulu-Natal, where they form the basement on which the Mesoarchaean Pongola Supergroup had been deposited. In order to assess the position of these granites within the geochronological framework of Archaean felsic mag...

U–Pb and Lu–Hf signatures of detrital zircon from conglomerates and sandstones of the Ordovician Natal Group, South Africa were determined using laser ablation inductively coupled plasma mass spectrometry. The basal conglomerates are dominated by Palaeo- to Mesoarchaean detrital zircon with εHf values from +3 to –4 with minor Mesoproterozoic input,...