Jean-Marc Baele

Université de Mons · Department of Geology and Applied Geology

This paper presents and discusses new geochronological and petrological data on a suite of calc-alkaline plutons composed predominantly of diorites and tonalites from the West Massif Central. Their petrochemical fingerprints are compatible with partial melting of a hydrous mantle wedge followed by fractional crystallization of amphibole and plagioc...

Methane has been widely regarded as an important source of greenhouse gas that modulated Earth’s paleoclimate. Notably, it has been proposed that a massive release of methane via clathrate destabilization may have played a critical role during and/or in the immediate aftermath of the Marinoan deglaciation. One key piece of supporting evidence for t...

In phosphorites, the content and distribution of rare earth elements are linked to the environment of phosphogenesis. This paper focuses on the question of sources and processes controlling the rare earth element content of apatite from Belgian phosphorites formed during three major phosphogenic events in the Lower Palaeozoic, Late Cretaceous and C...

Meeting the growing demand for Critical Raw Materials (CRM) is one of the greatest challenges for the next decades in Europe and worldwide. In this context, research and development are required regarding resource availability, multi-scale CRM identification and characterisation, and environmental impact of mining and processing CRM. Flexible, rapi...

The subsurface provides multiple resources of which the exploitation has a lasting impact on future potential provision. Establishing sustainability in terms of fundamental principles, and fitting these principles into a practical framework, is an ongoing endeavour focused mainly on surface activities. The principles of ecological economics lead to...

The Early Cambrian Mo-Ni-PGE sulphidic black shale in the Niutitang Formation on the margin of the Yangtze Craton (Southern China) is known for its extremely high metal concentrations. It is also very rich in phosphate that formed contemporaneously with the sulphides. Detailed petrological as well as in-situ trace element and Sr isotope analyses of...

The Ediacaran Shuram excursion (SE) records a global decrease in carbonate carbon isotope (δ¹³Ccarb) values from +6‰ down to ca. –10‰, representing the largest δ¹³Ccarb negative anomaly in Earth history. While the SE is widely recorded in the upper Doushantuo Formation of South China, it shows highly variable δ¹³Ccarb profiles among correlative sec...

Le gisement de Talc de Nkob, situé au Sud-Est de la boutonnière de Sirwa dans l'Anti-Atlas central, est encaissé dans les métacarbonates du groupe de Taghdout en contact avec le granite édiacarien d'Amassine. Il se présente sous forme d'une lentille stratiforme au sein de laquelle s'alternent des bancs décimétriques à métriques de marbres, de talci...

La collection des iguanodons de Bernissart (Belgique) constitue l'un des plus grands ensembles de restes de dinosaures connus à ce jour dans le monde, et l'une des plus importantes découvertes de l'histoire de la paléontologie. La trentaine de spécimens d'Iguanodon extraite du gisement de 1878 à 1881 a permis des avancées considérables concernant l...

The Nkob talc deposit located in the central Anti-Atlas Pan-African belt is hosted by magnesian and siliceous metacarbonates in the contact aureole of the Ediacaran Amassine granite. It consists of a stratified succession of green serpentine-rich marbles, black dolomitic marbles, talcitites and phlogopitites (variously retrogressed into chloritites...

Laser-Induced Breakdown Spectroscopy (LIBS) is a fast in-situ analytical technique based on spectroscopic analysis of atomic emission in laser-induced plasmas. Geochemical mapping at macroscopic scale using LIBS was applied to a decimetric Zn-Pb ore sample from east Belgium, which consists of alternating sphalerite and galena bands. A range of elem...

The Ediacaran Period (ca. 635-539 Ma) witnessed the earliest paleontological evidence for macroscopic life (i.e., Ediacara biota) and geochemical observations of the largest carbon cycle J o u r n a l P r e-p r o o f Journal Pre-proof anomaly in Earth history (i.e., Shuram Excursion, SE). Numerous hypotheses have been proposed for the origins of th...

The largest carbon isotope (δ13C) negative anomaly recorded in marine carbonates in Earth history — the Ediacaran Shuram Excursion (SE) — preserves values down to ca. –10‰ on a global scale. Despite the intensive geochemical and theoretical work published in the past decade, its origin and the degree to which its geochemical signature has been diag...

The Siilinjärvi phosphate deposit (Finland) is hosted by an Archean carbonatite complex. The main body is composed of glimmerite, carbonatite and combinations thereof. It is surrounded by a well-developed fenitization zone. Almost all the rocks pertaining to the glimmerite-carbonatite series are considered for exploitation of phosphate. New petrolo...

The Ediacaran-Cambrian Bambuí Group in Brazil records an anomalously positive excursion in carbonate carbon isotopes (δ13Ccarb) with a sustained plateau of ca. +15‰ (aka the Middle Bambuí positive Excursion–MIBE). Considering that the δ13Ccarb signals in Ediacaran-Cambrian seawaters do not typically exceed +6‰, the MIBE therefore represents a profo...

The Ediacaran-Cambrian Bambuí Group in Brazil records an anomalously positive excursion in carbonate carbon isotopes (δ 13 Ccarb) with a sustained plateau of ca. +15‰ (aka the Middle Bambuí positive Excursion-MIBE). Considering that the δ 13 Ccarb signals in Ediacaran-Cambrian seawaters do not typically exceed +6‰, the MIBE therefore represents a p...

The Ediacaran-Cambrian Bambuí Group in Brazil records an anomalously positive excursion in carbonate carbon isotopes (δ¹³Ccarb) with a sustained plateau of ca. +15‰ (aka the Middle Bambuí positive Excursion–MIBE). Considering that the δ¹³Ccarb signals in Ediacaran-Cambrian seawaters do not typically exceed +6‰, the MIBE therefore represents a profo...

Laser-induced plasma atomic emission spectroscopy (LIBS) which is a less costly and simple to implement, technique is starting to prevail in qualitative and quantitative analyses of the various elements of the periodic system. She is based on the interaction of a laser pulse that only lasts a few nanoseconds with the material to be analyzed. LIBS t...

The Moroccan Anti-Atlas orogenic belt encloses several Precambrian inliers comprising two major Neoproterozoic ophiolitic complexes: the Sirwa and Bou Azzer ophiolites. These ophiolites expose crustal and mantle units, thrusting over fragments of a long-lived intra-oceanic arc system. We present a detailed geochronological and petro-geochemical stu...

GOEMAERE, E., BAELE, J.-M., DEJONGHE, L. TOURNEUR, F. & YANS, J. (2020). - Les ressources minérales du Massif ardennais. : 47-50. In : Meilliez & Goemaere. Le massif ardennais. Un jeune massif ancien. Géochronique, 154 :14-60.

It is revealed that the lowest 1010 m of the Saint-Ghislain borehole (-4393 to -5403 m), of which cuttings are available, constitutes a crucial source of information to investigate, amongst others, the deep geothermal potential within the Brabant Parautochthon, underlying the Mons Basin, Hainaut. The lithological succession of this interval was rec...

We present an integrated study combining detailed field, geochronological and geochemical data of a Neoproterozoic intra-oceanic arc systems exposed in the Pan-African belt of the Moroccan Anti-Atlas. The arc rock units exposed in Bou Azzer and Sirwa inliers consist of a tectonic patchwork of back-arc ophiolitic sequences to the north thrusted onto...

The Phalaborwa world-class phosphate deposit (South Africa) is hosted by a Paleoproterozoic alkaline complex mainly composed of phoscorite, carbonatite, pyroxenitic rocks, and subordinate fenite. In addition, syenite and trachyte occur in numerous satellite bodies. New petrological and in-situ geochemical data along with O and Sr isotope data obtai...

Carbonate carbon isotope (δ¹³Ccarb) chemostratigraphy is a valuable tool in Precambrian stratigraphic correlation. The effectiveness of this tool rests on the assumption that δ¹³Ccarb data record global seawater signals. However, in some cases δ¹³Ccarb data may exhibit rapid and noisy stratigraphic variations that appear to have been influenced by...

The globally-recorded Ediacaran Shuram Excursion (SE) represents the largest carbonate carbon isotope (δ13Ccarb) negative anomaly in Earth’s history. Typically, the SE is characterized by δ13Ccarb values that plunge to a nadir of ca. −10‰ over a short stratigraphic interval and then rise steadily in the overlying tens or hundreds of meters before r...

The Marinoan glaciation (a.k.a. the Snowball Earth) represents a profound paleoclimatic anomaly in deep time. However, the detailed mechanism of its termination remains largely unknown. It was hypothesized that massive releases of methane via clathrate destabilization at ~635 Ma may have played a role in terminating the glaciation. A key piece of s...

Central Italy has been a cradle of geology for centuries. For more than 100 years, studies at the Umbria and Marche Apennines have led to new ideas and a better understanding of the past, such as the Cretaceous-Paleogene (K-Pg) boundary event, or the events across the Eocene-Oligocene transition from a greenhouse to an icehouse world. The Umbria-Ma...

The geochemical signatures of sparry calcite-sealing expansion breccias, calcite veins, and host clasts were analyzed for their strontium (87Sr/86Sr) and oxygen and carbon (δ18O, δ13C) stable isotopic signatures. The breccias occur within the Lower Cretaceous Maiolica Formation. Related but different breccias are found in a few places in the Upper...

The cathodoluminescence (CL) of minerals reflects with great sensitivity the physiochemical conditions in mineralized systems and their evolution through time. CL textures, colors, and spectra provide Earth scientists with unique signatures that can decipher multistage mineralization, fingerprint ore deposit type, relate ore deposition to specific...

one of the fossil record's most puzzling features is the absence of preserved eggs or eggshell for the first third of the known 315 million year history of amniote evolution. Our meagre understanding of the origin and evolution of calcareous eggshell and amniotic eggs in general, is largely based on Middle Jurassic to Late Cretaceous fossils. For d...

40Ar / 39Ar absolute dating on tobelite (an ammonium-rich white mica) has been performed in order to provide geochronological constraints on the Sb ± Au mineralization and hydrothermalism at the Saint-Aubin-des-Châteaux base metal-Sb ± Au occurrence (Variscan Central Armorican Domain, France). The results show that the Sb ± Au deposition occurred a...

Mortars developed for the reconstitution and ‘plastic repair’ of natural stones have become increasingly popular. They are an alternative for the replacement of deteriorated stones, since they are capable of preserving the (memory of) diversity in building materials. This article addresses some key elements for the compatibility between repair mort...

The Oued Belif 48 borehole samples have been analyzed in order to reveal the mineralogical composition of the Triassic successions and their alteration outcomes, namrly, chlorite, phlogopite and talc. Clay minerals from Oued Belif borehole were studied via XRD, SEM, TEM, CL and AEM. In this work, we are interested in the petrographic, mineralogical...

We present a petrological, geochronological and geochemical study of Neoproterozoic ophiolitic units exposed in the Pan-African orogenic belt (Moroccan Anti-Atlas). These units comprise two main complexes: (i) the Khza ophiolite (in the Sirwa window) to the west and (ii) the Aït Ahmane ophiolite to the east (in the Bou Azzer inlier). Both complexes...

Le Massif central français occidental est classiquement subdivisé en unités tectono-métamorphiques comprenant (1) le para-autochtone, dominé par des micaschistes du faciès schistes vert, (2) l'unité des gneiss inférieurs (UGI) dominé par des orthogneiss et des paragneiss du faciès amphibolite (localement migmatitiques), (3) une unité des gneiss sup...

Dans le Hainaut, le front varisque se caractérise par la présence d’écailles tectoniques - Ecailles Haine-Sambre-Meuse (HSM) - pincées entre une unité autochtone relativement peu déformée (Parautochtone brabançon) et une unité allochtone fortement plissée (Allochtone ardennais). Le front varisque est recouvert en discordance par une couverture Méso...

Karst landforms can result from a single stage process in which chemical dissolution and mechanical erosion proceed simultaneously or from a two stage process in which chemical dissolution precedes mechanical erosion. During the second of these processes, chemical dissolution leads to the creation of karst features hosting a residual weathering pro...

The use of heavy minerals as a stratigraphic tool in the study of loess sequences from NW Europe originated some 70 years ago. One major problem in using the available data sets is the heterogeneous stratigraphic context of the samples, given the complex historic evolution of the stratigraphic framework of loess sequences. This paper aims at presen...

In the French Armorican Variscan belt, most of the economically significant hydrothermal U deposits are spatially associated with peraluminous leucogranites emplaced along the south Armorican shear zone (SASZ), a dextral lithospheric scale wrench fault that recorded ductile deformation from ca. 315 to 300 Ma. In the Pontivy-Rostrenen complex, a com...

We present here a petrological and geochemical study of Neoproterozoic ophiolitic relics from the Moroccan Anti-Atlas orogenic belt. They comprise two main complexes: (i) the Khzama ophiolite (in the Sirwa window) to the west and (ii) the Aït Ahmane ophiolite to the east (in the Bou Azzer inlier). Ultramafic lithologies are dominant in both complex...

Magmatism in the Rocroi inlier (Ardenne Allochton, southeastern Avalonia during eo-Hercynian times) consists of a swarm of bimodal dykes (diabase and/or microgranite) emplaced in Middle to Upper Cambrian siliciclastics (Revin Group). Felsic volcanites interbedded within the Upper Silurian/Lower Devonian transgressive strata on the eastern edge of t...

We present a detailed geologic study of the Thebes Formation at Gebel Gurnah in its locus typicus on the West Bank (opposite Luxor) of the Nile River in the Upper Nile Valley, Egypt. This is the first detailed measurement and lithologic description of the ∼340 m thick (predominantly) carbonate section. The Thebes Formation is divided into thirteen...

We have investigated quartz cement in silcretes and puddingstones from uppermost Paleocene to lowermost Eocene, terrestrial to coastal and shallow marine sediments in north France and Belgium using cathodoluminescence (CL) and trace element electron probe micro-analysis (EPMA). The syntaxial cement overgrowing quartz grains exhibits mostly dark to...

Many intra-oceanic paleo-arcs are exposed in the Pan-African belt surrounding the West African Craton. In the Moroccan Anti-Atlas, remnants of Intra-Oceanic Subduction Zone (IOSZ) are preserved in few erosional windows moulded along the Anti-Atlas Major fault. These complexes highlight a Neoproterozoic paleo-suture made of 760 My back-arc ophiolite...

The Matongo carbonatite intrusive body in the Neoproterozoic Upper Ruvubu alkaline plutonic complex (URAPC) in Burundi is overlain by an economic phosphate ore deposit that is present as breccia lenses. The ore exhibits evidence of supergene enrichment but also preserves textures related to the concentration of fluorapatite in the carbonatitic syst...

Geologica Belgica Conference Proceedings VOLUME 2 (2016) 5th International Geologica Belgica Congress 26-29 January 2016 - Mons, Belgium GB2016 MOTHER EATH Conference programs & abstract book

The Neoproterozoic Upper Ruvubu Alkaline Plutonic Complex (URAPC), Burundi, is located along the western branch of the East African Rift. It comprises oversaturated and undersaturated syenites and a shallow-level carbonatite body (the Matongo carbonatite) that does not outcrop but has been sampled by drill-cores. The elliptic map contour of the URA...

Alkaline massifs worldwide are generally atectonic. In Burundi, during the break-up of Rodinia, 700 Ma ago, the Upper Ruvubu Alkaline Plutonic Complex emplaced syntectonically. Large shear zones affecting the intrusion accommodated a regional NE-SW shortening in the regional extensional setting associated with Rodinia breakup. Magmatic dykes and ma...

The Pan-African belt of West and North Africa exposes many intra-oceanic arc complexes while they are rather uncommon in Phanerozoic orogenic belts. Intra-Oceanic Subduction Zone (IOSZ) in the Moroccan Anti-Atlas crop out in two tectonic windows moulded along the Anti-Atlas Major fault: the Sirwa (western-) and the Bou Azzer (eastern-part) inliers,...

Les mudmounds waulsortiens sont des formations lenticulaires de plusieurs kilom etres de long pour quelques centaines de m` etres d'´ epaisseur. Elles correspondent a des accumulations de boues carbonatées déposées au Carbonif ere (Tournaisien, Viséen) notamment dans l'aire de sédimentation de Dinant (Sud de la Belgique). Ces lentilles ont subi une...

Cathodoluminescence (CL) is a powerful technique for studying ores and associated rocks in combination with classical techniques. This contribution illustrates the use of CL in ore geology through a few case studies. Total CL imaging is efficient in revealing minerals that may difficult to observe in thin-sections such as fluorite, apatite, monazit...

En Belgique, des phosphates de terres rares diagénétiques ont été décrits dans les terrains paléozoïques des massifs du Brabant et de l’Ardenne. Il s’agit classiquement des monazites « grises », d’abord identifiées dans les concentrés d’orpaillage, puis dans les pélites paléozoïques. L’utilisation de la cathodoluminescence permet de repérer rapidem...

Le gaz de houille est une ressource non-conventionnelle de combustible fossile constitué de méthane presque pur. Il est généré au cours de processus très longs de dégradation de matière organique d’origine végétale, dont le résidu solide forme le charbon. La fraction du gaz qui est libérée formera éventuellement des gisements conventionnels. L’autr...

Terrestrial runoff and sedimentation have been implicated in a variety of impacts on scleractinian corals. However, despite accumulating evidence, little work has been done to investigate their influence on coral disease development. This study examined the role that river runoff and the associated sedimentation could play in affecting the prevalen...

This paper presents an extensive review of the process of ghost-rock karstification and highlights its role in the formation of cave systems. The process integrates chemical weathering and mechanical erosion and extends a number of existing theories pertaining to continental landscape development. It is a two stage process that differs in many resp...

The weathering of limestone results in the partial dissolution of calcium carbonate and leaves a soft porous material called alterite. The properties of the weathered rock differ significantly from those of its parent due to the changes in composition and the removal of soluble materials. The resulting increase in porosity modifies the hydrological...

The traditional concept of karstification is the result of the transition of chemical compounds from the solid phase to a liquid phase. Dissolved elements and insoluble parts are carried by the water flows. We called this paradigm the karstification by total removal. Through a joint (bedding plane, tectonic joint, fault), the water dissolves the wa...

The Waulsortian mudmounds consist of massive limestones that developed from late Tournaisian to early Visean. Secondary dolomitization has locally affected these mudmounds conducting to the coexistence of dolostone and limestone patches. Numerous karst cavities are preferentially developed in dolomitic intervals and are geometrically related to one...