Larryn William Diamond

• PhD
• Head of Department at University of Bern

Amagmatic geothermal systems within regional‐scale orogenic faults are promising renewable resources for heat and possibly electricity production. However, their behavior needs to be better understood to improve their exploration and assessment of energy potential. To provide more insight, we report geochemical, geological, and geophysical studies...

Porosity and permeability are key controls on hydrothermal circulation and alteration in magmatically heated upper oceanic crust. However, the hydraulic properties of basalts altered above 200°C are largely unknown, leaving their role in high‐temperature systems unclear. Here, we assess rock‐matrix porosities and permeabilities of pervasively alter...

Numerical modeling is used to understand the regional scale flow dynamics of the fault‐hosted orogenic geothermal system at the Grimsel Mountain Pass in the Swiss Alps. The model is calibrated against observations from thermal springs discharging in a tunnel some 250 m underneath Grimsel Pass to derive estimates for the bulk permeability of the fau...

Multispectral remote sensing of hydrothermal alteration in volcanogenic massive sulfide (VMS) ore systems in mafic crust is relatively uncommon, in part due to the short-wave infrared spectral similarity of several key alteration minerals: epidote, chlorite, actinolite, and serpentine. In this study, we developed regional mosaic generation and clas...

Many meteoric‐recharged, fault‐hosted geothermal systems in amagmatic orogenic belts have been active through the Pleistocene glacial/interglacial climate fluctuations. The effects of climate‐induced recharge variations on fluid flow patterns and residence times of the thermal waters are complex and may influence how the geothermal and mineralizati...

Much of the hydrothermal circulation through the oceanic crust occurs within the upper layer of permeable basaltic lavas. Major faults are accepted channels of fluid flow in this setting but less is known about flow through the blocks of largely intact lavas that lie between major faults. The pervasive hydrothermal alteration of these blocks testif...

Geothermal systems in amagmatic orogens involve topography‐driven infiltration of meteoric water up to 10 km deep into regional‐scale faults and exfiltration of the heated water in surface springs. The thermal anomalies along the upflow zones have not been quantified, yet they are key to estimating the geothermal exploitation potential of such syst...

Numerous studies have revealed genetic similarities between Tethyan ophiolites and oceanic “proto-arc” sequences formed above nascent subduction zones. The Semail ophiolite (Oman–U.A.E.) in particular can be viewed as an analogue for this proto-arc crust. Though proto-arc magmatism and the mechanisms of subduction initiation are of great interest,...

Subsurface sedimentary strata in northern Switzerland, such as the Middle Triassic Upper Muschelkalk, are attracting interest as potential reservoirs for CO2 sequestration and for geothermal energy production. Characterizing facies in such strata aids prediction of reservoir properties in unexplored areas. Although well studied elsewhere, the Swiss...

Creation of secondary dissolution porosity in carbonate rocks during deep burial has the potential to improve reservoir properties for hydrocarbons, gas storage, and geothermal applications. However, the occurrence and mechanisms of such porosity enhancement are controversial. Here, we present compelling evidence for generation of deep burial poros...

Over four decades of research on the Semail ophiolite (Oman-U.A.E.) has greatly influenced our understanding of processes occurring at fast-spreading ocean ridges. While the well-developed sheeted dike complex and comagmatic lower pillow lavas indicate that the early Semail crust formed at a spreading axis, the precise tectonic setting of this axis...

Warm springs emanating from deep-reaching faults in orogenic belts with high topography and orographic precipitation attest to circulation of meteoric water through crystalline bedrock. The depth to which this circulation occurs is unclear, yet it is important for the cooling history of exhuming orogens, for the exploitation potential of orogenic g...

The changes in rock-matrix porosity and permeability that carbonate reservoirs undergo with increasing burial depth are poorly understood. This lack of understanding raises the risks involved in exploring and engineering deep reservoirs for geo-energy applications. To provide more insight into compaction processes, the present study examines the ef...

The scientific objectives of the 2020 ExoMars rover mission are to search for traces of past or present life and to characterise the near-sub surface. Both objectives require study of the rock/regolith materials in terms of structure, textures, mineralogy, and elemental and organic composition. The 2020 ExoMars rover payload consists of a suite of...

The Trigonodus Dolomit is the dolomitized portion of the homoclinal ramp sediments of the Middle Triassic Upper Muschelkalk in the south‐east Central European Basin. Various dolomitizing mechanisms, followed by recrystallization, have been previously invoked to explain the low δ¹⁸O, high ⁸⁷Sr/⁸⁶Sr, extensive spatial distribution and early nature of...

The La Colosa porphyry Au deposit is located on the eastern flank of the Central Cordillera of Colombia, within the Middle Cauca metallogenic belt. The deposit contains more than 800 t (22.37 Moz) Au at grades up to 0.8 g/t and is hosted by a composite porphyry stock of dioritic to tonalitic composition, which was emplaced into Triassic-Cretaceous...

The suitability of swelling clays as a barrier to isolate nuclear waste in deep geological disposal is based on their microstructure, characterized by pore sizes down to the nanometre scale, and by their physico-chemical properties such as an excellent retention capacity for many radionuclides. A process-based understanding of the key features of r...

Most rare earth element deposits form from magmatic fluids, but there have also been discoveries of heavy rare earth element (HREE)– enriched hydrothermal xenotime deposits within sedimentary basins. As xenotime is notoriously insoluble, the question arises as to whether these lesser-known deposits form at typical basin temperatures or by influx of...

Results from reactive transport simulations performed for the geothermal plant in Kirchstockach, located in the Bavarian Molasse Basin in southern Germany, are presented to unravel the formation of calcite scaling. Simulation results successfully predict the calcite scaling profile observed along the production well if supersaturation with respect...

The Upper Muschelkalk carbonate aquifer within the Swiss Molasse Basin is currently being investigated for its potential for geothermal energy exploitation and geological storage of gas. Porosities of up to 25% are locally observed where early diagenetic (Triassic) anhydrite has been dissolved by groundwater. However, the dimensions and the spatial...

We use reactive transport simulations to evaluate the CO2 sequestration potential of a carbonate-hosted aquifer. Results show that in carbonate aquifers the dissolution of CO2 into the brine is the only effective chemical trapping mechanism. Its efficiency is controlled by the solubility of CO2 and by the mobility of the CO2 plume which affects its...

The carbonate-dominated Malm aquifer in the Bavarian Molasse Basin in Southern Germany is being widely exploited and explored for geothermal energy. Despite favorable reservoir conditions, the use of geothermal wells for heat and power production is highly challenging. The main difficulty, especially in boreholes>3000 m deep with temperatures>120 °...

Meteoric diagenesis of carbonate ramps is often difficult to interpret and can commonly be confused with other coinciding diagenetic processes. The Middle Triassic Upper Muschelkalk of Switzerland provides an insightful case in which the effects of several overprinting diagenetic environments, including matrix dolomitization, can be clearly unravel...

In this study we report on the source and evolution of fluids associated with secondary vein and replacement minerals in low-permeability carbonate units in the Michigan Basin. This petrogenetic information was collected using thermometric data from fluid inclusions combined with C-, O- and Sr-isotope data, and focuses on mm- or cm-wide vein and vu...

Secondary vein minerals in low-permeability sedimentary rocks provide a unique opportunity to understand solute transport with deep basin fluids. Here we report on the source and evolution of fluids that contributed to secondary mineral formation in Ordovician limestones and Cambrian siliciclastics of the Michigan Basin. Microthermometric measureme...

The classic model of hydrothermal alteration of the upper oceanic crust identifies epidosites (basalts altered to epidote + quartz + titanite ± Fe-oxides) as markers of discharging hydrothermal fluid. Epidosites are depleted in metals and therefore they have been proposed as sources for the metals in volcanogenic massive sulfide deposits. However,...

The Close-Up Imager (CLUPI) onboard the ESA ExoMars Rover is a powerful high-resolution color camera specifically designed for close-up observations. Its accommodation on the movable drill allows multiple positioning. The science objectives of the instrument are geological characterization of rocks in terms of texture, structure, and color and the...

Hydrothermal seafloor alteration is best preserved in obducted oceanic lithosphere. Among the alteration types in the basaltic crustal section of ophiolites are rocks which have been completely altered to epidote + quartz ± titanite ± Fe-oxides, so-called epidosites. These rocks have been interpreted to form within the base of hydrothermal discharg...

Pervasive epidotization of igneous rocks is a common feature in the ophiolite record of hydrothermally altered oceanic crust. Current genetic models view epidosites as markers of focussed upflow of hydrothermal fluid beneath oceanic spreading ridges. The epidosites are envisaged to form at the base of the sheeted dike complex (SDC) during active pl...

Dieser Band bietet eine Einführung in die Entstehung und Geschichte unseres Planeten. Im Zentrum stehen dabei die Plattentektonik, die verschiedenen Minerale und Gesteine sowie die geologischen Vorgänge im Erdinneren und an der Oberfläche. «Erdwissenschaften» richtet sich an alle BA-Studierenden der Geologie und Geographie sowie an interessierte L...

The Upper Muschelkalk (Anisian/Ladinian) is an extensive deep saline aquifer in the Molasse Basin of northern Switzerland, which is under investigation for its potential for geothermal energy production and for industrial CO2 storage. It is subdivided into a lower limestone unit (Hauptmuschelkalk) and a fully dolomitized formation (Trigonodus Dolom...

The architecture of the Upper Muschelkalk (Anisian/Ladinian) in Switzerland is that of a gently inclined carbonate ramp at the southeastern extent of the Upper Muschelkalk Sea of the German basin. The sea experienced a wide-scale 3rd order transgressive – regressive event, which deposited an easily recognizable suite of lithofacies assemblages in a...

A reactive transport model based on the abandoned EGS at Basel is constructed.•Implications of fluid–rock reactions in the reservoir for scaling and corrosion are assessed.•An increase in H2,aq and Fe2+ in the fluid and scales indicate incipient corrosion.•Common solute geothermometers may not work in “young” stimulated reservoirs.

Cathodoluminescence (CL) studies have previously shown that some secondary fluid inclusions in luminescent quartz are surrounded by dark, non-luminescent patches, resulting from fracture-sealing by late, trace-element-poor quartz. This finding has led to the tacit generalization that all dark CL patches indicate influx of low temperature, late-stag...

The Semail ophiolite in Oman is capped by up to 2 km of basaltic-andesitic lavas that host copper-dominant, Cyprus-type, volcanogenic massive sulfide (VMS) deposits. This study identifies multiple volcanostratigraphic horizons on which the deposits are situated, based on characterization of footwall and hanging-wall lavas from 16 deposits or deposi...

Numerical simulations based on plans for a deep geothermal system in Basel, Switzerland are used here to understand chemical processes that occur in an initially dry granitoid reservoir during hydraulic stimulation and long-term water circulation to extract heat. An important question regarding the sustainability of such enhanced geothermal systems...

Illustrations are an essential part of most CCS communication materials. This article looks at the role of illustrations in communication and education in general, and in CCS communication in particular. First, literature on multimedia learning is reviewed and general guidelines for designing graphical displays deduced. This is followed by a discus...

Extraction of useful geochemical, petrologic and structural information from deformed fluid inclusions is still a challenge in rocks displaying moderate plastic strain. In order to better understand the inclusion modifications induced by deviatoric stresses, six deformation experiments were performed with a Griggs piston-cylinder apparatus. Natural...

The Triassic Trigodonus Dolomite unit of Upper Muschelkalk, a saline carbonate-hosted aquifer in Northerm Switzerland, is considered a possible target for sequestering CO2. The porosity of the aquifer ranges from 4-25 %. The porosity can be divided into macropores (mm to cm scale) and micropores (µm to nm scale). Intermittent bedding-parallel layer...

The upper Muschelkalk saline aquifer consists of partly dolomitized to completely dolomitized carbonate rocks of mid Triassic age (~230 Ma). This aquifer is present throughout the Swiss Molasse Basin (SMB), north of the Alps. A regional appraisal of the SMB indicates that this Formation is a potential host aquifer for sequestered CO2. However, the...

Predictive numerical models are required to assess the processes during and after the injection of CO2 over spatial- and time-scales that are inaccessible to direct observation. We present results from numerical simulations that examine the effect of perm

The naturally occurring layered double hydroxides (LDH, or anionic clays) are of particular interest in environmental geochemistry because of their ability to retain hazardous cations and especially anions. However, incorporation of these minerals into predictive models of water–rock interaction in contaminant environments, including radioactive-wa...

The scientific objectives of the 2018 ExoMars rover mission are to search for traces of past or present life and to characterise the near-sub surface. Both objectives require study of the rock/regolith materials in terms of structure, textures, mineralogy, and elemental and organic composition. The 2018 ExoMars rover payload consists of a suite of...

Possibilities to sequester anthropogenic CO2 in deep geological formations are being investigated worldwide, but the potential within Switzerland has not yet been evaluated. This study presents a first-order appraisal based solely on geological criteria collated from the literature. The Swiss Molasse Basin (SMB) and the adjacent Folded Jura are the...

Fluid inclusions in quartz are known to modify their densities during shear deformation. Modifications of chemical composition are also suspected. However, such changes have not been experimentally demonstrated, their mechanisms remain unexplained, and no criteria are available to assess whether deformed inclusions preserve information on paleoflui...

Fluid inclusions in quartz are known to modify their shapes and microstructures (textures) during weak plastic deformation. However, such changes have not been experimentally demonstrated and criteria are not available to relate them to paleostress conditions. To address these issues, quartz crystals containing natural CO2–H2O–NaCl fluid inclusions...

Experimental measurements of the solubility of CO2 in aqueous NaCl solutions have been assembled from 21 literature studies and tested for consistency using analytical and thermodynamic criteria. Of the 508 data compiled, 170 data (33%) were discarded and 36 were reserved to test the high-pressure dependency of the model. Possible reasons for the o...

A layered double hydroxide (LDH) hydrotalcite–pyroaurite solid-solution series Mg 3 (Al x Fe 1 − x)(CO 3) 0.5 (OH) 8 with 1 − x = 0.0, 0.1……1.0 was prepared by co-precipitation at 23 ± 2 °C and pH = 11.40 ± 0.03. The compositions of the solids and the reaction solutions were determined using ICP-OES (Mg, Al, Fe, and Na) and TGA techniques (CO 3 2−...

We use reactive-transport simulations of the geothermal system at Bad Blumau, austria, and of the planned geothermal system at Basel, Switzerland, to examine chemical processes during fluid circulation. In carbonate-dominated systems (Bad Blumau), separation of co 2 gas from the production fluid leads to increases in pH and to carbonate precipitati...

Recent improvements in chemical analysis of fluid inclusions (using techniques such as LA-ICP-MS, PIXE, SXRF, LIBS and SIMS for individual inclusions, and crush-leach analysis for bulk samples), now permit ratios of certain solute elements to be determined with high accuracy. In order to apply these results to geochemical problems, the element rati...

Fluid inclusion studies together with volcanological and petrochemical data allow reconstruction of the magma feeding system of basaltic-andesitic to andesitic activity during the oldest and intermediate stages of development of Lipari Island (223–81ka). A major magma storage zone is active during the overall investigated time span at depths of 22k...

The orogenic gold deposit at Brusson, NW Italian Alps, consists of quartz-carbonate-sulphide veins, which are known to have formed from a CO 2-H 2 O-NaCl hydrothermal fluid. Our recent discovery of an aqueous type of fluid inclusion, previously unknown at this location, raises the question of which processes triggered gold deposition. New petrograp...

Experimental measurements of the solubility of CO 2 in aqueous NaCl solutions have been assembled from 21 literature studies and tested for consistency using analytical and thermodynamic criteria. Of the 508 data compiled, 36 were reserved to test the high-pressure dependency of the model and 170 data (33%) were discarded. The 302 measurements that...

We use reactive-transport simulations of the geothermal system at Bad Blumau, Austria, and of the planned geothermal system at Basel, Switzerland, to examine chemical processes during fluid circulation. In carbonate-dominated systems (Bad Blumau), separation of CO2 gas from the production fluid leads to increases in pH and to carbonate precipitatio...

The orogenic gold deposit at Brusson, NW Italian Alps, consists of quartz-carbonate-sulphide veins, which are known to have formed from a CO2–H2O–NaCl hydrothermal fluid. Our recent discovery of an aqueous type of fluid inclusion, previously unknown at this location, raises the question of which processes triggered gold deposition. New petrographic...

Experimental measurements of the solubility of CO2 in aqueous NaCl solutions have been assembled from 21 literature studies and tested for consistency using analytical and thermodynamic criteria. Of the 508 data compiled, 36 were reserved to test the high-pressure dependency of the model and 170 data (33%) were discarded. The 302 measurements that...

Diffusion of water and solutes through compacted clays or claystones is important when assessing the barrier function of engineered or geological barriers in waste disposal. The shape and the connectivity of the pore network as well as electrostatic interactions between the diffusant and the charged clay surfaces or cations compensating negative su...

We use reactive-transport models patterned after the geothermal system at Bad Blumau, Austria, to track the fate of a fluid during its ascent from the geothermal reservoir to the surface, where it undergoes heat- and CO2-extraction, and during its subsequent reinjection into the deep aquifer. The fluid in the reservoir is in equilibrium with the ca...

We use 2D reactive transport simulations to assess the hydraulic, thermal and chemical implications of an ultramafic body of lherzolitic composition within a basalt-dominated oceanic hydrothermal system. The simulations are fully coupled and hence account for the progressive serpentinization and the associated porosity/permeability reduction of the...

Knowledge of the solubility of quartz over a broad spectrum of aqueous fluid compositions and T–P conditions is essential to our understanding of water–rock interaction in the Earth’s crust. We propose an equation to compute the molality of aqueous silica, mSiO2(aq), mol·(kg H2O)−1, in equilibrium with quartz and water–salt–CO2 fluids, as follows:H...

The effect of temperature and ionic strength on the diffusion of HTO parallel to the direction of compaction through 5 highly compacted clay minerals (bulk dry density, ρb,d = 1.90 ± 0.05 Mg/m3), namely montmorillonite (Na- and Ca-form), illite (Na- and Ca-form), and kaolinite, was studied. The diffusion experiments were carried out at temperatures...

The water diffusion in four different, highly compacted clays [montmorillonite in the Na- and Ca-forms, illite in the Na- and Ca-forms, kaolinite, and pyrophyllite (bulk dry density rho(b)=1.85+/-0.05 gcm(3))] was studied at the atomic level by means of quasielastic neutron scattering. The experiments were performed on two time-of-flight spectromet...

Pure CO2 fluid inclusions are observed in fifteen quartz-rich xenoliths collected in basaltic-andesitic to andesitic volcanic products relevant to the older evolutionary stages of Lipari Island (223-105 ka). In volcanics forming central composite volcanoes (M. Mazzacaruso, 223-127 ka; M. S.Angelo, 105 ka), fluid inclusions are trapped during two di...

Laser-ablation inductively coupled-plasma mass spectrometry (LA-ICPMS) is an established method of analyzing the elemental composition of individual fluid inclusions in minerals. While the method affords good spatial control of ablation pits, we have found that stray light from the UV (193 nm) laser may permanently modify the gas species in adjacen...

Sites of oceanic hydrothermal activity constitute complex systems in which numerous physical and chemical processes interact at various rates. Most numerical studies of these systems that have been carried out to date have focused on either the physical or the chemical aspects of the hydrothermal activity, while greatly simplifying the other aspect...

Some of the petroleum currently produced in the Pannonian Basin in Hungary stems from buried metamorphic basement domes that form structural highs between Neogene sedimentary sub-basins. In the Békés sedimentary sub-basin, the source rocks of the petroleum are known to be of Middle to Late Miocene age, whereas at least part of the petroleum in the...

We propose the following equation to compute the molality of aqueous silica, m SiO2(aq), in equilibrium with quartz in water-salt-CO 2 systems: 1gmSio 2 = A(T) + B (T) 1g 18.0152/ V* H 2O + 21gxH 2O Here A(T) and B(T) are polynomials from Manning's (1994) equation for quartz solubility in pure water, and xH 2O and V* H 2O stand for the mole fractio...

Circulation of seawater through the oceanic crust and the chemical reactions that occur along the flowpath are the most important processes controlling the composition of vent fluids and mineral formation within the crust and on the seafloor. We use three variably coupled reactive transport models to explore the evolution and the interaction of flu...

The molar volume (Vm) and chemical composition (x) of saline aqueous inclusions and gas inclusions in minerals can be calculated satisfactorily from microthermometric and other analytical data. For complex gas-bearing aqueous inclusions, however, calculation of Vm - x properties requires additional input of the volume-fractions of the inclusion pha...

A new equation of state (EoS) for describing the thermodynamic properties of aqueous non-electrolytes at infinite dilution is proposed. It is based on the accurate EoS for the solvent (H2O) given by Hill [21], it requires only three empirical parameters to be fitted to experimental data, and these are independent of temperature and pressure. Knowle...

Fault-bound hydrothermally mineralized breccias with a multistage deformation history occur in crystalline rocks of the Aar massif at Grimsel Pass, Central Swiss Alps. The breccias crop out over 4.5 km E–W along strike and over 900 m in vertical extent between Trübtensee and Gletsch, and are up to 2 m wide. A characterization of these "Grimsel Brec...

Experimental measurements of the solubility of CO2 in pure water at pressures above 1 MPa have been assembled from 25 literature studies and tested for their accuracy against simple thermodynamic criteria. Of the 520 data compiled, 158 data were discarded. Possible reasons for the observed discrepancies between datasets are discussed. The 362 measu...

A new, virial-like equation of state (EoS) for describing the thermodynamic properties of aqueous nonelectrolytes at infinite dilution is proposed. It is based on the accurate EoS for a solvent (H2O) given by Hill (1990) and requires only three empirical parameters to be fitted to experimental data, and these are independent of temperature and pres...

Fluid inclusions were synthesized in quartz from silver oxalate (Ag2C2O4) and a 6-wt.% NaCl aqueous solution to produce a CO2–H2O–NaCl fluid, following the method of previous workers. Synthesis conditions of 500–650°C and 1500–4500 bar were chosen with the intention of trapping a homogeneous, ternary fluid. The resulting inclusions were analyzed by...

Aqueous solutions that contain volatile (gas) components are one of the most important types of fluid in the Earth's crust. The record that such fluids have left in the form of fluid inclusions in minerals provides a wealth of insight into the geochemical and petrologic processes in which the fluids participated. This article reviews the systematic...