Peter I. Nabelek

University of Missouri | Mizzou · Department of Geological Sciences

Many continental large igneous provinces coincide with climate perturbations and mass extinctions. When basaltic plumbing systems traverse carbon-rich sedimentary rocks, large volumes of greenhouse gases may be generated. We document how intrusive sills of the Mesozoic High Arctic Large Igneous Province affected surrounding fine-grained, organic-ri...

Using target-matching techniques combining 40Ar/39Ar crystal-mapping with elemental mapping and high-resolution electron microscopy, this study investigates the 40Ar behavior in very-slowly cooled muscovite from the Harney Peak Granite (HPG, South Dakota, USA). Detailed age mapping along (001) in single crystals from different localities of the HPG...

Most Eoarchean rocks are characterized by positive μ¹⁸²W anomalies averaging ~ +13 ppm (where μ¹⁸²W values are the part per million difference in ¹⁸²W/¹⁸⁴W between a sample and a laboratory reference material presumed to be representative of the bulk silicate Earth, BSE). Prior studies have concluded that the positive ¹⁸²W anomalies in the upper ma...

Textural and compositional variations in titanite constrain the roles of magma mixing and hydrothermal alteration in two plutons in central Utah: the Jurassic Notch Peak and the Oligocene Little Cottonwood stocks. In the Notch Peak intrusion, magmatic titanite grains usually have oscillatory zones combined with BSE-bright sector zones, in some case...

Tourmaline is a common mineral in granites and metamorphic rocks in collisional orogens. This paper describes graphite-bearing, metasomatic tourmalinites in sillimanite-zone schists of the Proterozoic Black Hills Orogen, South Dakota. The tourmalinites bound quartz veins and beyond about 1 m grade into schists with disseminated tourmaline, and ulti...

In the continental crust, the probability of dike propagation out of magma chambers is governed by thermal, rheological, and pressure conditions of magma chamber‐wall rock systems. Incremental injection of melt into an average‐size, laccolith‐shaped, midcrustal magma chamber produces a volume of mobile magma at the bottom of the chamber that has th...

Leucogranites are a characteristic feature of collisional orogens. Their generation is intimately related to crustal thickening and the active deformation and metamorphism of metapelites. Data from Proterozoic to present day orogenic belts show that collisional leucogranites (CLGs) are peraluminous, with muscovite, biotite and tourmaline as charact...

Monzonitic plutons associated with continental arc magmatism are present in volumes much smaller than calc-alkaline plutons in the same tectonic setting, and the relationship between the two is largely unknown. The Jurassic Eureka Valley–Joshua Flat–Beer Creek (EJB) composite pluton is one such example of monzonites associated with a largely calc-a...

This article is hosted at the following web address: http://www.largeigneousprovinces.org/18apr - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - The Natkusiak continental flood basalts and Franklin sills of Victoria Island preserve an exceptional record of the ca. 716-723 Ma Franklin large igneous province (LIP) (Heaman et al., 1992), w...

Carbonatites (sensu stricto) are igneous rocks typically associated with continental rifts, being emplaced at relatively shallow crustal levels or as extrusive rocks. Some carbonatites are, however, related to subduction and lithospheric collision zones, but so far, no carbonatite has been reported from ultrahigh-pressure metamorphic (UHP) terranes...

Zones of partial melt in the middle crust of Lhasa Block, Southern Tibet, have been geophysically observed as seismically reflective “bright spots” in the past 20 years. These batholiths bear important relevance for geodynamics as they serve as the principal observation at depth supporting channel-flow models in the Himalaya-Tibet orogen. Here we a...

Zones of partial melt in the middle crust of Lhasa Block, Southern Tibet, have been geophysically observed as seismically reflective “bright spots” in the past 20 years. These batholiths bear important relevance for geodynamics as they serve as the principal observation at depth supporting channel-flow models in the Himalaya-Tibet orogen. Here we a...

Plutons of the White–Inyo Range (WIR) represent the easternmost extent of Mesozoic subduction magmatism in California. Over twenty recognized granitic to gabbroic plutons intruded during two magmatic events at ca. 180–167 Ma and 102–86 Ma into greenschist facies Neoproterozoic and Cambrian sedimentary units. This study utilized Sr, Nd, and Pb isoto...

The Papoose Flat pluton in the White-Inyo Range, California, is one of the best examples of forcefully emplaced plutons within an arc crust, having internal fabrics and a contact aureole that deformed in a ductile manner. A 2-D numerical model for the thermo-rheological evolution of the pluton–wall rock system is proposed. We explore how the freque...

Fluid inclusions in the metamorphic aureole of the Eureka Valley-Joshua Flat-Beer Creek (EJB) pluton in the White-Inyo Range, California, reveal the compositions and origin of fluids that were present during variable recrystallization of quartzite with sedimentary grain shapes to metaquartzite with granoblastic texture. Metamorphosed sedimentary fo...

Clumped isotope compositions of slowly-cooled calcite and dolomite marbles record apparent equilibrium temperatures of roughly 150-200 °C and 300-350 °C, respectively. Because clumped isotope compositions are sensitive to the details of T-t path within these intervals, measurements of the Δ47 values of coexisting calcite and dolomite can place new...

Thermometric properties and compositions of fluid inclusions in quartz are used to constrain the roles that fluid-soluble elements, principally Li, B, Cl, and F, have in controlling the transition from magmatic to hydrothermal mineral paragenesis in pegmatites and to ultimately understand why some pegmatites in the San Diego County pegmatite distri...

Within the highly strained aureole surrounding the Eureka Valley – Joshua Flat – Beer Creek composite (EJB) pluton of eastern California, an inversion in microstructures and crystallographic preferred orientations (CPO) exists with distance from the contact. An inner aureole (< 250m from the contact) consists of quartzites that are interbedded with...

Geoscience Map 103, 1:50,000. Geologic Survey of Canada. Natural Resources Canada. Ottawa.

The Southern Feeder Dike Complex is part of the Franklin Large Igneous Province (LIP), exposed in the Minto Inlier of Victoria Island in the Canadian Arctic. Previous field and geochemical studies on the Franklin LIP considered its igneous rocks to be prospective for Fe-Ni-Cu mineralization. The Southern Feeder Dike Complex comprises a series of NW...

The authors regret that Eq. (2) has an incorrect form and the coefficients a, b, and c do not correspond to the ones in Table 1. The proper form of Eq. (2) is:

Gabbroic sills of the widespread, ca. 720 Ma Franklin large igneous event intruded sedimentary strata of the Neoproterozoic Shaler Supergroup exposed in the Minto Inlier on Victoria Island in the western Arctic. The mafic magmatism occurred during breakup of the supercontinent Rodinia and preceded Sturtian glaciation. Calc-silicate metamorphic reac...

It is generally thought that garnet in metapelites is produced by continuous reactions involving chlorite or chloritoid. Recent publications have suggested that the equilibrium temperatures of garnet-in reactions may be significantly overstepped in regionally metamorphosed terranes. The growth of small spessartine-almandine garnet crystals on Mn-si...

This contribution addresses contact metamorphism and fluid flow in calcareous rocks of the Neoproterozoic Shaler Supergroup on Victoria Island, Arctic Canada. These processes occurred due to intrusion of gabbroic sills and dykes at c. 720 Ma during the Franklin magmatic event, which was associated with the break‐up of Rodinia. The intrusive sheets...

Thermal diffusivity (D) was measured using laser-flash analysis on pristine and remelted obsidian samples from Mono Craters, California. These high-silica rhyolites contain between 0.013 and 1.10 wt% H2O and 0 to 2 vol% crystallites. At room temperature, D glass varies from 0.63 to 0.68 mm2 s−1, with more crystalline samples having higher D. As T i...

The causes of some stable isotopic variations in felsic rocks are not well understood. In particular, the origin of the heavy Fe isotopic compositions (i.e., high δ56Fe values, deviation in ‰ of the 56Fe/54Fe ratio relative to IRMM-014) of granites with SiO2 > 70 wt.% compared with less silicic rocks is still debated. It has been interpreted to ref...

The Neoproterozoic Franklin large igneous province on Victoria Island, Canada, is characterized by continental flood basalts and a sill-dominated feeder system. Field relationships indicate that fault-guided transfer zones allowed magma to jump up-section to form higher-level intrusions. Where sills connect to dikes and magmas moved up-section, roo...

We explore the conductive cooling rates of plutons and temperature-time paths of their wall rocks using numerical methods that explicitly account for the temperature dependence of thermal diffusivity (α) and heat capacity (CP). We focus on α because it has the strongest influence on the temperature-dependence of thermal conductivity (k = ρ·CP·α) at...

We examined the petrology and stable isotope compositions of metamorphic rocks in the thermal aureole of the Eureka Valley-Joshua Flat-Beer Creek (EJB) composite pluton, White Mountains, eastern California, to determine the physical conditions of contact metamorphism and associated fluid flow. The Jurassic EJB pluton is one of several bodies intrud...

The Neoproterozoic Franklin large igneous province preserves up to 1.1 km thickness of basaltic volcanics (Natkusiak Fm.). The Natkusiak volcanics include basal agglutinate and local hyaloclastite breccias and pillows, lensoid or sheet flows, some picritic, and lahar deposits that seem to infill paleo-valleys. The overlying main series lavas are mo...

Magma emplaced in a sheet intrusion has two potential fates: to crystallize, or quench to glass. Rapidly chilled sheet margins are typically glassy or microcrystalline, while interiors are coarser-grained. The actual textures result from a combination of thermal history and crystallization kinetics, which are related by various feedback mechanisms....

Seismic low-velocity zone along the MHT Recent Hi-CLIMB seismic experiment, using an 800 km long, densely spaced seismic array across Nepal and southern Tibet has revealed a low-velocity zone along the Main Himalaya Thrust (MHT; Nabelek et al, 2009). The narrow low-velocity zone extends approximately from the 28.5°N latitude, dipping to ~40 km dept...

We explore the importance of strain heating in ductile shear zones for production of leucogranites and high-temperature metamorphism in collisional orogens with temperature-dependent thermal diffusivity (D) and rock rheology. New measurements on metamorphic rocks from the Bohemian Massif show that D is ˜1.3 mm2/s at 25°C and decreases exponentially...

We've created a new model for the average continental geotherm by incorporating accurate thermal conductivity values into Fourier's law. Previous geotherm models used thermal conductivities (k) with systematic errors: (1) Pores and microcracks in polycrystalline samples provide artificially low k compared to buried rocks, (2) conventional measureme...

Heat transfer controls the rates and styles of fundamental planetary processes including the formation and differentiation of planetary crust, the rheological behavior of the lithosphere and asthenosphere, and the secular cooling of the Earth following its accretion. The Earth's first few hundred million years were characterized by much higher radi...

Granite pegmatite sheets in the continental crust are characterized by very large crystals. There has been a shift in viewing pegmatites as products of very slow cooling of granite melts to viewing them as products of crystal growth in undercooled liquids. With this shift there has been a renewed debate about the role of H2O in the petrogenesis of...

Transport properties of silicate melts: temperature- and composition-dependence of thermal diffusivity and viscosity, and some geologic applications

The production of leucogranites and high-temperature metamorphism in thickened orogens has been an intriguing problem because of the difficulty of producing sufficient heat to cause them. Deep burial of crustal materials with high radioactive element contents or unusually high mantle heat flux have been considered as sources of elevated T in thicke...

Ongoing laser-flash analysis (LFA) of thermal diffusivity (D) show a monotonic decrease with temperature, such that constant or nearly constant values are attained at very high temperature (T) for diverse single-crystals and glasses. Phase transitions provide a lambda curve in 1/D, which otherwise follows a low-order polynomial in T. Upon melting,...

The physical properties controlling heat flow are thermal diffusivity (D) and conductivity (k = DρCP), where ρ denotes density and CP denotes specific heat capacity at constant pressure. We have measured D of synthetic and natural glasses and melts of diverse compositions including silica, feldspar and pyroxene end-members, MORB and obsidian using...

A series of 18 quartzite samples and 5 marble samples collected across the intensely deformed NE aureole of the Jurassic Eureka Valley-Joshua Flat-Beer Creek (EJB) pluton in eastern California were analyzed for crystallographic preferred orientations (CPO), microstructures, metamorphic phase relationships, fluid inclusions (FI) and oxygen isotopes....

Numerical simulations were performed to examine the relationships between variable contact-aureole permeability, the kinetics of calc-silicate reactions, and the fluxes of mixed CO 2 -H 2 O fluids around a crystallizing granite laccolith. The role of magmatic water was explicitly considered. The Notch Peak contact-metamor-phic aureole in Utah was u...

This special issue on the numerical modeling of hydrothermal fluids is an outgrowth of a thematic session convened at the 2007 Geological Society of America meeting in Denver. Here we briefly review some of the previous research into numerical modeling of hydrothermal fluids and summarize the contributions in this special issue. We find that despit...

The thermal evolution of planetary crust and lithosphere is largely governed by the rate of heat transfer by conduction. The governing physical properties are thermal diffusivity (kappa) and conductivity (k = kapparhoC(P)), where rho denotes density and C(P) denotes specific heat capacity at constant pressure. Although for crustal rocks both kappa...

A Sr, Nd, and O isotopic study of Variscan granitoid rocks from the Western Carpathians reveals the dominance of heterogeneous crustal sources for the most of the granitic rocks. Their neodymium crustal index (NCI) is 0.4 to 1.0 (mainly 0.6–0.8). Initial (87Sr/86Sr)350 of 0.7053 to 0.7078 and εNd (350) of -0.6 to -6.9 preclude a simple mantle and/o...

Precambrian Research j o u r n a l h o m e p a g e : w w w . e l s e v i e r . c o m / l o c a t e / p r e c a m r e s a b s t r a c t Four suites of mafic to intermediate intrusions and flows that occur in the Precambrian core of the Black Hills were analyzed for major and trace elements to establish tectonic settings of magmatism during the late...

In the lithium-cesium-tantalum-type pegmatite dikes of San Diego County, California, USA, tourmaline is the main reservoir for Li, except in the cores and the pockets of the dikes where other Li-bearing minerals also occur. Tourmaline from three subhorizontal dikes was analyzed for bulk Li concentrations and Li isotope ratios. The bottom portion of...

The thermal evolution of orogenic belts is governed by the rates of heat transfer by advection and conduction. The physical properties governing heat conduction are thermal diffusivity (kappa) and conductivity (k = kapparhoCP), where rho is density and CP is heat capacity. Numerical models of orogenic belts typically assume constant values for kapp...

Fluid inclusions in quartz veins within Proterozoic metamorphic rocks in the Black Hills, South Dakota, were examined by microthermometry and Raman spectroscopy to assess the evolution of fluid compositions during regional metamorphism of organic-rich shales and late-orogenic magmatism, both of which were related to the collision of the Wyoming and...

Mineral assemblages in contact-metamorphic aureoles are the products of the interplay between heat transfer and fluid flow induced by intrusion of magma. In wall rocks containing carbonate and silicate minerals, metamorphic reactions produce CO2, which then becomes part of the hydrodynamic system. Although observed assemblages are the ultimate prod...

The Black Hills region provides an excellent field laboratory to study numerous aspects of the continental evolution of North America from the Neoarchean to the Recent. The Neoarchean basement consists of 2.60- 2.56 Ga gneissic granitoids that formed during an early episode of convergent thermotectonism. In the Paleoproterozoic the region experienc...

Late Archean and Early Proterozoic continental margin pelites, graywackes, and quartzites in today's Black Hills were regionally metamorphosed during the collision of the Archean Wyoming and Superior provinces beginning at similar to 1755 Ma. During east-west regional compression, metamorphism reached incipient garnet-biotite grade conditions at si...

Leucogranites are typical products of collisional orogenies. They are found in orogenic terranes of different ages, including the Proterozoic Trans-Hudson orogen, as exemplified in the Black Hills, South Dakota, and the Appalachian orogen in Maine, both in the USA, and the ongoing Himalayan orogen. Characteristics of these collisional leucogranites...

Carbon isotope fractionations between calcite and graphite in the Panamint Mountains, California, USA, demonstrate the importance of mass balance on carbon isotope values in metamorphosed carbon-bearing minerals while recording the thermal conditions during peak regional metamorphism. Interbedded graphitic marbles and graphitic calcareous schists i...

Previous models of hydrodynamics in contact metamorphic aureoles assumed flow of aqueous fluids, whereas CO2 and other species are also common fluid components in contact metamorphic aureoles. We investigated flow of mixed CO2–H2O fluid and kinetically controlled progress of calc-silicate reactions using a two-dimensional, finite-element model cons...

We propose that the internally zoned, Li-bearing Tin Mountain pegmatite in the Harney Peak granite-pegmatite system of the Black Hills, South Dakota, crystallized from fluid-rich, compositionally complex melts at ˜400 350 °C. The low crystallization temperatures resulted from the combined fluxing effects of Li, B, P, H2O, and carbonate anions. The...

A microthermometric study of inclusions in granites and pegmatites in the Proterozoic Harney Peak Granite system identified four types of inclusions. Type 1 inclusions are mixtures of CO2 and H2O and have low salinities, on average 3.5 wt.% NaCleq; type 2 inclusions are aqueous solutions of variable salinities, from 0 to 40% wt.% NaCleq; type 3 inc...

Dawsonite-NaAl(CO3)(OH)2-was identified in primary fluid inclusions in quartz from the Li-rich Tin Mountain pegmatite, Black Hills, South Dakota, by petrography, SEM-EDS analysis, and Raman spectroscopy. This is the first report of dawsonite as an inclusion mineral in a pegmatite. The presence of dawsonite in the inclusions is evidence for the exis...

Tectonic activity during the Miocene exhumation of the Tatra granitoid basement resulted in frictional melting of granite. The activity marks the early stages of the faulting that is responsible for uplift of the High Tatras. As indicated by pre-existing cataclasite metamorphic mineral assemblages, the ambient pressure was about 250–300 MPa, corres...

We investigated the macroscale fluid flow and oxygen isotope exchange in contact-metamorphic aureoles by using two-dimensional finite-element modeling. The model parameters are assigned according to geologic observations in the Notch Peak metamorphic aureole, Utah. The results show that fluid flow in contact aureoles depends strongly on time and sp...

Fluid compositions and bedding-scale patterns of fluid flow during contact metamorphism of the Weeks Formation in the Notch Peak aureole, Utah, were determined from mineralogy and stable isotope compositions. The Weeks Formation contains calc-silicate and nearly pure carbonate layers that are interbedded on centimetre to decimetre scales. The progr...

The abundance and distribution of B and Li in metasedimentary rocks and in the Harney Peak Granite (HPG) in the Black Hills, South Dakota, U.S.A., elucidate the behavior of these two elements during (1) regional metamorphism that began at ~1760 Ma; (2) subsequent contact metamorphism associated with emplacement of the HPG and associated pegmatites...

This paper evaluates thermotectonic models for metamorphism and leucogranite generation during the Proterozoic Trans-Hudson orogeny, as recorded in rocks exposed in the Black Hills, SD. Intrusion of the Harney Peak Granite and associated pegmatites at ∼1715 Ma occurred at the waning stages of regional deformation and staurolite-grade regional metam...

The trace element batch melting equation of Schilling (1966), Cl = Co/[D(1-F)+F], is a simple yet an elegant description of the equilibrium and mass-balance relationships of trace element distribution in a partially molten system. The power of this equation was demonstrated in classic papers by Gil Hanson (1978, 1980) on trace element modeling of i...

We have investigated the control of layered and transient permeability structures on fluid flow and thermal evolution in contact metamorphic aureoles using two-dimensional numerical modeling with petrological and geochemical constraints from the Notch Peak aureole, Utah. The model includes interbedded aquitard and aquifer lithologies on the scale o...

Combined B, O, H, and Sr isotopic studies of groundwaters from Mt. Etna provide new constraints on their origin and the consequences of fluid-rock interaction within this hydrologic system. Variations in δ18O (−9.7 to −7.2‰) and δD (−62 to −23‰) mainly lie along the regional meteoric water line and suggest that most waters originated as local preci...

In order to elucidate how mineralogy and composition of crustal sources influences production of leucogranite magmas, we modelled the potential fertility of a sequence of metapelites and metagraywackes from the Black Hills, South Dakota, U.S.A., using a least-squares mixing approach. Rocks analogous to the Black Hills schists were the sources of th...