Geochemistry and petrogenesis of the East Branch Brook metagabbroic dykes in the Sawyer Brook fault zone, Clarence Stream gold prospect, southwestern New Brunswick

The East Branch Brook (EBB) metagabbroic dykes, host to a portion of the Clarence Stream gold deposit, are situated within the contact metamorphic aureole of the Middle Devonian I-type Magaguadavic Granite on the northwestern margin of the post-orogenic Saint George Bathohth. They are highly deformed, light- (type I), intermediate- (type 2) to dark-coloured (type 3) dykes containing auriferous quartz veins that occupy brittle to ductile northeast-trending shear zones in shallow marine, hornfelsed, volcaniclastic, sedimentary rocks of the Silurian Waweig and Oak Bay formations. The shear zones parallel the regional structure as a result of proximity to the faulted boundary (Sawyer Brook fault) between the Ordovician St. Croix terrane to the northwest and the Silurian to Early Devonian Mascarcne Basin to the southeast. Geochemical studies of the EBB dykes indicate that three pulses (Fe-rich. intermediate, and Mg-rich) of subalkaline to slightly alkaline continental tholeiitc magmas were generated in a transpressional environment during the Early Silurian to Early Devonian Positive εNd values indicate their derivation from a partially depleted mantle source during faulting and nft-related events Although the geochemical data (Fe- and Ti-depletion) indicate calc-alkaline affinity for the nearby Bocabec intrusive complex, εNd values and primitive mantle-normalized spider diagram patterns are similar to those of the EBB dykes. In contrast, the St. Stephen Intrusion appears more primitive with within-plate tholeiitic to slightly alkalie affinity RÉSUMÉ Les dykes metagabbroïques du ruisseau East Branch, qui abritent une partie du gite aurifière dc Clarence Stream, sont situées à l'inténeur de 1'auréolc de métamorphismc de contact du granite du Dévonian moyen de type 1 de Magaguadavic sur la limite nord-ouest du batholithe postorogénique de Saint George. Il s'agit de dykes extrémemeni déformés de teinte pàle (type 1) et intermédiaire (type 2) à foncée (type 3) renfermant des filons de quartz aurifere qui occupent des zones de eisaillement cassantes à déformables, orientées ver\ Ic nord-est. dans des roches sédimcntaires volcanoclastiques à coméenncs marines peu profondes des formations silunennes de Wawcig el d'Oak Bay. La proximilé de la limite faillée (faille du runsseau Sawyer) entre le terrane ordovicien de St. Croix, au nord-ouest et le bassin du Silurien au Dévonien inférieur de Mascarenc. au sud-est, a amené les zones du eisaillement à longer parallélement la structure régionale. Des éludes géochimiques des dykes du ruisseau East Branch révèlent que trois impulsions (composante riche en Fer. composante intermédiaire et composante riche en Mg) de magmas tholéutiques continentaux, allant de subalcalins à légèrement alcalms sont survenues dans un environnement transpressionnel pendant la période du Silurien inferieur au Dévonien infèrieur. Les vateurs positives de εNd lémoignent de leur provenance d'un manteau particllement appauri pendant la formation de failles et des phénomènes apparcntes à une distension Même les données géeochimiques (appaurassement en Fe et en Ti) revèlent unc affinité calcoalcaline du complexe intrusif proche de Bocabec. les valeurs de εNd et les configurations de diagrammes en araignée normalisées du manteau primitif sont analogues a celles des dykes du ruisseau East Branch Par contre, l'intrusion de Saint Stephen semble plus primitive avec une affinite mira-plaques allant de tholénlique à légèrcment alcaline Traduit par la rédactio

Visualizing Spacetime Curvature via Frame-Drag Vortexes and Tidal Tendexes III. Quasinormal Pulsations of Schwarzschild and Kerr Black Holes

In recent papers, we and colleagues have introduced a way to visualize the full vacuum Riemann curvature tensor using frame-drag vortex lines and their vorticities, and tidal tendex lines and their tendicities. We have also introduced the concepts of horizon vortexes and tendexes and 3-D vortexes and tendexes (regions where vorticities or tendicities are large). Using these concepts, we discover a number of previously unknown features of quasinormal modes of Schwarzschild and Kerr black holes. These modes can be classified by mode indexes (n,l,m), and parity, which can be electric [(-1)^l] or magnetic [(-1)^(l+1)]. Among our discoveries are these: (i) There is a near duality between modes of the same (n,l,m): a duality in which the tendex and vortex structures of electric-parity modes are interchanged with the vortex and tendex structures (respectively) of magnetic-parity modes. (ii) This near duality is perfect for the modes' complex eigenfrequencies (which are well known to be identical) and perfect on the horizon; it is slightly broken in the equatorial plane of a non-spinning hole, and the breaking becomes greater out of the equatorial plane, and greater as the hole is spun up; but even out of the plane for fast-spinning holes, the duality is surprisingly good. (iii) Electric-parity modes can be regarded as generated by 3-D tendexes that stick radially out of the horizon. As these "longitudinal," near-zone tendexes rotate or oscillate, they generate longitudinal-transverse near-zone vortexes and tendexes, and outgoing and ingoing gravitational waves. The ingoing waves act back on the longitudinal tendexes, driving them to slide off the horizon, which results in decay of the mode's strength. (iv) By duality, magnetic-parity modes are driven in this same manner by longitudinal, near-zone vortexes that stick out of the horizon. [Abstract abridged.]Comment: 53 pages with an overview of major results in the first 11 pages, 26 figures. v2: Very minor changes to reflect published version. v3: Fixed Ref

Gravitational Wave Emission from the Single-Degenerate Channel of Type Ia Supernovae

The thermonuclear explosion of a C/O white dwarf as a Type Ia supernova (SN Ia) generates a kinetic energy comparable to that released by a massive star during a SN II event. Current observations and theoretical models have established that SNe Ia are asymmetric, and therefore--like SNe II--potential sources of gravitational wave (GW) radiation. We perform the first detailed calculations of the GW emission for a SN Ia of any type within the single-degenerate channel. The gravitationally-confined detonation (GCD) mechanism predicts a strongly-polarized GW burst in the frequency band around 1 Hz. Third-generation spaceborne GW observatories currently in planning may be able to detect this predicted signal from SNe Ia at distances up to 1 Mpc. If observable, GWs may offer a direct probe into the first few seconds of the SNe Ia detonation.Comment: 8 pages, 4 figures, Accepted by Physical Review Letter

Monsters, black holes and the statistical mechanics of gravity

We review the construction of monsters in classical general relativity. Monsters have finite ADM mass and surface area, but potentially unbounded entropy. From the curved space perspective they are objects with large proper volume that can be glued on to an asymptotically flat space. At no point is the curvature or energy density required to be large in Planck units, and quantum gravitational effects are, in the conventional effective field theory framework, small everywhere. Since they can have more entropy than a black hole of equal mass, monsters are problematic for certain interpretations of black hole entropy and the AdS/CFT duality. In the second part of the paper we review recent developments in the foundations of statistical mechanics which make use of properties of high-dimensional (Hilbert) spaces. These results primarily depend on kinematics -- essentially, the geometry of Hilbert space -- and are relatively insensitive to dynamics. We discuss how this approach might be adopted as a basis for the statistical mechanics of gravity. Interestingly, monsters and other highly entropic configurations play an important role.Comment: 9 pages, 4 figures, revtex; invited Brief Review to be published in Modern Physics Letters

Frame-Dragging Vortexes and Tidal Tendexes Attached to Colliding Black Holes: Visualizing the Curvature of Spacetime

When one splits spacetime into space plus time, the spacetime curvature (Weyl tensor) gets split into an "electric" part E_{jk} that describes tidal gravity and a "magnetic" part B_{jk} that describes differential dragging of inertial frames. We introduce tools for visualizing B_{jk} (frame-drag vortex lines, their vorticity, and vortexes) and E_{jk} (tidal tendex lines, their tendicity, and tendexes), and also visualizations of a black-hole horizon's (scalar) vorticity and tendicity. We use these tools to elucidate the nonlinear dynamics of curved spacetime in merging black-hole binaries.Comment: 4 pages, 5 figure

Observability of Quantum State of Black Hole

We analyze terms subleading to Rutherford in the $S$-matrix between black hole and probes of successively high energies. We show that by an appropriate choice of the probe one can read off the quantum state of the black hole from the S-matrix, staying asymptotically far from the BH all the time. We interpret the scattering experiment as scattering off classical stringy backgrounds which explicitly depend on the internal quantum numbers of the black hole.Comment: 19 pages, latex, no figure

Visualizing Spacetime Curvature via Frame-Drag Vortexes and Tidal Tendexes I. General Theory and Weak-Gravity Applications

When one splits spacetime into space plus time, the Weyl curvature tensor (vacuum Riemann tensor) gets split into two spatial, symmetric, and trace-free (STF) tensors: (i) the Weyl tensor's so-called "electric" part or tidal field, and (ii) the Weyl tensor's so-called "magnetic" part or frame-drag field. Being STF, the tidal field and frame-drag field each have three orthogonal eigenvector fields which can be depicted by their integral curves. We call the integral curves of the tidal field's eigenvectors tendex lines, we call each tendex line's eigenvalue its tendicity, and we give the name tendex to a collection of tendex lines with large tendicity. The analogous quantities for the frame-drag field are vortex lines, their vorticities, and vortexes. We build up physical intuition into these concepts by applying them to a variety of weak-gravity phenomena: a spinning, gravitating point particle, two such particles side by side, a plane gravitational wave, a point particle with a dynamical current-quadrupole moment or dynamical mass-quadrupole moment, and a slow-motion binary system made of nonspinning point particles. [Abstract is abbreviated; full abstract also mentions additional results.]Comment: 25 pages, 20 figures, matches the published versio

Formation of Black Holes from Collapsed Cosmic String Loops

The fraction of cosmic string loops which collapse to form black holes is estimated using a set of realistic loops generated by loop fragmentation. The smallest radius sphere into which each cosmic string loop may fit is obtained by monitoring the loop through one period of oscillation. For a loop with invariant length $L$ which contracts to within a sphere of radius $R$, the minimum mass-per-unit length $\mu_{\rm min}$ necessary for the cosmic string loop to form a black hole according to the hoop conjecture is $\mu_{\rm min} = R /(2 G L)$. Analyzing $25,576$ loops, we obtain the empirical estimate $f_{\rm BH} = 10^{4.9\pm 0.2} (G\mu)^{4.1 \pm 0.1}$ for the fraction of cosmic string loops which collapse to form black holes as a function of the mass-per-unit length $\mu$ in the range $10^{-3} \lesssim G\mu \lesssim 3 \times 10^{-2}$. We use this power law to extrapolate to $G\mu \sim 10^{-6}$, obtaining the fraction $f_{\rm BH}$ of physically interesting cosmic string loops which collapse to form black holes within one oscillation period of formation. Comparing this fraction with the observational bounds on a population of evaporating black holes, we obtain the limit $G\mu \le 3.1 (\pm 0.7) \times 10^{-6}$ on the cosmic string mass-per-unit-length. This limit is consistent with all other observational bounds.Comment: uuencoded, compressed postscript; 20 pages including 7 figure