Atmospheric carbon dioxide (CO2) data for the last 420 million years (My) show long-term fluctuations related to supercontinent cycles as well as shorter cycles at 26 to 32 My whose origin is unknown. Periodicities of 26 to 30 My occur in diverse geological phenomena including mass extinctions, flood basalt volcanism, ocean anoxic events, deposition of massive evaporites, sequence boundaries, a...

[1] We utilize seismic converted phases on more than 700 receiver functions calculated for 42 stations in the South Island, New Zealand, to infer crustal and uppermost mantle structure. We determine the crustal thickness from direct observations of conversion from the Moho interface and infer zone of the maximum thickness being located along the axis of the Southern Alps, just east from the Alp...

We study the 3-D strain evolution of the northern Aegean and the vertical coherency of deformation. We observe that finite strain orientations in the mantle inferred from published shear-wave (SKS) fast polarization orientations, midto upper-crustal stretching lineations in metamorphic core complexes of mainly Miocene age, and the gradient in regional crustal thickness variations, are subparall...

The shortand long-period body waves of five moderate (M L 5 to 6) earthquakes that took place in the nearshore region of southcentral California between 1969 and 1981 are modeled to obtain the source parameters. Both regional Pnl waveforms and teleseismic P waveforms are used in this analysis. Four of the events are thrust earthquakes with strikes that rotate southwestward as the epicenters mov...

In this study, we analyze regional seismograms to obtain the crustal structure in the eastern Great Basin and western Colorado plateau. Adopting a forward-modeling approach, we develop a genetic algorithm (GA) based parameter search technique to constrain the one-dimensional crustal structure in these regions. The data are broadband three-component seismograms recorded at the 1994-95 IRIS PASSC...

Scattering of teleseismic body waves is conventionally used to investigate crustal and mantle structure using the so-called “receiver function” technique. This approach makes use of the fact that teleseismic events have nearvertical incidence upon horizontally layered structure, ensuring minimum phase, and assumes that source-time functions can be approximated by energy on the P component of mo...

Intermediate-period Rayleigh and Love waves propagating across Tibet require marked radial anisotropy within the mid-lower crust, consistent with a thinning of it. The anisotropy is largest in the western part of the plateau where the moment tensors of earthquakes indicate active crustal thinning. A preferred orientation of mica crystals resulting from the crustal thinning can account for the o...

[1] Magnetic fields measured by the satellite Lunar Prospector show large scale features resulting from remanently magnetized crust. Vector data synthesized at satellite altitude from a spherical harmonic model of the lunar crustal field, and the radial component of the magnetometer data, have been used to produce spatially continuous global magnetization models for the lunar crust. The magneti...

This paper reviews the literature on dyking as a mechanism of felsic magma extraction from a source and transport to shallower crustal levels, and review the recent literature suggesting a range of alternative mechanisms of magma migration in hot crustal zones which produce mesoscale pervasive granite sheet intrusions. Recent papers have strongly favoured dyking as the main mechanism controllin...

16 17 This study characterizes the spatial and temporal patterns of aerosol and precipitation 18 composition at six sites across the United States Southwest between 1995 and 2010. Precipitation 19 accumulation occurs mostly during the wintertime (December February) and during the 20 monsoon season (July September). Rain and snow pH levels are usually between 5 – 6, with 21 crustal-derived speci...