Water-rock interactions within the seafloor are responsible for significant energy and solute fluxes between basaltic oceanic crust and the overlying ocean. Permeability is the primary hydrologic property controlling the form, intensity, and duration of seafloor fluid circulation, but after several decades of characterizing shallow oceanic basement, we are still learning how permeability is cre...

[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...

the mapping of the crust-mantle boundary surface is an important geophysical task, which the method of seismic profiling has dealt with profitably. there are, however, areas where the crustal structure is not known up to the present, and where the moho has as yet not been determined by geophysical sounding. in such areas the isostatic theory may be applied to give a first estimate of the depths...

Natural basaltic glasses recovered from Leg 37 of the Deep Sea Drilling Project have been dated by fission track methods. Close agreement in results indicates that the age of the oceanic crust drilled at Site 332 is 3.67 ±0.40 m.y. The age of the crust at Site 335 is less well defined, the average of the three dates obtained from this site being 14.45 ±2.27 m.y.

Electron – impurity scattering in the crust of neutron stars may be a relevant mechanism in delaying the cooling and in enhancing the decay of the pulsar’s magnetic field. Extending previous work, in the present note I investigate the physics of the interfaces between layers in the crust of an isolated neutron star. The calculations confirm the possible presence of high impurity concentrations ...

Introduction: The lower crust of the Moon remains a critical unknown for models of lunar compositional mass balance and for models of petrogenesis of lunar rock types. Key questions addressed here are (1) how mafic are the rocks of the lower crust and (2) are they ferroan or magnesian? Answers to these questions bear on the concentration and distribution of radiogenic heat-producing elements an...

Zircon age peaks at 2100–1650 and 1200–1000 Ma correlate with craton collisions in the growth of supercontinents Nuna and Rodinia, respectively, with a time interval between collisions mostly <50 Myr (range 0–250 Myr). Collisional orogens are two types: those with subduction durations <500 Myr and those ≥500 Myr. The latter group comprises orogens with long-lived accretionary stages between Nun...

It is generally accepted that continental subduction and crustal exhumation play an important role in the evolution of many orogenic belts. A variety of geological evidence suggests that continental crust is occasionally subducted to depths of tens to perhaps 150 km (e.g. Chopin, 1984; Dewey et al., 1993; Matte et al., 1997). Recently, a series of simulations (Chemenda, 1993; Chemenda et al., 1...

a r t i c l e i n f o Keywords: East Pacific Rise mid-ocean ridge oceanic crust off-axis magmatism waveform modeling Formation of oceanic crust along the East Pacific Rise is thought to be complete within a few kilometers of the rise axis. Here, however, we present evidence for magmatism 20 km from the spreading center in 300-ka-old crust. Seismic data reveal an intrusive complex ~ 2 km beneath...

Assuming that the period 2.75–2.65 Ga corresponds to a single, but global, geodynamic event, we investigate—through numerical experiments—the mechanisms that could have led to the profound continental reworking that occurred at that time. Although the extent of the crisis at the Earth’s surface pledges in favour of the involvement of mantle plumes, our numerical experiments suggest that the the...