Recommended Citation Burney, David. "Modeling the magmatic plumbing system beneath an off-rift volcanic deposit on Iceland, using textural analyses and geothermobarometry." MS ii To Laura and Hazel. Without you this never would have happened. iii ABSTRACT The emplacement of tholeiitic magmas along two NE-SW trending rift zones is the dominant mechanism of crustal accretion on Iceland. Small vol...

Microbial communities of methanogenic, sulfate-reducing and methanotrophic prokaryotes from deepsea environments were investigated by molecular phylogenetic analysis of the deduced amino acid sequences of the genes encoding for the methyl coenzyme M reductase (mcrA), dissimilatory sulfite reductase (dsrAB) and particulate methane monoxygenase (pmoA), respectively. Clone libraries of PCR amplifi...

S U M M A R Y We argue that subduction may be initiated at passive continental margins without shortening the lithosphere. Overcoming the lithosphere’s high compressive strength requires special circumstances, and these make it difficult to explain the nearly complete recycling of old sea-floor. Instead, we present a model that predicts tensile decoupling of the continental and oceanic lithosph...

[1] We analyze geophysical data that extend from 0 to 25-Myr-old seafloor on both flanks of the Southwest Indian Ridge (SWIR). Lineated marine magnetic anomalies are consistent and identifiable within the study area, even over seafloor lacking a basaltic upper crust. The full spreading rate of 14 km/Myr has remained nearly constant since at least 20 Ma, but crustal accretion has been highly asy...

One of the remarkable tectonic features of the Earth’s crust is the widespread presence of long, approximately straight and geomorphically prominent strike-slip faults which are a kinematic consequence of large-scale motion of plates on a sphere (Wilson 1965). Strike-slip faults form in continental and oceanic transform plate boundaries; in intraplate settings as a continental interior response...

Subduction initiation is a critical link in the plate tectonic cycle. Intraoceanic subduction zones can form along transform faults and fracture zones, but how subduction nucleates parallel to mid-ocean ridges, as in e.g., the Neotethys Ocean during the Jurassic, remains a matter of debate. In recent years, extensional detachment faults have been widely documented adjacent to slow-spreading and...

Leg 209 was devoted to drilling mantle peridotites and associated gabbroic rocks along the Mid-Atlantic Ridge from 14° to 16°N. This area was identified at the 1996 Workshop on Oceanic Lithosphere and Scientific Drilling into the 21st Century (OL Workshop) as the ideal region for drilling of a strike line of short holes to sample the upper mantle in a magma-starved portion of a slow-spreading r...

Reef habitats of the tropical Atlantic are separated by river outflows and oceanic expanses that may preclude larval dispersal or other population connections in shorefishes. To examine the impact of these habitat discontinuities on the intraspecific phylogeography of reef-associated species we conducted range-wide surveys of two amphi-Atlantic reef fishes that have dispersive pelagic larval st...