New seafloor mapping and sampling demonstrates that the eruption of the high-Ca boninites is clearly associated with rifting of the northern Tonga ridge and the northern Lau Basin at the northern termination of the Tonga Trench. There is very strong evidence for OIB plume related mantle sources involved in the...
Basaltic volcanism provides a window into the Earth’s mantle. Seeing through this window requires seeing through the processes of magma genesis and evolution that distort the view. Radiogenic isotope ratios, and to a lesser extent incompatible elements and stable isotope ratios, allow us to see through these distortions and infer...
We report on geochemical data from anoxic sequences of the Nicobar Fan, recovered during International Ocean Discovery Program (IODP) expedition 362 to the Sumatra subduction zone. Analyses include strontium and carbon isotope composition of pore fluids, elemental and isotopic composition of carbonate concretions, and whole sediment analyses.
Studies of Hawaiian volcanoes contribute valuable insights about Earth processes and mantle evolution, and are fundamental for understanding the construction of the largest volcanoes on terrestrial planets. The pre-shield stage exists in every Hawaiian volcano, but is usually blanketed by high volume tholeiitic lava flows during the main shield stage....
Many disciplines of geochemistry have no data reporting standards, and their use of metadata is inadequately developed. This presents problems to the quality of the published science, and it limits the utility of computers in data analysis and the exploitation of Information Technology (IT). We discuss problems of data and...
Gravity and magnetic data from cruises by the R/V Yaquina in 1973
and the R/V Wecoma in 1975 provide new data that make possible the construction of a map of the free-air gravity anomalies at sea and simple
Bouguer anomalies on lano in Panama, western Colombia, and the eastern
Panama...
Two thermal convection problems of geophysical interest are
examined, theoretically. First, convection in the earth's mantle is
treated on the basis of a one-dimensional 'strip model'. This model
results from further simplification of the well known 'Rayleigh model'.
For homogeneous, Newtonian fluids, the strip model yields results
similar to those...
The Easter Seamount Chain and Nazca Ridge are two of the most conspicuous volcanic features on the Nazca plate. Many questions about their nature and origin have remained unresolved because of a lack of geochronological and geochemical data for large portions of both chains. New ⁴⁰Ar⁻³⁹Ar incremental heating age determinations...
Using temperature gradients measured in 10 holes at 6 sites, we generate the first high fidelity heat flow measurements from Integrated Ocean Drilling Program drill holes across the northern and central Lesser Antilles arc and back arc Grenada basin. The implied heat flow, after correcting for bathymetry and sedimentation effects,...
The Yanacocha mining district is located in the Andes of northern Peru in an area of
relatively thick continental crust (~35 km) and long-lived Cenozoic subduction-related
volcanism. Volcanic activity in the district began at ~20 Ma, and gold deposits (total
resource of ~1500 tonnes of gold) are spatially and temporally...
