469 datasets found

Trace element analyses (first-series transition elements, Ti, Rb, Sr, Zr, Y, Nb, and REE) were carried out on whole rocks and minerals from 10 peridotite samples from both...

Serpentinite seamounts in the Mariana forearc have been explained as diapirs rising from the Benioff zone. This hypothesis predicts that the serpentinites should have low...

The <63-µm fractions of serpentinite muds from two seamounts on the Mariana and Izu-Bonin forearcs were analyzed for mineral composition by X-ray diffraction and for chemical...

Geophysical surveys of the Mariana forearc, in an area equidistant from the Mariana Trench and the active Mariana Island Arc, revealed a 40-m-deep graben about 13 km northwest...

Many ash-rich layers, varying from a few millimeters to several centimeters thick, were identified in the sedimentary sequences penetrated during Ocean Drilling Program Leg 125...

Twenty-six samples representing the wide range of lithologies (low- and intermediate-Ca boninites and bronzite andesites, high-Ca boninites, basaltic andesites-rhyolites)...

Clasts of metamorphosed mafic igneous rock of diverse composition were recovered in two drill sites on a serpentine mud volcano in the outer Mariana forearc during Ocean...

During Leg 125, two serpentinite seamounts were drilled in the Mariana and Izu-Ogasawara forearcs. Together with abundant serpentinized peridotites, low-grade metamorphic rocks...

Thirty-five samples from Hole 778A were prepared for X-ray diffraction (XRD) mineralogical analyses and for chemical analyses of major and trace elements. Most of the selected...

Eocene-Oligocene volcanic rocks drilled at Site 786 in the Izu-Bonin forearc cover a wide range of compositions from primitive boninites to highly evolved rhyolites. K-Ar dating...

The 720 m of igneous basement that was penetrated at Site 786 of Ocean Drilling Program Leg 125 consists of boninite-series volcanics. Bronzite andesites dominate the lithology...

The Mariana arc-trench system, the easternmost of a series of backarc basins and intervening remnant arcs that form the eastern edge of the Philippine Sea Plate, is a well-known...

Abundant serpentinite seamounts are found along the outer high of the Mariana forearc at the top of the inner slope of the trench. One of them, Conical Seamount, was drilled at...

A morphologically complex igneous basement was penetrated at Leg 125 Site 786 beneath approximately 100 m of Eocene-Pleistocene sediments at 31°52.45 'N, 141°13.59'E in a 3082-m...

Eleven glasses recovered from Holes 786A and 786B were fresh enough for volatile analysis by infrared spectroscopy. The compositions of these glasses range from boninitic to...

The benthic foraminifer fauna at Sumisu Rift Sites 790 and 791 indicates that a deep open-ocean (>2300 m) or a basin with open-ocean access existed between 1.1 and 0.7 Ma at...

Radiolarians were recovered from three of the five holes investigated during Leg 125. Relative abundances are estimated at Holes 782A and 784A, where preservation is poor to...

Drilling at Site 786, located in the center of the Izu-Bonin forearc basin, penetrated an apparently continuous section of middle Eocene/lower Oligocene volcaniclastic breccias...

During Ocean Drilling Program Leg 125, a thick sequence of middle Eocene to Pleistocene pelagic sediments, volcanogenic sediments, and predominantly extrusive volcanic rocks was...

During Leg 125 of the Ocean Drilling Program, nine sites were drilled in the Mariana and Izu-Bonin areas. The sediments recovered range in age from early Pliocene to late...