The Von Damm Vent Field (VDVF) is located on the flanks of the Mid-Cayman Spreading Centre, 13 km west of the axial rift, within a gabbro and peridotite basement. Unlike any other active vent field, hydrothermal precipitates at the VDVF comprise 85-90% by volume of the magnesium silicate mineral, talc. Hydrothermal fluids vent from a 3-m high, 1-m diameter chimney and other orifices at up to 21...

The permeability of the upper mantle controls melt segregation beneath spreading centers. Reconciling contradictory geochemical and geophysical observations at ocean ridges requires a better understanding of transport properties in partially molten rocks. Using x-ray synchrotron microtomography, we obtained three-dimensional data on melt distribution for mantle peridotite with various melt frac...

ONE petrological approach to upper mant le studies is to determine which ultramafic rocks represent mantle material. Ultramafic rocks occur in a variety of field and petrographic associations : in recent reviews, Wyllie [1967b, 1968] outlined eleven petrographic associations, some with subdivisions. In this summary, it is convenient to consider these in four larger groups: (1) layered, stratifo...

The iron isotopic compositions of 93 well-characterized basalts from geochemically and geologically diverse mid-ocean ridge segments, oceanic islands and back arc basins were measured. Forty-three MORBs have homogeneous Fe isotopic composition, with dFe ranging from +0.07& to +0.14& and an average of +0.105 ± 0.006& (2SD/ p n, n = 43, MSWD = 1.9). Three back arc basin basalts have similar dFe t...

Abstract IODP Expedition 357 drilled 17 shallow sites scattered over ~ 10 km in the west to east spreading direction across Atlantis Massif oceanic core complex (OCC, MAR, 30 ºN). Mantle exposed footwall of Atlantic OCC is nearly wholly serpentinized (80–100%) harzburgite and subordinate dunite. A recent whole-rock chemistry study by Whattam et al. (Chemical Geology 594. 10.1016/j.chemgeo.2021....