Marine Boulanger

University of Clermont Auvergne | Univ BPC · Laboratoire Magmas et Volcans

The structure of the lithosphere and the associated magmatic systems found in different locations along slow‐spreading ridges can vary dramatically, from melt‐starved to magmatically robust segments. A growing number of studies suggest that the evolution of the magmatic crust being governed solely by fractional crystallization is too simplistic. Re...

Volcanism is the surface expression of extensive magmatic systems, with their intrusive counterpart representing ~80% of the total magma budget. Our knowledge of igneous processes therefore largely relies on our understanding of deep plutonic processes. In continental or oceanic environments, most of the intrusive igneous rocks bear geochemical cum...

Several ODP-IODP expeditions drilled oceanic core complexes interpreted as exhumed portions of lower crust close to the ridge axis, and provide the community with invaluable sampling opportunity for further constraining magmatic processes involved in the formation of the slow-spreading lower oceanic crust. ODP Hole 735B presents the most primitive...

Owing to the lack of persistent magma chamber and the complex interplay between magmatism and tectonism at slow- to ultraslow-spreading ridges, the likeliness of fractional crystallization being the predominant process of evolution of crustal magmas is weak. Here, we report a detailed petro-geochemical investigation from the lower crustal gabbroic...

Reactive porous or focused melt flows are common in crystal mushes of mid-ocean ridge magma reservoirs. Although they exert significant control on mid-ocean ridge magmatic differentiation, their role in metal transport between the mantle and the ocean floor remains poorly constrained. Here we aim to improve such knowledge for oceanic crust formed a...

Volcanism is the surface expression of extensive magmatic systems, with their intrusive counterpart representing~80% of the total magma budget. Our knowledge of igneous processes therefore largely relies on our understanding of deep plutonic processes. In continental or oceanic environments, most of the intrusive igneous rocks bear geochemical cumu...

Magma migration and differentiation processes are key to understanding the development and evolution of oceanic magma reservoirs. To provide new quantitative geochemical constraints on these processes, we applied a high‐resolution approach to study an interlayered section of the lower oceanic crust sampled at Atlantis Bank, on the (ultra)slow‐sprea...

Beneath slow‐spreading ridges, melt bodies are generally considered to represent ephemeral magma reservoirs filled with crystal mushes. Formation of the oceanic crust requires at least partial extraction of melts from these crystal mushes. However, melts collection and extraction are processes yet to be fully constrained. We investigate olivine gab...

Excel spreadsheet for prediction of rare earth element partitioning between clinopyroxene and alkaline melts

Trace element partitioning between minerals and liquids provides crucial constraints on igneous processes. We quantified trace element concentrations in clinopyroxene (Cpx) phenocrysts and their phonolite melt inclusions from the 2007–08 eruption of Oldoinyo Lengai (Tanzania), and report Cpx-melt partition coefficients (D) and corresponding partiti...

Magmatic processes that govern crustal accretion at mid-ocean ridges still need to be better constrained. Among the processes potentially involved in the evolution of the lower crust magma reservoirs, reactions associated with reactive porous flow through crystal mushes tend to be considered as one of the predominant processes together with simple...

Oceanic crust accreted at mid-ocean ridges represents ~70% of Earth's surface; nevertheless magmatic processes implicated in the formation of the lower crust remain poorly understood. Fossilized sections document its complexity in structure and composition, and recent studies show that melt migration and interactions within a crystallizing mush are...

Layered portions of gabbros were described at slow-spreading environments in at least two different Oceanic Core Complexes (OCC), which are interpreted as exhumed portions of lower crust at the ridge axis. Two ODP-IODP Holes drilled into the Atlantis Bank OCC (SW Indian Ridge) present locally such features, which provide essential insights on melts...

Magma evolution in the lower oceanic crust affects the metal contents in the derivative magmas and the formation of seafloor massive sulfides. At spreading segments with low magma supply, sulfide differentiate primarily by melt-mantle reaction, with subordinate role of fractional crystallization 1,2. At spreading segments with high magma supply, di...