Segregation of Magma from a Mostly Crystalline Mush

Research Article| August 01, 1974 Segregation of Magma from a Mostly Crystalline Mush NORMAN H. SLEEP NORMAN H. SLEEP 1Department of Earth and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 Search for other works by this author on: GSW Google Scholar GSA Bulletin (1974) 85 (8): 1225–1232. https://doi.org/10.1130/0016-7606(1974)85<1225:SOMFAM>2.0.CO;2 Article history first online: 01 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation NORMAN H. SLEEP; Segregation of Magma from a Mostly Crystalline Mush. GSA Bulletin 1974;; 85 (8): 1225–1232. doi: https://doi.org/10.1130/0016-7606(1974)85<1225:SOMFAM>2.0.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGSA Bulletin Search Advanced Search Abstract A model based on the fluid dynamics of intermixed fluids indicated that favorable conditions for segregation of melt from a mostly crystalline mush upwelling from the asthenosphere included a high concentration of melt, a narrow conduit containing the mush, a large grain size, and a large ratio of the viscosity of grains to the viscosity of melt. The greater depth, inferred geochemically, of the source regions of seamount lavas, compared with mid-oceanic ridge lavas, is attributable to the dependence of segregation on conduit width. For thermal reasons, conduit width is smaller at greater depths for small sources of material such as seamounts. Observed systematic enrichment of seamount and island-arc lavas in radiogenic isotopics (which, for chemical reasons, would be most abundant in domains containing high fractions of water) relative to mid-oceanic ridge lavas may be due to disproportionate representation of ubiquitous, small-scale, water-rich domains in the source region of seamount lavas. The fraction of melt is strongly dependent on water content in the deep source regions of seamount lavas but only weakly dependent in the shallow source regions of mid-oceanic ridge lavas. This also complicates identification of subducted sediments in island-arc lavas. The viscosity of partial melt in the asthenosphere, inferred from seismic attenuation studies, is too high for that melt to segregate efficiently. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.