TY - JOUR
T1 - Ultrafast source-to-surface movement of melt at island arcs from 226Ra-230Th systematics
AU - Turner, Simon
AU - Evans, Peter
AU - Hawkesworth, Chris
PY - 2001/5/18
Y1 - 2001/5/18
N2 - Island arc lavas have radium-226 excesses that extend to higher values than those observed in mid-ocean ridge or ocean island basalts. The initial ratio of radium-226 to thorium-230 is largest in the most primitive lavas, which also have the highest barium/thorium ratios, and decreases with increasing magmatic differentiation, Therefore, the radium-226 excesses appear to have been introduced into the base of the mantle melting column by fluids released from the subducting plate, Preservation of this signal requires transport to the surface arguably in only a few hundreds of years and directly constrains the average melt velocity to the order of 1000 meters per year. Thus, melt segregation and channel formation can occur rapidly in the mantle.
AB - Island arc lavas have radium-226 excesses that extend to higher values than those observed in mid-ocean ridge or ocean island basalts. The initial ratio of radium-226 to thorium-230 is largest in the most primitive lavas, which also have the highest barium/thorium ratios, and decreases with increasing magmatic differentiation, Therefore, the radium-226 excesses appear to have been introduced into the base of the mantle melting column by fluids released from the subducting plate, Preservation of this signal requires transport to the surface arguably in only a few hundreds of years and directly constrains the average melt velocity to the order of 1000 meters per year. Thus, melt segregation and channel formation can occur rapidly in the mantle.
UR - http://www.scopus.com/inward/record.url?scp=0035907068&partnerID=8YFLogxK
U2 - 10.1126/science.1059904
DO - 10.1126/science.1059904
M3 - Article
C2 - 11359009
AN - SCOPUS:0035907068
VL - 292
SP - 1363
EP - 1366
JO - Science (New York, N.Y.)
JF - Science (New York, N.Y.)
SN - 0036-8075
IS - 5520
ER -