Subduction and recycling of nitrogen along the central American margin

Citation:
Fischer, TP, Hilton DR, Zimmer MM, Shaw AM, Sharp ZD, Walker JA.  2002.  Subduction and recycling of nitrogen along the central American margin. Science. 297:1154-1157.

Date Published:

Aug

Keywords:

arc lavas, carbon, convergent margin, costa-rica, helium, isotopic composition, mantle, organic-matter, sediment input, volatiles

Abstract:

We report N and He isotopic and relative abundance characteristics of volatiles emitted from two segments of the Central American volcanic arc. In Guatemala, delta(15)N values are positive (i.e., greater than air) and N-2/He ratios are high (up to 25,000). In contrast, Costa Rican N-2/He ratios are low ( maximum 1483) and delta(15)N values are negative ( minimum -3.0 per mil). The results identify shallow hemipelagic sediments, subducted into the Guatemalan mantle, as the transport medium for the heavy N. Mass balance arguments indicate that the subducted N is efficiently cycled to the atmosphere by arc volcanism. Therefore, the subduction zone acts as a barrier to input of sedimentary N to the deeper mantle.

Notes:

n/a

Website

DOI:

10.1126/science.1073995