Spatially and Geochemically Anomalous Arc Magmatism: Insights From the Andean Arc

Geochemically diverse Gondwana magmatism, Falkland Islands

The Pacific: from “Arc of Instability” to “Arc of Responsibility” and then to “Arc of Opportunity”?

This special volume of Security Challenges contains contributions from leading experts and Pacific scholars that reflect on progress and prospects in the “Pacific arc”. This Introduction begins by identifying common themes that emerge from the contributions regarding the way in which Australia relates to the arc, and how the arc responds to Australia. It then summarises the contributors’ conclu...

Trace elements in clinopyroxenes from Aleutian xenoliths: Implications for primitive subduction magmatism in an island arc

Trace element abundances in clinopyroxene (cpx) from cumulate xenoliths are used to characterize the nature of primitive magma-forming processes beneath the Aleutian island arc. Clinopyroxenes from deformed mafic and ultramafic xenoliths hosted in a Neogene-age mafic sill from Kanaga Island have widely varying trace element abundances (Sr=8–32, Y=2–64, Zr=2–38, Nd=0.65–16 ppm) that are generall...

PETROGENESIS AND ORIGIN OF THE CHENAR GRANITOID STOCK, NW OF KERMAN, IRAN: EVIDENCE OF NEOTETHYS SUBDUCTION RELATED ARC MAGMATISM

The lower to middle Miocene Chenar granitoid stock, a part of Central Iranian volcanic belt, is intruded into Eocene volcano-sedimentary complex in northwestern Kerman in south Central Iran. The Chenar granitoid stock consists mainly of coarse to medium grain granodiorite and monzogranite with subordinate tonalite and syenogranite. Alkali granites as aplitic veins and quartz dioritic dykes freq...

Arc-Disjoint Cycles and Feedback Arc Sets

Isaak posed the following problem. Suppose T is a tournament having a minimum feedback arc set which induces an acyclic digraph with a hamiltonian path. Is it true that the maximum number of arc-disjoint cycles in T equals the cardinality of minimum feedback arc set of T? We prove that the answer to the problem is in the negative. Further, we study the number of arc-disjoint cycles through a ve...