G. Pepiper et Cn. Kotopouli, PALEOZOIC VOLCANIC-ROCKS OF CHIOS, GREECE - RECORD OF A PALEOTETHYAN SUTURE, Neues Jahrbuch fur Mineralogie Monatshefte, (1), 1994, pp. 23-39
Hypabyssal intrusions and pyroclastics of basaltic andesite to rhyolit
ic composition cut and overlie a Carboniferous accretionary wedge mela
nge in northeast Chios. The igneous rocks are pre-Triassic; correspond
ing rocks in Lesbos are overlain by Permian sediments. They are older
than uppermost Permian rocks in Attika with which they have previously
been correlated. The igneous rocks of Chios correlate with the early
Permian granodiorites of the Kazdag-Uludag region of Anatolia, which f
orm part of the Karakaya Complex. The volcanic rocks consist of low-K
calc - alkaline basaltic andesites and dacites. Two types of basaltic
andesite are distinguished by Ti and Nb content. A primitive low-Ti, l
ow-Nb magma was derived from partial melting of downwelling hydrated l
ithospheric mantle and a more fractionated high-Ti, high-Nb magma was
derived from an asthenospheric OIB source. The co-existence of such ma
gmas in a subduction zone suggests significant back-arc extension. The
Chios igneous rocks record final subduction of a Paleotethyan oceanic
region.