TY - JOUR
T1 - Neoproterozoic continental arc volcanism at the northern edge of the Arabian Plate, SE Turkey
AU - Gürsu, Semih
AU - Möller, Andreas
AU - Göncüoglu, M. Cemal
AU - Köksal, Serhat
AU - Demircan, Huriye
AU - Köksal, Fatma Toksoy
AU - Kozlu, Hüseyin
AU - Sunal, Gürsel
N1 - Publisher Copyright:
© 2015 Elsevier B.V.
PY - 2015/3/1
Y1 - 2015/3/1
N2 - New geochemical, Sr/Nd isotope and zircon U-Pb LA-ICP-MS data from the Derik Volcanics in the Southeast Anatolian Autochthone Belt of Turkey are consistent with an Andean-type Cadomian arc that developed along the northern edge of the Arabian Plate during the Late Neoproterozoic. The Derik Volcanics represent a volcanic complex including andesites, rhyolites and basalts, with volcanoclastic and fluvial sediments. They are unconformably overlain by playa sediments with Early Cambrian ichno-fossils, followed by Middle Cambrian-Silurian shallow marine deposits.Geochemically, the Derik Volcanics (DV) display transitional-calcalkaline affinities. On Th/Nb-Ti/Zr diagram, DV display negative trends from rhyolites to late to early-stage andesites and mafic dykes, respectively. The REE patterns are highly to moderately fractionated, with [(La/Yb)N=5.20-6.77 in late-stage andesites, 4.38-10.51 in rhyolites, 2.58-4.65 in the early-stage andesites, and 2.51-4.21 in mafic dykes]. Normalized trace element and REE diagrams display Th, La, Ce, Sm enrichment and depletion of Nb, Ti and Eu as is typical for Andean-type active continental margin igneous rocks. The enrichment of LILE and LREE, combined with depletion of HREE also suggests that the Derik Volcanic rocks were formed in relation with a subduction zone. Negative Eu anomalies (Eu/Eu)N, range from 0.50 to 1.81, indicates fractional crystallization of feldspar. The DV have positive e{open}Nd (+0.15 to +4.20) and mean model ages of 1.28Ga for the early-stage andesites, 1.34Ga for rhyolites, 1.35 for late-stage andesites, and 1.36Ga for mafic dykes. The positive e{open}Nd(T) data show that DV are product of mantle-derived magmas. Lower 143Nd/144Nd isotope ratios than the depleted MORB mantle (DMM) source indicate that the DV may have been contaminated by crustal material during magma genesis. Geochemical modeling shows that all four volcanic rock types may have been formed by different percentages of batch melting of DMM and subducting slab sources.Zircon LA-ICP-MS data give crystallization ages of 581.4. ±. 3.5. Ma (. n=. 7) and 559.2. ±. 3.2. Ma (. n=. 3) for the early and late-stage andesitic rocks, as well as ages of 569.6. ±. 1.6. Ma (. n=. 17), 571.6. ±. 1.9. Ma (. n=. 18), 575.4. ±. 4.3. Ma (. n=. 6) for the rhyolites.The geological and geochemical features together with the new age data suggest that the Derik Volcanics formed along a continental arc in the course of the southward subduction of Prototethys oceanic lithosphere along the northern margin of the Arabian Plate, which is attributed to a late-stage phase of the Cadomian Orogeny of the Pan-African cycle.
AB - New geochemical, Sr/Nd isotope and zircon U-Pb LA-ICP-MS data from the Derik Volcanics in the Southeast Anatolian Autochthone Belt of Turkey are consistent with an Andean-type Cadomian arc that developed along the northern edge of the Arabian Plate during the Late Neoproterozoic. The Derik Volcanics represent a volcanic complex including andesites, rhyolites and basalts, with volcanoclastic and fluvial sediments. They are unconformably overlain by playa sediments with Early Cambrian ichno-fossils, followed by Middle Cambrian-Silurian shallow marine deposits.Geochemically, the Derik Volcanics (DV) display transitional-calcalkaline affinities. On Th/Nb-Ti/Zr diagram, DV display negative trends from rhyolites to late to early-stage andesites and mafic dykes, respectively. The REE patterns are highly to moderately fractionated, with [(La/Yb)N=5.20-6.77 in late-stage andesites, 4.38-10.51 in rhyolites, 2.58-4.65 in the early-stage andesites, and 2.51-4.21 in mafic dykes]. Normalized trace element and REE diagrams display Th, La, Ce, Sm enrichment and depletion of Nb, Ti and Eu as is typical for Andean-type active continental margin igneous rocks. The enrichment of LILE and LREE, combined with depletion of HREE also suggests that the Derik Volcanic rocks were formed in relation with a subduction zone. Negative Eu anomalies (Eu/Eu)N, range from 0.50 to 1.81, indicates fractional crystallization of feldspar. The DV have positive e{open}Nd (+0.15 to +4.20) and mean model ages of 1.28Ga for the early-stage andesites, 1.34Ga for rhyolites, 1.35 for late-stage andesites, and 1.36Ga for mafic dykes. The positive e{open}Nd(T) data show that DV are product of mantle-derived magmas. Lower 143Nd/144Nd isotope ratios than the depleted MORB mantle (DMM) source indicate that the DV may have been contaminated by crustal material during magma genesis. Geochemical modeling shows that all four volcanic rock types may have been formed by different percentages of batch melting of DMM and subducting slab sources.Zircon LA-ICP-MS data give crystallization ages of 581.4. ±. 3.5. Ma (. n=. 7) and 559.2. ±. 3.2. Ma (. n=. 3) for the early and late-stage andesitic rocks, as well as ages of 569.6. ±. 1.6. Ma (. n=. 17), 571.6. ±. 1.9. Ma (. n=. 18), 575.4. ±. 4.3. Ma (. n=. 6) for the rhyolites.The geological and geochemical features together with the new age data suggest that the Derik Volcanics formed along a continental arc in the course of the southward subduction of Prototethys oceanic lithosphere along the northern margin of the Arabian Plate, which is attributed to a late-stage phase of the Cadomian Orogeny of the Pan-African cycle.
KW - Arabian Plate
KW - Cadomian Orogeny
KW - Derik Volcanics
KW - Late Neoproterozoic
KW - Magmatic arc
KW - SE Turkey
UR - http://www.scopus.com/inward/record.url?scp=84921301203&partnerID=8YFLogxK
U2 - 10.1016/j.precamres.2014.12.017
DO - 10.1016/j.precamres.2014.12.017
M3 - Article
AN - SCOPUS:84921301203
SN - 0301-9268
VL - 258
SP - 208
EP - 233
JO - Precambrian Research
JF - Precambrian Research
ER -