NE-SW trending fault system seems to be one of the most important structural elements in the geology of the eastern Pontide region. Some of these faults are also well-associated with some recent hot springs, i.e. the Ayder, Andon and Ilıca hot springs, and some young volcanics and volcano-clastics accompanied with the fracture in-filling obsidian flows in the Cagirankaya yayla of the Ikizdere-Rize district of the eastern Pontide region. The Cagirankaya obsidian crops out in six discrete bodies, with an observable thickness of somewhat between 50 and 100 m, determining the ENE-WSW and NW-SE lienaments in the field which are inferred to be faults that concealed by the volcanic eruptions. Petrographic and wholerock geochemical studies reveal a very homogenous character for these rocks which may have been produced during a very short eruption time span of a highly evolved silicic melt. The plateau fission-track ages, ranging from 1.73 + 0.15 to 1.93 + 0.15 Ma represent a very short time interval, Uppermost Pliocene-Pleistocene, and corroborate the interpretation given for such a homogeneity of petrographic and geochemical features. Thus, the determination of an Uppermost Pliocene – Pleistocene plateau fission-track age for the Cagirankaya obsidian represents that some of these NE-SW trending faults have been used as channels by volcanic activity to reach to earth surface in Plio-Quaternary, at least those of the Cagirankaya (Ikizdere-Rize) district in the eastern Pontide region of Turkey.
Kırık Dolgusu Şeklinde Yüzeylenen Çağırankaya Obsidiyeninin (Rize-İkizdere) Fission-Track Radyometrik Yaş Tayini: KD-GB Doğrultulu Faylar Boyunca Meydana Gelen Pliyo-Kuvaterner Yaşlı Püskürme
ODDONE, MASSIMO;
2005-01-01
Abstract
NE-SW trending fault system seems to be one of the most important structural elements in the geology of the eastern Pontide region. Some of these faults are also well-associated with some recent hot springs, i.e. the Ayder, Andon and Ilıca hot springs, and some young volcanics and volcano-clastics accompanied with the fracture in-filling obsidian flows in the Cagirankaya yayla of the Ikizdere-Rize district of the eastern Pontide region. The Cagirankaya obsidian crops out in six discrete bodies, with an observable thickness of somewhat between 50 and 100 m, determining the ENE-WSW and NW-SE lienaments in the field which are inferred to be faults that concealed by the volcanic eruptions. Petrographic and wholerock geochemical studies reveal a very homogenous character for these rocks which may have been produced during a very short eruption time span of a highly evolved silicic melt. The plateau fission-track ages, ranging from 1.73 + 0.15 to 1.93 + 0.15 Ma represent a very short time interval, Uppermost Pliocene-Pleistocene, and corroborate the interpretation given for such a homogeneity of petrographic and geochemical features. Thus, the determination of an Uppermost Pliocene – Pleistocene plateau fission-track age for the Cagirankaya obsidian represents that some of these NE-SW trending faults have been used as channels by volcanic activity to reach to earth surface in Plio-Quaternary, at least those of the Cagirankaya (Ikizdere-Rize) district in the eastern Pontide region of Turkey.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
