Ar40-Ar39dating of biotite and sanidine in tuffaceous sediments and related intrusive rocks: Implications for the Early Miocene evolution of the Gördes and Selendi basins, W Turkey
- 1 August 2005
- journal article
- research article
- Published by Taylor & Francis in Geodinamica Acta
- Vol. 18 (3-4), 239-253
- https://doi.org/10.3166/ga.18.239-253
Abstract
The precise ages of the sedimentary successions within two prominent NE-SW-trending basins, the Gordes Basin and the Selendi Basin, are critical to an understanding of the Neogene evolutionary setting of western Turkey and associated calc-alkaline magmatism. Early radiometric dating was not always sufficiently precise to resolve alternative interpretations. During this study, high-precision Ar-40-Ar-39 radiometric ages were determined on single crystals of biotite and sanidine from silicic tuffs and associated intrusive rocks. Fine-grained tuffaccous sediments near the top of the sedimentary succession in the Selendi Basin gave ages of 18.89 +/- 0.58 Ma to 16.42 +/- 0.09 Ma. Coarser-grained tuffaceous sediments near the top of the equivalent sedimentary succession in the Gordes Basin to the NW yielded ages of 18.78 +/- 0.3 Ma to 17.04 +/- 0.35 Ma. Associated intrusive rocks were dated at 20.86 +/- 0.08 Ma to 17.62 +/- 0.07 Ma. An andesitic body on the northern margin of the Gediz (Alasehir) Graben further south gave ages of 16.08 +/- 10.91 to 14.65 +/- 0.06 Ma. Combined with published radiometric age data, these new results confirm an Early Miocene age for the clastic sedimentary fills of the Gordes and Selendi basins. The results from the Gediz Graben are consistent with its formation in Early Miocene time, earlier than the Late Miocene or Plio-Quaternary ages suggested in some interpretations. (c) 2005 Lavoisier SAS. All rights reserved. The precise ages of the sedimentary successions within two prominent NE-SW-trending basins, the Gordes Basin and the Selendi Basin, are critical to an understanding of the Neogene evolutionary setting of western Turkey and associated calc-alkaline magmatism. Early radiometric dating was not always sufficiently precise to resolve alternative interpretations. During this study, high-precision Ar-40-Ar-39 radiometric ages were determined on single crystals of biotite and sanidine from silicic tuffs and associated intrusive rocks. Fine-grained tuffaccous sediments near the top of the sedimentary succession in the Selendi Basin gave ages of 18.89 +/- 0.58 Ma to 16.42 +/- 0.09 Ma. Coarser-grained tuffaceous sediments near the top of the equivalent sedimentary succession in the Gordes Basin to the NW yielded ages of 18.78 +/- 0.3 Ma to 17.04 +/- 0.35 Ma. Associated intrusive rocks were dated at 20.86 +/- 0.08 Ma to 17.62 +/- 0.07 Ma. An andesitic body on the northern margin of the Gediz (Alasehir) Graben further south gave ages of 16.08 +/- 10.91 to 14.65 +/- 0.06 Ma. Combined with published radiometric age data, these new results confirm an Early Miocene age for the clastic sedimentary fills of the Gordes and Selendi basins. The results from the Gediz Graben are consistent with its formation in Early Miocene time, earlier than the Late Miocene or Plio-Quaternary ages suggested in some interpretations. (c) 2005 Lavoisier SAS. All rights reserved. The precise ages of the sedimentary successions within two prominent NE-SW-trending basins, the Gordes Basin and the Selendi Basin, are critical to an understanding of the Neogene evolutionary setting of western Turkey and associated calc-alkaline magmatism. Early radiometric dating was not always sufficiently precise to resolve alternative interpretations. During this study, high-precision Ar-40-Ar-39 radiometric ages were determined on single crystals of biotite and sanidine from silicic tuffs and associated intrusive rocks. Fine-grained tuffaccous sediments near the top of the sedimentary succession in the Selendi Basin gave ages of 18.89 +/- 0.58 Ma to 16.42 +/- 0.09 Ma. Coarser-grained tuffaceous sediments near the top of the equivalent sedimentary succession in the Gordes Basin to the NW yielded ages of 18.78 +/- 0.3 Ma to 17.04 +/- 0.35 Ma. Associated intrusive rocks were dated at 20.86 +/- 0.08 Ma to 17.62 +/- 0.07 Ma. An andesitic body on the northern margin of the Gediz (Alasehir) Graben further south gave ages of 16.08 +/- 10.91 to 14.65 +/- 0.06 Ma. Combined with published radiometric age data, these new results confirm an Early Miocene age for the clastic sedimentary fills of the Gordes and Selendi basins. The results from the Gediz Graben are consistent with its formation in Early Miocene time, earlier than the Late Miocene or Plio-Quaternary ages suggested in some interpretations. (c) 2005 Lavoisier SAS. All rights reserved. The precise ages of the sedimentary successions within two prominent NE-SW-trending basins, the Gordes Basin and the Selendi Basin, are critical to an understanding of the Neogene evolutionary setting of western Turkey and associated calc-alkaline magmatism. Early radiometric dating was not always sufficiently precise to resolve alternative interpretations. During this study, high-precision Ar-40-Ar-39 radiometric ages were determined on single crystals of biotite and sanidine from silicic tuffs and associated intrusive rocks. Fine-grained tuffaccous sediments near the top of the sedimentary succession in the Selendi Basin gave ages of 18.89 +/- 0.58 Ma to 16.42 +/- 0.09 Ma. Coarser-grained tuffaceous sediments near the top of the equivalent sedimentary succession in the Gordes Basin to the NW yielded ages of 18.78 +/- 0.3 Ma to 17.04 +/- 0.35 Ma. Associated intrusive rocks were dated at 20.86 +/- 0.08 Ma to 17.62 +/- 0.07 Ma. An andesitic body on the northern margin of the Gediz (Alasehir) Graben further south gave ages of 16.08 +/- 10.91 to 14.65 +/- 0.06 Ma. Combined with published radiometric age data, these new results confirm an Early Miocene age for the clastic sedimentary fills of the Gordes and Selendi basins. The results from the Gediz Graben are consistent with its formation in Early Miocene time, earlier than the Late Miocene or Plio-Quaternary ages suggested in some interpretations. (c) 2005 Lavoisier SAS. All rights reserved.Keywords
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