New insights into source and dispersal of Mediterranean S1 tephra, an early Holocene marker horizon erupted at Mt. Erciyes (Turkey)
New insights into source and dispersal of Mediterranean S1 tephra, an early Holocene marker horizon erupted at Mt. Erciyes (Turkey)
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对地中海 S1 火山灰的来源和传播的新见解，这是埃尔吉耶斯山（土耳其）喷发的全新世早期标志地平线
DOI：
10.1016/j.quascirev.2020.106606
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发表时间：
2020
影响因子：
4
通讯作者：
Friedrichs B
中科院分区：
文献类型：
--
作者：
Friedrichs B
全新世早期东地中海S1烟体和黑海隐烟体的沉积与新月沃地被称为新石器革命的文化转变以及非洲湿润期气候变化期间的冲力形成相吻合，将它们归类为考古学和古气候学的重要区域标志层。它们与埃尔西耶斯山层状火山复合体（安纳托利亚中部）的具体喷发的相关性仍然没有定论。本文采用(U-Th)/He法和U-Th不平衡法进行锆石双定年、主微量元素tephra glass地球化学和tephra扩散概率模拟，试图对Erciyes山晚第四纪近端所有主要tephra进行表征，并将其与远端沉积联系起来。此外，我们讨论对比近端和远端tephra分散。在全新世早期，Erciyes火山喷发了三个几乎同时期的流纹岩卫星圆顶（Dikkartın、Perikartın和Karagüllü），它们的圆顶喷发之前都发生了爆炸阶段，产生了火山碎屑物质，形成了火山碎屑坠落和火山碎屑流沉积。近端Dikkartın浮石的新喷发年龄为9.03±0.55 ka （1σ不确定性），与远端位置基于14c的S1火山年代学（平均为8.92±0.03 cal ka BP）一致。根据两组已公布的14c年龄，Perikartın火山碎屑流沉积早于S1 tephra约0.8 ka，而地层上的Karagüllü沉降物的年代为8.2±1.8 ka。Erciyes山的近端火山喷发于晚（85.2±4.9 ka）和中更新世（154.5±5.3 ka）。S1辐射玻璃的化学性质与Dikkartın辐射玻璃相似，但也与Perikartın辐射玻璃难以区分。Karagüllü浮石的特点是具有独特的玻璃化学成分，这与在黑海东南部报道的未命名的隐球菌相关，这些结果要求对现有的年龄模型进行重新评估。近端Dikkartın沉降物的最大岩屑大小等条表明，平流层风向东扩散了20±5公里高的喷发羽流，这与概率火山灰扩散模型的结果一致。这个方位角与已知的S1 tephra在Erciyes山以南的远端位置的分布形成对比。在距离最远达1300公里且与平流层风向正交的地方出现明显的瘟热，要么是由非常不典型的风况（概率≪10%）造成的，要么是由盛行的低空风输送瘟热造成的。对于低空运输，提出了两种情况：原生沉降物的风成再造（更有可能来自更广泛的Dikkartın沉积物），或共烟灰云的扩散（更有可能来自主要产生火山碎屑流的Perikartın喷发）。由于S1麻黄的主要和微量元素玻璃成分与Dikkartın和Perikartın在化学上无法区分，因此其确切的来源和扩散机制仍然不明确，尽管Perikartın的14c年龄比S1麻黄的14c年龄更有利于Dikkartın的来源。
Deposition of early Holocene Eastern Mediterranean S1 tephra and a Black Sea cryptotephra coincides with cultural transitions in the Fertile Crescent termed the Neolithic Revolution as well as sapropel formation during climate variability of the African humid period, classifying them as paramount regional marker horizons for archaeology as well as paleoclimatology. Their correlations with specific eruptions of the Mt. Erciyes stratovolcanic complex (Central Anatolia) remained inconclusive though. Here, we use zircon double-dating by (U–Th)/He and U–Th disequilibrium methods, major and trace element tephra glass geochemistry, and probabilistic modeling of tephra dispersal in an attempt to characterize all major late Quaternary proximal tephras of Mt. Erciyes, and to correlate them with distal deposits. Furthermore, we discuss contrasting proximal and distal tephra dispersal.Three nearly-coeval rhyolitic satellite domes (Dikkartın, Perikartın, and Karagüllü) erupted at Mt. Erciyes in the early Holocene, and their dome extrusions were all preceded by explosive phases producing pyroclastic material that formed tephra fall and pyroclastic flow deposits. The new eruption age of 9.03 ± 0.55 ka (1σ uncertainty here and elsewhere) for proximal Dikkartın pumice is consistent with14C-based S1 tephra chronologies in distal locations averaging 8.92 ± 0.03 cal ka BP. Perikartın pyroclastic flow deposits predate S1 tephra by ca. 0.8 ka according to a pair of published14C ages, and stratigraphically overlie Karagüllü fall-out, here dated to 8.2 ± 1.8 ka. Previously undated proximal tephras of Mt. Erciyes erupted in the Late (85.2 ± 4.9 ka) and Middle Pleistocene (154.5 ± 5.3 ka). S1 tephra glass is chemically similar to that of Dikkartın fall-out, but also indistinguishable from that of Perikartın fall-out. Karagüllü pumice is characterized by a distinct glass chemical composition, which correlates with that of unnamed cryptotephra reported for the southeastern Black Sea instead, where these results call for a re-evaluation of existing age models.Maximum lithic clast size isopleths for proximal Dikkartın fall-out indicate eastward dispersal of a 20 ± 5 km high eruption plume by stratospheric winds, in agreement with results of probabilistic tephra dispersal modeling. This azimuth contrasts with the known distribution of S1 tephra at distal locations that are all south of Mt. Erciyes. Significant tephra occurrences at up to 1300 km distance and orthogonal to prevalent stratospheric wind directions either result from very atypical wind conditions (probability ≪10 %), or are caused by tephra transport by prevailing low altitude winds. Two scenarios are proposed for low altitude transport: eolian reworking of primary fall-out (more likely from the more widespread Dikkartın deposits), or co-ignimbrite ash cloud dispersal (more likely from the Perikartın eruption which predominantly produced pyroclastic flows). Because S1 tephra is chemically indistinguishable from both Dikkartın and Perikartın by major and trace element glass compositions, its exact source and dispersal mechanism remain ambiguous, although existing14C ages for Perikartın predating those for S1 tephra favor Dikkartın as its source.
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影响因子：
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作者：
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DOI：
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DOI：
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发表时间：
2019
期刊：
Mediterranean Geoscience Reviews
影响因子：
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作者：
O. Ersoy;E. Aydar;E. Şen;A. Gourgaud
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影响因子：
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作者：
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通讯作者：
Tryon, Christian A.