The impact of topography on isotopes in precipitation across the Central Anatolian Plateau (Turkey)
The impact of topography on isotopes in precipitation across the Central Anatolian Plateau (Turkey)
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地形对安纳托利亚中部高原降水同位素的影响（土耳其）
DOI：
10.2475/02.2013.01
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发表时间：
2013
影响因子：
2.9
通讯作者：
A. Mulch
中科院分区：
文献类型：
--
作者：
F. Schemmel;T. Mikes;B. Rojay;A. Mulch
基于稳定同位素气候和降水记录的山地带和造山高原的古海拔重建极大地受益于当今的校准，这些校准将降水中氢（δD）和氧（δ18O）同位素的分馏与地形降雨联系起来。在这里，我们建立了横跨安纳托利亚中部高原 (CAP) 及其毗邻的本都山脉和金牛座山脉的现代大气水 δD 和 δ18O 的一阶模板。我们确定了高原内部和高原边缘的关键区域，这些区域有可能可靠地记录从稳定同位素古土壤、化石牙齿或脂质代理数据中恢复的与地形相关的古温度和古降水变化。基于来自小型流域和泉水的 480 多个地表水样本的 δD 和 δ18O 数据，我们描述了影响 CAP 降水净同位素预算的水分源，并分析了地形降雨和高原干旱如何塑造降水中 δD 和 δ18O 的现代模式。南部与 CAP 接壤的金牛座山脉是主要冬季湿气输送的主要地形屏障，在近 3000 m 的海拔范围内，δD 的同位素递减率约为 -20‰/km，δ18O 的同位素递减率约为 -2.9‰/km。 CAP北缘的庞蒂克山脉迫使常年水分上升并凝结，显示δD递减率为-19‰/km，δ18O递减率为-2.6‰/km。 CAP 南缘和北缘（北非与大西洋气团）主要水汽来源的差异表现为高原中部地带近海平面大气水成分的系统性南北差异，Δ(δDN-S) ∼20 permil 和 Δ(δ18ON-S) ∼3 permil。来自半干旱高原内部的稳定同位素数据，降雨量低至 300 至 500 毫米/年，夏季平均气温达到 23 °C，为蒸发状况提供了明确的证据，该蒸发状态极大地影响了地表水和径流成分，并导致高原内部的当地大气水位线遵循 δD = 4.0 · δ18O − 29.3。强烈的蒸发条件与高原边缘的降雨模式形成鲜明对比，包括其紧邻的背风侧翼，其中δD-和δ18O-高程关系是现代地形的可靠预测因子。
Paleoelevation reconstructions of mountain belts and orogenic plateaus based on stable isotope climate and precipitation records benefit greatly from present-day calibrations that relate the fractionation of hydrogen (δD) and oxygen (δ18O) isotopes in precipitation to orographic rainfall. Here, we establish a first-order template of δD and δ18O of modern meteoric waters across the Central Anatolian Plateau (CAP) and its bordering Pontic and Taurus Mountains. We identify key regions in the plateau interior and along the plateau margins that have the potential to reliably record topography-related paleotemperature and paleoprecipitation changes as recovered from stable isotope paleosol, fossil teeth or lipid proxy data. Based on δD and δ18O data of more than 480 surface water samples from small catchments and springs, we characterize moisture sources affecting the net isotopic budget of precipitation over the CAP and analyze how orographic rainout and plateau aridity shape modern patterns of δD and δ18O in precipitation. The Taurus Mountains bordering the CAP to the south act as a major orographic barrier for transport of predominantly winter moisture and exhibit isotopic lapse rates of approximately −20‰/km for δD and −2.9‰/km for δ18O across an elevation range of nearly 3000 m. The Pontic Mountains at the northern margin of the CAP force perennial moisture to ascend and condensate revealing lapse rates of −19‰/km for δD and −2.6‰/km for δ18O. The difference in the predominant moisture source for the southern and northern margins of the CAP (North African versus Atlantic air masses) is manifested in systematic north-south differences in near-sea level meteoric water compositions of Δ(δDN-S) ∼20 permil and Δ(δ18ON-S) ∼3 permil in a swath across the central part of the plateau. Stable isotope data from the semi-arid plateau interior with rainfall as low as 300 to 500 mm/yr and mean summer temperatures attaining 23 °C, provide clear evidence for an evaporative regime that drastically affects surface water and runoff compositions and results in a local meteoric water line for the plateau interior that follows δD = 4.0 · δ18O − 29.3. Strongly evaporitic conditions contrast rainfall patterns along the plateau margins including their immediate leeward flanks where δD- and δ18O-elevation relationships are reliable predictors of modern topography.
影响因子：
5.3
作者：
Campani, M.;Mulch, A.;Mancktelow, N.
通讯作者：
Mancktelow, N.