Miocene precipitation in Europe: Temporal trends and spatial gradients
Miocene precipitation in Europe: Temporal trends and spatial gradients
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DOI：
10.1016/j.palaeo.2010.09.028
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发表时间：
2011-05-01
影响因子：
3
通讯作者：
Ilg, August
中科院分区：
文献类型：
--
作者：
Boehme, Madelaine;Winklhofer, Michael;Ilg, August
从现代气候可以看出，降水的时间和空间变化可能比温度的变化更明显，从而对生态系统和人类社会产生更大的影响。然而，过去对这种变化知之甚少。在这里，我们提出了一个分析的206个古降水数据从两个1200万年长的代理记录的降水西南（卡拉塔尤-特鲁埃尔盆地）和中欧（西部和中部副特提斯），跨越晚早中新世和中晚中新世（17.8-5.3马）的时间分辨率约80 kyr和200 kyr，分别。降水量的估计是基于爬行动物组合的生理生态结构。结果表明，这两个地区的降水变化有很大的幅度在中新世具有可比的时间趋势在较长的时间尺度。当地每年的降雨量比现在多300毫米至1000毫米，早期Langhian和Tortonian是相对湿润的时期，而晚期Langhian和晚期Serravallian相对干燥，降水量比现在少300至500毫米。最潮湿的时间间隔是早期和中期托托洗衣房气候时期。总的来说，我们的数据表明，在欧洲从中新世中期到晚期的纬度降水梯度是高度可变的，一般倾向于降低梯度相对于今天的值。梯度在变冷期间减小，在变暖期间增大，类似于未来气候变化的模拟结果。有趣的是，在第二个洗衣房气候时期和早墨西拿，这可能会导致负的水文平衡在东部副特提斯在后者的时间，降水梯度被逆转。然而，我们重建的梯度曲线显示没有直接的相关性与全球温度信号的氧同位素，这意味着一个非线性的区域响应。我们的研究结果进一步表明，降水梯度的主要波动可以负责生态系统分布的变化，特别是在西南欧的动物营业额。(C)2010 Elsevier B. V.保留所有权利。
It is known from present-day climates that both temporal and spatial variations in precipitation can be more pronounced than those in temperature and thus influence ecosystems and human society in more substantial way. However, very little is known about such variations in the past. Here we present an analysis of 206 palaeoprecipitation data from two twelve million year long proxy records of precipitation for Southwest (Calatayud-Teruel basin) and Central Europe (Western and Central Paratethys), spanning the late Early and Middle to Late Miocene (17.8-5.3 Ma) at a temporal resolution of about 80 kyr and 200 kyr, respectively. The estimates of precipitation are based on the ecophysiological structure of herpetological assemblages. The results show that precipitation variations in both regions have large amplitudes during the Miocene with comparable temporal trends at longer time scales. With locally 300 mm up to more than 1000 mm more rainfall per year than present, the early Langhian and the Tortonian were relatively wet periods, whereas the late Langhian and late Serravallian were relatively dry, with up to 300 to 500 mm less precipitation than present. The most humid time intervals were the early and middle Tortonian washhouse climate periods. Overall, our data suggest that the latitudinal precipitation gradient in Europe from the Middle to Late Miocene were highly variable, with a general tendency towards a reduced gradient relative to present day values. The gradient decreases during cooling periods and increases during warming periods, similar to results from simulations of future climate change. Interestingly, the precipitation gradient was reversed during the second washhouse climate period and the Early Messinian, which may have causes a negative hydrologic balance in the Eastern Paratethys during the latter time. Yet, our reconstructed gradient curve shows no direct correlation with the global temperature signal from oxygen isotopes, which implies a non-linear regional response. Our results further suggest that major fluctuations in the precipitation gradient can be responsible for shifts in ecosystem distribution, and particularly, for faunal turnover in South Western Europe. (C) 2010 Elsevier B.V. All rights reserved.