Palaeogeographical and palaeoenvironmental reconstruction of the Medjerda delta (Tunisia) during the Holocene
Palaeogeographical and palaeoenvironmental reconstruction of the Medjerda delta (Tunisia) during the Holocene
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全新世梅杰尔达三角洲（突尼斯）的古地理和古环境重建
DOI：
10.1016/j.quascirev.2019.07.017
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发表时间：
2019
影响因子：
4
通讯作者：
N. Fagel
中科院分区：
文献类型：
--
作者：
Elisa Pleuger;J. Goiran;I. Mazzini;Hugo Delile;A. Abichou;Ahmed Gadhoum;H. Djerbi;N. Piotrowska;A. Wilson;E. Fentress;I. B. Jerbania;N. Fagel
自19世纪以来，Medjerda三角洲的扩张一直是许多研究的主题。这种现象的规模和速度在早期引起了各个领域的研究人员的兴趣，例如地貌学，地质学，古地理学，历史学，考古学或地质考古学。事实上，三角洲在3000年的时间里扩大了大约10公里。据推测，尤蒂卡的腓尼基城市建立于公元前世纪末，当时它坐落在一个沐浴在大海中的海角上，但Medjerda携带的沉积物逐渐封闭了海湾，使尤蒂卡海角的尖端现在向内陆10公里。因此，这一地区是沿着突尼斯海岸的一个例外，因为在同一时期，由于海平面上升了几分米，其他地方的海岸线都后退了。本文通过对两条取芯样带的多指标分析，重建了中全新世以来Medjerda三角洲扩张的古环境和古地理，其中一些方面在古代资料中有描述。研究结果特别突出了公元4世纪左右的高强度洪水事件，这与罗马时期结束时流域内记录的高洪水事件和沉积速率增加是一致的。尤蒂卡市的逐渐废弃肯定与梅杰尔达河的活动有关，但我们的研究结果表明，这是因为河流沉积物的增加与源头的侵蚀危机有关，而不是因为很久以前就发生的河道变化。
The progradation of the Medjerda delta has been the subject of many studies since the 19th century. The scale and the rapidity of this phenomenon interested researchers in various fields early on, such as geomorphology, geology, palaeogeography, history, archaeology, or geoarchaeology. Indeed, the delta prograded by around 10 km over 3 millennia. At the time of its foundation supposedly at the end of the 12th century BC, the Phoenician city of Utica was located on a promontory bathed by the sea, but the sediments carried by the Medjerda progressively sealed the bay, leaving the tip of the Utica promontory now 10 km inland. This area is therefore an exception to the general pattern along the Tunisian coast, since as over the same period everywhere else there is a regression of the coastline, owing to a sea level rise of several decimeters. Based on multi-proxy analyses of two coring transects, this paper aims to reconstruct the palaeoenvironments and the palaeogeography of the Medjerda delta’s progradation since the mid-Holocene, some aspects of which are described in ancient sources. The results highlight in particular an episode of high-intensity flooding around the 4th century AD, which is consistent with episodes of high floods and an increase in sedimentation rates recorded in the watershed at the end of the Roman period. The gradual abandonment of the city of Utica can certainly be related to the activity of the Medjerda River, but our results show that it is because of an increase of fluvial sediment contribution in connection with an erosive crisis in the headwaters, and not because of the change of course of the river, which had occurred long before.