کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
5785069 1639928 2017 31 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Interpreting drivers of change in fluvial archives of the Western Mediterranean - A critical view
ترجمه فارسی عنوان
تفسیر رانندگان تغییر در آرشیوهای رودخانه غربی مدیترانه - دیدگاه انتقادی
کلمات کلیدی
رفتار فلولی، بازسازی محیط زیست، محاصره آب و هوا، تاثیر انسانی، آرشیوهای زمینی، اسپانیا، تونس،
موضوعات مرتبط
مهندسی و علوم پایه علوم زمین و سیارات زمین شناسی
چکیده انگلیسی

Fluvial archives, in particular, late glacial to Holocene floodplain records may provide valuable information regarding past environmental conditions and stages of landscape evolution. In view of the high significance of floodplain dynamics for the development of entire landscapes, the number of studies that have been performed on floodplain sediments remains comparatively low, especially regarding the Western Mediterranean region. However, one of the reasons could be seen in the high complexity and diversity of processes and factors that control and influence fluvial activity that often hampers a straightforward interpretation of floodplain dynamics. Therefore, a basic demand on fluvial archive research is to address the complexity of the factors that control the characteristics of fluvial sequences in order to provide a robust basis for their interpretation.As a starting-point for discussion this paper aims to give an overview of fluvial dynamic patterns in the Western Mediterranean for the last 15 ka in order to examine their relevance for palaeoenvironmental reconstructions. The basis for this is provided by previous investigations on four different river systems in Spain and northern Africa the results of which are herein synthesized in order to propose a regional Late Pleistocene and Holocene fluvial history for the Western Mediterranean realm. Basic results are related to alluvial floodplain deposits and visible features within them such as alluvial soils, incision marks and aggradation phenomena. Since fluvial systems are open systems, we discuss our findings against the background of different influencing factors that could modify fluvial architecture and may restrict palaeoenvironmental reconstructions. A more comprehensive interpretation focuses on signals that are common to each of the studied river systems. In this respect, we critically discuss the customary nature of cumulative probability functions for the identification of regional flooding episodes and point out the benefits of a stratigraphy-supported approach for characterizing regional floodplain dynamics. Finally, three alluvial soil formation periods were found in all settings: a first phase after 15 ka, ending with the Younger-Dryas Event; a second one from 7 to 5 ka with a break between 6.5 and 5.5 ka, and a third phase between 3 and 2 ka. These soil formation periods were interrupted and framed by fluvial dynamic phases accompanied by channel aggradation, floodplain deposition, floodplain erosion and/or river incision. In particular, after 5 ka, around 1.6 and at 1 ka, and during the Little Ice Age (LIA) floodplain aggradation affected river systems in Iberia and northern Africa as well. A cautious assessment of these results and extensive comparisons with secondary archive information prompts us to relate the aggradation periods with climate forcing by means of a supra-regional aridification that effected large areas of the Western Mediterranean. In contrast, the three mentioned soil formation periods can be linked with landscape stability, most probably triggered by favorable climate conditions in the Western Mediterranean.Apart from these large-scale patterns we discuss the reliability of information emerging from floodplain records against the background of individualistic river behavior and self-organization. Regarding future work we want to emphasize the great potential of yet rarely applied system-oriented approaches that also attach importance to sub-catchment dynamics as a link between catchment slopes and the main river floodplain.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Earth-Science Reviews - Volume 174, November 2017, Pages 53-83
نویسندگان
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