‘De-Greening’ of the central Sahara – northern Sahel: Holocene environmental dynamics and oases economies between 14-19°N (DeGree)

撒哈拉中部 â 萨赫勒北部的“去绿化”：全新世环境动态和北纬 14-19° 之间的绿洲经济（DeGree）

• 批准号: 404354295
• 负责人: Dr. Philipp Hoelzmann
• 金额: --
• 依托单位: Institut für Geographische Wissenschaften
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/404354295?language=en
• 关键词: De; Greening; central; Sahara; northern

Today the Sahara, as the world’s largest hot desert, separates northern Africa into two parts, while a Green Sahara facilitated interactions during early and mid-Holocene between the Mediterranean and rainforest. Concomitant palaeoecological shifts imply changing resources, thereby affecting subsistence strategies. Environmental variability thus represents both, an important limiting factor as well as a driving force for inner-african transregional contacts and strategies of human societies and their mobility patterns. The goal of the second phase pursues the basic approach from the first funding phase in using sedimentary archives to decipher Holocene environmental dynamics with a stronger emphasis to archaeological research questions that have developed from the findings of the joint collaboration within the SPP2143. It became obvious that biotic resources of landscapes are a major determinant for interregional contacts and thus their identification on a spatiotemporal scale are key.The project’s focus is on two ecologically favourable areas from the Republic of Chad that provide sedimentary archives for palynological and geochemical analyses: (1) The groundwater oases east of Ounianga within the central Sahara (19°N) and (2) the Kanem Region east of present Lake Chad in the Sahel (14-15°N) with its interdunal depressions that are often occupied by wetlands. A chronological framework of palaeoenvironmental changes will be established for a time period during which these groundwater oases and their economies developed.The northern sites along the Ounianga escarpment acted as oases since the mid-Holocene de-greening of the Sahara whereas the southern sites of the Kanem Region provide oases insights since the fading of the Mega-Lake Chad around 4200 cal BP until today. This research thus provides unique opportunities for understanding of (1) the spatio-temporal appearance of palaeoecological shifts, (2) the development of groundwater oases sites, as well as (3) land use changes through time. The SPP2143 will benefit from these insights on a supra-regional scale as they render visible multi-layered entanglements from this region of transit.

今天，撒哈拉沙漠作为世界上最大的炎热沙漠，将北非分为两部分，而绿色撒哈拉促进了全新世早期和中期地中海与热带雨林之间的相互作用。随之而来的古生态变化意味着资源的变化，从而影响生存战略。因此，环境的多变性既是一个重要的限制因素，也是非洲内部人类社会及其流动模式的跨区域接触和战略的推动力。第二阶段的目标追求第一个资助阶段的基本方法，即利用沉积档案破译全新世环境动力学，更加重视考古研究问题，这些问题是从SPP2143内联合合作的结果发展而来的。显然，景观的生物资源是区域间联系的主要决定因素，因此在时空尺度上确定它们是关键。项目的重点是乍得共和国的两个生态有利地区，这两个地区为孢粉学和地球化学分析提供了沉积档案：(1)撒哈拉中部奥尼扬加以东的地下水绿洲(19°N)和(2)萨赫勒现在乍得湖以东的卡纳姆地区(14-15°N)及其经常被湿地占据的丘间洼地。将建立这些地下水绿洲及其经济发展时期的古环境变化年代学框架。自撒哈拉沙漠全新世中期以来，沿Ounianga悬崖的北部遗址就是绿洲，而卡纳姆地区的南部遗址提供了自约4200卡BP以来乍得巨湖褪色至今的绿洲洞察。因此，这项研究为理解(1)古生态变化的时空表现，(2)地下水绿洲遗址的发育，以及(3)土地利用随时间的变化提供了独特的机会。SPP2143将在超区域范围内受益于这些洞察力，因为它们提供了来自这一过境区域的可见的多层纠缠。