The nature and timing of early postglacial landscape change, central coast, British Columbia

不列颠哥伦比亚省中部海岸冰期早期景观变化的性质和时间

• 批准号: RGPIN-2017-03803
• 负责人: Lian, Olav
• 金额: $ 1.6万
• 依托单位: Fraser Valley
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2018
• 资助国家: 加拿大
• 起止时间: 2018-01-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=657553
• 关键词: nature; timing; early; postglacial; landscape

The history of landscape change along coastal British Columbia (BC) since the end of the last ice age (glaciation), about 15,000 years ago, is complex and poorly understood. This is because of several factors, including a relative sea level (RSL) that varied considerably from region to region during postglacial time, due to complex relationships between the depression of the earth's crust as a result of differential loading by glacial ice; the presence of a high-energy and variable wind and wave regimes that bring, or erode, sediment from the coast in a complex fashion; the sensitivity of coastal sedimentary landforms, such as modern and relict beaches and dunes, to short term changes in climate; and access – many of the areas of interest are remote and can only be accessed by boat, helicopter, or by small amphibious aircraft. Gaining insight into the character of how the coastal landscape evolved since the last glaciation is important if predictions about how it will adjust as a result of predicted future climate change (e.g., rising global temperature and sea level, and increased coastal storm activity) are to be made. The BC coast has also been identified as a possible early migration route for the peopling of the Americas. There is new information that suggests that regions of the central coast where RSL change since the end of the last glaciation was minimal were areas of early and prolonged human settlement. There is also evidence that suggests that parts of the BC central coast were ice-free during the last and preceding glaciations. These regions would have served as places of refuge for plants and animals, and they would have spread from these places each time glaciation ended. It is therefore important to confirm the presence (in both time and space) of these refugia, and what survived in them, if the evolution of the landscape and the pattern of human migration and settlement is to be understood. Understanding the nature and timing of landscape change along the BC central coast is therefore not only of interest to geoscientists, but also to archaeologists and anthropologists, and the general public. This research program will investigate short and long-term changes to the coastal geomorphology of regions of the BC central coast, building on preliminary work done by others and by us on Calvert Island, with the aim of providing a more constrained (in time and space) record of landscape change. Landforms to be investigated are relict (raised) beaches dunes, and deltas that represent periods of transitory landscape stability and instability; special attention will be given to landforms that have been identified as having archaeological significance. Haida Gwaii will be revisited with the goal of gaining further evidence for the presence of biological refugia during the penultimate glaciation, which has so far been found at only one site.

自大约15,000年前的最后一个冰河时代（冰川作用）结束以来，沿着沿海不列颠哥伦比亚省（BC）的景观变化历史是复杂的，人们对此知之甚少。这是由于若干因素造成的，其中包括：由于冰川冰的不同负荷造成的地壳下陷之间的复杂关系，在冰后期，各区域的相对海平面差异很大;存在着高能量和多变的风和波浪状况，它们以复杂的方式从海岸带来或侵蚀沉积物;海岸沉积地貌，如现代和残留的海滩和沙丘，对短期气候变化的敏感性;以及交通-许多感兴趣的地区都很偏远，只能通过船只、直升机或小型水陆两用飞机才能到达。了解自末次冰期以来沿海景观如何演变的特征是重要的，如果预测它将如何调整作为预测未来气候变化的结果（例如，全球气温和海平面上升，沿海风暴活动增加）。不列颠哥伦比亚省海岸也被认为是美洲人早期可能的迁徙路线。有新的信息表明，自末次冰期结束以来RSL变化最小的中部海岸地区是早期和长期人类定居的地区。还有证据表明，BC中部海岸的部分地区在最后一次和之前的冰川期是无冰的。这些地区曾是动植物的避难所，每次冰川结束时，它们都会从这些地方扩散开来。因此，如果要了解景观的演变以及人类迁移和定居的模式，就必须确认这些避难所的存在（在时间和空间上），以及其中幸存的东西。因此，了解不列颠哥伦比亚省中部海岸沿着景观变化的性质和时间不仅对地球科学家感兴趣，而且对考古学家和人类学家以及公众也很感兴趣。这项研究计划将调查BC中部海岸地区的海岸地貌的短期和长期变化，建立在其他人和我们在卡尔弗特岛所做的初步工作的基础上，目的是提供一个更受限制的（在时间和空间上）景观变化记录。要调查的地貌是残留的（凸起的）海滩、沙丘和三角洲，这些地貌代表了地貌稳定和不稳定的过渡时期;将特别注意已被确定为具有考古意义的地貌。海达冰川将被重新访问，目的是获得进一步的证据，证明倒数第二次冰期期间存在生物避难所，迄今为止只在一个地点发现了生物避难所。