Late Precambrian Epeirogenic Uplift and Erosion of Southern Canadian Shield

加拿大地盾是一个广阔的基岩平原，地势低，覆盖了美国北方和加拿大的大部分地区。这些裸露的岩石是地球上最古老的岩石之一，通常是在高温高压下形成的。地形盾是由大约16亿至5亿年前北美大陆的广泛隆起形成的。隆起的原因和时间尚不清楚：隆起的唯一直接证据是存在10亿年的侵蚀间断。本项目的目标是通过测量从安大略和邻近地区的屏蔽层采集的表面样品的磷灰石裂变径迹冷却历史，重建屏蔽层在侵蚀间断期间的隆起历史。研究结果有望限制隆升的时间和速率，这是大范围隆升原因的重要线索。

The Canadian Shield is an extensive bedrock plain of low relief that covers the northern United States and most of Canada. The exposed rocks are among the oldest on earth and were formed generally at elevated temperatures and pressures. The topo- graphic shield was formed by a broad uplift of the North American continent between about 1.6 and 0.5 billion years ago. The cause and timing of uplift is unknown: the only direct evidence for uplift is the presence of a 1 billion year erosional hiatus. The objective of this project is to reconstruct the uplift history of the shield during this erosional hiatus by measuring the apatite fission track cooling histories of surface samples collected from the shield in Ontario and adjacent areas. Results are expected to constrain the timing and rate of uplift which are important clues to the causes of the widespread uplift.