The Paleoproterozoic of Central Colorado: Accreted Arcs or Rifted Older Crust

美国西南部的古元古代由一系列附属于苏必利尔省的增生地体组成。假定这些地体是幼年弧，本质上代表新的地幔衍生地壳，这对地壳生长的计算产生了重大影响。然而，其中一些岩石含有明显的双峰火山套，并被钙碱性岩体侵入。这种联系更符合裂谷构造环境，提出了存在更古老物质的可能性，而不仅仅是年轻物质。该项目将研究科罗拉多中部地区的岩石，以探索这种可能性。研究结果对区域重建和地壳研究具有重要意义。

9805013 Bickford The Paleoproterozoic of southwestern United States consists of a series of accreted terranes attached to the Superior province. The assumption that these terranes are juvenile arcs and represent essentially new mantle-derived crust has had a major impact on calculations of crustal growth. However, some of these rocks contain a distinctly bimodal volcanic suite which are intruded by calcalkaline plutons. This association is more consistent with a rifting tectonic environment, bringing up the possibility of the presence of older material, not just juvenile. This project will study rocks in the Central Colorado region to explore this possibility. Results will very significant to regional reconstructions and crustal studies.