The big picture: A lithospheric cross section of the North American continent

[摘要] A lithosphericcross section constructed within a 6000-km-long corridor across southern Canadaand its margins at 45–55?N illuminates the assembly of the North American continentat an unprecedented scale. Based on coordinated, multidisciplinary research, theprofile emphasizes lithospheric-scale relationships between orogens—plate collisionsand accretions have sequentially stacked orogen upon orogen such that the oldercrust forms basement to the next younger. This large-scale perspective highlightsthe similarities among crustal structures produced by orogenic processes despitethe broad range of age from the Mesoarchean to the present. Heterogeneities in the lithospheric mantle suggestthat, in certain situations, relict subducted or delaminated lithosphere can remainintact beneath, and eventually within, cratonic lithospheric mantle. In contrast,the dominantly subhorizontal Moho appears to be re-equilibrated through mechanicaland/or thermal processes; few crustal roots beneath orogens are preserved.

[学科分类] 地质学

[关键词] Fire safety;fatal fires;smoke alarms