| Title | Seismic evidence for a mantle suture and implications for the origin of the Canadian Cordillera |
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| Author | Chen, Y; Gu, Y J; Currie, C A; Johnston, S T; Hung, S -H; Schaeffer, A J ; Aufet, P |
| Source | Nature Communications vol. 10, 2249, 2019 p. 1-10, https://doi.org/10.1038/s41467-019-09804-8  Open Access |
| Links | Seismic data for USArray, RAVEN, and CANOE networks (IRIS Data Management
Center)
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| Links | Seismic data for CNSN network (Canadian National Data
Centre)
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| Links | Traveltime data
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| Image |  |
| Year | 2019 |
| Alt Series | Natural Resources Canada, Contribution Series 20190343 |
| Publisher | Springer Nature |
| Document | serial |
| Lang. | English |
| Media | paper; on-line; digital |
| File format | pdf; html |
| Province | Alberta; British Columbia; Saskatchewan |
| NTS | 64K; 64L; 72; 73; 74; 82; 83; 84; 92B; 92C; 92F; 92G; 92H; 92I; 92J; 92K; 92N; 92O; 92P; 93A; 93B; 93C; 93F; 93G; 93H; 93I; 93J; 93K; 93N; 93O; 93P; 94 |
| Area | Washington State; Idaho; Montana; Canada; United States of America |
| Lat/Long WENS | -127.0000 -103.0000 60.0000 48.0000 |
| Subjects | tectonics; geophysics; Nature and Environment; Science and Technology; crustal evolution; crustal models; crustal structure; tectonic evolution; sutures; lithosphere; mantle; orogenesis; accretion;
craton; tectonic models; plate margins; geophysical surveys; seismic surveys; seismic velocities; anomalies; seismic waves; seismological network; seismic arrays; thermal analyses; Canadian Cordillera; North American Craton; Laurentia; Canadian
National Seismograph Network; Canadian Rockies and Alberta Network (CRANE); Canadian Northwest Seismic Experiment (CANOE); Regional Alberta Observatory for Earthquake Studies Network (RAVEN); USArray; Cordilleran Deformation Front; Rocky Mountain
Trench; Tintina Fault; Great Slave Lake Shear Zone; Snowbird Tectonic Zone; Trans-Hudson Orogen; Medicine Hat Block; Great Falls Tectonic Zone; Vulcan Structure; Fraser Fault; Hearne Domain; Phanerozoic; Mesozoic; Cretaceous; Precambrian |
| Illustrations | location maps; geoscientific sketch maps; schematic cross-sections; geophysical profiles; plots; 3-D diagrams; models |
| Program | Public Safety Geoscience Assessing Earthquake Geohazards |
| Released | 2019 05 21 |
| Abstract | The origin of the North American Cordillera and its affinity with the bounding craton are subjects of contentious debate. The mechanisms of orogenesis are rooted in two competing hypotheses known as the
accretionary and collisional models. The former model attributes the Cordillera to an archetypal accretionary orogen comprising a collage of exotic terranes. The latter, less popular view argues that the Cordillera is a collisional product between an
allochthonous ribbon microcontinent and cratonic North America. Here we present new seismic evidence of a sharp and structurally complex Cordillera-craton boundary in the uppermost mantle beneath the southern Canadian Cordillera, which can be
interpreted as either a reshaped craton margin or a Late Cretaceous collisional boundary based on the respective hypotheses. This boundary dips steeply westward underneath a proposed (cryptic) suture in the foreland, consistent with the predicted
location and geometry of the mantle suture, thus favoring a collisional origin. |
| Summary | (Plain Language Summary, not published)
Understanding the construction of our continental landmasses has important implications for understanding not only large scale tectonic history, but also
for its relevant insights on ongoing processes a present day active plate boundaries. Numerous details on the past construction of the Canadian Cordillera and its relationship with the stable Canadian shield to its east remain uncertain. Unearthing
these details will provide insights into the processes we observe at today's active plate boundaries. It has been commonly accepted that the Canadian Cordillera was constructed through an accretionary process where exotic blocks were slowly smeared
onto the outboard edge of North America. In contrast, the collisional model, which proposes more energetic events involving the collision of narrow aspect-ratio "ribbon-continents", is somewhat less well adopted, despite evidence in the rock record
to support it. In this study, we examined the detailed morphology of the suture between the Canadian Shield and Cordillera deep in the lithospheric mantle using geophysical methods, largely inaccessible to conventional geological techniques. Here we
find a deep suture, which is interpreted as a collisional, rather than accretionary feature. |
| GEOSCAN ID | 321452 |
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