Paleogene Sedimentation and Eurekan Deformation in the Stenkul Fiord Area of Southeastern Ellesmere Island (Canadian Arctic): Evidence for a Polyphase History
Field studies and interpretative mapping of the area southeast of Stenkul Fiord (Ellesmere Island) revealed that the Margaret Formation clastic deposits consist of at least four sedimentary units (Units 1–4) separated by unconformities. Several centimeter-thick volcanic ash layers, identified within...
| Main Authors: | , , , |
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| Format: | Text |
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ScholarWorks
2018
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| Online Access: | https://scholarworks.boisestate.edu/geo_facpubs/762 https://doi.org/10.1130/2018.2541(16 |
| Summary: | Field studies and interpretative mapping of the area southeast of Stenkul Fiord (Ellesmere Island) revealed that the Margaret Formation clastic deposits consist of at least four sedimentary units (Units 1–4) separated by unconformities. Several centimeter-thick volcanic ash layers, identified within coal layers and preserved as crandallite group minerals (Ca-bearing goyazite), suggest an intense volcanic ash fall activity. Based on new U-Pb zircon dating (ID-TIMS) of three ash samples from one layer, this activity took place at 53.7 Ma in the early Eocene, i.e., within the period of the Eocene Thermal Maximum 2 hyperthermal. This age further suggests that the lowermost Unit 1 can be assigned to the late Paleocene–earliest Eocene, Unit 2 to the early Eocene, whereas Units 3 and 4 might be early to middle Eocene in age. Sedimentation was followed and partly accompanied by compressive Eurekan deformation after ~53.7 Ma, which led to the formation of fold and fault structures. Several pulses of deformation caused uplift and erosion and were followed by sedimentation of the next unit above an unconformity. Deformation presumably ended before the middle Eocene. An earlier phase of probably extensional Eurekan deformation in Unit 1 can be assigned to the latest Paleocene–earliest Eocene. These results show that Paleocene/Eocene sedimentation and Eurekan deformation represent a protracted history comprising several phases of ongoing clastic sedimentation, deformation, uplift, and erosion. This suggests that the Eurekan deformation on Ellesmere Island cannot be assigned to a single fixed time in the Paleogene only. |
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