Deciphering shallow paleomagnetic inclinations: 2. Implications from Late Cretaceous strata overlapping the Insular/Intermontane Superterrane boundary in the southern Canadian Cordillera

Enkin, Randolph J.; Mahoney, J. Brian; Baker, J.; Riesterer, J W; Haskin, M L

doi:10.1029/2002jb001983

Cited by 38 publications

(45 citation statements)

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“…In addition, evidence from Upper Cretaceous strata overlying the Spences Bridge arc requires an even larger southerly displacement between 104 and 95 Ma. These Upper Cretaceous strata are geologically and paleomagnetically correlative with the Silverquick/Powell Creek succession of the Insular Superterrane [ Enkin et al , 2003]. Paleomagnetic analysis of these strata requires that the composite Insular/Intermontane Superterrane was at the latitude of central Mexico at 95 Ma.…”

Section: Discussionmentioning

confidence: 99%

“…Independent methods, such as paleoclimatic analysis, geological correlation, paleontologic reconstructions and sedimentary provenance studies, usually provide compatible results that support paleomagnetic interpretations. In this paper and its companion [ Enkin et al , 2003], we present a case where paleomagnetic and geologic stratigraphic correlations coincide, yet the paleogeographic implications of the calculated paleomagnetic latitudes disagree with interpretation of geological constraints and plate motions. Resolution of this dichotomy has proven elusive, and requires an objective reappraisal of paleogeographic constraints provided by both paleomagnetic and geological methods.…”

Section: Introductionmentioning

confidence: 99%

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Deciphering shallow paleomagnetic inclinations: 1. Implications from correlation of Albian volcanic rocks along the Insular/Intermontane Superterrane boundary in the southern Canadian Cordillera

et al. 2003

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Geologic and paleomagnetic data lead to two contradictory hypotheses regarding the paleoposition of the Insular and Intermontane Superterranes that presently constitute the western Canadian Cordillera. Paleomagnetic data from the Insular and Intermontane superterranes suggest a southerly origin coinciding with the latitude of Mexico and the northwest United States, respectively, during the mid‐Cretaceous. Geologic evidence points to a northerly origin for these same tectonic entities during this period; both models cannot be correct. Geologic and paleomagnetic data from the Empire Valley–Churn Creek area in south central British Columbia (51.5°N, 122.5°W) are critical to resolving these contradictory hypotheses. Late Cretaceous rocks correlated to the Insular Superterrane with large paleomagnetic displacements unconformably overlie mid‐Cretaceous rocks correlative to the Spences Bridge Group of the Intermontane Superterrane. We provide paleomagnetic evidence of this correlation based on similar magnetic properties, opaque mineral assemblages, demagnetization behavior, fold test results, mean inclinations, clockwise vertical axes rotations, and statistically indistinguishable paleomagnetic poles and displacement estimates. This correlation and the observed geologic relationships in the Empire Valley–Churn Creek area indicate that the Insular and Intermontane Superterranes were linked by the mid‐Cretaceous. Sites from the two previous Spences Bridge Group studies are combined with their correlatives in the Empire Valley–Churn Creek area to give 81 sites that yield a paleomagnetic pole of 60.5°N, 304.5°E, dp = 3.7°, dm = 5.5° which corresponds to 1050 ± 450 km of displacement from the south. This new displacement estimate suggests that the Spences Bridge arc formed at the latitude of southern Oregon during the mid‐Cretaceous.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Deciphering shallow paleomagnetic inclinations: 1. Implications from correlation of Albian volcanic rocks along the Insular/Intermontane Superterrane boundary in the southern Canadian Cordillera

et al. 2003

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“…(Schmidt & Williams 1995;Sohl et al 1999, Geological Society of America Data Repository item) yielded a direction of D ¼ 208.38 and I ¼ 2 12.98 (a 95 ¼ 4.28), indicating a palaeopole at 43.78S, 359.38E (dp ¼ 2.18, dm ¼ 4.28) and a palaeolatitude of 6.5 + 2.28. The following observations indicate only minor compaction-related inclination shallowing (Williams 2008;Williams et al 2008): (i) the typical shallow inclination of the Elatina palaeomagnetic remanence obtained for samples of different lithologies (fine-, medium-and coarse-grained sandstone, with mudstone and muddy diamictite being avoided); (ii) the comparable inclinations determined for samples from flat-lying strata in the condensed succession on the cratonic platform and from folded strata in basinal successions; and (iii) the low anisotropy of magnetic susceptibility (mean ,4% for 65 samples), which indicates only slight magnetic foliation (Enkin et al 2003). The findings are supported by a palaeolatitude of 8.4 þ 6.2/-5.78 determined for the immediately preglacial Yaltipena Fm.…”

Section: Palaeolatitude and Palaeogeographymentioning

confidence: 91%

Chapter 70 The Elatina glaciation (late Cryogenian), South Australia

Williams

Gostin

McKirdy

et al. 2011

Memoirs

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Deposits of the late Cryogenian Elatina glaciation constitute the Yerelina Subgroup in the Adelaide Geosyncline region, South Australia. They have a maximum thickness of c. 1500 m, cover 200 000 km 2 , and include the following facies: basal boulder diamictite with penetrative glaciotectonites affecting preglacial beds; widespread massive and stratified diamictites containing faceted and striated clasts, some derived from nearby emergent diapiric islands and others of extrabasinal provenance; laminated siltstone and mudstone with dropstones; tidalites and widespread glaciofluvial, deltaic to marine-shelf sandstones; a regolith of frost-shattered quartzite breccia up to 20 m thick that contains primary sand wedges 3 þ m deep and other large-scale periglacial forms; and an aeolian sand sheet covering 25 000 km 2 and containing primary sand wedges near its base. These deposits mark a spectrum of settings ranging from permafrost regolith and periglacial aeolian on the cratonic platform (Stuart Shelf) in the present west, through glaciofluvial, marginal-marine and inner marine-shelf in the central parts of the Adelaide Geosyncline, to outer marine-shelf in sub-basins in the present SE and north.The Elatina glaciation has not been dated directly, and only maximum and minimum age limits of c. 640 and 580 Ma, respectively, are indicated. Palaeomagnetic data for red beds from the Elatina Formation (Fm.) and associated strata indicate deposition of the Yerelina Subgroup within 108 of the palaeoequator. The Yerelina Subgroup is unconformably to disconformably overlain by the dolomitic Nuccaleena Fm., which in most places is the lowest unit of the Wilpena Group and marks Early Ediacaran marine transgression.

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“…How such a significant tectonic boundary could be cryptic remains unclear [54,55], but the answer may lie in resolving the significant post-150 Ma translations that have occurred within the orogen. Paleomagnetic data implies that large portions of the orogen underwent significant midCretaceous southerly displacements [57], coeval with fold and thrust belt formation within the foreland, widespread dextral strike-slip faulting and voluminous granitic magmatism as far inboard as the eastern limit of Selwyn basin [58]. Paleomagnetic data from Late Cretaceous strata require significant northward translations, relative to the autochthon [59,60] coeval with fold and thrust belt formation in the foreland and oroclinal buckling of the ribbon continent in Alaska [55].…”

Section: Accretionary Orogensmentioning

confidence: 99%

The odyssey of the Cache Creek terrane, Canadian Cordillera: Implications for accretionary orogens, tectonic setting of Panthalassa, the Pacific superwell, and break-up of Pangea

Johnston

Borel²

2007

Earth and Planetary Science Letters

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The Cache Creek terrane (CCT) of the Canadian Cordillera consists of accreted seamounts that originated adjacent to the Tethys Ocean in the Permian. We utilize Potential Translation Path plots to place quantitative constraints on the location of the CCT seamounts through time, including limiting the regions within which accretion events occurred. We assume a starting point for the CCT seamounts in the easternmost Tethys at 280 Ma. Using reasonable translation rates (11 cm/a), accretion to the StikiniaQuesnellia oceanic arc, which occurred at about 230 Ma, took place in western Panthalassa, consistent with the mixed Tethyan fauna of the arc. Subsequent collision with a continental terrane, which occurred at about 180 Ma, took place in central Panthalassa, N 4000 km west of North America yielding a composite ribbon continent. Westward subduction of oceanic lithosphere continuous with the North American continent from 180 to 150 Ma facilitated docking of the ribbon continent with the North American plate.The paleogeographic constraints provided by the CCT indicate that much of the Canadian Cordilleran accretionary orogen is exotic. The accreting crustal block, a composite ribbon continent, grew through repeated collisional events within Panthalassa prior to docking with the North American plate. CCT's odyssey requires the presence of subduction zones within Panthalassa and indicates that the tectonic setting of the Panthalassa superocean differed substantially from the current Pacific basin, with its central spreading ridge and marginal outward dipping subduction zones. A substantial volume of oceanic lithosphere was subducted during CCT's transit of Panthalassa. Blanketing of the core by these cold oceanic slabs enhanced heat transfer out of the core into the lowermost mantle, and may have been responsible for the Cretaceous Normal Superchron, the coeval Pacific-centred mid-Cretaceous superplume event, and its lingering progeny, the Pacific Superswell. Far field tensile stress attributable to the pull of the slab subducting beneath the ribbon continent from 180 to 150 Ma instigated the opening of the Atlantic, initiating the dispersal phase of the supercontinent cycle by breaking apart Pangea. Docking of the ribbon continent with the North American plate at 150 Ma terminated the slab pull induced stress, resulting in a drastic reduction in the rate of spreading within the growing Atlantic Ocean.

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Deciphering shallow paleomagnetic inclinations: 2. Implications from Late Cretaceous strata overlapping the Insular/Intermontane Superterrane boundary in the southern Canadian Cordillera

Cited by 38 publications

References 68 publications

Deciphering shallow paleomagnetic inclinations: 1. Implications from correlation of Albian volcanic rocks along the Insular/Intermontane Superterrane boundary in the southern Canadian Cordillera

Deciphering shallow paleomagnetic inclinations: 1. Implications from correlation of Albian volcanic rocks along the Insular/Intermontane Superterrane boundary in the southern Canadian Cordillera

Chapter 70 The Elatina glaciation (late Cryogenian), South Australia

The odyssey of the Cache Creek terrane, Canadian Cordillera: Implications for accretionary orogens, tectonic setting of Panthalassa, the Pacific superwell, and break-up of Pangea

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