The tectonic evolution of the Arctic since Pangea breakup: Integrating constraints from surface geology and geophysics with mantle structure

Shephard, Grace E.; Müller, R. Dietmar; Seton, Maria

doi:10.1016/j.earscirev.2013.05.012

Cited by 171 publications

(229 citation statements)

References 106 publications

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“…20) shows that a substantial number of Isachsen Formation lavas follow the mixing curve between the two end-members and therefore requires addition of subducted sediments of up to 10%. Our major assumption in constructing the subducted sediment mixing model is that the Ba/Nb, Ba/ Th and time-integrated Sm-Nd isotopic compositions that have been compiled for the Aleutian and Alaska subduction zone (Plank & Langmuir, 1998) remained essentially constant from ~200 Ma to the present-day in the north Pacific Ocean (Shephard et al, 2013). As Fig.…”

Section: Crustal Interaction Levelsmentioning

confidence: 99%

“…It has been speculated that the downgoing slab imaged in tomographic models represents the remains of the Farallon, Izanagi and Cache Creek slabs (depending on specific locations: Shephard et al, 2013Shephard et al, , 2014 which are precursors to the present-day Juan de Fuca and Aleutian subduction zones. Based on seismic and numerical modelling, only about 15-30% of sediment gets accreted onto accretionary wedges at subduction zones, the balance (70-85%) being subducted into the Earth's interior (e.g., von Huene & Scholl, 1991).…”

Section: Crustal Interaction Levelsmentioning

confidence: 99%

“…What might have been the cause of this heterogeneity? Based on time-integrated tomographic modelling, multiple north-verging paleosubduction zone fronts have been hypothesised to have existed beneath Canada's Arctic Islands (Shephard et al, 2013(Shephard et al, , 2014). An issue to address here is whether there is evidence to suggest the chemistry of magmas feeding either the South Fiord intrusions (which we suggest are linked with the younger Strand Fiord Formation lavas) or the older Isachsen Formation lavas were affected by subducted sediment in the upper mantle.…”

Section: Crustal Interaction Levelsmentioning

confidence: 99%

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The High Arctic LIP in Canada: Trace element and Sm–Nd isotopic evidence for the role of mantle heterogeneity and crustal assimilation

Kingsbury¹,

Ernst²,

Cousens³

et al. 2016

NJG

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The Cretaceous geological evolution of the Canadian Arctic was marked by voluminous magmatism comprising Canada's portion of the High Arctic large igneous province (HALIP) that is thought to have resulted from a mantle plume head. This magmatism is largely recorded as extensive Early Cretaceous lavas of the Isachsen Formation, Late Cretaceous continental flood basalts of the Strand Fiord Formation, and an extensive network of dykes and sills forming their plumbing systems. Axel Heiberg Island near South Fiord contains a small, structurally complex portion of the overall network of HALIP tabular intrusions, from which samples from the South Fiord intrusions and Isachsen Formation basaltic lavas were analysed to better understand their petrogenesis. Specifically, we apply trace-element ratios together with Sm-Nd isotope systematics in order to identify processes that shaped the chemical evolution of the South Fiord intrusions and Isachsen Formation lavas, to identify (1) mantle source chemistries and (2) the role of crustal assimilation. On the basis of Sm-Nd isotopic results, South Fiord intrusion magmas were derived from a homogeneous mantle source whereas a more heterogeneous source is invoked for the Isachsen Formation lavas. Furthermore, modelling with Th/ La, Nb/U, Ba/Th and Ba/Nb suggests that South Fiord intrusive magmatism was contaminated by sedimentary rocks from the Sverdrup Basin. Conversely, a trend towards high Ba/Th in Isachsen Formation lavas suggests a subducted sediment component derived from extinct subduction zones. We surmise that (1) South Fiord intrusive rocks are geochemically distinct from the Isachsen Formation lavas and (2) the HALIP mantle plume head intersected and incorporated sediments from ancestral subduction zones to the present-day Aleutian and Alaska subduction zones to produce the Isachsen Formation flows, whereas the South Fiord intrusions (and correlated Strand Fiord magmatism) were generated from plume material that interacted with upper crustal sedimentary rocks.

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Section: Crustal Interaction Levelsmentioning

confidence: 99%

Section: Crustal Interaction Levelsmentioning

confidence: 99%

Section: Crustal Interaction Levelsmentioning

confidence: 99%

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The High Arctic LIP in Canada: Trace element and Sm–Nd isotopic evidence for the role of mantle heterogeneity and crustal assimilation

Kingsbury¹,

Ernst²,

Cousens³

et al. 2016

NJG

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“…The temporal relationship between the main intervals of the HALIP magmatism at c. 130-120 Ma and c. 100 Ma and the rift-drift transition in the segments of the Amerasia Basin is still unclear and the time for the onset of seafloor spreading is discussed controversially (summarised by Dove et al, 2010;Funck et al, 2011;Shephard et al, 2013). The geochronological database is still very limited and more samples and data from the basement of the Amerasia Basin and the Alpha-Mendeleev Ridge as well as from the possible conjugate Siberian margin are necessary to understand the geological history of the Amerasia Basin of the Arctic Ocean.…”

Section: North Greenlandmentioning

confidence: 99%

Multistage Cretaceous magmatism in the northern coastal region of Ellesmere Island and its relation to the formation of Alpha Ridge – evidence from aeromagnetic, geochemical and geochronological data

Estrada¹,

Damaske²,

Henjes‐Kunst³

et al. 2016

NJG

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The poorly studied Alpha-Mendeleev Ridge of the Amerasia Basin of the Arctic Ocean is covered by a large magnetic high and interpreted to be part of the Cretaceous High Arctic Large Igneous Province (HALIP). At the north coast of Ellesmere Island, in the Yelverton Bay area, this characteristic magnetic high overlaps the shelf and the coastal area. Results of aeromagnetic surveys, geological fieldwork, geochronological, geochemical and Sr-Nd isotope analysis were combined to study the tectonic history of this part of the Canadian Polar margin. The basement, consisting of metamorphic rocks of the Pearya Terrane, was strongly affected by HALIP-related magmatism that is responsible for characteristic positive magnetic anomaly patterns. A broad magnetic high that can be traced to the Alpha Ridge covers the shelf and coastal areas of Yelverton Bay. It is caused by a voluminous intrusion into the continental crust at a depth of ca. 6-15 km. A chain of small positive magnetic anomalies crosses Wootton Peninsula from SW to NE and then curves into a NNE-SSW trend. It follows the coastline onshore and offshore and superimposes the southern and eastern margins of the broad magnetic high. On land, the anomaly chain covers fault-bounded outcrops of the Wootton Intrusive Complex (WIC) and the Hansen Point Volcanic Complex (HPVC), indicating that the entire anomaly chain is associated with a volcanogenic sequence. Rhyodacite that forms large parts of the HPVC east and west of Yelverton Bay extruded between c. 104 and 97 Ma (LA-ICP-MS U-Pb zircon ages). It originates from a tholeiitc suite and is probably genetically related to the deep intrusion. The HPVC together with the rhyodacite has an age range of c. 104-74 Ma and includes the mildly alkaline WIC (93-92 Ma). The northern coast of Ellesmere Island shows some characteristic features of a magma-rich rifted margin indicating an extensional evolution parallel to the North American margin between the openings of the Canada Basin and the Eurasian Basin.

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“…The Gakkel Ridge, for example, is one of the earth's two ultraslow spreading ridges, and the creation of new crust at the ridge, through volcanism and tectonic faulting, is poorly understood. While the evolution of the Eurasian Basin is generally known, the evolution of the Amerasian Basin is controversial ( Shephard et al, 2013). Other features of the Arctic, such as the Lomonosov Ridge and Chukchi Shelf, are even less well understood.…”

Section: Monitoring Seismicity In the Arcticmentioning

confidence: 99%

Multipurpose Acoustic Networks in the Integrated Arctic Ocean Observing System

Mikhalevsky¹,

Sagen²,

Worcester³

et al. 2015

ARCTIC

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ABSTRACT. The dramatic reduction of sea ice in the Arctic Ocean will increase human activities in the coming years. This activity will be driven by increased demand for energy and the marine resources of an Arctic Ocean accessible to ships. Oil and gas exploration, fisheries, mineral extraction, marine transportation, research and development, tourism, and search and rescue will increase the pressure on the vulnerable Arctic environment. Technologies that allow synoptic in situ observations year-round are needed to monitor and forecast changes in the Arctic atmosphere-ice-ocean system at daily, seasonal, annual, and decadal scales. These data can inform and enable both sustainable development and enforcement of international Arctic agreements and treaties, while protecting this critical environment. In this paper, we discuss multipurpose acoustic networks, including subsea cable components, in the Arctic. These networks provide communication, power, underwater and under-ice navigation, passive monitoring of ambient sound (ice, seismic, biologic, and anthropogenic), and acoustic remote sensing (tomography and thermometry), supporting and complementing data collection from platforms, moorings, and vehicles. We support the development and implementation of regional to basin-wide acoustic networks as an integral component of a multidisciplinary in situ Arctic Ocean observatory.

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The tectonic evolution of the Arctic since Pangea breakup: Integrating constraints from surface geology and geophysics with mantle structure

Cited by 171 publications

References 106 publications

The High Arctic LIP in Canada: Trace element and Sm–Nd isotopic evidence for the role of mantle heterogeneity and crustal assimilation

The High Arctic LIP in Canada: Trace element and Sm–Nd isotopic evidence for the role of mantle heterogeneity and crustal assimilation

Multistage Cretaceous magmatism in the northern coastal region of Ellesmere Island and its relation to the formation of Alpha Ridge – evidence from aeromagnetic, geochemical and geochronological data

Multipurpose Acoustic Networks in the Integrated Arctic Ocean Observing System

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