scholarly journals Ulungarat Basin: Record of a major Middle Devonian to Mississippian syn-rift to post-rift tectonic transition, eastern Brooks Range, Arctic Alaska

Geosphere ◽  
2021 ◽  
Author(s):  
Arlene V. Anderson ◽  
Kristian E. Meisling
Keyword(s):  
Middle Devonian ◽  
Passive Margin ◽  
Rift Basin ◽  
Early Devonian ◽  
Marine Strata ◽  
The North ◽  
Tectonic Transition ◽  
Arctic Alaska ◽  
Tectonic Settings ◽  
Rifted Margin

The Ulungarat Basin of Arctic Alaska is a unique exposed stratigraphic record of the mid-Paleozoic transition from the Romanzof orogeny to post-orogenic rifting and Ellesmerian passive margin subsidence. The Ulungarat Basin succession is composed of both syn-rift and post-rift deposits recording this mid-Paleozoic transition. The syn-rift deposits unconformably overlie highly deformed Romanzof orogenic basement on the mid-Paleozoic regional angular unconformity and are unconformably overlain by post-rift Endicott Group deposits of the Ellesmerian passive margin. Shallow marine strata of Eifelian age at the base of the Ulungarat Formation record onset of rifting and limit age of the Romanzof orogeny to late Early Devonian. Abrupt thickness and facies changes within the Ulungarat Formation and disconformably overlying syn-rift Mangaqtaaq Formation suggest active normal faulting during deposition. The Mangaqtaaq Formation records lacustrine deposition in a restricted down-faulted structural low. The unconformity between syn-rift deposits and overlying post-rift Endicott Group is interpreted to be the result of sediment bypass during deposition of the outboard allochthonous Endicott Group. Within Ulungarat Basin, transgressive post-rift Lower Mississippian Kekiktuk Conglomerate and Kayak Shale (Endicott Group) are older and thicker than equivalents to the north. North of Ulungarat Basin, deformed pre-Middle Devonian rocks were exposed to erosion at the mid-Paleozoic regional uncon­formity for ~50 m.y., supplying sediments to the rift basin and broader Arctic Alaska rifted margin beyond. Although Middle Devonian to Lower Mississip­pian chert- and quartz-pebble conglomerates and sandstones across Arctic Alaska share a common provenance from the eroding ancestral Romanzof highlands, they were deposited in different tectonic settings.

scholarly journals Chapter 4. Paleozoic granitoid magmatism of South and Middle Tien Shan in Uzbekistan

2020 ◽  
pp. 102-163
Author(s):  
Dmitry L. Konopelko ◽  
Keyword(s):  
Early Carboniferous ◽  
Tien Shan ◽  
Passive Margin ◽  
Granitoid Magmatism ◽  
Northern Margin ◽  
The North ◽  
History Of ◽  
Different Depths ◽  
Andean Type ◽  
Tectonic Settings

The Paleozoic evolution of the Southern and Middle Tien Shan terranes is generally associated with the history of two ocean basins - the Turkestan and Paleotethys. Ages of ophiolites indicate the opening of the oceans in Cambrian – Ordovician, and partial closure with formation of an island arc in the northern part of the basin in Ordovician - Silurian. At the northern margin of the Turkestan ocean, the northward subduction under the Middle Tien Shan continued until Devonian, which led to formation of an active margin with granitoids emplaced between 429 and 416 Ma. In the late Devonian, subduction-related magmatism terminated and the whole region developed as passive margin. Northward subduction resumed in the early Carboniferous and formed magmatic Andean-type belt exposed in the Chatkal-Kurama terrane. Late Carboniferous collision resulted in crust thickening and emplacement of postcollisional granitoids. Formation of postcollisional intrusions in different terranes took place in various tectonic settings. Shoshonitic granitoids of the Chatkal-Kurama terrane formed as a result of slab break off at postcollisional stage. Voluminous postcollisional magmatism of Kyzylkum can be explained by delamination of lower crust and its replacement by the material of astenospheric mantle. Coeval emplacement of geochemically contrasting granitoids in the North Nuratau fault zone could result from contemporaneous melting of different protoliths at different depths in a translithospheric shear zone.

scholarly journals Supplemental Material: Ulungarat Basin: Record of a major Middle Devonian to Mississippian syn-rift to post-rift tectonic transition, eastern Brooks Range, Arctic Alaska

2021 ◽  
Author(s):  
A.V. Anderson ◽  
K.E. Meisling
Keyword(s):  
Middle Devonian ◽  
Depositional Environments ◽  
Reference List ◽  
Brooks Range ◽  
Tectonic Transition ◽  
Arctic Alaska ◽  
Age Constraints

<div>Describes the organization, sedimentology, and depositional environments of the Ulungarat Basin succession including description of type sections of the Ulungarat and Mangaqtaaq formations. Table S1 documents published fossil and radiometric age constraints used to construct the mid-Paleozoic tectonostratigraphic chart (Fig. 12), including basis for age assignment and list of source references. A reference list of all sources cited in Table S1 is included.<br></div>

scholarly journals Supplemental Material: Ulungarat Basin: Record of a major Middle Devonian to Mississippian syn-rift to post-rift tectonic transition, eastern Brooks Range, Arctic Alaska

2021 ◽  
Author(s):  
A.V. Anderson ◽  
K.E. Meisling
Keyword(s):  
Middle Devonian ◽  
Depositional Environments ◽  
Reference List ◽  
Brooks Range ◽  
Tectonic Transition ◽  
Arctic Alaska ◽  
Age Constraints

<div>Describes the organization, sedimentology, and depositional environments of the Ulungarat Basin succession including description of type sections of the Ulungarat and Mangaqtaaq formations. Table S1 documents published fossil and radiometric age constraints used to construct the mid-Paleozoic tectonostratigraphic chart (Fig. 12), including basis for age assignment and list of source references. A reference list of all sources cited in Table S1 is included.<br></div>

scholarly journals Supplemental Material: Ulungarat Basin: Record of a major Middle Devonian to Mississippian syn-rift to post-rift tectonic transition, eastern Brooks Range, Arctic Alaska

2021 ◽  
Author(s):  
A.V. Anderson ◽  
K.E. Meisling
Keyword(s):  
Middle Devonian ◽  
Depositional Environments ◽  
Reference List ◽  
Brooks Range ◽  
Tectonic Transition ◽  
Arctic Alaska ◽  
Age Constraints

<div>Describes the organization, sedimentology, and depositional environments of the Ulungarat Basin succession including description of type sections of the Ulungarat and Mangaqtaaq formations. Table S1 documents published fossil and radiometric age constraints used to construct the mid-Paleozoic tectonostratigraphic chart (Fig. 12), including basis for age assignment and list of source references. A reference list of all sources cited in Table S1 is included.<br></div>

Devonian–Carboniferous paleogeography and orogenesis, northern Yukon and adjacent Arctic Alaska

2007 ◽  
Vol 44 (5) ◽  
pp. 679-694 ◽  
Author(s):  
Larry S Lane
Keyword(s):  
Early Carboniferous ◽  
Sensu Stricto ◽  
Thrust Faults ◽  
Mackenzie Delta ◽  
Early Devonian ◽  
The North ◽  
Late Cambrian ◽  
Arctic Alaska ◽  
Tectonic Transport ◽  
Regional Tectonic

Surface and subsurface data from northern Yukon document a northward facies transition from shelf carbonates to basinal graptolitic shales and cherts from Late Cambrian to Early Devonian time. Parts of this north-facing continental margin were deformed during separate orogenic events of Early Devonian and Early Carboniferous ages. The first event, the Romanzof Orogeny, is identified in exposures across northwestern Yukon, in adjacent northeastern Alaska, and locally in the subsurface of the Alaska North Slope. It resulted in tight folds, north-directed thrust faults, and intrusion by Late Devonian posttectonic granitic plutons. Notwithstanding the thrust-fault orientations, southward diminution of deformation intensity combined with facies variations suggest that tectonic transport was generally southward. Evidence for an Early Carboniferous event is preserved in the northern Richardson Mountains and locally in the subsurface of the Mackenzie Delta region. It consists of detached open folds and minor thrust faults. Geological and geophysical data from northern Yukon document the location and orientation of the Early Carboniferous deformation front, and define a regional tectonic transport direction toward the south or southeast. This event is a distal foreland element of the Ellesmerian Orogeny (sensu stricto) of the Canadian Arctic Islands and is distinct from the Romanzof event in age, intensity, and extent. Endicott and Lisburne group strata, deposited on a southwest-facing subsiding shelf, overstep rocks deformed by the Romanzof event even as Ellesmerian deformation encroached from the north.

The Ammassalik Rifted Margin TSE, southern East and South-East Greenland margin

2021 ◽  
pp. M57-2016-8
Author(s):  
Michael B. W. Fyhn ◽  
John R. Hopper ◽  
Joanna Gerlings
Keyword(s):  
Petroleum System ◽  
Continental Margins ◽  
East Greenland ◽  
Marine Strata ◽  
The North ◽  
Main Challenge ◽  
Fault Structures ◽  
Uplift And Erosion ◽  
Greenland Margin ◽  
Rifted Margin

AbstractThe Ammassalik Rifted Margin TSE comprises the Ammassalik and the Kangerlussuaq rift basins located on the southern East and South-East Greenland margin. The offshore Ammassalik Basin is one of the last virtually undescribed segments of the North Atlantic continental margins with a very sparse seismic coverage. The basin is compartmentalized into smaller sub-basins up to at least 4 km deep blanketed by Paleocene-Eocene basalt towards the east. Albian sediments cored in the basin suggest an at least partly Cretaceous age, making the Ammassalik Basin a likely analogue to basins on the conjugate outer British continental margin. However, the deeper, undated succession could include pre-Cretaceous strata. Located onshore southern East Greenland, the Kangerlussuaq Basin contains a Barremian/Aptian-Danian succession of estuarine-marine strata overlain by Paleocene fluvial sediments, basalts and thinner marine interludes. The sedimentary succession is less than 1 km thick. Cenozoic uplift and erosion affected both basins. Unlike the Kangerlussuaq Basin, the Ammassalik Basin may contain a working petroleum system. Together with the very large fault structures identified in the basin, this makes the Ammassalik Basin an interesting future exploration target, with the main challenge being to demonstrate a mature source rock, together with qualifying the effects of the Paleocene-Eocene magmatism and Cenozoic exhumation on the potential petroleum system.

scholarly journals Supplemental Material: Ulungarat Basin: Record of a major Middle Devonian to Mississippian syn-rift to post-rift tectonic transition, eastern Brooks Range, Arctic Alaska

2021 ◽  
Author(s):  
A.V. Anderson ◽  
K.E. Meisling
Keyword(s):  
Middle Devonian ◽  
Depositional Environments ◽  
Reference List ◽  
Brooks Range ◽  
Tectonic Transition ◽  
Arctic Alaska ◽  
Age Constraints

<div>Describes the organization, sedimentology, and depositional environments of the Ulungarat Basin succession including description of type sections of the Ulungarat and Mangaqtaaq formations. Table S1 documents published fossil and radiometric age constraints used to construct the mid-Paleozoic tectonostratigraphic chart (Fig. 12), including basis for age assignment and list of source references. A reference list of all sources cited in Table S1 is included.<br></div>

scholarly journals Palynological indications for Silurian – earliest Devonian age strata in the Netherlands

2021 ◽  
Vol 100 ◽  
Author(s):  
Alexander J.P. Houben ◽  
Geert-Jan Vis
Keyword(s):  
The Netherlands ◽  
Core Material ◽  
Late Devonian ◽  
Time Interval ◽  
The South ◽  
Early Devonian ◽  
The North ◽  
Depositional Settings ◽  
Palynological Study ◽  
Devonian Age

Abstract Knowledge of the stratigraphic development of pre-Carboniferous strata in the subsurface of the Netherlands is very limited, leaving the lithostratigraphic nomenclature for this time interval informal. In two wells from the southwestern Netherlands, Silurian strata have repeatedly been reported, suggesting that these are the oldest ever recovered in the Netherlands. The hypothesised presence of Silurian-aged strata has not been tested by biostratigraphic analysis. A similar lack of biostratigraphic control applies to the overlying Devonian succession. We present the results of a palynological study of core material from wells KTG-01 and S05-01. Relatively low-diversity and poorly preserved miospore associations were recorded. These, nonetheless, provide new insights into the regional stratigraphic development of the pre-Carboniferous of the SW Netherlands. The lower two cores from well KTG-01 are of a late Silurian (Ludlow–Pridoli Epoch) to earliest Devonian (Lochkovian) age, confirming that these are the oldest sedimentary strata ever recovered in the Netherlands. The results from the upper cored section from the pre-Carboniferous succession in well KTG-01 and the cored sections from the pre-Carboniferous succession in well S05-01 are more ambiguous. This inferred Devonian succession is, in the current informal lithostratigraphy of the Netherlands, assigned to the Banjaard group and its subordinate Bollen Claystone formation, of presumed Frasnian (i.e. early Late Devonian) age. Age-indicative Middle to Late Devonian palynomorphs were, however, not recorded, and the overall character of the poorly preserved palynological associations in wells KTG-01 and S05-01 may also suggest an Early Devonian age. In terms of lithofacies, however, the cores in well S05-01 can be correlated to the upper Frasnian – lower Famennian Falisolle Formation in the Campine Basin in Belgium. Hence, it remains plausible that an unconformity separates Silurian to Lower Devonian strata from Upper Devonian (Frasnian–Famennian) strata in the SW Netherlands. In general, the abundance of miospore associations points to the presence of a vegetated hinterland and a relatively proximal yet relatively deep marine setting during late Silurian and Early Devonian times. This differs markedly from the open marine depositional settings reported from the Brabant Massif area to the south in present-day Belgium, suggesting a sediment source to the north. The episodic presence of reworked (marine) acritarchs of Ordovician age suggests the influx of sedimentary material from uplifted elements on the present-day Brabant Massif to the south, possibly in relation to the activation of a Brabant Arch system.

scholarly journals I.—On a New Cephalaspis Discovered in America, etc.

1870 ◽  
Vol 7 (75) ◽  
pp. 397-399
Author(s):  
E. Ray Lankester
Keyword(s):  
Middle Devonian ◽  
Lower Devonian ◽  
The North ◽  
North Side

Principal Dawson, of Montreal,. Canada, has placed in my hands for description a remarkably interesting specimen, indicating a species of the genus Cephalaspis in transatlantic Silurio-Devonian beds. He writes, “The specimen was found by one of my assistants, Mr. G. F. Kennedy, B.A., when collecting with me, in a bed charged with remains of Psilophyton, on the north side of Gaspé Bay. The geological horizon is below the middle of the Gaspé Sandstones, but several hundreds of feet above their actual base, so that the specimen may be regarded as either Lower Devonian or Lower Middle Devonian.

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