Tectonic evolution and significance of Silurian – Early Devonian hinterland-directed deformation in the internal Humber zone of the southern Quebec Appalachians

2003 ◽  
Vol 40 (2) ◽  
pp. 255-268 ◽  
Author(s):  
Sébastien Castonguay ◽  
Alain Tremblay
Keyword(s):  
New England ◽  
Tectonic Evolution ◽  
Normal Faults ◽  
Early Devonian ◽  
Middle Ordovician ◽  
Tectonic History ◽  
History Of ◽  
Connecticut Valley ◽  
Laurentian Margin ◽  
Nappe Emplacement

In the southern Quebec Appalachians, the early tectonic history of the Laurentian margin (Humber zone) comprises foreland-propagating, northwest-directed thrust faulting, nappe emplacement, and regional prograde metamorphism in response to the obduction of large ophiolitic nappes during the Taconian orogeny. In the internal Humber zone, this event is dated at 462 ± 3 Ma (late Middle Ordovician), which is interpreted to represent the timing of near-peak Taconian metamorphism. Superimposed hinterland-directed structures are accompanied by retrograde metamorphism and consist of back thrusts and normal faults, which respectively delimit the northwestern and southeastern limbs of the Sutton and Notre-Dame mountains anticlinoria, both salient structures of the internal Humber zone of southern Quebec. Geochronologic data on the timing of hinterland-directed deformation vary from 431 to 411 Ma. Two tectonic models are presented and discussed, which may account for the Silurian – Early Devonian evolution of the Laurentian margin: (1) back thrusting and syn- to post-compressional crustal extension in response to the tectonic wedging of basement-cored duplexes inducing delamination of supracrustal rocks; (2) tectonic exhumation of the internal Humber zone by extensional collapse. Evidence for Silurian – Early Devonian extensional tectonism in the Humber zone provides the basement infrastructures necessary for the creation and the onset of sedimentation in the Gaspé Belt basins (e.g., Connecticut Valley – Gaspé synclinorium). Several structural, metamorphic features in the internal Humber zone of the northwestern New England Appalachians yield analogous characteristics with those of southern Quebec and may have shared a similar Silurian – Early Devonian tectonic evolution.

Paleozoic subduction of the Mongol-Okhotsk oceanic plate: insight from the petrogenesis of Ordovician to Devonian granitic plutons in the Hangay Range, central Mongolia

2021 ◽  
Author(s):  
jiaqi Ling ◽  
pengfei Li
Keyword(s):  
Tectonic Evolution ◽  
Magma Source ◽  
Oceanic Plate ◽  
Early Devonian ◽  
Central Mongolia ◽  
Middle Ordovician ◽  
Basaltic Rocks ◽  
History Of ◽  
Geochemical Studies ◽  
T Values

<p>Email: [email protected]; [email protected]</p><p> </p><p>The pre-Mesozoic subduction history of the Mongol-Okhotsk oceanic plate has been poorly understood. Here we conducted geochronological and geochemical studies on four granitic plutons in the westernmost Mongol-Okhotsk Orogen (Hangay Range), with an aim to understand their petrogenesis and role in the Paleozoic tectonic evolution of the Mongol-Okhotsk Orogen. Our geochronological results constrain four granitic plutons to be emplaced from middle Ordovician to early Devonian. Geochemically, the Ordovician pluton belongs to A2-type granites, and three Silurian to Devonian plutons show the characteristics of I-type granites. These granitic plutons were probably generated by partial melting of basaltic rocks in the lower crust given the high contents of Na<sub>2</sub>O and K<sub>2</sub>O. The negative ε<sub>Nd</sub>(t) values (-4.7 to -0.9) and variable ε<sub>Hf</sub>(t) values (-2.6 to +6.1) for the four granitic plutons suggest that ancient basement materials were possibly involved in the magma source. We further investigate the geodynamic origin of these plutons in the context of the Paleozoic tectonics of the Mongol-Okhotsk Orogen, and we conclude that they were probably formed in response to the Ordovician to Devonian subduction of the Mongol-Okhotsk oceanic plate.</p>

scholarly journals Plans d’eau glaciaires et isostasie dans les bassins de la haute Ware et de la rivière Otter, Massachusetts (2e partie)

2005 ◽  
Vol 17 (41) ◽  
pp. 251-264
Author(s):  
Gilbert Cestre
Keyword(s):  
New England ◽  
Eastern Canada ◽  
Low Area ◽  
Proglacial Lakes ◽  
Close Relationship ◽  
Long Time ◽  
History Of ◽  
Connecticut Valley ◽  
The City ◽  
Detailed Work

The present study is one of the unpublished research projects which are known to have been conducted in New England and in Eastern Canada under the guidance of the late Richard J. LOUGEE, long-time professor of Geomorphology at Clark University. Over a number of years, this writer has worked in close relationship with Lougee and much evidence in the field was studied together. It is believed that here has been recorded a most detailed work of surveying, and this undoubtedly accounts for the somewhat exceptional results that will be presented. The area selected for this study (about 80% of it is woodland) is located in the highlands of Central Massachusetts in Worcester County, about twenty miles (32 kilo-meters) northwest of the city of Worcester. It consists of the valley of the Otter River draining north, and of a small portion of the East Branch of the Ware River draining south. Since completion of this study, parts of the low area which held the ancient glacial lakes have been flooded to become water reservoirs. That proglacial lakes, though temporary they may have been, once submerged much of the area under study, is shown by an abundance of deltas, kames, eskers and deltaic kames terraces. It is believed that all of these were built under water in such lakes. Other features, such as kettle-holes and glacial outlets, especially ice-marginal channels cut diagonally down the slope, have also been studied. By plotting on a profile of the most characteristic elevations (often carefully surveyed), it is possible to find the water planes of ancient proglacial lakes. To this must be added experiments conducted in a sedimentation tank as also measurements of both the imbrication of cobbles in eskers and the « smoothness indexes » of such stones and pebbles, using A. Cailleux' methods. Thus were obtained results which tend to show that : 1- the area under study probably was in a deep interlobate space created between the Connecticut Valley lobe to the west and the Boston Basin lobe to the east ; 2— ice-marginal channels are an indication of the existence of a thick, fast-retreating ice border ; 3- an isostatic balance restored itself by sometimes quick and strong adjustments of the crust of the earth ; 4— an early upwarping, made up of various zones of tilting articulated on hinge lines, has been referred to as Hubbard Uplift and is the earliest known in the post-Glacial history of New England.

scholarly journals The Services of the Mathers in New England Religious Development

1893 ◽  
Vol 5 ◽  
pp. 61-85
Author(s):  
Williston Walker
Keyword(s):  
New England ◽  
Religious Development ◽  
General Observation ◽  
Three Generations ◽  
History Of ◽  
Connecticut Valley ◽  
Successive Generations ◽  
Universal Law ◽  
Democratic Constitution ◽  
Universal Rule

It is a fact of general observation that hereditary talent is rare. The history of our country, whether in the ecclesiastical or secular field, shows but few instances in which prominent service has been rendered by three generations of the same lineage. There have been, indeed, conspicuous exceptions to this wellnigh universal rule. The Winthrops and the Adamses of Massachusetts, for instance, or the Edwardses in the Connecticut valley, have placed their country in debt to their successive generations. But these illustrations are noticeable for their uncommonness. They seem to defy the universal law; and we look upon them with interest because, while they reveal the possibility of an aristocracy of birth and service, they show that the democratic constitution of America accords substantially with the general principles which govern our race in its development.

Lower Paleozoic stratigraphic and biostratigraphic correlations in the Canadian Cordillera: implications for the tectonic evolution of the Laurentian margin

2003 ◽  
Vol 40 (12) ◽  
pp. 1739-1753 ◽  
Author(s):  
Leanne J Pyle ◽  
Christopher R Barnes
Keyword(s):  
Tectonic Evolution ◽  
Passive Margin ◽  
Lower Paleozoic ◽  
Early Devonian ◽  
Southern Rocky Mountains ◽  
Peace River ◽  
Regional Correlation ◽  
Laurentian Margin ◽  
Peace River Arch ◽  
Early Late

The ancient Laurentian margin rifted in the latest Neoproterozoic to early Cambrian but appears not to have developed as a simple passive margin through a long, post-rift, drift phase. Stratigraphic and conodont biostratigraphic information from four platform-to-basin transects across the margin has advanced our knowledge of the early Paleozoic evolution of the margin. In northeastern British Columbia, two northern transects span the Macdonald Platform to Kechika Trough and Ospika Embayment, and a third transect spans the parautochthonous Cassiar Terrane. In the southern Rocky Mountains, new conodont biostratigraphic data for the Ordovician succession of the Bow Platform is correlated to coeval basinal facies of the White River Trough. In total, from 26 stratigraphic sections, over 25 km of strata were measured and > 1200 conodont samples were collected that yielded over 100 000 conodont elements. Key zonal species were used for regional correlation of uppermost Cambrian to Middle Devonian strata along the Cordillera. The biostratigraphy temporally constrains at least two periods of renewed extension along the margin, in the latest Cambrian and late Early Ordovician. Alkalic volcanics associated with abrupt facies changes across the ancient shelf break, intervals of slope debris breccia deposits, and distal turbidite flows suggest the margin was characterized by intervals of volcanism, basin foundering, and platform flooding. Siliciclastics in the succession were sourced by a reactivation of tectonic highs, such as the Peace River Arch. Prominent hiatuses punctuate the succession, including unconformities of early Late Ordovician, sub-Llandovery, possibly Early to Middle Silurian and Early Devonian ages.

scholarly journals A Lower Devonian age for the Corvock Granite and its significance for the structural history of South Mayo and the Laurentian margin of western Ireland

2021 ◽  
Author(s):  
John Graham ◽  
Nancy Riggs
Keyword(s):  
Lower Devonian ◽  
Early Devonian ◽  
North East ◽  
The North ◽  
Granite Emplacement ◽  
History Of ◽  
Western Ireland ◽  
Laurentian Margin ◽  
Devonian Age ◽  
Restraining Bend

The Silurian Croagh Patrick succession, which crops out just south of a fundamental Caledonian structural zone near Clew Bay, western Ireland, is a series of psammites and pelites with a strong penetrative cleavage. These rocks are intruded by the Corvock granite. A suite of minor intrusions associated with the granite contains the regional cleavage whereas the Corvock granite is undeformed. New U-Pb dates are 413 + 7 / -4 Ma for a strongly cleaved sill and 410 ± 4 Ma for the main granite and closely constrain the age of crystallization of the granite and coeval cleavage formation as Lower Devonian (Lochkovian or Pragian), implying syn- to late-kinematic granite emplacement. These data are consistent with evidence for strong sinistral shear shown by the Ox Mountains granodiorite just to the north-east dated at 412.3 ± 0.8 Ma. This Devonian cleavage is superimposed on Ordovician rocks of the South Mayo Trough. The localisation of the strong deformation is interpreted as being due to its position at a restraining bend during regional sinistral motion on a segment of the Fair Head-Clew Bay Line to the north. Contemporaneous deformation in the syn-kinematic Donegal batholith suggests a transfer of sinistral motion to this intra-Grampian structure rather than simple along-strike linkage to the Highland Boundary Fault in Scotland. Our new data indicate diachronous deformation during the late Silurian and early Devonian history of the Irish and Scottish Caledonides and also support previous interpretations of diachronous deformation between these areas and the Appalachian orogens.

scholarly journals Late Cretaceous to Paleogene post-obduction extension and subsequent Neogene compression in the Oman Mountains

GeoArabia ◽  
2006 ◽  
Vol 11 (4) ◽  
pp. 17-40 ◽  
Author(s):  
Marc Fournier ◽  
Claude Lepvrier ◽  
Philippe Razin ◽  
Laurent Jolivet
Keyword(s):  
Late Cretaceous ◽  
Large Scale ◽  
Early Miocene ◽  
Normal Faults ◽  
Zagros Mountains ◽  
Lower Eocene ◽  
Oman Mountains ◽  
Tectonic History ◽  
History Of ◽  
Arabian Platform

ABSTRACT After the obduction of the Semail ophiolitic nappe onto the Arabian Platform in the Late Cretaceous, north Oman underwent several phases of extension before being affected by compression in the framework of the Arabia-Eurasia convergence. A tectonic survey, based on structural analysis of fault-slip data in the post-nappe units of the Oman Mountains, allowed us to identify major events of the Late Cretaceous and Cenozoic tectonic history of northern Oman. An early ENE-WSW extensional phase is indicated by synsedimentary normal faults in the Upper Cretaceous to lower Eocene formations. This extensional phase, which immediately followed ductile extension and exhumation of high-pressure rocks in the Saih Hatat region of the Oman Mountains, is associated with large-scale normal faulting in the northeast Oman margin and the development of the Abat Basin. A second extensional phase, recorded in lower Oligocene formations and only documented by minor structures, is characterized by NNE (N20°E) and NW (N150°E) oriented extensions. It is interpreted as the far-field effect of the Oligocene-Miocene rifting in the Gulf of Aden. A late E-W to NE-SW directed compressional phase started in the late Oligocene or early Miocene, shortly after the collision in the Zagros Mountains. It is attested by folding, and strike-slip and reverse faulting in the Cenozoic series. The direction of compression changed from ENE-WSW in the Early Miocene to almost N-S in the Pliocene.

INTERPRETING REACTION HISTORIES AND P-T-T PATHS FROM IN-SITU MONAZITE AND XENOTIME PETROCHRONOLOGY: IMPLICATIONS FOR THE TECTONIC HISTORY OF NEW ENGLAND

2020 ◽  
Author(s):  
Ian W. Hillenbrand ◽  
◽  
Michael L. Williams ◽  
Michael J. Jercinovic ◽  
Daniel J. Tjapkes
Keyword(s):  
New England ◽  
Tectonic History ◽  
History Of
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