Stratigraphy and structure of the Kootenay Arc in the Riondel area, southeastern British Columbia

1977 ◽  
Vol 14 (10) ◽  
pp. 2301-2315 ◽  
Author(s):  
Trygve Höy
Keyword(s):  
Root Zone ◽  
Phase 1 ◽  
Small Scale ◽  
Reverse Fault ◽  
Lake Area ◽  
Phase 2 ◽  
The West ◽  
Lower Paleozoic ◽  
Metasedimentary Rocks ◽  
The North

The succession of metasedimentary rocks in the Riondel area is correlated with a Hadrynian–Cambrian sequence established in the Duncan Lake area to the north and the Salmo area to the south. The succession includes phyllite, schist, and quartz-pebble conglomerate of the Horset hie f Creek Group; quartzite, siltstone, and schist of the Hamill Group; calcareous schist of the Mohican Formation; and a prominent marble, the Badshot Formation. The youngest metasedimentary rocks include para-amphibolite, calc-silicate gneiss, and pelitic schist of the Lardeau Group.A lower Paleozoic succession of metasedimentary locks in the western part of the Riondel area forms a large overturned panel which is the lower limb of a phase 1 recumbent anticline, the 'Riondel nappe'. The root zone of the nappe is inferred to lie beneath a west-dipping reverse fault, the 'West Bernard fault', which separates the inverted panel of rocks on the west from the right-way-up panel in the east. Tight to isoclinal north–south trending phase 2 folds with upright to west-dipping axial surfaces and sub-horizontal fold axes are superposed on the Riondel nappe. Small-scale, south westerly trending phase 3 warps and open folds are overprinted on the limps of the older folds.The age of the Riondel nappe cannot be positively determined. It is assumed to have developed during the Caribooan orogeny in Devono-Mississippian (?) time and subsequently to have been deformed by phase 2 folding and associated faulting in middle Jurassic to early Cretaceous time.

Geology of the Nemo Lakes belt, northern Valhalla Range, southeast British Columbia

1981 ◽  
Vol 18 (5) ◽  
pp. 944-958 ◽  
Author(s):  
Randall R. Parrish
Keyword(s):  
British Columbia ◽  
Large Scale ◽  
Phase 1 ◽  
Normal Fault ◽  
Columbia River ◽  
Ultramafic Rocks ◽  
Phase 2 ◽  
Metasedimentary Rocks ◽  
The North ◽  
Gneiss Complex

High-grade metasedimentary rocks, probably of both early Paleozoic and late Paleozoic – Triassic ages, underlie an area termed the Nemo Lakes belt between Slocan and Arrow Lakes in the northern Valhalla Range, southeastern British Columbia. The rocks have experienced two possibly related periods of major folding. Phase 1, accompanied and outlasted by metamorphism at P–T conditions of 5.0–6.8 kbar (500–680 MPa) and 630–680 °C, involved emplacement of ultramafic rocks, major faulting, and folding. Phase 2 involved large-scale inclined to upright folds which were dominantly south-verging, deforming the phase 1 fabric. Both phases probably occurred in the Middle to Late Jurassic, as part of the Columbian Orogeny.Rocks lithologically and structurally similar to those of the Nemo Lakes belt are found across the Rodd Creek fault near the Columbia River and extend the general continuity of the belt into the Shuswap metamorphic complex.Plutonic rocks, some of which bracket the movement on the Rodd Creek fault, the southern extension of the Columbia River fault zone, range in age from Middle Jurassic to EoceneIn the valley of Slocan Lake, a major normal fault is postulated on structural and metamorphic grounds and may be related to the north–south arching of the Valhalla gneiss complex. It is suggested that this arching and uplift, which followed phase 2 deformation, produced both the fault and a zone of cataclasis on the eastern side of the complex, and gave rise to its domal shape.

scholarly journals Tilt and strain change during the explosion at Minami-dake, Sakurajima, on November 13, 2017

2021 ◽  
Author(s):  
Kohei Hotta ◽  
Masato Iguchi
Keyword(s):  
Ground Deformation ◽  
Large Strain ◽  
Phase 1 ◽  
Small Strain ◽  
Phase 2 ◽  
The North ◽  
Strombolian Eruption ◽  
Strain Change ◽  
Tilt Change

Abstract We herein propose an alternative model for deformation caused by an eruption at Sakurajima, which have been previously interpreted as being due to a Mogi-type spherical point source beneath Minami-dake. On November 13, 2017, a large explosion with a plume height of 4,200 m occurred at Minami-dake. During the three minutes following the onset of the explosion (November 13, 2017, 22:07–22:10 (Japan standard time (UTC+9); the same hereinafter), phase 1, a large strain change was detected at the Arimura observation tunnel (AVOT) located approximately 2.1 km southeast from the Minami-dake crater. After the peak of the explosion (November 13, 2017, 22:10–24:00), phase 2, a large deflation was detected at every monitoring station due to the continuous Strombolian eruption. Subsidence toward Minami-dake was detected at five out of six stations whereas subsidence toward the north of Sakurajima was detected at the newly installed Komen observation tunnel (KMT), located approximately 4.0 km northeast from the Minami-dake crater. The large strain change at AVOT as well as small tilt changes of all stations and small strain changes at HVOT and KMT during phase 1 can be explained by a very shallow deflation source beneath Minami-dake at 0.1 km below sea level (bsl). For phase 2, a deeper deflation source beneath Minami-dake at a depth of 3.3 km bsl was found in addition to the shallow source beneath Minami-dake which turned inflation after the deflation obtained during phase 1. However, this model cannot explain the tilt change of KMT. Adding a spherical deflation source beneath Kita-dake at a depth of 3.2 km bsl can explain the tilt and strain change at KMT and the other stations. The Kita-dake source was also found in a previous study of long-term ground deformation. Not only the deeper Minami-dake source MD but also the Kita-dake source deflated due to the Minami-dake explosion.

scholarly journals The country rocks of Devonian magmatism in the North Patagonian Massif and Chaitenia

2018 ◽  
Vol 45 (3) ◽  
pp. 301 ◽  
Author(s):  
Francisco Hervé ◽  
Mauricio Calderón ◽  
Mark Fanning ◽  
Robert Pankhurst ◽  
Carlos W. Rapela ◽  
...  
Keyword(s):  
Metamorphic Grade ◽  
Oceanic Island ◽  
Detrital Zircons ◽  
Island Arc ◽  
Ultramafic Rocks ◽  
The West ◽  
Metasedimentary Rocks ◽  
The North ◽  
The Andes ◽  
Late Neoproterozoic

Previous work has shown that Devonian magmatism in the southern Andes occurred in two contemporaneous belts: one emplaced in the continental crust of the North Patagonian Massif and the other in an oceanic island arc terrane to the west, Chaitenia, which was later accreted to Patagonia. The country rocks of the plutonic rocks consist of metasedimentary complexes which crop out sporadically in the Andes on both sides of the Argentina-Chile border, and additionally of pillow metabasalts for Chaitenia. Detrital zircon SHRIMP U-Pb age determinations in 13 samples of these rocks indicate maximum possible depositional ages from ca. 370 to 900 Ma, and the case is argued for mostly Devonian sedimentation as for the fossiliferous Buill slates. Ordovician, Cambrian-late Neoproterozoic and “Grenville-age” provenance is seen throughout, except for the most westerly outcrops where Devonian detrital zircons predominate. Besides a difference in the Precambrian zircon grains, 76% versus 25% respectively, there is no systematic variation in provenance from the Patagonian foreland to Chaitenia, so that the island arc terrane must have been proximal to the continent: its deeper crust is not exposed but several outcrops of ultramafic rocks are known. Zircons with devonian metamorphic rims in rocks from the North Patagonian Massif have no counterpart in the low metamorphic grade Chilean rocks. These Paleozoic metasedimentary rocks were also intruded by Pennsylvanian and Jurassic granitoids.

Évolution paléogéographique de la marge nord-ouest de l'Afrique du Cambrien à la fin du Carbonifère (du Maroc au Libéria)

1991 ◽  
Vol 28 (7) ◽  
pp. 1121-1130 ◽  
Author(s):  
Michel Villeneuve ◽  
Jean-Jacques Cornée
Keyword(s):  
West African ◽  
The West ◽  
Lower Paleozoic ◽  
West African Craton ◽  
Middle Cambrian ◽  
Early Devonian ◽  
Middle Ordovician ◽  
The North ◽  
Marine Platform ◽  
General Regression

Paleogeographic reconstructions of Paleozoic time are presented for the northwest margin of the West-African Craton. An extensional regime and a marine transgression were dominant during the Early Cambrian. During the Middle Cambrian, the Rokélides orogen was responsible for the sea regression to the south, while the proto-Atlantic opening was active to the north of the Reguibat shield. A large stable marine platform was present during Early and Middle Ordovician. A general regression and the formation of the West-African Inlandsis took place during the Late Ordovician. During Silurian time, this sea transgressed over most of the African platform. Incipient Hercynian deformations during the Early Devonian produced horsts and grabens in Morocco. At the end of the Devonian and the beginning of the Carboniferous, the sea was restricted to isolated basins and tectonic trenches. Collision between West Africa and North America during the Late Carboniferous transformed the Lower Paleozoic margin into an Hercynian orogenic belt, whose structure is controlled by the presence of crustal blocks, generated as early as the Cambrian, and probably reflecting, in turn, older Panafrican zones of weakness. [Translated by the Journal]

The North American Multimodel Ensemble: Phase-1 Seasonal-to-Interannual Prediction; Phase-2 toward Developing Intraseasonal Prediction

2014 ◽  
Vol 95 (4) ◽  
pp. 585-601 ◽  
Author(s):  
Ben P. Kirtman ◽  
Dughong Min ◽  
Johnna M. Infanti ◽  
James L. Kinter ◽  
Daniel A. Paolino ◽  
...  
Keyword(s):  
North American ◽  
Phase 1 ◽  
Phase 2 ◽  
Multimodel Ensemble ◽  
The North ◽  
North American Multimodel Ensemble

The North Korean Nuclear Crisis and U.S. Strategy in Northeast Asia

Asian Survey ◽  
2007 ◽  
Vol 47 (4) ◽  
pp. 601-621 ◽  
Author(s):  
Gilbert Rozman
Keyword(s):  
Phase 1 ◽  
Northeast Asia ◽  
Phase 2 ◽  
The North ◽  
Nuclear Crisis ◽  
The U.S

The nuclear crisis tested the U.S. in four distinct periods from 2002 to 2007, as slowly its strategy shifted toward multilateralism. After failing to rally any state but Japan to its side, the U.S. approved the Joint Agreement by working more closely with China. With Phase 1 finishing, Phase 2 puts a premium on multilateralism for which the U.S. is unprepared.

scholarly journals PSII-5 Carcass characteristics and growth performance of market pigs fed reduced lysine diets in bedded hoop barns

2019 ◽  
Vol 97 (Supplement_2) ◽  
pp. 229-230
Author(s):  
Peter J Lammers ◽  
Chad A Stahl ◽  
Mark S Honeyman
Keyword(s):  
Growth Performance ◽  
Soybean Meal ◽  
Large Scale ◽  
Phase 1 ◽  
Stocking Density ◽  
Carcass Characteristics ◽  
Small Scale ◽  
P Value ◽  
Phase 2 ◽  
Des Moines

Abstract A 2 × 2 × 2 factorial design was used to compare the effect of SID Lys:ME concentration (current vs. reduced), stocking density (1.30 vs. 4.05 m2/pig), and harvest month (August vs. March) on pigs raised in bedded hoop barns in Western Iowa. For each harvest month, 420 pigs produced from the mating of Duroc boars (Choice Genetics; West Des Moines, IA) to Camborough females (PIC; Hendersonville, TN) were sorted into 12 pens. Six pens were inside 3 large-scale (9.1 × 18.3 m) hoop barns and were stocked with 64 pigs/pen (32 barrows and 32 gilts; 1.30 m2/ pig). Six pens were inside 3 small-scale (6.0 × 10.8 m) hoop barns and were stocked with 6 pigs/pen (3 barrows and 3 gilts; 4.05 m2/pig). Within each stocking density, pens were randomly assigned to 1 of 2 diets which were fed in 2 phases. Corn-soybean meal diets were formulated to deliver 2.94 or 2.34 g SID Lys per Mcal ME in phase 1 (72.6–95.0 kg) and 2.34 or 1.76 g SID Lys per Mcal ME in phase 2 (> 95.0 kg). Pigs were individually weighed every 28 days and feed disappearance was recorded. When pigs in a pen averaged 129.3 kg the entire pen of pigs were harvested. A single chop (last-rib location; 2.54 cm thick) was collected from each carcass to assess pork quality. Pigs harvested in the summer grew faster, more efficiently, and with more intramuscular fat than those harvested in winter (P-value ≤ 0.05) but had lower 10th rib pH (P-value < 0.0001). Pigs allotted 4.05 m2/pig grew more efficiently but had reduced last rib pH as compared to pigs stocked at 1.30 m2/pig (P-value < 0.05). Reducing SID Lys:ME did not impact growth performance or carcass characteristics (P-value > 0.10). Lower concentrations of SID Lys:ME may be adequate for pigs housed in bedded hoop barns but further study is warranted.

Kilometre-scale folding in the Teslin zone, northern Canadian Cordillera, and its tectonic implications for the accretion of the Yukon-Tanana terrane to North America

1999 ◽  
Vol 36 (3) ◽  
pp. 479-494 ◽  
Author(s):  
Martin de Keijzer ◽  
Paul F Williams ◽  
Richard L Brown
Keyword(s):  
North America ◽  
Shear Zone ◽  
North American ◽  
Root Zone ◽  
Fault System ◽  
Canadian Cordillera ◽  
The West ◽  
The North ◽  
South Central ◽  
North American Craton

The Teslin zone in south-central Yukon has previously been described as a discrete zone with a steep foliation unique to the zone. It includes the Anvil assemblage and the narrowest portion of the Yukon-Tanana terrane (the Nisutlin assemblage), and is defined by post-accretionary faults: the Big Salmon fault to the west and the d'Abbadie fault system to the east. The zone was interpreted as a lithospheric suture or a crustal-scale transpression zone, and as the root zone of klippen lying on the North American craton to the east. We demonstrate that deformation and metamorphism are the same inside and outside the zone. The steep transposition foliation in the zone, in contrast to adjacent rocks to the east, coincides with the steep limb of a regional F3 structure. This fold has a shallow limb in the easternmost part of the zone and immediately east of the zone. Thus we reject earlier interpretations. If a suture exists between the obducted Anvil and Yukon-Tanana Nisutlin assemblages and North America, it is a shear zone that occurs at the base of the obducted rocks, which has been folded by the F3 fold. However, evidence that this thrust boundary is a lithospheric suture is lacking. A consequence of our interpretation is that North American rocks pass under the eastern Teslin zone and outcrop to the west of the Nisutlin and Anvil assemblages. This geometry precludes the possibility of the Teslin zone being the root zone of the klippen.

Excavations at Verulamium, 1961. Seventh and Final Interim Report

1962 ◽  
Vol 42 (2) ◽  
pp. 148-159 ◽  
Author(s):  
S. S. Frere
Keyword(s):  
Small Scale ◽  
Natural Soil ◽  
Masonry Building ◽  
Interim Report ◽  
The West ◽  
North East ◽  
The North

Two small-scale excavations were carried out at Verulamium during 1961. In January it became necessary to explore the site about to be occupied by the museum extension, and several trenches were cut on the north-east and south-east sides of the existing museum building. It was not possible in the time and with the resources available to excavate down to natural soil, but only to examine those layers due for removal by the builders. Considerable depths of deposit are known to exist here, possibly filling an early ditch. The site lies in the west corner of Insula XVIII: the earliest structure reached was a timber-framed building, burnt down possibly c. A.D. 155. This was succeeded by an Antonine masonry building with channel hypocausts. Possibly c. A.D. 300 this building was enlarged by encroachment on the street frontages. It clearly extends some way outside the area excavated both towards east and south. The character of the structure is domestic.

Recent tectonic reorganization of the Nubia-Eurasia convergent boundary heading for the closure of the western Mediterranean

2011 ◽  
Vol 182 (4) ◽  
pp. 279-303 ◽  
Author(s):  
Andrea Billi ◽  
Claudio Faccenna ◽  
Olivier Bellier ◽  
Liliana Minelli ◽  
Giancarlo Neri ◽  
...  
Keyword(s):  
Subduction Zone ◽  
Mediterranean Area ◽  
Western Mediterranean ◽  
Small Scale ◽  
The West ◽  
Seismic Reflection Data ◽  
Basin Inversion ◽  
The North ◽  
Reflection Data ◽  
Back Arc

Abstract In the western Mediterranean area, after a long period (late Paleogene-Neogene) of Nubian (W-Africa) northward subduction beneath Eurasia, subduction has almost ceased, as well as convergence accommodation in the subduction zone. With the progression of Nubia-Eurasia convergence, a tectonic reorganization is therefore necessary to accommodate future contraction. Previously-published tectonic, seismological, geodetic, tomographic, and seismic reflection data (integrated by some new GPS velocity data) are reviewed to understand the reorganization of the convergent boundary in the western Mediterranean. Between northern Morocco, to the west, and northern Sicily, to the east, contractional deformation has shifted from the former subduction zone to the margins of the two back-arc oceanic basins (Algerian-Liguro-Provençal and Tyrrhenian basins) and it is now mainly active in the south-Tyrrhenian (northern Sicily), northern Liguro-Provençal, Algerian, and Alboran (partly) margins. Onset of compression and basin inversion has propagated in a scissor-like manner from the Alboran (c. 8 Ma) to the Tyrrhenian (younger than c. 2 Ma) basins following a similar propagation of the cessation of the subduction, i.e., older to the west and younger to the east. It follows that basin inversion is rather advanced on the Algerian margin, where a new southward subduction seems to be in its very infant stage, while it has still to really start in the Tyrrhenian margin, where contraction has resumed at the rear of the fold-thrust belt and may soon invert the Marsili oceanic basin. Part of the contractional deformation may have shifted toward the north in the Liguro-Provençal basin possibly because of its weak rheological properties compared with those of the area between Tunisia and Sardinia, where no oceanic crust occurs and seismic deformation is absent or limited. The tectonic reorganization of the Nubia-Eurasia boundary in the study area is still strongly controlled by the inherited tectonic fabric and rheological attributes, which are strongly heterogeneous along the boundary. These features prevent, at present, the development of long and continuous thrust faults. In an extreme and approximate synthesis, the evolution of the western Mediterranean is inferred to follow a Wilson Cycle (at a small scale) with the following main steps : (1) northward Nubian subduction with Mediterranean back-arc extension (since ~35 Ma); (2) progressive cessation, from west to east, of Nubian main subduction (since ~15 Ma); (3) progressive onset of compression, from west to east, in the former back-arc domain and consequent basin inversion (since ~8–10 Ma); (4) possible future subduction of former back-arc basins.

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