The Metamorphism of the Manx Slate Series, Isle of Man

1964 ◽  
Vol 101 (1) ◽  
pp. 20-36 ◽  
Author(s):  
Alexander Simpson
Keyword(s):  
Present Author ◽  
Large Scale ◽  
Present Contribution ◽  
Polyphase Deformation ◽  
The Third ◽  
Isle Of Man ◽  
Tectonic History ◽  
History Of

AbstractPrevious research by the present author has established the Caledonian tectonic history of the Manx Slate Series. In particular three episodes of folding (F1, F2, F3) were recognized. The present contribution describes the sequence of metamorphic textures impressed on these metasediments during this polyphase deformation.Two distinct episodes of metamorphism have affected the Manx Slate Series. A syn-tectonic F1 metamorphism produced a chloritezone alteration throughout the Island. A later F2 metamorphism was primarily responsible for the growth of small porphyroblasts of several minerals within the pre-existing F1 fabric. This second metamorphism is confined to the hinge of the large-scale F2 Manx synform and its effects are visible in an elongate belt following the middle of the Island. The emplacement of the porphyroblasts began during the F2 movement and continued into the static interval which preceded the third (F3) movement-phase. It was completed prior to the F3 deformation.

scholarly journals I višap armeni. Appunti per una storia della ricezione

2020 ◽  
Author(s):  
Alessandra Gilibert
Keyword(s):  
Middle Ages ◽  
Large Scale ◽  
South Caucasus ◽  
Political Messages ◽  
Complex Sequence ◽  
The Third ◽  
Third Millennium ◽  
Third Millennium Bce ◽  
History Of ◽  
Unknown Point

Vishaps are large-scale prehistoric stelae decorated with animal reliefs, erected at secluded mountain locations of the South Caucasus. This paper focuses on the vishaps of modern Armenia and traces their history of re-use and manipulations, from the end of the third millennium BCE to the Middle Ages. Since their creation at an unknown point in time before 2100 BCE, vishaps functioned as symbolic anchors for the creation and transmission of religious and political messages: they were torn down, buried, re-worked, re-erected, transformed and used as a surface for graffiti. This complex sequence of re-contextualisations underscores the primacy of mountains as political arenas for the negotiation of religious and ritual meaning.

ARENA

2021 ◽  
pp. 126-165
Author(s):  
James Loxton
Keyword(s):  
Large Scale ◽  
Right Wing ◽  
Left Wing ◽  
Military Rule ◽  
Death Squad ◽  
Powerful Source ◽  
Fourth Section ◽  
The Third ◽  
History Of ◽  
High Level

This chapter examines ARENA in El Salvador and argues that, like the UDI in Chile, its success was the product of authoritarian inheritance and counterrevolutionary struggle. The first section discusses El Salvador’s long history of right-wing military rule. The second section examines the October 1979 coup and the resulting establishment of a left-wing Revolutionary Governing Junta. The third section discusses the intense counterrevolutionary response that the junta triggered. This included large-scale death squad violence, with future ARENA founder Roberto D’Aubuisson playing a key role. The fourth section examines the formation of ARENA in response to an impending transition to competitive elections. The fifth section shows how D’Aubuisson’s role as a high-level official in the pre-1979 military regime endowed ARENA with several valuable resources. The final section discusses how ARENA’s origins in counterrevolutionary struggle served as a powerful source of cohesion.

A Bibliography of the Tectonics of England and Wales

1932 ◽  
Vol 69 (5) ◽  
pp. 233-237
Author(s):  
R. H. Rastall
Keyword(s):  
Great Britain ◽  
British Isles ◽  
England And Wales ◽  
The Third ◽  
Tectonic History ◽  
History Of ◽  
The Subject

FOR more than twenty-five years the compiler of this bibliography has been deeply interested in the tectonic history of the British Isles: for the greater part of this time he has also been struck by the absence of any adequate and annotated treatment of the subject, since the appearance of the third edition of Jukes-Browne's Building of the British Isles, 1911. (The so-called 4th edition of this work, dated 1922, appears to be merely an unrevised reprint of the 3rd edition.) In 1929 this want was in part supplied by the publication of The Physiographical Evolution of Britain, by Dr. L. J. Wills. Even in this admirable work, however, the stress is on physiography rather than on tectonics, and many of the more important writings on this side of the subject are not referred to. In the Handbook of the Geology of Great Britain, which appeared in the same year, the exiguous section on “Morphology” includes no bibliography, while the whole scheme of treatment is in the main palaeontological, and little help on the tectonic aspect is to be obtained from the text of most of the sections. The present publication may in a sense be regarded as a supplement to that work.

scholarly journals HISTORY OF THE CHANNEL SYSTEMS REORGANIZATION OF THE KAMA-KELTMA LOWLAND IN THE LATE PLEISTOCENE – HOLOCENE

2020 ◽  
pp. 6-17
Author(s):  
Nikolai N. Nazarov ◽  
◽  
Sergei V. Kopytov ◽  
Keyword(s):  
Late Pleistocene ◽  
Radiocarbon Dating ◽  
Large Scale ◽  
Bottom Relief ◽  
Short Term ◽  
Second Stage ◽  
The Third ◽  
Third Stage ◽  
History Of ◽  
Channel Systems

The analysis of the actual data on the age and stages of the channel systems formation in the Kama-Keltma lowland was based on the altitudinal differentiation of different stages of the relief and the results of radiocarbon dating of organics from the channel and floodplain facies. Late Pleistocene lake terrace is the highest level in the Upper Kama depression and Keltma hollow. The research into the geomorphological structure and age of deposited materials, with a particular focus on separate elements of the Kama-Keltma lowland erosive and accumulative relief, indicates the existence of six stages of the channel systems formation (reorganization). The first stage (end of the Kalinin stadial) is the Chepets hollow formation. The hollow was preserved after large-scale changes in the bottom relief of the Upper Kama depression. The second stage (Mologa-Sheksna interstadial) is the first Kama terrace formation. The third stage (Ostashkov stadial, 20-18 ka) is the period of the runoff hollow formation (including the ‘large terrace hollow’), which actively dissected the surface of aeolian landforms. The fourth stage (LGM, 18-10 ka) is the formation of the macromeanders of the South Keltma, Pilva, and Timsher, as well as the multi-arm channel of the Kama during alternating periods of relatively short-term warming and cooling. The fifth stage is the wide Kama floodplain formation in the Preboreal – Subboreal, represented by segmental generations. The sixth stage (modern) is characterized by the ‘straightening’ of the Kama channel – the formation of a relatively straight channel throughout the Kama-Keltma lowland.

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.

scholarly journals Deep time diversity and the early radiations of birds

2021 ◽  
Vol 118 (10) ◽  
pp. e2019865118
Author(s):  
Yilun Yu ◽  
Chi Zhang ◽  
Xing Xu
Keyword(s):  
Evolutionary History ◽  
Large Scale ◽  
Evolutionary Rate ◽  
Rapid Evolution ◽  
Morphological Data ◽  
Deep Time ◽  
The Third ◽  
Time Diversity ◽  
History Of

Reconstructing the history of biodiversity has been hindered by often-separate analyses of stem and crown groups of the clades in question that are not easily understood within the same unified evolutionary framework. Here, we investigate the evolutionary history of birds by analyzing three supertrees that combine published phylogenies of both stem and crown birds. Our analyses reveal three distinct large-scale increases in the diversification rate across bird evolutionary history. The first increase, which began between 160 and 170 Ma and reached its peak between 130 and 135 Ma, corresponds to an accelerated morphological evolutionary rate associated with the locomotory systems among early stem birds. This radiation resulted in morphospace occupation that is larger and different from their close dinosaurian relatives, demonstrating the occurrence of a radiation among early stem birds. The second increase, which started ∼90 Ma and reached its peak between 65 and 55 Ma, is associated with rapid evolution of the cranial skeleton among early crown birds, driven differently from the first radiation. The third increase, which occurred after ∼40 to 45 Ma, has yet to be supported by quantitative morphological data but gains some support from the fossil record. Our analyses indicate that the bird biodiversity evolution was influenced mainly by long-term climatic changes and also by major paleobiological events such as the Cretaceous–Paleogene (K–Pg) extinction.

Three-dimensional visualization of top-down superimposed thrust sheets in the SW Grenville Province, Ontario

2019 ◽  
Vol 157 (2) ◽  
pp. 149-159
Author(s):  
Jacob W.D. Strong ◽  
Alan P. Dickin
Keyword(s):  
Large Scale ◽  
3D Visualization ◽  
3D Structure ◽  
Three Dimensional ◽  
Grenville Province ◽  
Tectonic History ◽  
Thrust Sheets ◽  
History Of ◽  
Seismic Sections ◽  
Back Arc

AbstractTo properly understand the tectonic history of the Grenville Province it is necessary to have a reliable, scientifically based understanding of the present-day three-dimensional (3D) structure of the orogen. Based on detailed Nd isotope mapping of surface boundaries and Lithoprobe seismic sections, this study provides the first detailed visualization of the 3D structure of the Grenville gneiss belt in Ontario using the SketchUp software package. The 3D visualization supports a model in which thrust geometry was imposed from the top downwards, controlled by the NW boundary of the Central Metasedimentary Belt that originated as a failed back-arc rift zone. The Central Metasedimentary Belt boundary controlled the trajectory of the Allochthon Boundary Thrust, its underlying tectonic duplex and, ultimately, the Grenville Front. This process of superimposed thrusting explains the large-scale change in the trajectory of the Grenville Front north of Georgian Bay that has been called the ‘Big Bend’. To assist in visualizing the 3D model, a fly-through animation is provided in the supplementary material.

XIX.—Metamorphic History of the Schichallion Complex (Perthshire)

1958 ◽  
Vol 63 (2) ◽  
pp. 413-431 ◽  
Author(s):  
N. Rast
Keyword(s):  
Regional Metamorphism ◽  
Igneous Rocks ◽  
Metamorphic Rocks ◽  
Present Contribution ◽  
Scottish Highlands ◽  
Metamorphic History ◽  
Fine Grain ◽  
Tectonic History ◽  
History Of ◽  
Garnet Zone

SynopsisThe Schichallion complex is situated in the Central Highlands of Scotland between the villages Struan and Kinloch Rannoch. The area is of considerable geological interest and has been investigated stratigraphically and structurally by E. M. Anderson and Bailey and McCallien. As a consequence of their researches a complete stratigraphical succession has been established. Thus, the metamorphic rocks of the area are classified into the Moinian and Dalradian systems, which are separated by a plane of tectonic discontinuity known as the Boundary Slide. The Moinian rocks are quartz-felspathic granulites, whereas the Dalradian system includes pelitic schists, quartzites, limestones as well as a variety of meta-igneous rocks.In his previous research the present author has established the tectonic history of the complex. In particular three episodes of folding (F1to F3) and a much later episode of faulting (F4) were recognized. Of these the F3episode is of least significance. Consequently, events after the F2movements can be in many cases regarded as post-folding.The present contribution is concerned essentially with the mapping of the metamorphic zones (garnet and staurolite-kyanite) and with a detailed study of the mineralogical evolution of regionally metamorphosed rocks within these zones.In the field it is possible to prove that the staurolite-kyanite zone is essentially post-folding, since the kyanitepegmatites are found to cut across the minor F2-folds. In this respect textural studies confirm the field observations. The study of the internal inclusions in garnets indicates that the garnet zone has a much longer history, since pre-F2garnets are found in the southern part of the complex and throughout the central part of the area syn-tectonic F2garnets are apparent. The pre-F2garnets contain a very fine-grain F1fabric. Hence the garnets in relation to the F1movements are post-tectonic. Thus, the regional metamorphism can be subdivided into three phases: the F1metamorphism, the F2metamorphism and the post-F2metamorphism. The latter, on structural evidence appears to be at least in part contemporaneous with the F3movements.The meta-igneous rocks of the area are grouped into the hornblende-schists and granular epidiorites. The hornblende-schists appear to have suffered deformation and recrystallization during F1and F2episodes of movement. On the other hand the granular epidiorites are later than the F1and the F2movements. Although in the southern parts of the district the epidiorites have been slightly deformed, elsewhere they preserve the original ophitic texture and cut across the F1and F2folds. The deformation in the south is attributed to the effects of the F3folding. The epidiorites have been evidently emplaced as dolerites after the F2movements and before the F3metamorphism.The localized retrogressive metamorphism is associated with the F4movements, which are responsible for the Loch Tay Fault. The Fault is later than the minor intrusives associated with the Younger Granites of the Scottish Highlands and is suggested to be of a Lower or Middle O.R.S. age.On the basis of the chemical composition of the plagioclase felspars it is proposed to include all the staurolite and kyanite bearing rocks into the epidote-amphibolite facies. In this respect temperature and the hydrostatic pressure are assumed to have been the main factors, since similar minerals came into existence during static and dynamic stages of metamorphism alike.

Tectonic history of a segment of the Pelagonian zone, northeastern Greece

1981 ◽  
Vol 18 (7) ◽  
pp. 1111-1126 ◽  
Author(s):  
Damian Nance
Keyword(s):  
Large Scale ◽  
Root Zone ◽  
Regional Metamorphism ◽  
Late Eocene ◽  
Metamorphic Rocks ◽  
Tectonic History ◽  
History Of ◽  
Ophiolitic Rocks ◽  
Platform Carbonates ◽  
Pelagonian Zone

Continental metamorphic rocks and ophiolitic bodies within the Pelagonian zone of the Hellenides in the Livadi area, northeastern Greece, show repeated periods of deformation that accompany thermal events of Early Cretaceous and possibly Late Eocene age. Structures associated with the earlier deformation indicate thrusting towards the northeast accompanying regional metamorphism of upper greenschist to lower amphibolite facies. Later structures and a retrogression to lower greenschist facies associated with emplacement of the Livadi ophiolitic rocks into their present position are likewise attributed to northeast-directed thrusting and probably accompanied the allochthonous movement of the Pelagonian basement over the Mesozoic platform carbonates of Mt. Olympos.Emplacement vectors of northeast polarity are inconsistent with tectonic models of the Hellenides involving large-scale southwestward obduction of Mesozoic ophiolites from a single ocean located northeast of the Pelagonian zone. Tectonic models involving the converging emplacement of Mesozoic ophiolites from two oceans lying northeast and southwest of the Pelagonian zone are more compatible with the observed structures, the latter ocean providing a potential root zone for the deformed ophiolitic rocks at Livadi.The orientation of minor structures associated with thrusting that postdates the emplacement of the Livadi ophiolitic rocks is consistent with movement from north to south.

scholarly journals ‘n Kykie na kopstukke. Filosofie op Potchefstroom die afgelope eeu (1917-2017). Deel 3: die uitbouers

2018 ◽  
Vol 83 (1) ◽  
Author(s):  
Barend van der Walt
Keyword(s):  
History Of Philosophy ◽  
Past Century ◽  
Present Contribution ◽  
The Third ◽  
The Past ◽  
History Of ◽  
The Cross ◽  
Personal Interests

ABSTRACT A peep-hole on big guns; philosophy at Potchefstroom during the past century (1917-2017). Part 3: the elaborators This article is the third in a series of four which outlines the history of philosophy at Potchefstroom during more than a century. Firstly, two main professors, F. Postma and S.O. Los, who taught philosophy up to about 1917 received attention (cf. Van der Walt, 2017). After this first period of reconnoitring followed a second of systematisation by Proff H.G. Stoker and J.A. Taljaard (cf. Van der Walt, 2018). The present contribution covers the third period, viz. that of the further elaboration in various directions of a Christian-reformational philosophy. At the hand of their academic backgrounds, personal interests and publications the following seven heads of the Department of Philosophy (later School of Philosophy) march past: Proff B. Duvenage, N.T. van der Merwe, Pieter G.W. du Plessis, M. Elaine Botha, Johannes J. Venter, followed by an interim without a departmental head, Pieter J.J.S. Potgieter and Michael F. Heyns. This article is aligned with the framework of an extensive evaluative conclusion about the history of philosophy at Potchefstroom during more than a century as reviewed in this series. The fourth and final contribution will discuss the growing tension in the School has, by 2016, arrived at the cross-roads. SAMEVATTING In ʼn reeks van vier artikels is hierdie die derde wat die hooflyne van die geskiedenis van filosofie op Potchefstroom oor meer as ʼn eeu beskrywe (vgl. Van der Walt, 2017 en 2018 vir die vorige twee). Nadat op ʼn tydperk van filosofiese verkenning (tot ongeveer 1917) gelet is, is twee sisteembouers uit die tweede periode bekyk. Nou word nog sewe profiele van hulle opvolgers ten tonele gevoer, wat as verteenwoordigers van ʼn derde periode van die uitbouing van ʼn Christelike filosofie beskou kan word. Die volgende figure passeer die revue: (1) Benoon Duvenage (departementshoof vanaf 1974 tot 1980); (2) Nicolaas Theodor van der Merwe (vanaf ongeveer 1957 dosent en vanaf 1980 tot 1986 departementshoof); (3) Pieter G.W. du Plessis (dosent vanaf 1957 tot 1965 aan die PU verbonde en tussen 1988 en 1989 waarnemende departementshoof); (4) Marthina Elaine Botha (vanaf 1969 dosent en vanaf 1990 tot 1995 departementshoof; (5) Johannes Jacob Venter (vanaf 1970 dosent aan die PU, na ʼn tydperk (1979-1974) by die Universiteit van Fort Hare weer terug aan die PU en vanaf 1996 tot 1998 departementshoof; (6) Vanaf 1999 tot 2001 verloor filosofie sy selfstandigheid deurdat dit demoveer word tot slegs ʼn vakgroep binne een van die nuutgestigte skole, die Skool vir Sosiale en Owerheidstudies waarvan prof Willie van Wyk die direkteur was. (7) Pieter Jacobus Johannes Stephanus Potgieter (vanaf 2001 tot 2008 direkteur van die nuwe Skool vir Filosofie); (8) Michael F. Heyns (vanaf 2002 dosent in Filosofie en vanaf 2009 tot op datum direkteur van die Skool). Hierdie artikel word afgesluit met ʼn breedvoerige evaluerende terugskouing op die geskiedenis van filosofie op Potchefstroom gedurende meer as ʼn eeu. Die laaste (vierde) bydrae bespreek die groeiende spanning (sedert ongeveer 2010) en die huidige krisis in die Skool vir Filosofie.

Sign in / Sign up

Export Citation Format

Share Document