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result(s) for
"Morar Group"
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A fluvial origin for the Neoproterozoic Morar Group, NW Scotland; implications for Torridon-Morar Group correlation and the Grenville Orogen foreland basin
by
Cheer, David
,
Prave, Tony
,
Krabbendam, Maarten
in
Altnaharra Formation
,
Applecross Formation
,
Aultbea Formation
2008
Precambrian sedimentary successions are difficult to date and correlate. In the Scottish Highlands, potential correlations between the thick, undeformed siliciclastic \"Torridonian\" successions in the foreland of the Caledonian Orogen and the highly deformed and metamorphosed siliciclastic Moine succession within the Caledonian Orogen have long intrigued geologists. New and detailed mapping of the Neoproterozoic Altnaharra Formation (Morar Group, lowest Moine Supergroup) in Sutherland has discovered low-strain zones exhibiting well-preserved sedimentary features. The formation comprises 3-5 km of coarse, thick-bedded psammite with abundant nested trough and planar cross-bedding bedforms, defining metre-scale channels. Palaeocurrent directions are broadly unimodal to the NNE-ENE. We interpret the Altnaharra Formation as high-energy, braided fluvial deposits. The Altnaharra Formation and the unmetamorphosed, Neoproterozoic Applecross-Aultbea formations (Torridon Group) are similar in terms of lithology, stratigraphical thickness, sedimentology, geochemistry, detrital zircon ages and stratigraphical position on Archaean basement. Depositional age constraints for both successions overlap and are coeval with late Grenvillean orogenic activity. Detrital zircons imply similar source regions from the Grenville Orogen. The Morar and Torridon groups can thus be correlated across the Caledonian Moine Thrust and are best explained as parts of a single, large-scale, orogen-parallel foreland basin to the Grenville Orogen.
Journal Article
Sedimentology of the early Neoproterozoic Morar Group in northern Scotland; implications for basin models and tectonic setting
2012
The metasedimentary rocks of the Morar Group in northern Scotland form part of the early Neoproterozoic Moine Supergroup. The upper part of the group is c. 2-3 km thick and contains two large kilometre-scale facies successions: a coarsening-upwards marine-to-fluvial regression overlain by a fining-upwards fluvial-to-marine transgression. Fluvial facies make up less than a third of the total thickness; shallow-marine lithofacies make up the remainder. Combining these new findings with previously published data indicates that the Morar Group represents, overall, a transgressive stratigraphic succession c. 6-9 km thick, in which there is both an upward and eastward predominance of shallow-marine deposits, and a concomitant loss of fluvial facies. Smaller-scale (hundreds of metres thick) transgressive-regressive cycles are superimposed on this transgressive trend. Collectively, the characteristics of the succession are consistent with deposition in a foreland basin located adjacent to the Grenville orogen, and possibly linked to the peri-Rodinian ocean. Subsidence and progressive deepening of the Morar basin may have, at least in part, been driven by loading of thrust sheets emplaced during the Grenville orogeny, and aided by sediment loading. However, the relative contributions of thrust loading versus plate boundary effects and/or eustatic sea-level rise on basin evolution remain speculative.
Journal Article
Provenance of the Moine Supergroup of NW Scotland; evidence from geochronology of detrital and inherited zircons from (meta)sedimentary rocks, granites and migmatites
2003
Detrital and inherited zircons from rocks of the Moine Supergroup from structural and stratigraphic positions above and below the Sgurr Beag and Naver thrusts have been dated by ion microprobe. 207Pb/206Pb ages for 65 detrital zircons from the Moine Nappe (Morar Group) range between 2707 and 947 Ma, with a bimodal distribution with clusters at c. 1650 and 1400 Ma. Five grains (8% of the analyses) were Archaean. Analyses of 97 inherited zircons from two Caledonian migmatites and two granites from the Naver Nappe yield 207Pb/206Pb ages between c. 2940 and 926 Ma. They have a dominant cluster at c. 1650 Ma with significant clusters at c. 1400 and c. 1050 Ma. Eight Archaean grains were discovered (8.5% of analyses). Three rocks above the Sgurr Beag Thrust have been examined and a total of 42 analyses obtained. 207Pb/206Pb ages for 35 inherited zircons from two outcrops of the essentially in situ West Highland granite gneiss within the Glenfinnan and Loch Eil Groups range from c. 1889 to 947 Ma. A sample of the Lochailort pelite provided a further seven detrital analyses. These data have a distribution with clusters at c. 1500 and 1100 Ma. The combined datasets indicate that the Moine Supergroup was deposited in a post-Grenvillian basin(s) with detritus derived predominantly from a late Palaeoproterozoic source, e.g. Gothian or Labradorian with only a very small proportion from older sources. The data indicate that the Naver and Sgurr Beag nappes had different sediment sources and so may not correlate. The Morar Group is dominated by late Palaeoproterozoic detritus with lesser amounts of Grenville-aged detritus. The Glenfinnan and Loch Eil Groups appear to have roughly equal proportions of detritus from the two sources. The few Archaean grains indicate that the source comprised comparatively little material of this age, precluding the Lewisian Complex or sub-Moine basement as a significant source and arguing against correlation of the Moine with the Torridonian.
Journal Article
Late Precambrian U-Pb titanite age for peak regional metamorphism and deformation (Knoydartian Orogeny) in the western Moine, Scotland
2003
There has been controversy over the number and timing of orogenies in the Precambrian Moine block in the Scottish Caledonides since the earliest radiometric dating in the 1960s. This work challenges a recent hypothesis, that this sector of the Laurentian margin was subjected to continuous crustal extension between >900 and 470 Ma. U-Pb dating (thermal ionization mass spectrometry) of titanite from a calc-silicate pod in the Moine (Morar Group) of the western Highlands gives an age of 737±5 Ma. The titanite grew from Fe-Ti-bearing detrital minerals during the main progressive, syn-D2, amphibolite-facies (sillimanite zone) regional metamorphism, thus demonstrating that a Neoproterozoic contractional tectonothermal event (Knoydartian orogeny) affected the Moine block following the rift-related emplacement of the West Highland granite gneiss at 873 Ma. We conclude that the Sgurr Beag Thrust, a major tectonic break separating the Morar and Glenfinnan groups of the Moine, is mainly of Neoproterozoic, not Caledonian, age. The early tectonothermal event was succeeded by the Grampian Phase (Caledonian orogeny) at 460-470 Ma.
Journal Article
Structural setting and U–Pb zircon geochronology of the Glen Scaddle Metagabbro: evidence for polyphase Scandian ductile deformation in the Caledonides of northern Scotland
2008
Within the Scottish Caledonides, the Glen Scaddle Metagabbro was intruded into the Moine Supergroup of the Northern Highland Terrane after Grampian D2 folding and prior to regional D3 and D4 upright folding and amphibolite-facies metamorphism. A U–Pb zircon age of 426 ± 3 Ma obtained from the metagabbro is interpreted to date emplacement. D3–D4 folding is constrained to have occurred during the Scandian orogenic event. In contrast, polyphase folding and regional metamorphism of the Dalradian Supergroup southeast of the Great Glen Fault is entirely Grampian. These differences are consistent with published tectonic models that invoke a minimum of 700 km of post-Scandian sinistral displacements across the Great Glen Fault to juxtapose the Grampian and Northern Highland terranes.
Journal Article
MORN motifs in plant PIPKs are involved in the regulation of subcellular localization and phospholipid binding
by
Hui Ma Ying Lou Wen Hui Lin Hong Wei Xue
in
Amino Acid Motifs - genetics
,
Amino Acid Motifs - physiology
,
Amino Acid Sequence
2006
Multiple repeats of membrane occupation and recognition nexus (MORN) motifs were detected in plant phosphatidylinositl monophosphate kinase (PIPK), a key enzyme in PI-signaling pathway. Structural analysis indicates that all the MORN motifs (with varied numbers at ranges of 7-9), which shared high homologies to those of animal ones, were located at N-terminus and sequentially arranged, except those of OsPIPK1 and AtPIPK7, in which the last MORN motif was separated others by an -100 amino-acid "island" region, revealing the presence of two kinds of MORN arrangements in plant PIPKs. Through employing a yeast-based SMET (sequence of membrane-targeting) system, the MORN motifs were shown being able to target the fusion proteins to cell plasma membrane, which were further confirmed by expression of fused MORN-GFP proteins. Further detailed analysis via deletion studies indicated the MORN motifs in OsPIPK 1, together with the 104 amino-acid "island" region are involved in the regulation of differential subcellular localization, i.e. plasma membrane or nucleus, of the fused proteins. Fat Western blot analysis of the recombinant MORN polypeptide, expressed in Escherichia coli, showed that MORN motifs could strongly bind to PA and relatively slightly to PI4P and PI(4,5)P2. These results provide informative hints on mechanisms of subcellular localization, as well as regulation of substrate binding, of plant PIPKs.
Journal Article
Diaspora, Identity and Religion
by
Alfonso, Carolin
,
Kokot, Waltraud
,
Tölölyan, Khachig
in
Diaspora
,
Emigration
,
Emigration and immigration
2004,2003
Over the last decade, concepts of diaspora and locality have gained complex new meanings in political discourse as well as in social and cultural studies. Diaspora, in particular, has acquired new meanings related to notions such as global deterritorialization, transnational migration and cultural hybridity. The authors discuss the key concepts and theory, focus on the meaning of religion both as a factor in forming diasporic social organisations, as well as shaping and maintaining diasporic identities, and the appropriation of space and place in history. It includes up to date research of the Caribbean, Irish, Armenian, African and Greek diasporas.
1. Introduction 2.Deconstructing and Comparing Diasporas 3. Diasporic Spatiality and the Question of Identity Part 1: Identity Politics, History and Locality 4. 'Too close for comfort' - Re-membering the forgotten diaspora of Irish women in England 5. Place, Movement and Identity: Processes of Inclusion and Exclusion in a 'Caribbean' Family 6. Why Locality Matters - Diaspora Consciousness and Sedentariness in the AmericanDiaspora in Greece 7. Past and Present in the History of Modern Greek Diaspora 8. Griots, Roots and Identity in the African Diaspora 9. The Invention of History in the Irish American Diaspora: Myths of the Great Famine Part Two: Diasporic Aspects of Religion 10. Religion or Culture? Concepts of Identity in the Alevi Diaspora 11. A Double Minority: Notes on the Emerging Yezidi Diaspora 12. A Diachronic View at Diaspora, the Significance of Religion and the Hindu Trinidadians 13. They Prayed in Brazil and it Rained in Boston: Dominican and Brazilian Transnational Religious Life 14. Let it Flow - Economy, Spirituality and Gender in the Sindhi Network