scholarly journals Géologie d'un secteur situé entre les fjords de Sermiligârssuk et Arsuk, (SW du Groenland)

1971 ◽  
Vol 32 ◽  
pp. 1-53
Author(s):  
L Bonnard
Keyword(s):  
Dyke Swarm ◽  
Tectonic Deformation ◽  
The South ◽  
Variable Intensity ◽  
The North ◽  
Two Generations ◽  
Arctic Conditions ◽  
Recent Origin ◽  
Intense Deformation ◽  
Mutual Relations

South-west Greenland belongs to the Precambrian shield; it is buiIt up of metamorphic, eruptive and, to a lesser extent, sedimentary rocks. The chronology of these formations and their structural relations are now fairly well established and are referred to three periods - pre-Ketilidian, Ketilidian and Gardar. Important unconformities separate the rocks of these divisions at the type localities. The greater part of the rocks occurring in the region mapped by the author belong to the pre-Ketilidian; these are migmatites - quantitatively the most important, ultramafic rocks, and metadolerites in various stages of alteration. The Ketilidian period was marked by local tectonic movements, metamorphism and the intrusion of small granitic bodies; the Ketilidian supracrustal succession lies immediately to the east of the area under consideration. The Gardar period has left its imprint in the form of widespread fractures and a dyke swarm composed mainly of dolerites and trachytes. The migmatites are predominantly gneisses, homogeneous and nebulitic in the north, banded and veined in the south. AlI the gneisses have a granodioritic or quartz-dioritic composition. Small masses of granite and sorne lenses of gabbro-anorthosite make up the remainder of the migmatite area, which structurally consists of a succession of domes and synclines with axes oriented in a general NW-SE direction with a culmination in the region of Dubletsø. The migmatite complex was probably derived from pelitic and arkosic sediments; it is the product of the metamorphism, migmatisation and intense deformation which marked the pre-Ketilidian. The ultrabasic bodies appear as small bodies within the migmatites: they are classified as steatites, serpentinites and actinolitites, the mutual relations of which form the subject of various hypotheses; it is probable that there exist two generations of ultrabasics separated by a phase of folding and migmatisation. The pre-Ketilidian metadolerites (like the later Gardar dykes) trend for the most part NE-SW. In the southern part of the area they are almost totally recrystallised due to later (presumably Ketilidian) metamorphism. The Ketilidian activity in the area was characterised by a metamorphism of variable intensity, most marked in the south-east of the area where it accompanied tectonic deformation. Dykes of microgranite and sorne small granitic and microdioritic bodies also belong to this period. The Gardar dyke complex comprises rare lamprophyres, trachytes and above all very numerous dolerites of which it is possible to distinguish several generations on the basis of intersections and microscopic characters. The fracturing and wrench-faulting described are also of Gardar age. FinalIy, within·the area many features of Quaternary and recent origin may be seen; these are the result of glaciation and the present arctic conditions.

Inherited and Environmentally Induced Differences in Mutation Frequencies Between Wild Strains of Sordaria fimicola From “Evolution Canyon”

Genetics ◽  
1998 ◽  
Vol 149 (1) ◽  
pp. 87-99
Author(s):  
Bernard C Lamb ◽  
Muhammad Saleem ◽  
William Scott ◽  
Nina Thapa ◽  
Eviatar Nevo
Keyword(s):  
Genetic Variation ◽  
Spontaneous Mutation ◽  
The South ◽  
Natural Genetic Variation ◽  
The North ◽  
Ascospore Germination ◽  
Evolution Canyon ◽  
Two Generations ◽  
Wild Strains ◽  
Sordaria Fimicola

Abstract We have studied whether there is natural genetic variation for mutation frequencies, and whether any such variation is environment-related. Mutation frequencies differed significantly between wild strains of the fungus Sordaria fimicola isolated from a harsher or a milder microscale environment in “Evolution Canyon,” Israel. Strains from the harsher, drier, south-facing slope had higher frequencies of new spontaneous mutations and of accumulated mutations than strains from the milder, lusher, north-facing slope. Collective total mutation frequencies over many loci for ascospore pigmentation were 2.3, 3.5 and 4.4% for three strains from the south-facing slope, and 0.9, 1.1, 1.2, 1.3 and 1.3% for five strains from the north-facing slope. Some of this between-slope difference was inherited through two generations of selfing, with average spontaneous mutation frequencies of 1.9% for south-facing slope strains and 0.8% for north-facing slope strains. The remainder was caused by different frequencies of mutations arising in the original environments. There was also significant heritable genetic variation in mutation frequencies within slopes. Similar between-slope differences were found for ascospore germination-resistance to acriflavine, with much higher frequencies in strains from the south-facing slope. Such inherited variation provides a basis for natural selection for optimum mutation rates in each environment.

Research progress on the Zhongnan-Liyue Fault Zone in the South China Sea Basin

2020 ◽  
Author(s):  
Ziying Xu ◽  
Jun Wang ◽  
Hongfang Gao ◽  
Yongjian Yao
Keyword(s):  
Spatial Distribution ◽  
South China Sea ◽  
Fault Zone ◽  
South China ◽  
The South China Sea ◽  
Magnetic Data ◽  
Tectonic Deformation ◽  
The South ◽  
China Sea ◽  
The North

<p>We give a review of the up-to-date research situation about The Zhongnan-Liyue Fault Zone (ZLFZ), than analyze the spatial distribution and tectonic deformation feature of the ZLFZ based on the geophysical data including topographic, seismic, gravity and magnetic data. The results show that the ZLFZ has obvious north-south segmentation characteristics in in the South China Sea Basin. The north section, which is between northwest sub-basin and east sub-basin, is a narrow zone with the width of ~16 km, and is NNW trend from 18°N,115.5°E to 17.5°N,116°E. Meanwhile ,the south section, which is between southwest sub-basin and east sub-basin, is a wide zone with the width of 60-80 km, and is NNW trend from the east of ZhongshaBank to the west of LiyueBank. The main fault of the ZLFZ is NNW trend along the seamounts ridge of Zhongnan. the ZLFZ of transition region is NNE trend from the north section to the south section. According the sub-basin’s sedimentary thickness and oceanic crust thickness exist obvious difference, on both sides of the ZLFZ, we speculate that the ZLFZ play an important role on geological structure of sub-basin. According to the chang of crustal structure, We speculate that the ZLFZ is at least a crustal fracture zone.</p><p><strong>Key words: </strong>South China Sea Basin; Zhongnan-Liyue Fault Zone; Spatial distribution; Tectonic deformation<strong> </strong></p><p><strong>Foundation item:</strong> National Natural Science Foundation of China (41606080, 41576068); The China Geological Survey Program (GZH201400202, 1212011220117, DD20160138, 1212011220116).</p>

scholarly journals Population dynamics of four insect defoliators in a dryland South Island Eucalyptus plantation

2016 ◽  
Vol 69 ◽  
pp. 321-321
Author(s):  
H. Lin ◽  
T.J. Murray ◽  
E.G. Mason
Keyword(s):  
Population Dynamics ◽  
Larval Abundance ◽  
Limited Information ◽  
The South ◽  
Eucalyptus Plantation ◽  
Island Populations ◽  
The North ◽  
Pest Outbreaks ◽  
Eucalyptus Plantations ◽  
Two Generations

Exotic insect defoliators originally from Australia are present in New Zealand Eucalyptus plantations Pest outbreaks causing significant defoliation can reduce tree growth and productivity There is limited information on the population dynamics of major Eucalyptus defoliators in the South Island Populations of four defoliators were monitored monthly from November 2015 to March 2016 in a dryland Eucalyptus plantation in Marlborough by assessing 35 shoots from each of 225 trees Only one generation of Paropsis charybdis was observed Peak adult abundance was in December/January and adults disappeared in March This is different from North Island and Australian studies in which two generations are often observed Opodiphthera eucalypti had two distinct generations with larval populations peaking in December and February/March Most Phylacteophaga froggatti larvae were found after December but populations were relatively low throughout the monitoring period Strepsicrates macropetana reached peak larval abundance in February and had multiple overlapping generations These results suggest differences in the population dynamics of eucalypt defoliators in the South Island compared to those reported in the North Differences are likely due to local environmental conditions which were notably dry during this particular monitoring season These data provide important information for pest management in South Island dryland Eucalyptus plantations

Apercu morphotectonique et paleogeographique du domaine calabro-lucanien (Italie meridionale)

1961 ◽  
Vol S7-III (6) ◽  
pp. 610-618 ◽  
Author(s):  
Claude Grandjacquet
Keyword(s):  
North Africa ◽  
Structural Features ◽  
Western Mediterranean ◽  
Tectonic Deformation ◽  
North African ◽  
The South ◽  
African Region ◽  
Structural Pattern ◽  
The North ◽  
Upper Oligocene

Abstract In the region lying between Salerno and the Ofanto river on the north and Cetraro and the gulf of Tarento on the south and southeast, the south end of the Apennines merges into the structural pattern of the western Mediterranean region (southwestern Italy-Sicily-North Africa). After a cycle of sedimentation, tectonic deformation, and erosion extending from Triassic to upper Oligocene, a second cycle began in the late Oligocene and earliest Miocene. Mosaic faulting, in general based upon major structural features of the earlier cycle, occurred throughout the entire southern Italy-North African region. The age of the quartzite flysch remains unknown but is probably Jurassic-Cretaceous.

Cambrian and earliest Ordovician fauna and geology of the Sông Đà and adjacent terranes in Việt Nam (Vietnam)

2021 ◽  
pp. 1-26
Author(s):  
Nigel C. Hughes ◽  
Shanchi Peng ◽  
David A. T. Harper ◽  
Paul M. Myrow ◽  
Ngân Kim Phạm ◽  
...  
Keyword(s):  
South China ◽  
Detrital Zircon ◽  
North China ◽  
Tectonic Deformation ◽  
Viet Nam ◽  
Carbonate Facies ◽  
The South ◽  
The North ◽  
Lower Ordovician ◽  
A New Species

Abstract Later Cambrian and earliest Ordovician trilobites and brachiopods spanning eight horizons from five localities within the Sông Mã, Hàm Rồng and Đông Sơn formations of the Thanh Hóa province of Việt Nam, constrain the age and faunal affinities of rocks within the Sông Đà terrane, one of several suture/fault-bounded units situated between South China to the north and Indochina to the south. ‘Ghost-like’ preservation in dolomite coupled with tectonic deformation leaves many of the fossils poorly preserved, and poor exposure precludes collecting within continuously exposed stratigraphic successions. Cambrian carbonate facies pass conformably into Lower Ordovician carbonate-rich strata that also include minor siliciclastic facies, and the recovered fauna spans several uppermost Cambrian and Lower Ordovician biozones. The fauna is of equatorial Gondwanan affinity, and comparable to that from South China, North China, Sibumasu and Australia. A new species of Miaolingian ‘ptychopariid’ trilobite, Kaotaia xuanensis, is described. Detrital zircon samples from Cambrian–Ordovician rocks of the North Việt Nam and Sông Đà terranes, and from Palaeozoic samples from the Trường Sơn sector of Indochina immediately to the south, contain a predominance of ages spanning the Neoproterozoic period and have a typical equatorial Gondwanan signature. We associate the Cambrian and Tremadocian of the Sông Đà terrane with areas immediately to the north of it, including the North Việt Nam terrane and the southern parts of Yunnan and Guangxi provinces of China.

Co-existing low-Ti and high-Ti dolerites in two large dykes in the Gap Dyke swarm, southeastern Karoo Basin (South Africa)

2020 ◽  
Vol 123 (1) ◽  
pp. 19-34
Author(s):  
E.-R. Neumann ◽  
J.S. Marsh ◽  
C.Y. Galerne ◽  
S. Polteau ◽  
H. Svensen ◽  
...  
Keyword(s):  
Fractional Crystallization ◽  
Mantle Source ◽  
Crustal Contamination ◽  
Large Igneous Province ◽  
Dyke Swarm ◽  
The South ◽  
Southeastern Part ◽  
Nd Isotope ◽  
Karoo Basin ◽  
The North

Abstract This paper presents major, trace element and Sr-Nd isotope data on two large, east-west trending dolerite dykes in the southeastern part of the Karoo Basin, the South Gap (155 km long, ≤275 m wide) and the North Gap (150 km long, ≤190 m wide) dykes. The Gap dykes represent a rare case in the Karoo Large Igneous Province (LIP) where low-Ti (Gap1: <1.7 wt% TiO2, <130 ppm Zr, 200 to 330 ppm Sr, 6 to 17 ppm La, 87Sr/86Sr183: 0.7045 to 0.7075, ɛNd183: +0.31 to -7.5, ΔNb: +0.4 to -0.2) and high-Ti rocks (Gap2: 2.4 to 3.1 wt% TiO2, 110 to 240 ppm Zr, 260 to 390 ppm Sr, 12 to 24 ppm La, 87Sr/86Sr183: 0.7066 to 0.7074, ɛNd183: -3.2 to -4.1, ΔNb: +0.2 to -0.4) alternate along the same dykes. The aim of the study is to unravel the origin and petrogenesis of the two rock groups. The sample groups show the chemical traces of fractional crystallization in increasing concentrations of incompatible trace elements with decreasing MgO, and pivot points where elements such as Ti, Ca, P, and Sc change from trends of increasing to decreasing concentrations with decreasing MgO. Trends of increasing 87Sr/86Sr183 with decreasing ɛNd183 ratios indicate crustal contamination. However, three Gap1 samples from the South Gap dyke with the least enriched Sr-Nd isotope ratios and highest ΔNb may be derived from uncontaminated plume-type mantle melts. Modelling of Sr-Nd isotopes indicate that the Gap1 samples were subjected to assimilation of crustal melts (≤8%) and fractional crystallization in deep crustal magma chambers. There are no restrictions on the mantle source for the Gap2 rocks. However, because both geochemical signatures occur at different localities along the two Gap dykes, we favor a SA (South African) type mantle source for the two groups. The Gap2 rocks appear to have a two-stage assimilation history with one stage in the SCLM (subcontinental lithospheric mantle) or deep crust (decreasing the ɛNd183, increasing the 87Sr/86Sr183 ratios, and inducing the high-Ti character), followed by a second stage of contamination and fractional crystallization in the upper crust (increasing Sr isotope and (Sm/Yb)N ratios, with only minor decrease in ɛNd183).

Long-term Cyclic Variations of Prominences, Green and Red Coronae over Solar Cycles

2000 ◽  
Vol 179 ◽  
pp. 201-204
Author(s):  
Vojtech Rušin ◽  
Milan Minarovjech ◽  
Milan Rybanský
Keyword(s):  
Emission Lines ◽  
High Latitudes ◽  
Green Line ◽  
Solar Cycles ◽  
The South ◽  
Coronal Emission ◽  
Local Maxima ◽  
The North ◽  
Cyclic Variations

AbstractLong-term cyclic variations in the distribution of prominences and intensities of green (530.3 nm) and red (637.4 nm) coronal emission lines over solar cycles 18–23 are presented. Polar prominence branches will reach the poles at different epochs in cycle 23: the north branch at the beginning in 2002 and the south branch a year later (2003), respectively. The local maxima of intensities in the green line show both poleward- and equatorward-migrating branches. The poleward branches will reach the poles around cycle maxima like prominences, while the equatorward branches show a duration of 18 years and will end in cycle minima (2007). The red corona shows mostly equatorward branches. The possibility that these branches begin to develop at high latitudes in the preceding cycles cannot be excluded.

US and Russian policies and strategies in the Middle East: Iraq and Syria as a model

2019 ◽  
pp. 220
Author(s):  
Esraa Aladdin Noori ◽  
Nasser Zain AlAbidine Ahmed
Keyword(s):  
Middle East ◽  
East Asia ◽  
Balance Of Power ◽  
Western World ◽  
International Conflicts ◽  
The South ◽  
The West ◽  
The North ◽  
East Region ◽  
Middle East Region

The Russian-American relations have undergone many stages of conflict and competition over cooperation that have left their mark on the international balance of power in the Middle East. The Iraqi and Syrian crises are a detailed development in the Middle East region. The Middle East region has allowed some regional and international conflicts to intensify, with the expansion of the geopolitical circle, which, if applied strategically to the Middle East region, covers the area between Afghanistan and East Asia, From the north to the Maghreb to the west and to the Sudan and the Greater Sahara to the south, its strategic importance will seem clear. It is the main lifeline of the Western world.

Depositional Environment Drive as Overpressure Generation: Study Case in “Gap” Field, North West Java Basin

2020 ◽  
Author(s):  
A., C. Prasetyo
Keyword(s):  
Clay Mineral ◽  
Depositional Environment ◽  
Mineral Content ◽  
Hydrocarbon Generation ◽  
Well Test ◽  
Burial History ◽  
The South ◽  
North West ◽  
The North ◽  
Geological Processes

Overpressure existence represents a geological hazard; therefore, an accurate pore pressure prediction is critical for well planning and drilling procedures, etc. Overpressure is a geological phenomenon usually generated by two mechanisms, loading (disequilibrium compaction) and unloading mechanisms (diagenesis and hydrocarbon generation) and they are all geological processes. This research was conducted based on analytical and descriptive methods integrated with well data including wireline log, laboratory test and well test data. This research was conducted based on quantitative estimate of pore pressures using the Eaton Method. The stages are determining shale intervals with GR logs, calculating vertical stress/overburden stress values, determining normal compaction trends, making cross plots of sonic logs against density logs, calculating geothermal gradients, analyzing hydrocarbon maturity, and calculating sedimentation rates with burial history. The research conducted an analysis method on the distribution of clay mineral composition to determine depositional environment and its relationship to overpressure. The wells include GAP-01, GAP-02, GAP-03, and GAP-04 which has an overpressure zone range at depth 8501-10988 ft. The pressure value within the 4 wells has a range between 4358-7451 Psi. Overpressure mechanism in the GAP field is caused by non-loading mechanism (clay mineral diagenesis and hydrocarbon maturation). Overpressure distribution is controlled by its stratigraphy. Therefore, it is possible overpressure is spread quite broadly, especially in the low morphology of the “GAP” Field. This relates to the delta depositional environment with thick shale. Based on clay minerals distribution, the northern part (GAP 02 & 03) has more clay mineral content compared to the south and this can be interpreted increasingly towards sea (low energy regime) and facies turned into pro-delta. Overpressure might be found shallower in the north than the south due to higher clay mineral content present to the north.

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