Recherches geologiques preliminaires dans le massif du Parnasse (Grece)

1957 ◽  
Vol S6-VII (4-5) ◽  
pp. 571-583 ◽  
Author(s):  
Paul Celet
Keyword(s):  
Upper Triassic ◽  
Stratigraphic Sequence ◽  
The North ◽  
North And South ◽  
East West

Abstract The stratigraphic sequence of the Parnassus massif in Greece begins with coral-bearing upper Triassic dolomites and limestones, which are overlain by a thick series of Mesozoic limestones capped by red shaly marls and sandy Flysch formations. The structure was influenced by the rigidity of the limestone cover, which is faulted and overthrust in slices toward the east-northeast. The massif as a whole is cut by deep east-west-trending faults, along which the large grabens bounding the massif on the north and south were downdropped.

scholarly journals Global variations of local asymmetry in glacier altitude: separation of north–south and east–west components

2005 ◽  
Vol 51 (174) ◽  
pp. 469-482 ◽  
Author(s):  
Ian S. Evans ◽  
Nicholas J. Cox
Keyword(s):  
The Arctic ◽  
Equilibrium Line Altitude ◽  
Height Range ◽  
The North ◽  
Regional Trends ◽  
Strong Winds ◽  
The Tropics ◽  
New Evidence ◽  
North And South ◽  
East West

AbstractNorth–south and east–west differences in firn-line altitude, equilibrium-line altitude or middle altitudes of glaciers can be separated by regression on the cosine and sine of glacier aspect (accumulation area azimuth). Allowing for regional trends in altitude, the north–south differences expected from radiation and shade effects can be reliably quantified from World Glacier Inventory (WGI) data. The north–south differences are greater in sunnier climates, mid-latitudes and steeper relief. Local altitude differences between north- and south-facing glaciers are commonly 70–320 m. Such asymmetry is near-universal, although weak in the Arctic and tropics. East–west contrasts are less, and found mainly in the tropics and areas most exposed to strong winds. Altitude, latitude, glacier gradient and height range, calculable from most of the WGI data, are potential controls on the degree of north–south contrast, as well as surrogates for climatic controls (temperature, precipitation, radiation and cloudiness). An asymmetric sine–cosine power model is developed to describe the variation of north–south contrast with latitude. Multiple regression over 51 regions shows altitude and latitude to be the strongest controls of this contrast. Aspect–altitude analysis for former glaciers provides new evidence of cloudiness.

Subduction of an extinct rift and its role in the formation of submarine landslides in NW South America

2020 ◽  
Vol 500 (1) ◽  
pp. 311-322 ◽  
Author(s):  
Carlos A. Vargas ◽  
Gustavo A. Gutiérrez ◽  
Gustavo A. Sarmiento
Keyword(s):  
South America ◽  
Seismic Activity ◽  
Fault Reactivation ◽  
Submarine Landslides ◽  
Oceanic Plate ◽  
Sources Of Uncertainty ◽  
The North ◽  
Continental Plate ◽  
North And South ◽  
East West

AbstractOn the eastern margin of the Panama Basin, the Nazca oceanic plate converges towards the continental plate of South America at approximately 53 mm a−1. Subduction processes are accompanied by the presence of anomalous bathymetric elements including the Sandra Ridge. This east–west-orientated ridge is catalogued as an aborted rift derived from a magmatic spreading axis that was active between 12 and 9 Ma. Seismic activity within this structure is considered evidence of fault reactivation and tectonism. Once the structure reached the subduction trench several submarine landslides were triggered. Run-out lengths of these submarine landslides are perpendicular to the convergence of the structure with some units spreading and forming a wide fan that reaches tens of kilometres to the north and south of the trench. The area affected by the three main landslides varies between 130 and 300 km2 approximately, with relatively superficial earthquakes (<33 km) and with magnitudes that reach up to Mw 7.2. The morphology of the landslides suggests a retrogressive nature with younger events proximal to shore. This paper presents estimates of the age of these landslides and discusses sources of uncertainty regarding these times of occurrence.

Multiple Deformation in Archean Rocks of the Vermilion District, Northeastern Minnesota

1971 ◽  
Vol 8 (4) ◽  
pp. 423-434 ◽  
Author(s):  
P. R. Hooper ◽  
R. W. Ojakangas
Keyword(s):  
Iron Formation ◽  
Rock Outcrop ◽  
Kink Bands ◽  
Precambrian Rocks ◽  
The North ◽  
Multiple Deformation ◽  
North And South ◽  
East West

The structure of the Precambrian rocks of the Vermilion district is critically examined. It is demonstrated that two significant deformations (F1 and F2) have affected the area in addition to a later set of faults, joints, and kink-bands (F3). The F1 folds are tight to isoclinal with gently plunging axes and vertical axial planes trending west–northwest and containing iron formation and greenstones in anticlinal cores. The second deformation forms a series of open to close asymmetric folds (F2) with steep axes and vertical axial planes trending east–west. Of these, F1 has the more significant effect on the pattern of rock outcrop and it is suggested that it is directly related to the diapiric rise of the batholiths lying immediately to the north and south. The F2 folds may be accounted for by further compression between the two granite bodies.

scholarly journals Converging ice streams: an unreasonable hypothesis for deposition of the Oak Ridges Moraine, southern Ontario

2020 ◽  
Vol 57 (7) ◽  
pp. 781-800
Author(s):  
David R. Sharpe ◽  
Hazen A.J. Russell
Keyword(s):  
Process Model ◽  
Weight Of Evidence ◽  
Seismic Profiles ◽  
Ice Streams ◽  
Stratigraphic Sequence ◽  
Oak Ridges Moraine ◽  
The North ◽  
Ice Stream ◽  
Digital Elevation ◽  
East West

The hypothesis that Oak Ridges Moraine (ORM) formed between converging ice streams requires critical testing. Available data (e.g., digital elevation models, maps, seismic profiles, continuous cores, and pit exposures) are inconsistent with the converging ice stream hypothesis. Combined analysis of landform and subsurface data permits testing the ORM area stratigraphic sequence and sedimentary origin. Stratigraphic data indicate that drumlinized Newmarket Till, incised by north–south-oriented (tunnel) valleys, extends beneath ORM. Thus, streamlining on Newmarket Till is older than ORM and has no direct bearing on its formation. The north–south-trending valleys truncate streamlined Newmarket Till, extend to bedrock, have inset eskers, and occur beneath ORM. Hence, these valleys are older than ORM and have a subglacial rather than a proglacial origin. Overlying the mega-scale lineations and incised channels are topographically elevated (>300 m a.s.l.), ORM glaciofluvial–glaciolacustrine sequences. Its east to west paleoflow trend indicates an east–west-oriented hydraulic gradient, orthogonal to expected gradients of proposed north-south converging ice streams. The exclusive presence of ORM meltwater sediments, with rare deformation, is incompatible with a converging ice stream, deforming-bed hypothesis. Halton sediment grades upward from stratified sand (ORM) to interbedded diamicton and glaciolacustrine sediment, rather than deformation till. Halton sediment overlies ORM and consequently the proposed Halton ice streaming is younger than the moraine. Halton Till is present in few of the predicted ice stream areas, and where Halton Till is present, it has no mega-scale lineations. In sum, the weight of evidence unequivocally argues against a converging ice-stream process model for the ORM.

BAYU/UNDAN GAS-CONDENSATE DISCOVERY: WESTERN TIMOR GAP ZONE OF COOPERATION, AREA A.

1996 ◽  
Vol 36 (1) ◽  
pp. 142 ◽  
Author(s):  
D. M. Brooks ◽  
A. K. Goody ◽  
J. B. O'Reilly ◽  
K. L. McCarty
Keyword(s):  
Joint Venture ◽  
Gas Condensate ◽  
Normal Faults ◽  
Structural Element ◽  
Water Contact ◽  
The North ◽  
Wet Gas ◽  
Petroleum Company ◽  
North And South ◽  
East West

The Bayu/Undan Gas-Condensate Field straddles the boundary between the ZOCA 91-12 and ZOCA 91-13 PSC areas, within the Timor Gap Zone of Cooperation Area A (ZOCA). The field is located approximately 450 km north­west of Darwin, NT, and 350 km east-southeast of Kupang, Timor. The closure is the culmination of the Flamingo High, a major structural element within the northern Bonaparte Basin. This structure has been viewed as having significant hydrocarbon potential since Flamingo-1 recovered gas from Berriasian sandstones in 1971.The discovery well, Bayu-1, was drilled by the ZOCA 91-13 contract operator, Phillips Petroleum Company ZOC, in early 1995. Bayu-1 intersected a gross 155m gas-condensate column within Middle Jurassic sandstones at a depth of 2,954.5 mSS. The ZOCA 91-12 joint venture then drilled Undan-1,10 km northwest of Bayu-1, on a separate culmination within the closure defined by the Bayu-1 gas-water contact. Undan-1 and subsequent wells have confirmed the existence of one large gas-conden­sate field, with a most likely areal extent of over 160 km2.The sandstone reservoir consists of late Oxfordian to Callovian shallow marine, deltaic to shoreface, coarsen­ing upward parasequences, overlying Callovian to Bajocian marginal marine to coastal plain sediments. The trap is an east-west oriented horst block bounded by en-echelon normal faults to the north and south, with dip closure to the east and west. Seal is provided by Tithonian to Barremian marine claystones. A likely hydrocarbon source is contained within the Barremian to Callovian interval, some of which are mature for condensate and wet gas expulsion in the southern Sahul Syncline and Malita Graben.

Geology of the Gladys McCall Geopressured-Geothermal Prospect, Cameron Parish, Louisiana

1988 ◽  
Vol 110 (4) ◽  
pp. 255-261
Author(s):  
Chacko J. John
Keyword(s):  
Research Program ◽  
Department Of Energy ◽  
Well Control ◽  
Wildlife Refuge ◽  
Stratigraphic Section ◽  
Deep Well ◽  
The North ◽  
Lake Charles ◽  
North And South ◽  
East West

The Gladys McCall prospect lies at the western edge of the Rockefeller Wildlife Refuge about 88 km (55 mi) southeast of Lake Charles in Cameron Parish, Louisiana. The test well is 4825 m (15,831 ft) deep and was drilled in 1981 under the U. S. Department of Energy geopressured-geothermal research program. The well was shut in at the end of October 1987 after it had produced over 27 million barrels of brine and 676 MMscf gas, without any significant pressure decline. The stratigraphic section seen in this test well consists of alternating sandstones and shales with about 350 m (1150 ft) of net sand between 4393 m (14,412 ft) and 4974 m (16,320 ft). The producing reservoir is bounded on the north and south by faults. The east-west dimension is poorly defined due to lack of deep well control. Eleven prospective production zones have been identified. The pressure maintenance and the continuous high brine yield from the reservoir may be due to laterally overlapping and connected sandstones, communication between overlying and/or underlying reservoirs, growth faults acting as passageways for brine, shale dewatering, or possible communication of zones behind the casing.

The August 1975 Oroville earthquakes

1976 ◽  
Vol 66 (4) ◽  
pp. 1085-1099
Author(s):  
K. M. Lahr ◽  
J. C. Lahr ◽  
A.G. Lindh ◽  
C. G. Bufe ◽  
F. W. Lester
Keyword(s):  
Fault Plane ◽  
Aftershock Sequence ◽  
The West ◽  
Epicentral Area ◽  
Space And Time ◽  
The North ◽  
The Town ◽  
North And South ◽  
East West

abstract On August 1, 1975, a magnitude 5.9 (mb) earthquake occurred approximately 8 km SSE of the town of Oroville, California. This earthquake and its associated foreshock-aftershock sequence are of particular interest because of their possible relation to the impounding of the 4.3 billion m3 Lake Oroville. Hypocenter locations for 336 aftershocks that occurred during August define a fault plane striking N3°E and dipping 60° to the west to a depth of 10 km. Dimensions of the epicentral area are approximately 7 km in an east-west direction by 15 km in a north-south direction. The fault plane passes beneath Oroville Dam at 5-km depth, and if projected up dip, would crop out beneath the reservoir to the east. The distribution in space and time of foreshocks and aftershocks suggests that rupture began at depth and progressed up dip and to the north and south.

scholarly journals AN EVALUATION ON THE TEMPERATURE AND PRECIPITATION PREFERENCES OF THE IDA MOUNTAIN (TURKEY) FORESTS

2021 ◽  
Vol 9 (01) ◽  
pp. 289-326
Author(s):  
Berna Hepbilgin ◽  
Keyword(s):  
Pinus Nigra ◽  
Natural Forest ◽  
Precipitation Data ◽  
Geographical Differences ◽  
The North ◽  
Temperature And Precipitation ◽  
Tree Communities ◽  
North And South ◽  
East West

Ida Mountain presents a peculiar geographical structure in terms of the distribution of tree stands, like all the geographical differences on the north and south slopes with its location in the north of Edremit bay and with lying east-west direction roughly.Covering the area of ​​1823 km2 with its immediate surroundings, Ida Mountains natural forest section forms approximately 60% of the area. In the natural forest area of ​​Ida Mountain, Pinus brutia, Pinus nigra, Quercus, Abies, Fagus and Castanea are found as pure tree communities, and related varieties formed by the combination of these species in different bulk densities. In the eco-geographic study of forest areas, the two most basic bioclimatic factors are: knowing the temperature and precipitation preferences of tree species and stands. In this study, monthly, seasonal and annual temperature and precipitation preferences of tree stands in Ida Mountain were obtained by modeling the temperature and precipitation data obtained from meteorological stations around Mt. Ida. This case study aims to contribute to the future eco-geographical evaluations on the tree stands of Ida Mountain.

Rb–Sr dates for granodiorite intrusions on the northeast margin of the Shuswap Metamorphic Complex, Cariboo Mountains, British Columbia

1977 ◽  
Vol 14 (7) ◽  
pp. 1690-1695 ◽  
Author(s):  
Lee C. Pigage
Keyword(s):  
British Columbia ◽  
Upper Jurassic ◽  
Upper Triassic ◽  
Time Interval ◽  
Metamorphic Complex ◽  
The North ◽  
Regional Deformation ◽  
Shuswap Metamorphic Complex ◽  
North And South ◽  
Provincial Park

Whole rock Rb–Sr dates of 138 ± 12 Ma (all five whole rocks) and 163 ± 7 Ma were obtained for granodiorite stocks in Wells Gray Provincial Park, Cariboo Mountains, British Columbia. These dates bracket the biotite K–Ar date of 143 ± 14 Ma determined previously by the Geological Survey of Canada. Two biotite – whole rock ± hornblende dates of 119 ± 11 Ma and 77 ± 20 Ma indicate isotopic resetting. Initial 87Sr–86Sr ratios vary from 0.7061 ± 0.0001 to 0.7103 ± 0.0002 for rock and mineral dates.When combined with field relations, these dates restrict regional deformation and metamorphism in this area to the time interval between Upper Triassic and Upper Jurassic. The resetting event was probably Eocene, as shown in other areas along regional strike to the north and south.

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