scholarly journals Geology of the Northwestern Krania Basin

2019 ◽  
Vol 54 (1) ◽  
pp. 113
Author(s):  
Charlotte A Caplan ◽  
Helen C. Gildersleeves ◽  
Al G. Harding ◽  
Benedict J. R. Harris ◽  
Benedict W. W. Johnson ◽  
...  
Keyword(s):  
Middle Eocene ◽  
Late Eocene ◽  
Alluvial Fan ◽  
Normal Faulting ◽  
The West ◽  
Thrust Faulting ◽  
Extensional Faulting ◽  
Ophiolite Emplacement ◽  
Two Phases ◽  
Sedimentary Fill

We present a new map of 30 km2 of the northwestern Krania Basin at 1:10,000 scale, including rocks of the Pindos Ophiolite Group and associated units, and the sedimentary fill of the Krania Basin. The Krania Basin is a flexural basin developed in the Middle – Late Eocene and filled first with alluvial fan conglomerates and later with turbidite sandstones and siltstones, following a deepening of the basin. Analysis of the clasts within the sediment, combined with paleoflow analyses, suggest sediment input from the eroding Pindos Ophiolite to the west. The Pindos Ophiolite Group is represented in the area by pillow lavas, sheeted dykes and serpentinized harzburgites of the Aspropotamos Complex. The ophiolite forms imbricated, thrust bounded blocks which show two phases of thrusting, corresponding to Late Jurassic and Eocene stages of ophiolite emplacement. We identify five stages of deformation within the basin itself, starting with Early - Middle Eocene syndepositional extensional faulting associated with the formation of the basin. This was followed by four stages of post-depositional deformation, starting with Late Eocene compression associated with basin closure, which caused thrust faulting and folding of the sediments. Oligocene dextral faulting with a thrust component affected the basin margins. Finally, two normal faulting events with different orientations have affected the basin since the Miocene.

Les grands traits d'une structure nouvelle proposee pour le massif de Sainte-Victoire

1964 ◽  
Vol S7-VI (4) ◽  
pp. 545-553 ◽  
Author(s):  
Fernand Touraine
Keyword(s):  
Upper Cretaceous ◽  
Middle Miocene ◽  
Middle Eocene ◽  
Normal Faulting ◽  
The South ◽  
Southern France ◽  
Western Margin ◽  
Thrust Faulting ◽  
Differential Movement

Abstract The Sainte-Victoire mountain in southern France has been considered the overturned southern limb of the Vauvenargues anticline, but the structure east of the Delubre fault is complicated by an oblique fold. The western margin is concealed by transgressive Tortonian (middle Miocene) beds covering the plateau of Beaumettes. The anticline probably is upper Cretaceous. Folding was renewed in the upper Lutetian (middle Eocene), and resulted in overturning and thrust faulting of the south limb. Subsequent normal faulting compartmented the mass, resulting in selective differential movement of blocks as horsts and grabens. The term piano keys structure is given to this type of structure.

scholarly journals Thrust tectonics in the central part of the External Hellenides, the case of the Gavrovo thrust

2017 ◽  
Vol 47 (2) ◽  
pp. 540
Author(s):  
E. Kamberis ◽  
S. Sotiropoulos ◽  
F. Marnelis ◽  
N. Rigakis
Keyword(s):  
Structural Deformation ◽  
Thrust Belt ◽  
Seismic Profiles ◽  
The West ◽  
Thrust Faulting ◽  
Fold And Thrust Belt ◽  
Thrust Tectonics ◽  
Extensional Faulting ◽  
Surface Geology ◽  
Flat Geometry

Thrust faulting plays an important role in the structural deformation of Gavrovo and Ionian zones in the central part of the ‘External Hellenides’ fold-and-thrust belt. The Skolis mountain in NW Peloponnese as well as the Varassova and Klokova mountains in Etoloakarnania are representative cases of ramp anticlines associated with the Gavrovo thrust. Surface geology, stratigraphic data and interpretation of seismic profiles indicate that it is a crustal-scale thrust acted throughout the Oligocene time. It is characterized by a ramp-flat geometry and significant displacement (greater than 10 km). Out of sequence thrust segmentation is inferred in south Etoloakarnania area. Down flexure and extensional faulting in the Ionian zone facilitated the thrust propagation to the west. The thrust emplacement triggered halokenetic movement of the Triassic evaporites in the Ionian zone as well as diapirisms that were developed in a later stage in the vicinity of the Skolis mountain.

THE TECTONO-STRATIGRAPHY AND PETROLEUM POTENTIAL OF THE NORTHERN ABROLHOS SUB BASIN, WESTERN AUSTRALIA

1987 ◽  
Vol 27 (1) ◽  
pp. 112 ◽  
Author(s):  
Greg C. Smith ◽  
Robert G. Cowley
Keyword(s):  
Western Australia ◽  
Alluvial Fan ◽  
Source Rocks ◽  
Normal Faults ◽  
The West ◽  
Eastern Basin ◽  
Petroleum Potential ◽  
Lower Palaeozoic ◽  
Extensional Faulting ◽  
Stratigraphic Sequences

The Abrolhos Sub-basin lies offshore in Western Australia to the west of Geraldton and has geological affinities with the northern Perth Basin and the southern Carnarvon Basin. Both of these basins contain commercial petroleum accumulations, whereas the Abrolhos Sub-basin is a frontier area which is largely unexplored. A moderate seismic coverage of the sub-basin now exists but only two wells have been drilled, both of which were dry.Four main tectono-stratigraphic sequences are recognisable above Precambrian basement:Lower Palaeozoic Pre Rift SequenceCarboniferous-Permian Synrift/Rift Sequence S Triassic-Jurassic Rift Sequence4 Cretaceous to Recent Drift Sequence.The Lower Palaeozoic is only known on the eastern basin margins where it mainly consists of Silurian fluvial and alluvial fan red beds. The Carboniferous-Permian marine and coal measure volcanogenic synrift and rift sequences are characterised by north-south, mainly east-dipping extensional faulting, followed by widespread erosion. The Triassic sequence is about 2 km thick and comprises a basal marine Kockatea Shale, overlain by the marginal marine Woodada Formation and the Lesueur Formation red bed sequence. Subsidence during the Triassic was rapid but controlled by large NNW-SSE trending, high angle west-dipping, planar normal faults with minor rotation and extension. The Jurassic is poorly known, being confined to structurally deep blocks along the Mesozoic basin axis to the south and west. A renewed phase of NNW-SSE west-dipping extensional faulting began during the Jurassic and resulted in the development of rollover anticlines. Considerable erosion and non-deposition occurred forming a regional Neocomian unconformity. The postrift or drift sequence consists of transgressive marine shelf carbonates dipping basinward without further significant structuring.The main prospect types in the sub-basin include base Triassic transgressive sandstones or top Permian sandstones sealed by the Kockatea Shale in tilted fault blocks, and Triassic-Jurassic sandstones within rollover anticlines sealed by intraformational shales or the middle Jurassic Cadda Formation. The main source rocks include the Woodada and Kockatea formations which are within the oil generative zone over much of the sub-basin. However, identification of areas with the required coincidence of source, reservoir, seal and structural timing appears elusive.

A Tertiary Thermal Event in South-Central British Columbia

1974 ◽  
Vol 11 (8) ◽  
pp. 1116-1122 ◽  
Author(s):  
John V. Ross
Keyword(s):  
British Columbia ◽  
Country Rock ◽  
High Heat ◽  
Late Eocene ◽  
Ductile Deformation ◽  
Fold Belt ◽  
The West ◽  
Volcanic Province ◽  
Thrust Faulting ◽  
South Central

Foliated and unfoliated rhomb-porphyry dikes, genetically related to the andesitic Marron Formation, cut some westernmost exposures of the Shuswap Complex in the southern Okanagan Valley of British Columbia. Emplacement of these dikes was associated with northerly trending fractures and flexural-slip folding, localized high heat flow, re-setting of country rock K–Ar systems and hydrothermal alteration. All these events are set at 42–48 m.y. B.P. based on K–Ar measurements on dikes and country rocks.Rhomb-porphyry dikes are part of an andesitic volcanic province in south-central British Columbia that coincides in time with ductile deformation within the Cascade Fold Belt to the west and latest thrust faulting in the Rocky Mountains to the east. The volcanic province is associated in space with thinning of the crust, whereas thickening of the crust is associated with ductile shortening to the west. It is likely that the volcanic province marks the position of the ductile–brittle transition zone in the crust during late Eocene time.

scholarly journals Sedimentary Basin Reconstruction and Tectonic Development of Paleocene-Eocene Succession, Southern Iraq, by Geohistory Analysis

2021 ◽  
pp. 1213-1225
Author(s):  
Mahdi Ali Menshed ◽  
Aiad Ali Hussien Al-Zaidy
Keyword(s):  
Middle Eocene ◽  
Late Eocene ◽  
Oil Field ◽  
Transitional Period ◽  
The Other ◽  
Arabian Plate ◽  
The West ◽  
Tectonic Lineament ◽  
Western Side ◽  
Tectonic Boundary

The Paleocene-Early Eocene sequence is represented by Aliji and Umm Er Radhuma formations, while the Middle-Late Eocene sequence is represented by Jaddala and Dammam formations. The Rus Formation has been described and its basin was analyzed separately because it was deposited during the regression period (Middle Eocene), which is a transitional period between these two cycles.   This study includes analysis of the geohistory of this succession,  interpretation of the changes of the accumulation, and calculation of subsidence rates. The results were compared with the space available to explain the basin development. The study site included the boreholes of Garraf-84 and 92, Halfaya-1, Nasirya-13 and 40, and Noor-5 at the Mesopotamian Block, in addition to the  Ratawi-8, Tuba-15, Rumaila-217, Zubair-45, and West Qurna-60 at the Basra Block.      The Aliji basin was characterized by the decrease in accommodation values to the northeast direction and the increase in all the other parts of the study area. A comparison of the setting of this basin with the Umm Er Radhuma basin gives a clear evidence of the tectonic impact coming from the northeast. During the Middle Eocene stage, we notice that the basin was affected by comprehensive uplifting processes. This led to the generation of a very shallow basin (Rus basin) with the exposure of the northern part of the basin during the regression stage.      The Middle-Late Eocene basin is represented by a transgression stage with high subsidence, where the sea level had been raised and covered the northeastern and eastern parts of the studied area by deep sea deposits (Jaddala Formation). While the other parts of the study area were characterized by shallow sediments of Dammam Formation. This period ended with a clear tectonic uplift occurring in the northeastern parts and decreasing towards the southwest. This confirms the reactivation of the tectonic action from the northeast, represented by the continental collision. All these sources of evidence indicate that the study area is divided into a northern part and a southern part. Both of these parts are separated by a major tectonic lineament extending from the West Qurna oil field to the Nasiriya oil field, which confirms the presence of the tectonic boundary between the Mesopotamian block and the Basra block. In addition, there exists a secondary tectonic boundary that divides the Mesopotamian block into two parts, the first is to the east and the other is to the west. The results showed that the eastern side was most affected by the collision of the Iranian Plate with the Arabian Plate, which led to its uplift, while the western side was less affected by this tectonics evidence.

West coast North America record of the Paleogene marine stromboid gastropodRimellaand paleobiogeography of the genus

2013 ◽  
Vol 87 (5) ◽  
pp. 826-841 ◽  
Author(s):  
Richard L. Squires
Keyword(s):  
North America ◽  
West Coast ◽  
Western Europe ◽  
Middle Eocene ◽  
Late Eocene ◽  
New Combination ◽  
The West ◽  
Early Oligocene ◽  
Early Paleocene ◽  
First Time

The west coast of North America record of the shallow-marine stromboid gastropod genusRimellaAgassiz, 1841 is restudied for the first time in 90 years. This genus comprises a small group of Paleogene gastropods characterized by having an ornamented fusiform shell, a posterior canal ascending the spire, and simple (non-flared) outer lip.Rimella, whose familial ranking has been inconsistent, is placed here in family Rostellariidae Gabb, 1868, subfamily Rimellinae Stewart, 1927.EctinochilusCossmann, 1889;MacilentosClark and Palmer, 1923;VaderosClark and Palmer, 1923; andCowlitziaClark and Palmer, 1923 are recognized here as junior synonyms ofRimella. Four species are recognized from the west coast of North America: early to middle EoceneRimella macilentaWhite, 1889; early EoceneRimella oregonensisTurner, 1938; middle to late EoceneRimella supraplicata(Gabb, 1864) new combination, of whichRostellaria canaliferGabb, 1864,Cowlitizia washingtonensisClark and Palmer, 1923, andCowlitzia problematicaHanna, 1927 are recognized here as junior synonyms; and late EoceneRimella elongataWeaver, 1912.Rimellawas a warm-water gastropod whose earliest known record is of early Paleocene (Danian) age in Pakistan. Other than the west coast of North America,Rimellais found in Eocene strata in western Europe, Turkey, Egypt, Pakistan, southeastern United States, Panama, Peru, and, to a lesser degree, in Trinidad, Columbia, Java, and New Zealand. Global cooling near the end of the Eocene greatly diminished the genus. Its youngest known occurrences are of early Oligocene age in Germany, Italy, England, and Peru.

Apercu geologique sur les collines de Boutenac (Aude)

1962 ◽  
Vol S7-IV (3) ◽  
pp. 362-379
Author(s):  
Alain Combes
Keyword(s):  
Upper Cretaceous ◽  
Upper Triassic ◽  
Normal Faulting ◽  
The West ◽  
Southern France ◽  
Sandy Limestone

Abstract The Boutenac hills in the northeastern Corbieres region of southern France, are part of the autochthonous foreland of the eastern Corbieres nappe. They are an isolated massif between the Paleozoic formations of the Alaric mountain on the west, and the Jurassic and Cretaceous formations of the Fontfroide chain on the east, entirely surrounded by alluvium. Structurally, they comprise Mesozoic formations on the east thrust over the Eocene on the west, on a fault that is the prolongation of the Saint Chinian frontal fault to the northeast. The Mesozoic formations comprise upper (?) Triassic shale and dolomite, sandy limestone, dolomite, and limestone; Jurassic red sandstones and shales; and upper Cretaceous transgressive clastics. The Eocene is limestone and marl overlain by continental conglomerate and molasse, transgressive on the west upon the Alaric Paleozoics. Folding and thrust and normal faulting are important in the structure.

scholarly journals Geographic contingency, not species sorting, dominates macroevolutionary dynamics in an extinct clade of neogastropods (Volutospina; Volutidae)

Paleobiology ◽  
2021 ◽  
pp. 1-15
Author(s):  
Dana S. Friend ◽  
Brendan M. Anderson ◽  
Warren D. Allmon
Keyword(s):  
Middle Eocene ◽  
Ecological Factors ◽  
Geographic Range ◽  
Late Eocene ◽  
Range Size ◽  
Species Sorting ◽  
Extinction Rates ◽  
Geographic Range Size ◽  
Speciation Rates ◽  
Planktotrophic Larvae

Abstract Rates of speciation and extinction are often linked to many ecological factors, traits (emergent and nonemergent) such as environmental tolerance, body size, feeding type, and geographic range. Marine gastropods in particular have been used to examine the role of larval dispersal in speciation. However, relatively few studies have been conducted placing larval modes in species-level phylogenetic context. Those that have, have not incorporated fossil data, while landmark macroevolutionary studies on fossil clades have not considered both phylogenetic context and net speciation (speciation–extinction) rates. This study utilizes Eocene volutid Volutospina species from the U.S. Gulf Coastal Plain and the Hampshire Basin, U.K., to explore the relationships among larval mode, geographic range, and duration. Based on the phylogeny of these Volutospina, we calculated speciation and extinction rates in order to compare the macroevolutionary effects of larval mode. Species with planktotrophic larvae had a median duration of 9.7 Myr, which compared significantly to 4.7 Myr for those with non-planktotrophic larvae. Larval mode did not significantly factor into geographic-range size, but U.S. and U.K. species do differ, indicating a locality-specific component to maximum geographic-range size. Non-planktotrophs (NPTs)were absent among the Volutospina species during the Paleocene–early Eocene. The relative proportions of NPTs increased in the early middle Eocene, and the late Eocene was characterized by disappearance of planktotrophs (PTs). The pattern of observed lineage diversity shows an increasing preponderance of NPTs; however, this is clearly driven by a dramatic extinction of PTs, rather than higher NPT speciation rates during the late Eocene. This study adds nuance to paleontology's understanding of the macroevolutionary consequences of larval mode.

scholarly journals Impact of mid Eocene greenhouse warming on America’s southernmost floras

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Damián A. Fernández ◽  
Luis Palazzesi ◽  
M. Sol González Estebenet ◽  
M. Cristina Tellería ◽  
Viviana D. Barreda
Keyword(s):  
Middle Eocene ◽  
Pollen Grains ◽  
Late Eocene ◽  
Significant Rise ◽  
Spores And Pollen ◽  
Deep Time ◽  
Nonparametric Estimators ◽  
Southern Patagonia ◽  
Marine Realm ◽  
High Diversity

AbstractA major climate shift took place about 40 Myr ago—the Middle Eocene Climatic Optimum or MECO—triggered by a significant rise of atmospheric CO2 concentrations. The biotic response to this MECO is well documented in the marine realm, but poorly explored in adjacent landmasses. Here, we quantify the response of the floras from America’s southernmost latitudes based on the analysis of terrestrially derived spores and pollen grains from the mid-late Eocene (~46–34 Myr) of southern Patagonia. Robust nonparametric estimators indicate that floras in southern Patagonia were in average ~40% more diverse during the MECO than pre-MECO and post-MECO intervals. The high atmospheric CO2 and increasing temperatures may have favored the combination of neotropical migrants with Gondwanan species, explaining in part the high diversity that we observed during the MECO. Our reconstructed biota reflects a greenhouse world and offers a climatic and ecological deep time scenario of an ice-free sub-Antarctic realm.

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