scholarly journals New insights into the geological history of the basement rocks to the southwestern Athabasca Basin, Saskatchewan and Alberta

2007 ◽  
Author(s):  
C D Card ◽  
D Panã ◽  
R A Stern ◽  
N Rayner
Keyword(s):  
Geological History ◽  
Athabasca Basin ◽  
Basement Rocks ◽  
History Of

The origin of Ti-oxide minerals below and within the eastern Athabasca Basin, Canada

2020 ◽  
Vol 105 (12) ◽  
pp. 1875-1888
Author(s):  
Erin E. Adlakha ◽  
Keiko Hattori ◽  
Mitchell J. Kerr ◽  
Brandon M. Boucher
Keyword(s):  
Regional Metamorphism ◽  
Hydrothermal Activity ◽  
Geological History ◽  
Epma Data ◽  
Athabasca Basin ◽  
Basement Rocks ◽  
History Of ◽  
Oxide Minerals ◽  
High Concentrations ◽  
Late Diagenesis

Abstract Titanium oxide minerals along the P2 fault in the eastern Athabasca Basin are characterized to constrain their origin and the geological history of the area. Two types of rutile are recognized in the basement rocks. Early rutile is disseminated in graphitic metapelite and quartzite, and it formed during regional metamorphism and post-metamorphic hydrothermal activity. Late rutile occurs as a needle-like alteration product of mica and likely formed during retrogression of the basement. In graphitic metapelite, early rutile commonly occurs with an assemblage of oxy-dravite, quartz, graphite, zircon, pyrite, biotite, and muscovite. In quartzite, rutile occurs with quartz, sillimanite, muscovite, and zircon. Metamorphic rutile is characterized by high Nb/Ta ratios (up to 47) with high concentrations of U (up to 126 ppm) and V4+ (up to 1.44 wt%; V valance calculated from EPMA data). Hydrothermal rutile contains distinctly low Nb/Ta (as low as 4.80) with high Ta (≤3050 ppm), and relatively low V (as V 3+; as low as 0.02 wt%) and U (as low as 9.06 ppm), reflecting fluids in reduced oxidation conditions. Anatase forms small anhedral (rarely coarse and euhedral) grains in the basal sandstones and altered basement rocks. In sandstones, anatase occurs with the late diagenetic mineral assemblage, whereas in basement rocks it commonly occurs with the clay-sized minerals related to uranium mineralization. In both rocks, anatase likely formed through the dissolution of rutile and/or other Ti-bearing minerals. Anatase is characterized by variably high Fe (up to 0.99 wt%; possibly contributed by hematite micro-or nanoinclusions) and U (up to 180 ppm). The mineral assemblages and composition of anatase suggest its protracted crystallization from relatively low temperature, oxidizing, acidic, uraniferous fluids of the sandstones during late diagenesis and hydrothermal activity. Therefore, the occurrence of anatase records the incursion of basin fluids into the basement, and the interaction of basement rocks with fluids responsible for the formation of the McArthur River uranium deposit. The results of this study confirm that Ti-oxides are useful in unraveling the geological history of an area that underwent prolonged hydrothermal activity.

LATE QUATERNARY GEOLOGICAL HISTORY OF RIO GRANGE DO SUL COASTAL PLAIN, SOUTHERN BRAZIL

2000 ◽  
Vol 30 (3) ◽  
pp. 474-476 ◽  
Author(s):  
LUIZ JOSÉ TOMAZELLI ◽  
SÉRGIO REBELLO DILLENBURG ◽  
JORGE ALBERTO VILLWOCK
Keyword(s):  
Coastal Plain ◽  
Late Quaternary ◽  
Geological History ◽  
Southern Brazil ◽  
History Of

Geoinformation Mapping Through the Types of Geological and Geomorphological Structure of the Katun Valley (Altay Mountains) Based on Morphometric Indicators

2018 ◽  
Vol 938 (8) ◽  
pp. 38-43
Author(s):  
S.A. Kotler ◽  
I.D. Zolnikov ◽  
D.V. Pchelnikov
Keyword(s):  
Morphometric Parameters ◽  
Morphometric Parameter ◽  
Geological History ◽  
Mountain Rivers ◽  
Quaternary Period ◽  
Modern Variety ◽  
Altay Mountains ◽  
History Of

The types of geological and geomorphological structure of the Katun valley are distinguished in the work. For this, a method of geoinformation mapping using morphometric indicators of the valley’s width and meandering of the channel was developed. The morphometric parameter of the valley’s width was calculated as the total area of terraces. As the morphometric parameters of the channel’s meandering, the angles of the river segments’ deviation relative to each other were calculated. Conjugated analysis of these morphometric indicators enabled identifying 18 morphotypes. These morphotypes according to the geological and geomorphological structure of the valley were combined into 4 classes. Separation of the Katun valley in certain classes and morphotypes is due to the different geological history of these sites during the Quaternary period. The most important reasons predetermining the modern variety of geological and geomorphological types of the valley are neotectonic movements and exogenous phenomena (glaciers, dam lakes, landslides, etc.) naturally localized in the space from the upstream of the river to its exit into the foothills. The developed method can be applied for quantitative morphometric classification of the mountain rivers’ valleys in other regions.

BORON ISOTOPES AS TRACERS OF THE TECTONIC ORIGIN AND GEOLOGICAL HISTORY OF SERPENTINITES IN SUBDUCTION AND SUTURE ZONES

2016 ◽  
Author(s):  
Celine Martin ◽  
◽  
George E. Harlow ◽  
George E. Harlow ◽  
George E. Harlow ◽  
...  
Keyword(s):  
Boron Isotopes ◽  
Geological History ◽  
History Of ◽  
Tectonic Origin

scholarly journals Tectonic Evolution of the SE West Siberian Basin (Russia): Evidence from Apatite Fission Track Thermochronology of Its Exposed Crystalline Basement

Minerals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 604
Author(s):  
Evgeny V. Vetrov ◽  
Johan De Grave ◽  
Natalia I. Vetrova ◽  
Fedor I. Zhimulev ◽  
Simon Nachtergaele ◽  
...  
Keyword(s):  
Tectonic Evolution ◽  
Fission Track ◽  
Analytical Data ◽  
Tectonic Activity ◽  
Apatite Fission Track ◽  
Tectonic Processes ◽  
Basement Rocks ◽  
Fission Track Thermochronology ◽  
History Of ◽  
West Siberian Basin

The West Siberian Basin (WSB) is one of the largest intracratonic Meso-Cenozoic basins in the world. Its evolution has been studied over the recent decades; however, some fundamental questions regarding the tectonic evolution of the WSB remain unresolved or unconfirmed by analytical data. A complete understanding of the evolution of the WSB during the Mesozoic and Cenozoic eras requires insights into the cooling history of the basement rocks as determined by low-temperature thermochronometry. We presented an apatite fission track (AFT) thermochronology study on the exposed parts of the WSB basement in order to distinguish tectonic activation episodes in an absolute timeframe. AFT dating of thirteen basement samples mainly yielded Cretaceous cooling ages and mean track lengths varied between 12.8 and 14.5 μm. Thermal history modeling based on the AFT data demonstrates several Mesozoic and Cenozoic intracontinental tectonic reactivation episodes affected the WSB basement. We interpreted the episodes of tectonic activity accompanied by the WSB basement exhumation as a far-field effect from tectonic processes acting on the southern and eastern boundaries of Eurasia during the Mesozoic–Cenozoic eras.

Beyond Wallace: a new lineage of Chrysorthenches (Lepidoptera: Yponomeutoidea: Glyphipterigidae) reveals a journey tracking its host-plants, Podocarpus (Pinopsida: Podocarpaceae)

2020 ◽  
Vol 190 (2) ◽  
pp. 709-736
Author(s):  
Jae-Cheon Sohn ◽  
Shigeki Kobayashi ◽  
Yutaka Yoshiyasu
Keyword(s):  
Maximum Likelihood ◽  
East Asia ◽  
Host Plants ◽  
Morphological Characters ◽  
Species Group ◽  
Geological History ◽  
Dna Barcodes ◽  
History Of ◽  
Species Groups ◽  
Maximum Likelihood Phylogeny

Abstract A northward trans-Wallacean radiation is demonstrated for Chrysorthenches, a member of the Orthenches group. Here we review Chrysorthenches and allied genera resulting in a generic transfer of Diathryptica callibrya to Chrysorthenches and two new congeners: C. muraseaeSohn & Kobayashisp. nov. from Japan and C. smaragdinaSohnsp. nov. from Thailand. We review morphological characters of Chrysorthenches and allied genera, and find polyphyly of Diathryptica and the association of the Orthenches-group with Glyphipterigidae. These findings were supported in a maximum likelihood phylogeny of DNA barcodes from ten yponomeutoids. We analysed 30 morphological characters for 12 species of Chrysorthenches, plus one outgroup, via a cladistic approach. The resulting cladogram redefined two pre-existing Chrysorthenches species-groups and identified one novel lineage: the C. callibrya species-group. We review the host associations between Chrysorthenches and Podocarpaceae, based on mapping the working phylogenies. Our review suggests that ancestral Chrysorthenches colonized Podocarpus and later shifted to other podocarp genera. Biogeographical patterns of Chrysorthenches show that they evolved long after the Podocarpaceae radiation. Disjunctive trans-Wallacean distribution of the C. callibrya species-group is possibly related to the tracking of their host-plants and the complicated geological history of the island-arc system connecting Australia and East Asia.

scholarly journals The geological history of the Lake Rudolf Basin, Kenya colony

1939 ◽  
Vol 229 (560) ◽  
pp. 219-274 ◽  
Keyword(s):  
Rift Valley ◽  
Public Works ◽  
General Description ◽  
Geological History ◽  
East African ◽  
The Public ◽  
Geographical Society ◽  
History Of ◽  
African Rift ◽  
At Home

The Lake Rudolf Rift Valley Expedition was designed to carry out many different lines of investigation in the Lake Rudolf Basin. One of the chief of these was a study of the geological history of that part of the East African Rift Valley. The expedition was assisted financially by The Royal Society, The Geological Society of London, The Royal Geographical Society, The Percy Sladen Trustees and the Geographical and Geological Sections of the British Association. A general description of the activities of the Expedition was given in a paper read before the Royal Geographical Society (Fuchs 1935). Owing to the tragic loss of two members of the expedition, Dr W. S. Dyson and Mr W. R. H. Martin, two fruitless months were spent searching for them. Consequently a great amount of the work planned for the east side of the lake had to be abandoned. Nevertheless, the considerable distance travelled within the 50,000 sq. miles of the Rudolf Basin has enabled me to make out the chief events of its geological history. I am very much indebted to all those who assisted us in the field and at home, in particular to the Kenya Government, the Officers of the King’s African Rifles, and Mr H. L. Sikes of the Public Works Department; I would also like to thank Mr A. M. Champion, Provincial Commissioner of Turkana, who wholeheartedly assisted us in every way possible both in the field and at home, for he has placed at my disposal his own excellent topographical maps and his extensive observations on the geology of the area. I am also deeply indebted to Professor O. T. Jones, Mr Henry Woods and Mr W. Campbell Smith for their criticisms. Mr Campbell Smith has also given me provisional identifications of the rocks.

scholarly journals XIX.—The Bone-Cave in the Valley of Allt nan Uamh (Burn of the Caves), near Inchnadamff, Assynt, Sutherlandshire

1918 ◽  
Vol 37 ◽  
pp. 327-349 ◽  
Author(s):  
B. N. Peach ◽  
J. Horne ◽  
E. T. Newton
Keyword(s):  
Characteristic Feature ◽  
Late Glacial ◽  
Early History ◽  
The Arctic ◽  
Geological History ◽  
Collateral Evidence ◽  
History Of ◽  
Glacial Time

A characteristic feature of the plateau of Cambrian Limestone in the neighbourhood of Inchnadamff is the occurrence in it of swallow-holes, caves, and subterranean channels which are intimately associated with the geological history of the region. The valley of Allt nan Uamh (Burn of the Caves), locally known as the Coldstream Burn, furnishes striking examples of these phenomena. One of the caves in this valley yielded an interesting succession of deposits, from which were collected abundant remains of mammals and birds. The discovery of bones of the Northern Lynx, the Arctic Lemming, and the Northern Vole among these relics, and the collateral evidence of the materials forming some of these layers, seem to link the early history of this bone-cave with late glacial time, or at least with a period before the final disappearance of local glaciers in that region.

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