The Stratigraphic Position, Lithologic Character, and Preore Dissolution Features of Ore-Bearing Beds in the Leadville Dolomite, Leadville-Gilman Area

1990 ◽  
pp. 118-129
Keyword(s):  
Stratigraphic Position ◽  
Lithologic Character

Stratigraphic position and localities of the Temlyan flora from the Anadyr river lower course basin

Palaeobotany ◽  
2015 ◽  
Vol 6 ◽  
pp. 48-67 ◽  
Author(s):  
L. B. Golovneva ◽  
A. A. Grabovskiy
Keyword(s):  
Volcanic Activity ◽  
City Area ◽  
Plant Fossils ◽  
Stratigraphic Position ◽  
Early Paleocene ◽  
First Time ◽  
Systematic Composition ◽  
Stratigraphic Range

Plant fossils from the volcano-clastic deposits of the lower part of the Tanyurer Formation and lower part of the Tavaivaam Unit in the Anadyr city area (Northeastrn Russia) are described for the first time. This assemblage was named as the Temlyan flora. It consists of 25 taxa and includes ferns, horsetails, lycophytes, ginkgoaleans, czekanowskialeans, cycadophytes, conifers and angiosperms. The Temlyan flora is similar in systematic composition to the Rarytkin flora from the upper part of the Rarytkin Formation which was dated as the late Maastrichtian-Danian. But it is distinguished from the latter by presence of the numerous relicts (Lokyma, Nilssonia, Encephalartopsis, Phoenicopsis and Ginkgo ex gr. sibirica). Probably the presence of relicts in the Temlyan flora is connected with influence of volcanic activity. Age of the Temlyan flora is determined as the late Maastrichtian-Danian on the basis of systematic similarity with the Rarytkin Flora. However this age may be slightly younger, possibly only early Paleocene, because the Tanyurer Formation superposes the Rarytkin Formation. Stratigraphic range of Lokyma, Nilssonia, Encephalartopsis, Phoenicopsis and Ginkgo ex gr. sibirica is extended from its previously known latest records in the early Campanian or middle Maastrichtian up to as late as the latest Maastrichtian or early Paleocene. It is very possible, that these typical Mesozoic taxa may have persisted into the Paleogene.

The Gedan floristic assemblage from the Late Cretaceous deposits of the Kholchan Formation of the Okhotsk-Chukotka volcanogenic belt

Palaeobotany ◽  
2014 ◽  
Vol 5 ◽  
pp. 73-93 ◽  
Author(s):  
L. B. Golovneva ◽  
S. V. Shczepetov
Keyword(s):  
River Basin ◽  
Late Cretaceous ◽  
Middle Part ◽  
Isotopic Data ◽  
Volcanogenic Belt ◽  
Stratigraphic Position ◽  
Cretaceous Deposits

The Gedan floristic assemblage occurs from upper layers of the Kholchan Formation of the Okchotsk-Chukotka volcanogenic belt (OCVB). The locality is situated at the Gedan River in the middle part of the Arman River basin. The Gedan assemblage is composed of 6 taxa: Cladophlebis sp., Sphenobaiera sp., Ginkgo ex gr. adiantoides (Ung.) Heer, Taxodium amguemensis (Efimova) Golovn., Metasequoia sp., Pagiophyllum sp. The similarity of the Gedan floristic assemblage with the Karamken and the Khirumki floristic assemblages from the Kholchan Formation of the Okhotsk sector of the OCVB allows us to join them in the Kholchan flora. This flora is distinct from more ancient Arman flora, which dated as the Turonian-Coniacian and from younger Ola flora, which dated as the Santonian-early Campanian. The age of the Kholchan flora is estimated as the Coniacian on the basis of stratigraphic position, presence of Podozamites, Metasequoia and Quereuxia and also isotopic data. This flora is equivalent with the Chaun flora of Central Chukotka, with the Aleeki flora from the Villigha and Toomahni Rivers interfluve and with the Ulya flora from the southern part of the Okhotsk-Chukotka volcanogenic belt.

scholarly journals Holocene Key-Marker Tephra Layers in Kamchatka, Russia

1997 ◽  
Vol 47 (2) ◽  
pp. 125-139 ◽  
Author(s):  
Olga A. Braitseva ◽  
Vera V. Ponomareva ◽  
Leopold D. Sulerzhitsky ◽  
Ivan V. Melekestsev ◽  
John Bailey
Keyword(s):  
Grain Size ◽  
Size Distribution ◽  
Mineral Composition ◽  
Kamchatka Peninsula ◽  
Explosive Eruptions ◽  
Shiveluch Volcano ◽  
Stratigraphic Position ◽  
Tephra Layers ◽  
Characteristic Features ◽  
Important Marker

Detailed tephrochronological studies in Kamchatka Peninsula, Russia, permitted documentation of 24 Holocene key-marker tephra layers related to the largest explosive eruptions from 11 volcanic centers. Each layer was traced for tens to hundreds of kilometers away from the source volcano; its stratigraphic position, area of dispersal, age, characteristic features of grain-size distribution, and chemical and mineral composition confirmed its identification. The most important marker tephra horizons covering a large part of the peninsula are (from north to south; ages given in14C yr B.P.) SH2(≈1000 yr B.P.) and SH3(≈1400 yr B.P.) from Shiveluch volcano; KZ (≈7500 yr B.P.) from Kizimen volcano; KRM (≈7900 yr B.P.) from Karymsky caldera; KHG (≈7000 yr B.P.) from Khangar volcano; AV1(≈3500 yr B.P.), AV2(≈4000 yr B.P.), AV4(≈5500 yr B.P.), and AV5(≈5600 yr B.P.) from Avachinsky volcano; OP (≈1500 yr B.P.) from the Baraniy Amfiteatr crater at Opala volcano; KHD (≈2800 yr B.P.) from the “maar” at Khodutka volcano; KS1(≈1800 yr B.P.) and KS2(≈6000 yr B.P.) from the Ksudach calderas; KSht3(A.D. 1907) from Shtyubel cone in Ksudach volcanic massif; and KO (≈7700 yr B.P.) from the Kuril Lake-Iliinsky caldera. Tephra layers SH5(≈2600 yr B.P.) from Shiveluch volcano, AV3(≈4500 yr B.P.) from Avachinsky volcano, OPtr(≈4600 yr B.P.) from Opala volcano, KS3(≈6100 yr B.P.) and KS4(≈8800 yr B.P.) from Ksudach calderas, KSht1(≈1100 yr B.P.) from Shtyubel cone, and ZLT (≈4600 yr B.P.) from Iliinsky volcano cover smaller areas and have local stratigraphic value, as do the ash layers from the historically recorded eruptions of Shiveluch (SH1964) and Bezymianny (B1956) volcanoes. The dated tephra layers provide a record of the most voluminous explosive events in Kamchatka during the Holocene and form a tephrochronological timescale for dating and correlating various deposits.

Late Wisconsinan glacial stratigraphy and history of southeastern Manitoba

1980 ◽  
Vol 17 (1) ◽  
pp. 19-35 ◽  
Author(s):  
James T. Teller ◽  
Mark M. Fenton
Keyword(s):  
Carbonate Rocks ◽  
Lacustrine Sediment ◽  
Precambrian Rock ◽  
Lake Agassiz ◽  
Rock Fragments ◽  
Lithostratigraphic Units ◽  
Stratigraphic Position ◽  
History Of ◽  
International Boundary ◽  
Late Wisconsinan

The history of Late Wisconsinan glaciation in southwestern Manitoba has been established by identifying and correlating ice-laid lithostratigraphic units in the subsurface. Five Late Wisconsinan tills are defined on the basis of their texture, mineralogic composition, and stratigraphic position. These new formations are, from youngest to oldest, Marchand, Whitemouth Lake, Roseau, Senkiw, and Whiteshell Formations.Late Wisconsinan ice first invaded southeastern Manitoba 22 000 to 24 000 years ago. This Laurentide glacier advanced from the northeast across the Precambrian Shield and deposited the sandy Whiteshell and Senkiw tills, which contain abundant Precambrian rock fragments and minerals and few Paleozoic carbonate grains. Shortly after this, Keewatin ice advanced from the northwest over Paleozoic carbonate rocks, depositing the loamy carbonate-rich Roseau Formation throughout most of the area. This ice remained over southeastern Manitoba until after 13 500 years ago, when it rapidly retreated northward with Lake Agassiz on its heels. Two brief glacial readvances occurred. The first overrode Lake Agassiz lacustrine sediment as far south as central North Dakota shortly after about 13 000 years ago. The clayey Whitemouth Lake till was deposited in southern Manitoba at this time. After a rapid retreat, the ice briefly pushed southward over southeastern Manitoba about 12 000 years ago to just south of the International Boundary. The sandy carbonate-rich Marchand Formation was deposited at this time as the ice overrode its own sandy outwash. By 11 000 years ago, ice had disappeared from southeastern Manitoba.

Pleistocene stratigraphy of the Saskatoon area, Saskatchewan, Canada: an update

1992 ◽  
Vol 29 (8) ◽  
pp. 1767-1778 ◽  
Author(s):  
E. A. Christiansen
Keyword(s):  
Ice Sheet ◽  
Carbonate Content ◽  
Stratigraphic Position

Pleistocene deposits in the Saskatoon area are divided into the Sutherland and Saskatoon groups. The Sutherland Group is divided into the Mennon, Dundurn, and Warman formations, and the Saskatoon Group is divided into the Floral and Battleford formations. The Floral Formation is subdivided into the lower till, the Riddell Member, and the upper till. Each formation is composed of a sequence of deposits, including basal proglacial sediment, till, upper proglacial sediment, and nonglacial sediment. Each formation is defined primarily on the basis of carbonate content and stratigraphic position of its till, and commonly it is bounded by weathered zones and (or) nonglacial sediments. The Sutherland Group is pre-Illinoian in age, and the lower till of the Floral Formation is Illinoian in age. The Riddell Member, between the lower and upper tills of the Floral Formation, is late Rancholabrean, probably Sangamon, in age. Radiocarbon ages of sediments lying between the upper till of the Floral Formation (Early Wisconsin) and the Battleford Formation (Late Wisconsin) range from more than 38 000 to 18 000 BP. The dissipating ice sheet margin stood in the vicinity of Saskatoon about 12 000 BP.

scholarly journals Coal petrology analysis and implications in depositional environments from upper Cretaceous to Miocene: a study case in the Eastern Cordillera of Colombia

2021 ◽  
Author(s):  
Clara Guatame ◽  
Marco Rincón
Keyword(s):  
Late Cretaceous ◽  
Foreland Basin ◽  
Late Eocene ◽  
Depositional Environments ◽  
Estuarine System ◽  
Eastern Cordillera ◽  
Stratigraphic Position ◽  
San Fernando ◽  
Coal Facies ◽  
Oil Sector

AbstractThe Piedemonte Llanero Basin is located on the eastern side of the Eastern Cordillera of the Colombian Andes. It has been the subject of numerous geological studies carried out for the oil sector, mainly. This study presents the coal-petrographical features of 15 coal seams of four geological formations from Late Cretaceous to Middle Miocene (Chipaque formation, Palmichal group, Arcillas del Limbo formation, and San Fernando formation). Analysis of 33 samples indicates enrichment in vitrinite, while liptinite and inertinite concentrations vary according to the stratigraphic position. Reflectance indicates that the coal range gradually decreases from highly volatile bituminous C (Chipaque formation) to subbituminous C (San Fernando formation). The microlithotypes with the highest concentrations are clarite and vitrinertoliptite. Maceral composition and coal facies indicate changes in the depositional conditions of the sequence. The precursor peat from Late Cretaceous to Late Paleocene accumulated under limnic conditions followed by telmatic in Late Eocene–Early Miocene. The coal facies indices show wet conditions in forest swamps with variations in the flooding surface, influxes of brackish water and good tissue preservation. The tectonic conditions along the Piedemonte Llanero basin is evident, from post-rift to foreland basin, evidenced by oxic and anoxic periods reflected in the maceral composition and its morphology. The coal environment corresponds to an estuarine system started in the Chipaque formation evolving to the lacustrine conditions in the San Fernando formation.

Stratigraphic correlation of the Permian-Triassic red beds constrained by detrital zircon geochronology: Moscow basin, East European platform

2021 ◽  
Author(s):  
Alvina Chistyakova ◽  
Roman Veselovskiy
Keyword(s):  
Detrital Zircon ◽  
East European Platform ◽  
Lower Triassic ◽  
Detrital Zircons ◽  
Upper Permian ◽  
Stratigraphic Correlation ◽  
Red Beds ◽  
East European ◽  
Moscow Basin ◽  
Stratigraphic Position

<p>There's no doubt that nowadays detrital zircon U-Pb geochronology is actually required method of sedimentary basins analysis. Furthermore, this approach may have a lot of applications, such as a stratigraphic correlation. Here we present the first results of U–Pb LA–ICP–MS dating of detrital zircon from the Permian-Triassic red beds located within the Moscow Basin of the East European platform. Two outcrops have been studied: the Zhukov Ravine P/T boundary reference section and the Nedubrovo strata with uncertain stratigraphic position (uppermost Permian or lower Triassic?).</p><p>U–Pb ages of detrital zircon grains have been obtained for two samples – the Upper Permian and Lower Triassic age, which were taken in the proximity to the Permian–Triassic boundary in the Zhukov Ravine. Corresponding age distributions show contrasting provenance of the studied sedimentary rocks, pointing out that principal change in source of clastic material occurred on the Paleozoic-Mesozoic boundary. It means that detrital zircon U–Pb geochronology can be used as an additional independent tool for stratigraphic correlation of the Permian-Triassic red beds, at least within the Moscow Basin. We demonstrate this in the case of the Nedubrovo section with debated (Permian or Triassic?) stratigraphic position: the obtained data on detrital zircons persuasively suggests Early Triassic age of the Nedubrovo strata.</p><p>This study is supported by the Russian Foundation for Basic Research (project no. 18-05-00593).</p>

Facies Composition and Stratigraphic Position of the Quaternary Upper Yenisei Sequence in the Tuva and Minusa Depressions

2021 ◽  
Vol 62 (10) ◽  
pp. 1127-1138
Author(s):  
I.D. Zol’nikov ◽  
I.S. Novikov ◽  
E.V. Deev ◽  
A.V. Shpansky ◽  
M.V. Mikharevich
Keyword(s):  
Late Pleistocene ◽  
Lacustrine Sediments ◽  
Alluvial Fan ◽  
Luminescence Dating ◽  
Middle Pleistocene ◽  
Mountainous Area ◽  
Gorny Altai ◽  
Stratigraphic Position ◽  
Geochronological Dating ◽  
Current Ripples

Abstract —The paper concerns the sediment sequence, which is widespread in the Yenisei valley and in the Tuva and Minusa depressions and also present in the valleys of the southern Chulym plain. The sediments of this sequence were previously described as “Neogene mud-shedding”, as well as moraines, alluvial fan deposits, alluvium of Middle Pleistocene high terraces, and lacustrine sediments. The giant ripple marks on the Upper Yenisei terraces was commonly interpreted as ribbed moraines; however, in recent studies, these ridges have been repeatedly referred to as marks of giant current ripples. Besides, some recently published papers provide description of geology of this sequence fragments suggesting its deposition by cataclysmic floods. Geomorphological analysis of the area shows Pleistocene glaciers to have been localized within the medium–high mountainous areas. The glaciers did not reach the Tuva and Minusa depressions and occupied large areas only in the Todzha basin and on the periphery of the Darkhat basin, forming a glacial dam at its outlet, which resulted in glacial-dammed lakes filling the basin completely. These lakes outburst, and the resultant flooding led to the deposition of megaflood sediments, which we refer to here as the Upper Yenisei sediment sequence. A detailed analysis of its facies architecture revealed similarity of these sediments to those of the Sal’dzhar and Inya sequences in Gorny Altai. Most of the Upper Yenisei megaflood sediments are localized in topographic lows of the Tuva and Minusa depressions. Beyond the Altai–Sayan mountainous area, the megaflood sediments of the Upper Yenisei sequence compose high terraces of the Yenisei, Chulym, Chet’, and Kiya rivers in the southern Chulym plain. The formation of Upper Yenisei sequence dates to the first half of the Late Pleistocene, inasmuch as it contains inset alluvial sediments of the second terrace of the Yenisei River. The available data allow suggesting that the Upper Yenisei sequence formed in the first Late Pleistocene regional glaciation. The Sal’dzhar sequence in Gorny Altai and the fourth terrace of the Ob’ River on the Fore-Altai plain are stratigraphic analogs of the Upper Yenisei sequence. The Upper Yenisei and Sal’dzhar sequences can thus be considered future regional markers serving as a link for the local stratigraphic schemes of the Altai–Sayan mountainous area and adjacent West Siberian plains. The results obtained call for verification by geochronological dating, first of all, by modern luminescence dating methods covering a wider chronological interval than radiocarbon dating.

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