scholarly journals Lithofacial composition and distribution of middle albian strata within the Crimean Plains

2014 ◽  
pp. 6-11
Author(s):  
L. Kyselevych
Keyword(s):  
Volcanic Activity ◽  
Volcanic Rocks ◽  
Sedimentary Rocks ◽  
Structural Features ◽  
Marine Clay ◽  
The North ◽  
Almost Everywhere ◽  
Exploration Drilling ◽  
Facies Types ◽  
Intense Activity

The Middle Albian sedimentary complex is deposited on Middle Albian rocks, commonly with no evident unconformity, and includes, along with sedimentary rocks, volcanic activity products. Middlle Albian sediments are distributed almost everywhere within the North Crimean paleodepression. They occur at a depth of 2-5 km and are represented by sedimentary-volcanogenic formations whose generation was caused by intense activity of 6 stratovolcanoes and 3 shield volcanoes. Such formations fail to occur only on a few local sites of the paleodepression and in its northern nearside zone. Sediments are characterized by wide development in their section, along with sedimentary rocks, of pyroclastic and effusive formations whose generation was caused by volcanic activity. The volcanic activity was at its highest during the Middle Albian, which resulted in accumulations of facies-variable volcanogenic-sedimentary strata. Volcanogenic and volcanogeno-clastic Middle Albian sediments occur among marine clay formations as lens-shaped bodies, sheets and flows sometimes stretching over dozens of kilometers, their thickness ranging from a few metres to hundreds. Structural features of volcanogenic-sedimentary strata of different regions depend on their proximity to the centers of volcanic activity and are determined by the nature and characteristics of paleovolcanic eruptions. A closer proximity to paleovolcanoes accounts for an increase in volcanic rocks in the section, with effusive rocks being mostly abundant among them. At a longer distance from the centers of volcanic activity, pyroclastic, volcanogenic-sedimentary and sedimentary deposits become more abundant in the section. Synthesis and analysis of the lithological and petrographic characteristics of Middle Albian sediments, which were based on analyzing deep parametrical and exploration drilling data, made it possible to define 10 main Middle Albian types of lithofacies. These differ in their composition and the share of volcanic activity products found in marine clay sediments. Lithological-facies types of the Middle Albian sediment sections have been defined, as well as the limits of their lateral distribution within the North Crimean paleodepression of the Crimean plains.

Chronostratigraphy of Eocene volcanism, central British Columbia

2014 ◽  
Vol 51 (1) ◽  
pp. 56-103 ◽  
Author(s):  
Esther Bordet ◽  
Mitchell G. Mihalynuk ◽  
Craig J.R. Hart ◽  
Jim K. Mortensen ◽  
Richard M. Friedman ◽  
...  
Keyword(s):  
British Columbia ◽  
Volcanic Activity ◽  
Volcanic Rocks ◽  
Early Eocene ◽  
Isotopic Age ◽  
The North ◽  
Felsic Volcanism ◽  
Magma Compositions ◽  
Age Determinations

Onset and termination of Eocene felsic volcanism in the Chilcotin Plateau of central British Columbia is constrained between 54.6 and 46.6 Ma by 33 new U–Pb and 40Ar/39Ar isotopic age determinations. Dates were obtained from representative felsic coherent and fragmental volcanic rocks that comprise the Ootsa Lake Group. The resulting chronostratigraphy shows that magma compositions evolved from felsic to intermediate, with no spatial migration of the volcanic activity. Rhyolitic compositions are oldest; and are overlain by dacitic rocks with varied phenocrysts assemblages. In many parts of the Chilcotin Plateau, the Eocene stratigraphy is capped by distinctive vitreous black dacite lavas, which are contemporaneous with andesitic lavas of the Endako Group in the Nechako Plateau to the north. Crystallization ages from Ootsa Lake Group rocks of the Chilcotin Plateau overlap age determinations from correlative rocks of the Nechako Plateau and southern BC. Collectively, this geochronological dataset supports previous suggestions of a voluminous Early Eocene-aged (∼55–46 Ma) period of volcanism in the Intermontane Belt. The abrupt initiation of volcanism, as well as the wide extent, thickness, and compositions that characterize Eocene volcanic rocks may be explained by cessation of subduction and formation of a slab gap beneath British Columbia in the Early Eocene.

ARCHAEAN SEDIMENTARY ROCKS OF NORTH SPIRIT LAKE AREA, NORTHWESTERN ONTARIO

1965 ◽  
Vol 2 (6) ◽  
pp. 622-647 ◽  
Author(s):  
J. A. Donaldson ◽  
G. D. Jackson
Keyword(s):  
Volcanic Rocks ◽  
Sedimentary Rocks ◽  
Sole Source ◽  
Lake Area ◽  
Red Lake ◽  
Sedimentary Sequences ◽  
The North ◽  
Northwestern Ontario ◽  
History Of ◽  
Granitoid Rocks

Archaean sedimentary rocks of the North Spirit Lake area show little evidence of having been derived predominantly from associated Archaean volcanic rocks. Instead, compositions of the sediments reflect significant sedimentary and (or) granitoid provenance. A remarkably high content of clastic quartz in thick units of sandstone and conglomerate suggests either reworking of older quartzose sediments, or reduction of the labile constituents in quartz-rich granitoid rocks through prolonged weathering and rigorous transport. Observations for other sedimentary sequences in the region between Red Lake and Lansdowne House suggest that the North Spirit sediments are not unique in the Superior Province. Quartzose sandstones commonly are regarded as atypical of the Archaean, but such rocks arc abundant in northwestern Ontario. Frameworks of many Archaean greywackes actually are richer in quartz than typical greywackes from numerous Proterozoic and Phanerozoic sequences.The concept of rapidly rising volcanic arcs as the sole source of Archaean sedimentary detritus is rejected for the North Spirit area. The volcanies, rather than representing relicts of protocontinents, probably record events removed from initial volcanism in the history of the earth by one or more orogenic cycles. Major unconformities may therefore exist not only between sedimentary and volcanic units, but also between these units and older granitoid rocks.

U–Pb age constraints for the magmatic and tectonic evolution of the Pontiac Subprovince, Quebec

1993 ◽  
Vol 30 (9) ◽  
pp. 1970-1980 ◽  
Author(s):  
J. K. Mortensen ◽  
K. D. Card
Keyword(s):  
Tectonic Evolution ◽  
Volcanic Rocks ◽  
Sedimentary Rocks ◽  
Volcanic Zone ◽  
Volcanic Arcs ◽  
The North ◽  
Intrusive Rocks ◽  
History Of ◽  
Tonalitic Gneiss ◽  
Age Constraints

New U–Pb zircon, titanite, and monazite ages help constrain the history of magmatism and tectonism within the Pontiac Subprovince of western Quebec. The Pontiac Subprovince resembles other metasedimentary belts of the Superior Province; however, the stratigraphic relationships between the dominantly sedimentary rocks of the Pontiac and the adjacent, volcanic-dominated Abitibi belt to the north and west remain controversial. Volcanic rocks of the Belleterre volcanic zone in the southern part of the Pontiac Subprovince have been interpreted by other workers as klippen of Abitibi strata that were thrust southward onto the Pontiac Subprovince. However, volcanic rocks in the Belleterre zone give crystallization ages of 2689–2682 Ma, which are younger than any extrusive rocks dated thus far from the Abitibi belt. Single detrital zircon grains from Pontiac sedimentary rocks give ages as young as 2683 Ma, indicating that the sediments are similar in age, or younger than, the volcanic units. The volcanic rocks probably represent distal facies of small volcanic arcs deposited within a large turbidite basin.The Lac des Quinze tonalitic gneiss body gives U–Pb zircon and titanite ages of 2695 ± 1 Ma and 2673 ± 4 Ma, respectively. Although the gneiss may represent basement to the supracrustal units, field relationships indicate that it was tectonically juxtaposed against the supracrustal package. Alkaline intrusive rocks in the Pontiac Subprovince yield U–Pb ages that overlap with the youngest ages obtained from the volcanic units. This attests to a very short-lived cycle of sedimentation and arc magmatism, followed by late tectonic and posttectonic alkaline plutonism.

scholarly journals Palynostratigraphy of the Lower Tertiary volcanics and marine clastic sediments in the southern part of the West Greenland Basin: implications for the timing and duration of the volcanism

1992 ◽  
Vol 154 ◽  
pp. 13-31
Author(s):  
S Piasecki ◽  
L.M Larsen ◽  
A.K Pedersen ◽  
G.K Pedersen
Keyword(s):  
Volcanic Activity ◽  
Volcanic Rocks ◽  
Dinoflagellate Cysts ◽  
East Greenland ◽  
West Greenland ◽  
Second Stage ◽  
The Third ◽  
The North ◽  
Clastic Sediments ◽  
Third Stage

Volcanic rocks, forming hyaloclastites and subaqueous lava flows, were deposited intercalated with clastic sediments in a water-filled basin in West Greenland in the Early Tertiary. Three main stages of basin infilling occurred in the Disko-Nuussuaq area. The distribution of dinoflagellate cysts in the sediments shows that the basin was marine in the first stage and non-marine in the second stage of infilling. In the third stage the basin was displaced towards the south and was marginally marine. The dinoflagellate cysts form a typical mid-Paleocene assemblage which may be correlated with the calcareous nannoplankton (NP) zonation. The stratigraphically lowest investigated localities are coeval with the uppermost part of nannoplankton zone NP4, whereas the overlying localities within the marine basin (first stage) may be correlated with NP5-6. The localities from the non-marine second stage cannot be correlated with the NP zonation because they do not contain dinoflagellate cysts. Localities from the third stage are coeval with NP7-8. Younger volcanics are subaerially deposited. The total known range of the volcanics now falls within the NP3 to NP8 interval, giving a minimum duration for the main plateau-building stage of the volcanism of 4–6 million years. The subaerial basalts have previously been found to be mainly reversely magnetised, with one normally magnetised sequence which can now be stratigraphically correlated with NP4, and thereby identified as anomaly 27. The basalts in East Greenland started erupting during the NP9 zone, so that the volcanic activity in East Greenland largely succeeded that in West Greenland. In relation to the postulated mantle plume in the North Atlantic this means that the volcanic activity started in the peripheral part of the plume and only later switched to the central part.

scholarly journals VIII.—The Lower Carboniferous Volcanic Rocks of East Lothian (Garlton Hills)

1895 ◽  
Vol 37 (1) ◽  
pp. 115-126 ◽  
Author(s):  
Frederick H. Hatch
Keyword(s):  
Volcanic Activity ◽  
Volcanic Rocks ◽  
Lower Carboniferous ◽  
The North ◽  
The Rich ◽  
Firth Of Forth ◽  
North Western

The rich agricultural tract of country that forms the north-western part of East Lothian, undulating uniformly from the foot of the chain of the Lammermuirs towards the Firth of Forth, swells near Haddington into the cluster of the Garlton Hills, and the neighbouring masses of Traprain Law and North Berwick Law.The rocks that build up this elevated ground are lavas and tuffs that were produced during the period of volcanic activity that characterised the deposition of the Lower Carboniferous beds of Scotland. In East Lothian their eruption followed close on the deposition of the sandstones and marls that constitute the base of the calciferous sandstone group.

scholarly journals Composition of Rift-Related Igneous and Sedimentary Rocks of the Keweenawan Supergroup in the Poersch No. 1, OZ-1, Finn, and Friederich Wells, Northeastern Kansas

1993 ◽  
pp. 55-72
Author(s):  
Robert L. Cullers ◽  
Pieter Berendsen
Keyword(s):  
Volcanic Rocks ◽  
Sedimentary Rocks ◽  
Magnetic Polarity ◽  
Detrital Zircons ◽  
Primary Magma ◽  
High Alumina ◽  
Spinel Peridotite ◽  
Rift System ◽  
Reverse Fault ◽  
The North

A series of wells have been drilled up to a depth of 3,444 m (113,000 ft) into the midcontinent rift system (MRS) in northeastern Kansas. The age of a gabbro sill in the upper portion of the Precambrian rocks was determined to be 1,097.5 ± 3 Ma, and the magnetic polarity of the gabbro correlated to the lower Keweenawan rocks in the northern MRS (Van Schmus et al., 1990). The rocks below 2,259 m (7,411 ft) in the deepest well [Poersch no. 1, total depth 3,435 m (11,270 ft)] consist mostly of arkoses with subordinate amounts of shale, siltstone, and basalt. The rocks above 2,265 m (7,431 ft) in the Poersch well consist of basalt with minor siltstone, arkose, gabbro, and felsite. A proposed high-angle reverse fault could have juxtaposed the upper igneous rocks over the lower sedimentary rocks to produce a reversed stratigraphy. This would make the development of the southern MRS similar to that of the northern MRS. Thus, in the initial extensional phase of the MRS, broad subsidence coincided with abundant volcanism and little sediment production. Grabens formed in the later stages of rift development and were filled with abundant sedimentary rocks along with lesser volcanic rocks. The chemical characteristics of the basalts in the southern MRS are similar to those in the north. The southern basalts are subalkalic to alkalic and follow tholeiitic trends; a number of them are high-alumina basalts. Although there is a lot of scatter, Al2O3, Ni, and Cr concentrations decrease and Fe2O3, TiO2, K2O, rare earth elements, Ba, Hf, and Sc concentrations increase with decreasing Mg number. These trends are consistent with plagioclase, olivine, pyroxene, or spinel fractionation from primary basalts. One basalt could represent a primary magma because it has a high Mg number (0.68), high Ni (638 mg/kg) and Cr (233 mg/kg) concentrations, low incompatible element concentrations (e.g., La = 4.2 mg/kg), and a slight positive Eu anomaly. This possible primary magma could have formed by partial melting (20-25%) of an undepleted spinel peridotite at 30-40 km depth. Most basalts have not been contaminated by crustal rocks or silicic magmas. The mineralogy, chemical composition, and U-Pb geochronology of detrital zircons of the arkoses, siltstones, and shales are consistent with their derivation from the surrounding granitoid highlands with little or no input from the basalts. Even siltstones and arkoses within the mostly basaltic sequences are derived mostly from the granitoids, although the siltstones may have some input from the basalts (e.g., higher Ni concentration than the sandstones).

scholarly journals Materials and Tools across Volcanoes: Exploitation of Georesources in Piano dei Cardoni (Ustica, Italy) during Prehistory

2021 ◽  
Vol 64 (5) ◽  
pp. VO552
Author(s):  
Claudia Speciale ◽  
Roberta Mentesana ◽  
Giuseppe Montana ◽  
Vincenza Forgia ◽  
Filippo Mantia ◽  
...  
Keyword(s):  
Raw Materials ◽  
Volcanic Rocks ◽  
Late Neolithic ◽  
The North ◽  
Western Area ◽  
First Results ◽  
Western Sicily ◽  
Plant Processing ◽  
Intense Activity ◽  
North Western

   The paper aims at merging the first results from the analyses of the georesources exploited in the site of Piano dei Cardoni (Ustica island, Italy) during the Neolithic phases of its occupation (Middle-Late Neolithic, 4.7-4.2 ka cal BC). Grinding tools consist of a very varied typology of local volcanic rocks, easy to collect and available very close to the investigated site. A selection of shapes and lithology is applied to reach the best performance of the tools. The elevated number of grinders, pestles, mortars testify to an intense activity of food/plant processing in the site. The absence of chert or obsidian resources on the island pushed the human communities to import such raw materials from the Aeolian islands and probably from the north-western area of Palermo. Pumice is collected on the same island, probably due to the local availability and its good quality. Similarly, local clay resources are used for the manufacture of ceramics, mostly burnished and incised wares. Ustica was therefore almost autonomous for the exploitation of resources, with volcanic rocks readily available in abundance and with the most significant exception being chert and obsidian. This last one probably imported and worked on the island and then moved towards North-Western Sicily. 

A new volcanic province: evidence from glacial erratics in western North Greenland

2000 ◽  
pp. 35-41 ◽  
Author(s):  
Peter R. Dawes ◽  
Bjørn Thomassen ◽  
T.I. Hauge Andersson
Keyword(s):  
Volcanic Rocks ◽  
Iron Formation ◽  
Banded Iron Formation ◽  
Common Component ◽  
Volcanic Province ◽  
North West ◽  
North East ◽  
The North ◽  
Surficial Deposits ◽  
North Greenland

NOTE: This article was published in a former series of GEUS Bulletin. Please use the original series name when citing this article, for example: Dawes, P. R., Thomassen, B., & Andersson, T. H. (2000). A new volcanic province: evidence from glacial erratics in western North Greenland. Geology of Greenland Survey Bulletin, 186, 35-41. https://doi.org/10.34194/ggub.v186.5213 _______________ Mapping and regional geological studies in northern Greenland were carried out during the project Kane Basin 1999 (see Dawes et al. 2000, this volume). During ore geological studies in Washington Land by one of us (B.T.), finds of erratics of banded iron formation (BIF) directed special attention to the till, glaciofluvial and fluvial sediments. This led to the discovery that in certain parts of Daugaard-Jensen Land and Washington Land volcanic rocks form a common component of the surficial deposits, with particularly colourful, red porphyries catching the eye. The presence of BIF is interesting but not altogether unexpected since BIF erratics have been reported from southern Hall Land just to the north-east (Kelly & Bennike 1992) and such rocks crop out in the Precambrian shield of North-West Greenland to the south (Fig. 1; Dawes 1991). On the other hand, the presence of volcanic erratics was unexpected and stimulated the work reported on here.

Sign in / Sign up

Export Citation Format

Share Document