The first upper Silurian land-derived palynological assemblage from South America: Depositional environment and stratigraphic significance

2020 ◽  
Vol 559 ◽  
pp. 109970
Author(s):  
Silvia N. Césari ◽  
Sergio Marenssi ◽  
Carlos O. Limarino ◽  
Patricia L. Ciccioli ◽  
Fanny C. Bello ◽  
...  
Keyword(s):  
South America ◽  
Depositional Environment ◽  
Palynological Assemblage ◽  
Upper Silurian

Upper Silurian miospores from the Precordillera Basin, Argentina: biostratigraphic, palaeonvironmental and palaeogeographic implications

2013 ◽  
Vol 151 (3) ◽  
pp. 472-490 ◽  
Author(s):  
V. J. GARCÍA MURO ◽  
C. V. RUBINSTEIN ◽  
P. STEEMANS
Keyword(s):  
South America ◽  
North Africa ◽  
Environmental Conditions ◽  
Amazon Basin ◽  
Northern Spain ◽  
Cantabrian Mountains ◽  
Northern Brazil ◽  
Upper Silurian ◽  
Local Ecology ◽  
New Synonymy

AbstractThis study is concentrated on Ludlow (to Pridoli?) miospores from the Los Espejos Formation at the Quebrada Ancha locality, Central Precordillera, San Juan Province, Argentina. The Ludlow age is in agreement with the age based on acritarchs. The assemblage of continental palynomorphs is composed of 43 miospore species (29 trilete spores and 14 cryptospores). A new synonymy is proposed: Chelinospora poecilomorpha is here considered a junior synonym of Clivosispora verrucata. In addition, specimens belonging to C. verrucata var. verrucata and C. verrucata var. convoluta are included in a new morphon. This study represents the second Late Silurian miospore assemblage described from South America; the first was from the Urubu River, Amazon Basin, northern Brazil. The Quebrada Ancha assemblages allow a reasonably good correlation with biozones established for the Upper Silurian from the Cantabrian Mountains, northern Spain. The dendrogram analysis between coeval miospore assemblages from different localities shows a strong palaeogeographic affinity with the miospores recovered from northern Brazil and North Africa. Miospore assemblages from Spain show influences from Baltica and North Africa, demonstrating their intermediate position between these two continental plates. Conversely, dissimilarities recognized between Libya and Tunisia are most probably owing to local ecology and/or environmental conditions.

Age and depositional environment of the Rock River coal basin, Yukon Territory, Canada

1994 ◽  
Vol 31 (5) ◽  
pp. 865-880 ◽  
Author(s):  
D. G. F. Long ◽  
A. R. Sweet
Keyword(s):  
Depositional Environment ◽  
Middle Eocene ◽  
Late Eocene ◽  
Yukon Territory ◽  
Temperate Climate ◽  
Fluvial System ◽  
Coal Basin ◽  
Early Oligocene ◽  
Palynological Assemblage ◽  
Latest Eocene

Poorly exposed Late Eocene strata in the Rock River basin, 115 km northeast of Watson Lake, accumulated in an intermontane valley with a geometry and history controlled by subsidence associated with the Rock River Fault. The sequence, as seen in one outcrop and five borehole sections, is dominated by drab mudrocks with minor sandstones and some thick lenses of coal. The mudrocks accumulated in floodplain marsh and pond settings associated with a low-gradient, possibly anastomosed, fluvial system. River banks were stable owing to the abundance of plant roots in the channel walls. Although channel sandstone and conglomerate were not identified in the core, the abundance of coarsening- and fining-upwards sets of sandstone of splay origin indicates pronounced levee development. Woody coals accumulated in areas well away from the main channel, in a series of elongate forested swamps, which were periodically inundated by flood water.The overall palynological assemblage is typical of the Eocene and Early Oligocene. A Late Eocene age is inferred from the presence of Gothanipollis in combination with the absence of index species for the Early–Middle Eocene and the latest? Eocene and Oligocene. The low miospore diversity indicates a temperate climate. The dominance of the palynological assemblage by Taxodiaceae–Cupressaceae pollen indicates wet–humid conditions.

A taxonomic revision of the Early Devonian dalmanitid trilobite Kasachstania Maksimova, 1972 from central Kazakhstan

2020 ◽  
Vol 94 (4) ◽  
pp. 681-695
Author(s):  
Enrique A. Randolfe ◽  
Juan José Rustán ◽  
Arnaud Bignon
Keyword(s):  
United States ◽  
North America ◽  
South America ◽  
Type Species ◽  
Lower Devonian ◽  
Taxonomic Revision ◽  
The United States ◽  
Early Devonian ◽  
Upper Silurian ◽  
New Diagnosis

AbstractThe dalmanitid trilobite Kasachstania Maksimova, 1972, previously reported from the Lower Devonian of Kazakhstan and North America (USA) and the upper Silurian–Lower Devonian of South America (Bolivia and Argentina), is revised. Kasachstania kasachstanica (Balashova in Maksimova,1968) and K. septicostata (Maksimova, 1968) are regarded as junior synonyms of the type species K. saryarkensis (Maksimova, 1960), all from the Lower Devonian of the type locality in central Kazakhstan (northern Balkhash). On the basis of a new diagnosis, K. ulrichi ulrichi (Delo, 1940) from the Emsian of the United States, K. ulrichi asiatica (Maksimova, 1968), K. pristina (Maksimova, 1968), and K. alperovichi Pour et al., 2019, from the Lower Devonian of Kazakhstan, K. andii (Kozłowski, 1923) from the upper Silurian–Lower Devonian of Bolivia, and K. gerardoi Edgecombe and Ramsköld, 1994, from the upper Silurian–Lower Devonian of Bolivia and Argentina are excluded from Kasachstania. This genus, represented only by K. saryarkensis and K. kiikbaica (Maksimova, 1968), is restricted to the Lower Devonian of central Kazakhstan, corresponding to the Balkhash–Mongolo–Okhotsk province in the paleobiogeographic context of the Old World Realm, instead of being nearly cosmopolitan as previously considered. In addition, we provide some remarks about Saryarkella Maksimova, 1978b, a monospecific dalmanitid genus largely overlooked although valid from the Emsian of the same area in central Kazakhstan.

Oxygen-18 and carbon-13 in the carbonates of the Salina formation of southwestern Ontario

1988 ◽  
Vol 25 (2) ◽  
pp. 182-194 ◽  
Author(s):  
K. J. O'Shea ◽  
M. C. Miles ◽  
P. Fritz ◽  
S. K. Frape ◽  
D. E. Lawson
Keyword(s):  
Water Balance ◽  
Isotopic Composition ◽  
Shallow Water ◽  
Depositional Environment ◽  
Carbon Isotopic Composition ◽  
Depositional Environments ◽  
Michigan Basin ◽  
Anoxic Conditions ◽  
Carbon Isotopic ◽  
Upper Silurian

The oxygen and carbon isotopic composition of the carbonates of the Upper Silurian Salina formation of the Michigan Basin was investigated to aid in interpretation of depositional environments.13C results indicate that a change from generally anoxic bottom conditions to oxic conditions occurred during deposition of the B evaporite unit. The organic-rich A carbonate units were deposited in a shallow-water, evaporitic setting, most likely adjacent to a sabkha-type environment. A positive water balance maintained the anoxic conditions and buffered the carbon isotopes.Above the B evaporite, the isotopic composition suggests that the development of a similar depositional environment, a subaerial prograding sabkha, occurred over wide areas of the basin.18O results support the conclusion that Silurian oceans were depleted in 18O with respect to modem oceans by 5–6‰.

Sign in / Sign up

Export Citation Format

Share Document