Výsledky vyhledávání - "Robert L Ravn"

The species ofFROMEA, revisited, with comments on selected morphologically similar genera

Autor: Robert L. Ravn

Publikováno v: Palynology. 41:247-261

The form genus Fromea Cookson & Eisenack 1958 accommodates a variety of flask- or vase-shaped algal cysts of presumed marine origin found in Jurassic to Paleogene strata worldwide. Numerous species have geographically widespread but stratigraphically

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_________::5b0c729744f6ed8b8b9ca7b022abdbc3
https://doi.org/10.1080/01916122.2017.1366202

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New Insights on the Sequence Stratigraphic Architecture of the Dakota Formation in Kansas–Nebraska–Iowa from a Decade of Sponsored Research Activity

Autor: Brian J. Witzke, R.M. Joeckel, Preston Lee Phillips, Luis A. González, Greg A. Ludvigson, Robert L. Brenner, Robert L. Ravn

Publikováno v: Current Research in Earth Sciences. :1-35

The Cretaceous Dakota Formation in the areas of Kansas, Nebraska, and Iowa contains a rich and well-preserved microflora of fossil palynomorphs. A comprehensive listing of these taxa is presented in this publication as part of a continuing effort to

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_________::3f4f4f4a875de2c3d0c58955fed2483d
https://doi.org/10.17161/cres.v0i258.11813

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Late Albian Kiowa-Skull Creek Marine Transgression, Lower Dakota Formation, Eastern Margin of Western Interior Seaway, U.S.A

Autor: Robert L. Ravn, Brian J. Witzke, Erik P. Kvale, Greg A. Ludvigson, Ann Zawistoski, R.M. Joeckel, Richard L. Brenner

Publikováno v: Journal of Sedimentary Research. 70:868-878

An integrated geochemical-sedimentological project is studying the paleoclimatic and paleogeographic characteristics of the mid-Cretaceous greenhouse world of western North America. A critical part of this project, required to establish a temporal fr

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_________::d27cccb0e9c3ab5dabf397fb1d778bec
https://doi.org/10.1306/2dc4093e-0e47-11d7-8643000102c1865d

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Palynology of the upper Pennsylvanian Dalton coal, Palo Pinto county, texas, U.S.A

Autor: Judith A. Gennett, Robert L. Ravn

Publikováno v: Palynology. 17:115-122

The Dalton Coal of north‐central Texas yields a palynomorph assemblage characteristic of basal Late Pennsylvanian (Stephanian) coals from the Midcontinent U.S.A., and also indicative of an allochthonous origin for the greater part of the seam. The

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_________::d3b615392b797eaf70bfc454e48332fd
https://doi.org/10.1080/01916122.1993.9989422

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The mid-Cretaceous boundary in the Western Interior Seaway, central United States: Implications of palynostratigraphy from the type Dakota Formation

Autor: Brian J. Witzke, Robert L. Ravn

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_________::153481a5cd758fe960693f802c9c25a9
https://doi.org/10.1130/spe287-p111

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Recognizing the Albian-Cenomanian (OAE1d) sequence boundary using plant carbon isotopes: Dakota Formation, Western Interior Basin, USA

Autor: David F. Ufnar, Darren R. Gröcke, Stuart A. Robinson, Gregory A. Ludvigson, Brian L. Witzke, Robert L. Ravn, R.M. Joeckel

Publikováno v: Geology. 34:193

Analysis of bulk sedimentary organic matter and charcoal from an Albian-Cenomanian fluvial-estuarine succession (Dakota Formation) at Rose Creek Pit (RCP), Nebraska, reveals a negative excursion of ∼3‰ in late Albian strata. Overlying Cenomanian

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_________::dc715eb9b728ff38b9e8c94a47b8294a
https://doi.org/10.1130/g21998.1

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Montiapollisn.gen., Possible Portulacaceae Pollen from the Cenomanian of Iowa

Autor: Robert L. Ravn

Publikováno v: Grana. 26:243-247

A new and unusual pollen grain from the Cenomanian Dakota Formation of northwestern Iowa may be a representative of the angiosperm family Portulaceacae. Montiapollis hallii n.gen., n.sp., is characterized by a complex syncolpate geometry resembling t

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_________::faf5487d9b427f02f4cc62ff037e5191
https://doi.org/10.1080/00173138709428920

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Devonian miospores and reworked acritarchs from Southeastern Georgia, U.S.A

Autor: Robert L. Ravn, Don G. Benson

Publikováno v: Palynology. 12:179-200

An unnamed subsurface unit penetrated by wells in southwestern Georgia (U.S.A.) has yielded a rich and diverse palynoflora consisting dominantly of Emsian/Eifelian miospores with a lesser component of acritarchs considered to be reworked from older s

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_________::d45014adfc15ef1f0a773173c427d0b3
https://doi.org/10.1080/01916122.1988.9989343

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Microreticulatisporites sacalii (Deák and Combaz) n. comb., a stratigraphically significant miospore from the Cenomanian of the United States

Autor: Robert L. Ravn

Publikováno v: Journal of Paleontology. 60:772-777

The Cretaceous miospore Microreticulatisporites sacalii (Deák and Combaz) n. comb. occurs in the Dakota Formation of Iowa and the lower Tuscaloosa Group of Louisiana and Mississippi. These occurrences represent the first reported from North America.

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_________::c1beec997b34ad1e3bd8e7d0fa51da5c
https://doi.org/10.1017/s0022336000022290

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