Dinoflagellate cyst biostratigraphy of the La Casita Formation (Upper Jurassic), Cerro Los Panales, Chihuahua, Mexico

Author(s):  
Gary Olmstead
1992 ◽  
Vol 4 (3) ◽  
pp. 267-278 ◽  
Author(s):  
Michael G. Snape

An allochthonous block of the Nordenskjöld Formation from north-west James Ross Island, Antarctic Peninsula has yielded a diverse marine palynoflora. Dinoflagellate cyst assemblages from the 185 m thick sequence are described and compared with similar microfloras previously described from Australia, Papua New Guinea and Madagascar. A mid Tithonian (Late Jurassic) age is suggested for the section. One new genus, Helbydinium gen. nov. and four new species, Helbydinium scabratum sp. nov., Leptodinium acneum sp. nov., Leptodinium posterosulcatum sp. nov. and Rhynchodiniopsis foveata sp. nov. are described.


1982 ◽  
Vol 1 (1) ◽  
pp. 53-53 ◽  
Author(s):  
Michael J. Fisher ◽  
Leslie A. Riley

Abstract. In 1980, several new species of dinoflagellate cyst taxa were validly published and named from the Kimmeridge Clay of England as part of a larger study on Kimmeridgian-Valanginian dinoflagellate cyst assemblages (Fisher & Riley, 1980); this study was originally presented at the IV International Palynological Conference, Lucknow in 1976–77. This note, necessitated by the long publication delay and numerous printing errors, comprises taxonomic re-allocations, taking account of subsequent studies (Norris, 1978; Stover & Evitt, 1978; Davey, 1979; Riley, 1979) and corrects inadvertent taxonomic errors.


1989 ◽  
Vol 8 (1) ◽  
pp. 109-112 ◽  
Author(s):  
James B. Riding ◽  
Roger J. Davey

Abstract. The Upper Jurassic-Lower Cretaceous dinoflagellate cyst Cannosphaeropsis thula Davey 1982 does not conform to the morphological parameters of the genus Cannosphaeropsis O. Wetzel 1933 emend. Duxbury 1980. The species also exhibits no indications of belonging to the Spiniferites complex of Evitt (1985). The species is transferred to Rotosphaeropsis Davey 1987 by virtue of its shape, archaeopyle type, processes and trabeculae and the specific diagnosis is emended in the light of this reassessment.


2004 ◽  
Vol 5 ◽  
pp. 73-88 ◽  
Author(s):  
Stefan Piasecki ◽  
Michael Larsen ◽  
Jens Therkelsen ◽  
Henrik Vosgerau

Dinoflagellate cysts of the Middle–Upper Jurassic succession on northern Hold with Hope have been studied in order to establish a biostratigraphic framework and to date the succession. The Pelion Formation is characterised by abundant Chytroeisphaeridia hyalina and Sentusidinium spp., with some Ctenidodinium thulium and Paragonyaulacysta retiphragmata in the lower part. Mendicodinium groenlandicum appears higher in the formation followed by Trichodinium scarburghense in the upper part. The succeeding Payer Dal Formation contains Scriniodinium crystallinum, Rigaudella aemula and Leptodinium subtile in the lower part and Dingodinium jurassicum and Prolixosphaeridium granulosum in the uppermost part. The Bernbjerg Formation contains abundant Sirmiodinium grossii and Gonyaulacysta jurassica. Adnatospahaeridium sp., Cribroperidinium granuligerum, Glossodinium cf. dimorphum and Scriniodinium irregulare appear in the lower part of the formation, followed by Avellodinium spp. in the highest part. The dinoflagellate cyst assemblages in the Pelion Formation indicate an Early–Late Callovian age (C. apertum – P. athleta Chronozones). This is supported by ammonites in the lower part of the formation, which refer to the C. apertum and P. koenigi Chronozones. A significant hiatus, from Late Callovian to Middle Oxfordian, is present between the Pelion Formation and the overlying Payer Dal Formation. The age of the Payer Dal Formation is Middle Oxfordian to earliest Late Oxfordian (C. tenuiserratum – A. glosense Chronozones). The Payer Dal Formation is conformably overlain by the Bernbjerg Formation of Late Oxfordian to possibly earliest Kimmeridgian age (A. glosense – P. baylei Chronozones). The A. glosense Chronozone is also documented by abundant ammonites in the lowermost part of the formation.


2018 ◽  
Vol XV (1) ◽  
pp. 51-62 ◽  
Author(s):  
Marcin BARSKI

Examination of seven ammonite-calibrated palynological samples across the Oxfordian/Kimmeridgian boundary in the Flodigarry sections at Staffin Bay, Isle of Skye, northern Scotland, has revealed dinoflagellate cyst assemblages in general terms in line with previous contributions. The sparse occurrence of Emmetrocysta sarjeantii, Perisseiasphaeridium pannosum and Senoniasphaera jurassica slightly above the proposed Oxfordian/Kimmeridgian boundary may be used as a palynological approximation of the base of the Kimmeridgian. The high abundance of tests resembling modern zygnemataceous chlorophycean alga Spirogyra in two samples above the Oxfordian/Kimmeridgian boundary horizon is probably associated with increased eutrophication and possible association with ‟green tides”. This bloom is proposed as a palynofloral proxy event for the boundary in the Flodigarry section. According to previous studies, various eutrophication events may have a correlation potential in Subboreal Europe.


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