Topic
Grammoceras
About: Grammoceras is a research topic. Over the lifetime, 3 publications have been published within this topic receiving 19 citations.
Papers
Journal Article•
TL;DR: In this paper, the authors reported the composition and stratigraphic significance of 15 jurassic microfloras from Argentina, including four Lower and ten Middle jurassic assemblages from the Neuquen Basin; one Upper Jurassic assemblage from Extraandean Patagonia (Chubut Province).
Abstract: Composition and stratigraphic significance of 15 jurassic microfloras from Argentina are reported. Four Lower jurassic and ten Middle jurassic assemblages are from the Neuquen Basin; one Upper Jurassic assemblage from Extraandean Patagonia (Chubut Province). In the Lower Jurassic microfloras Classopollis is prevailing, and in one of them Nevesisporites vallatus de Jersey & Paten is an important marker. The incoming of Callialasporites dampieri (Balme ) Dev., Callialasporites segmentatus (Balme ) Srivastava and Inaperturopollenites turbatus is in the beds with Phymatoceras copiapense (Moricke) (lower Upper Toarcian, Zone of Grammoceras thouarsense); the Upper Toarcian and Middle and Upper jurassic rnicrofloras are characterized by the presence of Callialasporites dampieri and various sub-units can be distinguished within the dampieri-bearing assemblages: a) an Aalenian one with 60-70 % Classopollis and the presence of Inaperturopollenites turbatus; Microcachryidites is lacking; b) a Bajocian one with ± 40 % Classopollis and the presence of Inaperturopollenites indicus and Microcachryidites; e) a Lower Callovian one with less than 10 % Classopollis and prevailing of Podocarpidites, Microcachryidites, Callialasporites and Inaperturopollenites ; d) an Upper Jurassic one with prevailing Classopollis (67 and more %). The first typical specimens of Callialasporites trilobatus appear in this Upper jurassic assemblage which, on the other hand, is lacking Inaperturopolienites limbatus and Cicatricosisporites, forms which appear with great frequency near the Jurassic-Cretaceous boundary. The age of most of the Lower and Middle Jurassic microfloras is well documented by ammonites associated. This fact permits dating of comparable microfloras from non-rnarine beds, studied by Paten (1967), Reiser & Williams (1969) and de Jersey (1971) from the Surat Basin and Moreton Basin in Queensland (Australia). Microfloral similarities indicate close gondwanic relations between Australia and South America.
12 citations
TL;DR: In a small abandoned quarry on the northwestern edge of NagyPisznice Hill in the Gerecse Mts, fairly well preserved parts of a crocodile skeleton was found in 1996 and the bed which yielded the skeletal remains is the uppermost layer of the Kisgerecse Marl Formation exposed here and was determined as belonging to the Upper Toarcian Grammoceras thouarsense Zone as discussed by the authors.
Abstract: In the Jurassic rocks exposed in a small abandoned quarry on the northwestern edge of NagyPisznice Hill in the Gerecse Mts, fairly well preserved parts of a crocodile skeleton was found in 1996. The bed which yielded the skeletal remains is the uppermost layer of the Kisgerecse Marl Formation exposed here and was determined as belonging to the Upper Toarcian Grammoceras thouarsense Zone. The beds of the sequence above and below were carefully sampled in the late 1990s, and the encountered ammonites were evaluated biostratigraphically. As a result, the Lower Toarcian Harpoceras serpentinum Zone, the Middle Toarcian Hildoceras bifrons and Merlaites gradatus Zones, and the Upper Toarcian Grammoceras thouarsense and Geczyceras speciosum Zones were identified. Within most of these zones the subzones and even the faunal horizons were successfully recognized. The lowermost beds above the underlying Pliensbachian red limestone did not yield any fossils; thus the lowermost Toarcian Dactylioceras tenuicostatum Zone could not be documented. The highest Toarcian ammonite zones also remained unidentified, because the beds of the Tolgyhat Limestone above were not sampled all the way up. This paper presents the lithostratigraphic and biostratigraphic details of the sequence, and the paleontological descriptions of the most important ammonites.
8 citations
TL;DR: Toarcian biostratigraphy has been studied in the Queen Charlotte Islands of Canada and the Canadian Arctic as mentioned in this paper, where the first appearance of Dactylioceras was reported in North America.
5 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2013 | 1 |
| 2010 | 1 |
| 1994 | 1 |