학술논문

Late Ediacaran occurrences of the organic-walled microfossils Granomarginata and flask-shaped Lagoenaforma collaris gen. et sp. nov.
Document Type
Academic Journal
Source
Geological Magazine. 159(7):1071-1092
Subject
09|Paleobotany
12|Stratigraphy
acritarchs
Africa
Arctic region
assemblages
Avalon Peninsula
Avalonia
Baltica
biogeography
biostratigraphy
Cambrian
Canada
Dabis Formation
Digermulen Peninsula
Eastern Canada
Ediacaran
Europe
Gibbett Hill Formation
Granomarginata
Indreelva Member
Lagoenaforma
Lagoenaforma collaris
Manndrapselva Member
Mara Member
microfossils
morphology
Nama Group
Namibia
Neoproterozoic
new taxa
Newfoundland
Newfoundland and Labrador
Norway
paleoenvironment
Paleozoic
palynomorphs
phytoplankton
plankton
Precambrian
Proterozoic
Scandinavia
Signal Hill Group
Southern Africa
Stahpogieddi Formation
taxonomy
upper Precambrian
Western Europe
Language
English
ISSN
0016-7568
Abstract
New occurrences of flask-shaped and envelope-bearing microfossils, including the predominantly Cambrian taxon Granomarginata, are reported from new localities, as well as from earlier in time (Ediacaran) than previously known. The stratigraphic range of Granomarginata extends into the Cambrian System, where it had a cosmopolitan distribution. This newly reported Ediacaran record includes areas from Norway (Baltica), Newfoundland (Avalonia) and Namibia (adjacent to the Kalahari Craton), and puts the oldest global occurrence of Granomarginata in the Indreelva Member (< 563 Ma) of the Stáhpogieddi Formation on the Digermulen Peninsula, Arctic Norway. Although Granomarginata is rare within the assemblage, these new occurrences together with previously reported occurrences from India and Poland, suggest a potentially widespread palaeogeographic distribution of Granomarginata through the middle-late Ediacaran interval. A new flask-shaped microfossil Lagoenaforma collaris gen. et sp. nov. is also reported in horizons containing Granomarginata from the Stáhpogieddi Formation in Norway and the Dabis Formation in Namibia, and flask-shaped fossils are also found in the Gibbett Hill Formation in Newfoundland. The Granomarginata-Lagoenaforma association, in addition to a low-diversity organic-walled microfossil assemblage, occurs in the strata postdating the Shuram carbon isotope excursion, and may eventually be of use in terminal Ediacaran biostratigraphy. These older occurrences of Granomarginata add to a growing record of body fossil taxa spanning the Ediacaran-Cambrian boundary.