Middle Devonian lycopsids from high southern palaeolatitudes of Gondwana (Argentina)

Fossil plants are described from the upper part of the Devonian Lolén Formation, Sierra de la Ventana, Buenos Aires Province, Argentina, in the area of Estancia Las Acacias. The sequence is composed mainly of dark grey shales, and fossils were found in a single horizon where thin interlayered beds o...

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Bibliographic Details
Published in:Geological magazine 2002-11, Vol.139 (6), p.641-649
Main Authors: CINGOLANI, CARLOS A., BERRY, CHRISTOPHER M., MOREL, EDUARDO, TOMEZZOLI, RENATA
Format: Article
Language:English
Subjects:
Argentina
biostratigraphy
Buenos Aires Argentina
clastic rocks
Devonian
Estancia Las Acacias
Fossils
Geology
Gondwana
Haskinsia
leaves
Lolen Formation
Lycopsida
Middle Devonian
morphology
Paleobotany
paleoclimatology
paleoecology
paleogeography
Paleolatitude
paleomagnetism
paleotemperature
Paleozoic
Plantae
Pteridophyta
sedimentary rocks
shale
Sierra de la Ventana
South America
Stratigraphy
taxonomy
Temperate zones
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Summary:Fossil plants are described from the upper part of the Devonian Lolén Formation, Sierra de la Ventana, Buenos Aires Province, Argentina, in the area of Estancia Las Acacias. The sequence is composed mainly of dark grey shales, and fossils were found in a single horizon where thin interlayered beds of fine reddish-brown micaceous sandstones appear where the environment of marine deposition became more shallow. The age of the Lolén Formation is presently established on the basis of brachiopods, these being characteristic elements of the Malvinokaffric realm from the Gondwana Lower Devonian (Emsian). The fossil plants are remarkably preserved given that they are in rocks that have undergone intense deformation. The plants are identified as Haplostigma sp. and Haskinsia cf. H. colophylla, and suggest a Middle Devonian age (Givetian) for the fossil-bearing levels. Haskinsia, identified on the basis of leaf morphology, is the first well-delimited Middle Devonian lycopsid genus described from Argentina, and the record from the most southerly palaeolatitude. During the Middle Devonian, Haskinsia was distributed in tropical, warm temperate and high southern latitude, ?cool temperate zones.
ISSN:0016-7568
1469-5081
DOI:10.1017/S0016756802006957