Palinobiotas fósiles

VOLHEIMER, W.; QUATTROCCHIO M.E.; MARTÍNEZ, M.A; PRÁMPARO, M.B.; SCAFATATI, L.; MELENDI, D.

Neuquén

Congreso; XVIII Congreso Geológico Argentino; 2011

Asociación Geológica Argentina

ABSTRACT Fossil palynobiotas.- This paper presents a synthesis of the knowledge on Jurassic, Cretaceous and Paleogene palynobiotas of the Neuquén province. For the characterization of the Liassic microfloras, the very diverse Late Toarcian terrestrial (with the incoming of Callialasporites and coastal assemblages (with Nannoceratopsis) of the Nestares Formation at Alicura (Limay river) are selected. The Middle Jurassic Los Molles and Lajas formations of the central southern part of the basin represent shallow marine and deltaic environments with acanthomorph acritarchs (Micrhystridium) and sphaeromorphs (Leiosphaeridia). Among the terrestrial species are prevailing the pollen grains of the families Cheirolepidiaceae, Araucariaceae and Podocarpaceae, accompanied by ferns. During a new transgression in the middle and late Callovian (Lotena Formation) dinoflagellate cysts are getting more diverse and endemic. The interval Tithonian-Berriasian presents a palynostratigraphic uniformity, even if dinoflagellates allow subdivisions. The great microfloristic change occurs at the Berriasian-Valanginian boundary, with the first and abundant occurrence of Cyclusphaera psilata, whose maximal frequency is observed throughout the Agrio Formation (Late Valanginian to Barremian). In the Quili Malal Member (Rayoso Formation) appear grains of primitive angiosperms of the Huitrinipollenites-Stephanocolpites complex of Aptian- Albian age. The marine Atlantic ingression (K/T) recorded at the Añelo locality is characterized by a great diversity of dinocysts and a peak of abundance of conifers just above the boundary. In a Middle to Late Eocene microflora at Confluencia (Río Limay), intercalated in sediments of a volcanic arc, is dominating Nothofagidites (fusca and brassii groups), associated with other angiosperms which characterize a temperate and humid forest..- This paper presents a synthesis of the knowledge on Jurassic, Cretaceous and Paleogene palynobiotas of the Neuquén province. For the characterization of the Liassic microfloras, the very diverse Late Toarcian terrestrial (with the incoming of Callialasporites and coastal assemblages (with Nannoceratopsis) of the Nestares Formation at Alicura (Limay river) are selected. The Middle Jurassic Los Molles and Lajas formations of the central southern part of the basin represent shallow marine and deltaic environments with acanthomorph acritarchs (Micrhystridium) and sphaeromorphs (Leiosphaeridia). Among the terrestrial species are prevailing the pollen grains of the families Cheirolepidiaceae, Araucariaceae and Podocarpaceae, accompanied by ferns. During a new transgression in the middle and late Callovian (Lotena Formation) dinoflagellate cysts are getting more diverse and endemic. The interval Tithonian-Berriasian presents a palynostratigraphic uniformity, even if dinoflagellates allow subdivisions. The great microfloristic change occurs at the Berriasian-Valanginian boundary, with the first and abundant occurrence of Cyclusphaera psilata, whose maximal frequency is observed throughout the Agrio Formation (Late Valanginian to Barremian). In the Quili Malal Member (Rayoso Formation) appear grains of primitive angiosperms of the Huitrinipollenites-Stephanocolpites complex of Aptian- Albian age. The marine Atlantic ingression (K/T) recorded at the Añelo locality is characterized by a great diversity of dinocysts and a peak of abundance of conifers just above the boundary. In a Middle to Late Eocene microflora at Confluencia (Río Limay), intercalated in sediments of a volcanic arc, is dominating Nothofagidites (fusca and brassii groups), associated with other angiosperms which characterize a temperate and humid forest.Callialasporites and coastal assemblages (with Nannoceratopsis) of the Nestares Formation at Alicura (Limay river) are selected. The Middle Jurassic Los Molles and Lajas formations of the central southern part of the basin represent shallow marine and deltaic environments with acanthomorph acritarchs (Micrhystridium) and sphaeromorphs (Leiosphaeridia). Among the terrestrial species are prevailing the pollen grains of the families Cheirolepidiaceae, Araucariaceae and Podocarpaceae, accompanied by ferns. During a new transgression in the middle and late Callovian (Lotena Formation) dinoflagellate cysts are getting more diverse and endemic. The interval Tithonian-Berriasian presents a palynostratigraphic uniformity, even if dinoflagellates allow subdivisions. The great microfloristic change occurs at the Berriasian-Valanginian boundary, with the first and abundant occurrence of Cyclusphaera psilata, whose maximal frequency is observed throughout the Agrio Formation (Late Valanginian to Barremian). In the Quili Malal Member (Rayoso Formation) appear grains of primitive angiosperms of the Huitrinipollenites-Stephanocolpites complex of Aptian- Albian age. The marine Atlantic ingression (K/T) recorded at the Añelo locality is characterized by a great diversity of dinocysts and a peak of abundance of conifers just above the boundary. In a Middle to Late Eocene microflora at Confluencia (Río Limay), intercalated in sediments of a volcanic arc, is dominating Nothofagidites (fusca and brassii groups), associated with other angiosperms which characterize a temperate and humid forest.Micrhystridium) and sphaeromorphs (Leiosphaeridia). Among the terrestrial species are prevailing the pollen grains of the families Cheirolepidiaceae, Araucariaceae and Podocarpaceae, accompanied by ferns. During a new transgression in the middle and late Callovian (Lotena Formation) dinoflagellate cysts are getting more diverse and endemic. The interval Tithonian-Berriasian presents a palynostratigraphic uniformity, even if dinoflagellates allow subdivisions. The great microfloristic change occurs at the Berriasian-Valanginian boundary, with the first and abundant occurrence of Cyclusphaera psilata, whose maximal frequency is observed throughout the Agrio Formation (Late Valanginian to Barremian). In the Quili Malal Member (Rayoso Formation) appear grains of primitive angiosperms of the Huitrinipollenites-Stephanocolpites complex of Aptian- Albian age. The marine Atlantic ingression (K/T) recorded at the Añelo locality is characterized by a great diversity of dinocysts and a peak of abundance of conifers just above the boundary. In a Middle to Late Eocene microflora at Confluencia (Río Limay), intercalated in sediments of a volcanic arc, is dominating Nothofagidites (fusca and brassii groups), associated with other angiosperms which characterize a temperate and humid forest.Cyclusphaera psilata, whose maximal frequency is observed throughout the Agrio Formation (Late Valanginian to Barremian). In the Quili Malal Member (Rayoso Formation) appear grains of primitive angiosperms of the Huitrinipollenites-Stephanocolpites complex of Aptian- Albian age. The marine Atlantic ingression (K/T) recorded at the Añelo locality is characterized by a great diversity of dinocysts and a peak of abundance of conifers just above the boundary. In a Middle to Late Eocene microflora at Confluencia (Río Limay), intercalated in sediments of a volcanic arc, is dominating Nothofagidites (fusca and brassii groups), associated with other angiosperms which characterize a temperate and humid forest.Huitrinipollenites-Stephanocolpites complex of Aptian- Albian age. The marine Atlantic ingression (K/T) recorded at the Añelo locality is characterized by a great diversity of dinocysts and a peak of abundance of conifers just above the boundary. In a Middle to Late Eocene microflora at Confluencia (Río Limay), intercalated in sediments of a volcanic arc, is dominating Nothofagidites (fusca and brassii groups), associated with other angiosperms which characterize a temperate and humid forest.Nothofagidites (fusca and brassii groups), associated with other angiosperms which characterize a temperate and humid forest.