Papers by Valeria Perez Loinaze
Palaeogeography, Palaeoclimatology, Palaeoecology, 2018
Abstract The early Late Triassic Chanares Formation of Argentina contains one of the richest tetr... more Abstract The early Late Triassic Chanares Formation of Argentina contains one of the richest tetrapod-bearing assemblages of this age worldwide and is important for understanding the origin and early radiation of suchians, dinosauromorphs, and mammaliaforms. Here, we describe the fabric and microfossil content of herbivore coprolites produced by large kannemeyeriiform dicynodonts. Identified inclusions are dominated by fragmentary plant debris (wood, cuticles) with minor palynomorphs, the latter being of special significance as they represent the first palynological assemblage obtained for the formation. The palynological assemblage, which is dominated by bisaccate pollen grains, Alisporites and Platysaccus (Umkomasiales = Corystospermales), and minor striate pollen grains and fern spores, is characteristic of the Ipswich Phytogeographic Subprovince. Also present are Ovalipollis and Ellipsovelatisporites, which are typically absent in this phytogeographic subprovince (being characteristic elements of the Onslow Subprovince), but have been reported in the younger Ischigualasto Formation from the same basin. A statistical analysis of Triassic palynofloras across Gondwana results in a grouping containing the Ischigualasto and Chanares formations, with assemblages of East Antarctica, which together comprise a subprovince that is transitional between Ipswich and Onslow floras. The paleobotanical and palynological content of the coprolites also sheds light on the feeding behaviour of dicynodont producers, suggesting low-feeding habits and non-strict selectivity of the food source.
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The Baqueró Group is one of the most relevant units regarding the study of the early diversificat... more The Baqueró Group is one of the most relevant units regarding the study of the early diversification of
angiosperms in South America. Whereas the age of the upper part of the Group, namely the Punta del
Barco Formation, has been recently dated at 114.67 0.18 Ma, the rest of the unit still lacks precise
dating. In this contribution a CA-TIMS UePb zircon age of 118.23 0.09 Ma for a tuff interlayered with
fossiliferous rocks of the Anfiteatro de Ticó Formation (lower part of the Baqueró Group) is reported. This
age constrains the duration of deposition of the Baqueró Group to approximately 4 Ma and provides new
evidence for the age interpretation of the previously described angiosperm flora and associated pollen
assemblages from this unit, until now interpreted as early Aptian or possibly Barremian in age. The
Aptian age of the Baqueró Group allows a better comparison between the paleofloras from this southernmost
region.
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A new locality where Carboniferous glacial diamictite appears confined to paleovalleys is describ... more A new locality where Carboniferous glacial diamictite appears confined to paleovalleys is described in the north
of the Argentinian Precordillera. The glacial deposits of the lower part of the Carboniferous Quebrada Larga Formation
are divided in three stratigraphic intervals, all of them confined to a paleovalley carved into the granitic
and high-grade metamorphic basement. The lower section is composed of different types of massive and stratified
diamictite interpreted to record reworking of previously deposited poorly sorted glacial sediments. The middle
section comprises shale with dropstones, lenticular beds of diamictite and large-scale cross-bedded sets of
sandstone and conglomerate. These rocks represent a more advanced stage of deglaciation that comprises the
following succeeding steps: 1) amelioration of the climatic conditions, melting of glaciers, fluvial erosion,
2) the formation of a water body (onset of the fjord system) and 3) a later progradation of Gilbert-type deltas.
Diamictite is missing in the upper section, which is chiefly formed by cross-bedded sandstone and conglomerate
deposited in braided fluvial plains. A quantitative analysis of palynological assemblages through the sequence
allowed a reconstruction of the dynamics of the vegetation developed during the filling of the paleovalley. The
presence of monosaccate pollen grains supports an age not older than Serpukhovian and the recognition of the
characteristic species of the Raistrickia densa–Convolutispora muriornata Biozone reinforces a late Serpukhovian–
Bashkirian age for the assemblages.
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Revista del Museo Argentino de Cs. Nat. "B. Rivadavia", Nueva Serie, 2013
The Patquía Formation is one of the few Neopaleozoic units from the
Paganzo Basin lacking detail... more The Patquía Formation is one of the few Neopaleozoic units from the
Paganzo Basin lacking detailed palynological studies. Twelve samples from the midsection, deposited in a coastal
marine environment in the area of Cerro Veladero (La Rioja Province) allowed us to characterize their palynological
content. All associations recovered are dominated by pollen grains, with a important percentage of taeniate
pollen. A detailed comparison is made with other associations from Argentina and Brazil. The presence of several
species such as Protohaploxypinus and Vittatina together with Pakhapites fusus, Weylandites magmus and
Converrucosisporites confluens Morphon sustains its correlation with the Pakhapites fusus - Vittatina subsaccata
Biozone that defines the earliest Cisuralian in Argentina.
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Andean Geology, Jan 2014
At the outcrops of the Tupe Formation in the La Herradura Creek, San Juan Province, two transgres... more At the outcrops of the Tupe Formation in the La Herradura Creek, San Juan Province, two transgressive events are recorded, which range from few meters to tens of meters in thickness. These strata correspond to the stratotype of the faunal Tivertonia jachalensis–Streptorhynchus inaequiornatus Biozone. An evaluation of the timing of the two marine transgressions is made on the basis of palynological assemblages and available radiometric ages. A short-lived transgression is recorded in the latest Bashkirian-early Moscovian, and then a substantial sea level fall took place forming an irregular incision surface. Later, a major high eustatic sea-level occurred during the middle Moscovian resulting in a more important marine ingression. The palynological assemblages associated to the older transgressive event indicate the presence of the Raistrickia densa-Convolutispora muriornata (DM) Biozone (Subzone B). Palynofloras referred to the Subzone C of the DM Biozone characterize the strata of the younger transgression that also bear marine fauna of the Tivertonia jachalensis–Streptorhynchus inaequiornatus Biozone. Correlations with other Pennsylvanian outcrops in the region give support to the stratigraphic scheme here proposed.
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Palaeogeography Palaeoclimatology Palaeoecology, 323:22-41.
The continental deposits of the Baqueró Group preserve one of themost abundant Aptian floras on t... more The continental deposits of the Baqueró Group preserve one of themost abundant Aptian floras on the southern
margins of Gondwana. These floras represent an extinct biome thatwas subject to increasing regional volcanism.
In combination with the presence of shallow water bodies, this biome provided suitable environments for the
preservation of imprints and compressions of foliage together with permineralized trunks and palynofloras.
Eight facies associations were identified in nine sections, characterizing the evolution of lacustrine and fluvial
environments under intense volcanic activity. In addition, three depositional sequences were defined, with the
purpose of establishing a chronostratigraphic framework to which the positions of the fossiliferous levels identified
in the different sections can be referred. A 206Pb/238U age of 114.67±0.18Ma fromthe upper depositional
sequence constrains the succession as no younger than the late Aptian and probably represents an interval of
4–5 Myr, during which the vegetation was affected by increasing biotic stress conditions. A qualitative analysis
of the palynological assemblages and plant remains allowed a reconstruction of the dynamics of the vegetation
developed during the deposition of the Baqueró Group. Volcanic activity appears to have had relatively moderate
effects on the biota, at least at the Order level. Nevertheless, low species richness is observed toward the top of
the Baqueró Group, reflecting an increase in adverse environmental conditions. The possible interpretations of
the assemblages identified as biozones or, in contrast, biofacies related to changeable environmental conditions
are discussed herein.
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Micropaleontology, 58:335-350.
Palynological analysis is reported here for the first time from glacial and postglacial deposits ... more Palynological analysis is reported here for the first time from glacial and postglacial deposits of the lower-middle section
of the Guandacol Formation at the Huaco area, central Paganzo Basin, Argentina. Forty-nine spore species are assigned to twenty-seven genera and twenty-one pollen species are assigned to ten genera, however few acritarchs were identified. Biostratigraphic ranges of species suggest an age no older than late Serpukhovian for the section studied. This age is also supported by radiometric data that indicate an early Bashkirian age at the top of the Guandacol Formation. The palynofloras consistmostly of endemic spore species, and provide new evidence for delimiting the Subzone Aof the Raistrickia densa-Convolutispora muriornata Biozone in Argentina. Close correlation is
suggested with palynological associations belonging to thewidespread glaciation occurred during the Serpukhovian-early Bashkirian in South America and Australia.
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Cretaceous Research, 34:161-171, Jan 1, 2012
Palynomorph assemblages have been recovered from the upper levels of the Río Mayer Formation and
... more Palynomorph assemblages have been recovered from the upper levels of the Río Mayer Formation and
the basal levels of the Kachaike Formation exposed at the Puesto El Moro Creek, southwest of Santa Cruz
Province, Argentina. Forty-five spore species and 25 pollen taxa (including six angiosperms) have been
identified. The palynological assemblages of the upper levels of Río Mayer Formation are dominated by
pteridophytic spores, while Classopollis is a common element. In the Kachaike Formation, the angiosperm
pollen grains are more diverse and abundant than in the underlying unit, and Cheirolepidiaceae pollen
continues to dominate. The presence of scarce angiosperm pollen, represented by Clavatipollenites sp.,
allows reference of the assemblage recorded in the upper levels of the Río Mayer Formation to the Aptian
Antulsporites-Clavatipollenites Zone. In addition, the lower levels of the Kachaike Formation are referred
to the late Aptianeearly Albian, based on the presence of Asteropollis asteroides, Pennipollis peroreticulatus,
Clavatipollenites sp. and scarce tricolpate pollen. From the three major stages of the early
angiosperm evolution in southern South America that have been previously recognized, the palynoflora
of the upper levels of the Río Mayer Formation can be referred to Stage I (late BarremianeAptian),
whereas the assemblages recognized in the Kachaike strata are comparable to Stage II (latest Aptiane
earliest Albian).
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Ameghiniana, 48: 605-620., Jan 1, 2011
Well-preserved palynological assemblages have been obtained from the Guandacol Formation at Río F... more Well-preserved palynological assemblages have been obtained from the Guandacol Formation at Río Francia Creek, Paganzo
Basin, Argentina. The geological setting and stratigraphic provenance of the samples is provided. Forty-nine spore, twenty-three pollen
and two algal species are identified. Some species are recognized for the first time from this unit, such as: Brevitriletes levis, B. leptoacaina,
Lundbladispora areolata, Peppersites ellipticus, Psomospora detecta, Rattiganispora apiculata and Retusotriletes nigritelus. These assemblages are
referred to Subzone A of the Raistrickia densa-Convolutispora muriornata Biozone, late Serpukhovian–early Bashkirian in age. Palynological
samples from the Tupe Formation at the same locality were studied in order to compare the composition of both units, which present
a palynological composition similar to the associations recovered from the Guandacol Formation. Spelaeotriletes ybertii is restricted to the
palynological assemblages of the Tupe Formation studied herein. It is noteworthy that both units lack taeniate pollen. Some species restricted
at this locality to the Guandacol Formation, have a wider stratigraphic distribution elsewhere. The only species from this unit that seems to
have biostratigraphic significance is Tricidarisporites gutii. A new species of trilete spores is proposed, i.e., Cyclogranisporites cuerdae sp. nov.
from the Tupe Formation.
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Journal of South American Earth Sciences, 31:426-431., Jan 1, 2011
The Baqueró Group holds a rich fossil flora including macrofloristic and palynological remains th... more The Baqueró Group holds a rich fossil flora including macrofloristic and palynological remains that
characterize the Early Cretaceous vegetation of Argentina. The age of the upper part of the Group, known
as Punta del Barco Formation, has been a topic of several discussions in the past. The type locality of this
stratigraphic unit exposes fossiliferous tuffs together with muddy tuffs and tuffaceous sandstones beds.
However, there have been no reliable age constraints for the fossil assemblages. 206Pb/238U analyses of
zircon crystals yielded an age of 114.67 0.18 Ma. This age control makes possible an improved analysis
and comparison of the floras in the southern region.
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Geológica Acta, 8:483-493.
The palynological analysis of five samples from three levels in cores of the Mallorquín-1 well (P... more The palynological analysis of five samples from three levels in cores of the Mallorquín-1 well (Paraná Basin,
eastern Paraguay) is presented here. The borehole penetrated the San Miguel Formation, the basal lithostratigraphic
unit of the Independencia Group. This palynoflora represents the westernmost palynological record reported from
Upper Paleozoic sequences along this basin margin at this latitude. This diverse spore-pollen flora includes several
age marker taxa, viz. Verrucosisporites insuetus, Lueckisporites spp., Lunatisporites variesectus, Striatosporites
heyleri, Weylandites lucifer, and Tornopollenites toreutos, as well as Reduviasporonites chalastus. The assemblages
from the Mallorquín-1 well are assignable to the Lueckisporites virkkiae Zone from the Brazilian sector of the
Paraná Basin, thus suggesting a Late Cisuralian-Guadalupian age for the section studied and its correlation with
the Brazilian Palermo and Irati Formations. Moreover, palynostratigraphic regional correlation can be established
with the Tornopollenites toreutos Biozone (northern Brazil), the Striatites and Lueckisporites-Weylandites Biozones
(Argentina) and the Striatoabieites anaverrucosus-Staurosaccites cordubensis Biozone (Uruguay). The presence
of abundant taeniate pollen also suggests similarities with palynofloras from South Africa and Australia.
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Geológica Acta, 8:399-418., Jan 1, 2010
The age and depositional setting of two glacial events recognized in the western basins of Argent... more The age and depositional setting of two glacial events recognized in the western basins of Argentina are discussed
in this paper. The older one corresponds to diamictites identified in the upper member of the Cortaderas Formation
(Visean, Río Blanco Basin). The glacial sequence consists of shales, dropstone-bearing shales massive matrixrich
diamictites, massive clast-rich diamictites, and stratified diamictites, all of them interpreted as deposited in
distal glaciomarine settings. Palynological remains recovered from shales interstratified with diamictites were
referred to the late Visean Reticulatisporites magnidictyus-Verrucosisporites quasigobbettii Biozone. Younger
glacial deposits were studied at the base of the Guandacol Formation (Paganzo Basin) where are made up by
clast-poor massive diamictites, clast-rich massive diamictites, stratified diamictites, thinly-bedded dropstonebearing
diamictites, rhythmites, dropstone-bearing shales, and barren of dropstone shales. The whole sequence
is interpreted as deposited in low-relief proximal glaciomarine environments (morainal banks). The abundant
palynological assemblages found in the glacial interval were included in the subzone A of the Raistrickia densa-
Convolutispora muriornata Biozone which is considered Serpukhovian-early Bashkirian in age.
Palynological remains found in the Cortaderas Formation suggest that the beginning of the Glacial 2 event in
Gondwana (according to Isbell’s chronological proposal for glacial and interglacial stages) should be considered
late Visean while the end, according to the assemblages recovered from the Guandacol Formation, was not
younger than early Bashkirian. Moreover, sedimentological and stratigraphic data suggest the existence of a short
interglacial period between the Cortaderas and Guandacol glacial events.
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Ameghiniana, 47:263-239., Jan 1, 2010
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Ameghiniana, 46: 495-512., Jan 1, 2009
Palynological analysis of the Malanzán Formation in the Paganzo Basin, northwestern
Argentina, h... more Palynological analysis of the Malanzán Formation in the Paganzo Basin, northwestern
Argentina, has yielded six well-preserved palynological assemblages. Fifty-nine species were determined:
37 spores, 19 pollen grains, and 3 algae. Thirty-two of these species have not been recorded so far from the
Malanzán Formation, and all pollen species are illustrated for the first time. These assemblages are referred
to Sub-Biozone A of the Raistrickia densa-Convolutispora muriornata Biozone, Serpukhovian in age.
Moreover, the abundance of monosaccate pollen grains might constrain the Malanzán Formation to the
late Serpukhovian.
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Boletín de la Asociación Latinoamericana de Paleobotánica y Palinología. Asociación Latinoamericana de Paleobotánica y Palinología, 13: 43-60., 2009
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Ameghiniana, 45: 421-441., Jan 1, 2008
Well preserved Mississippian palynological assemblages have been obtained from the
Cortaderas Fo... more Well preserved Mississippian palynological assemblages have been obtained from the
Cortaderas Formation in the Río Blanco Basin, northwestern Argentina. In this second contribution, twenty-
eight from a total of seventy-eight spore species are described. A new species of trilete spores is proposed:
Densosporites scalabrinii sp. nov. Worldwide geographic and stratigraphic records of taxa are
analysed. The Cortaderas Formation is dated as late Viséan in age based on the presence of species of potential
stratigraphic relevance, such as Reticulatisporites magnidictyus Playford and Helby, Verrucosisporites
quasigobbettii Playford and Helby and Rugospora australiensis (Playford and Helby) Jones and Truswell and
the absence of pollen grains. The samples collected in the uppermost level of this unit, contain some of
spores typical of the Upper Carboniferous of Argentina and Brazil, although pollen grains are still absent.
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Ameghiniana, 45: 33-57., Jan 1, 2008
Well preserved Mississippian palynological assemblages have been obtained from the
Cortaderas Fo... more Well preserved Mississippian palynological assemblages have been obtained from the
Cortaderas Formation in the Río Blanco Basin, northwestern Argentina. The geological setting and stratigraphic
provenance of the samples is provided. In this first part, fifty-two species are described from a total
of seventy-eight species of spores recognized. Five new species are proposed: Verrucosisporites incompositus
sp. nov., Verrucosisporites perbrevis sp. nov., Anapiculatisporites exiguus sp. nov., Anapiculatisporites
expolitus sp. nov. and Dibolisporites insolitus sp. nov. Previous worldwide geographic and stratigraphic
records of taxa are detailed.
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Palynology, 31: 101-118., Jan 1, 2007
A new biozone for the late Viséan miospores from the Cortaderas Formation in western Argentina is... more A new biozone for the late Viséan miospores from the Cortaderas Formation in western Argentina is proposed. It is the Reticulatisporites
magnidictyus-Verrucosisporites quasigobbettii (MQ) Interval Biozone. The base of the biozone is defined by the range bases of
Apiculiretusispora microseta, Dibolisporites disfacies, Reticulatisporites magnidictyus, Rugospora australiensis, and Verrucosisporites
quasigobbettii. The upper limit of the MQ Interval Biozone is marked by the appearance of monosaccate pollen. Two distinct associations
are recognized; Association A is characterized by the range bases of the diagnostic species, and the presence of a group of long-ranging
species. Association B is characterized by the range bases of Anapiculatisporites austrinus, Anapiculatisporites kekiktukensis, Apiculatisporis
variornatus, Crassispora kosankei, Cristatisporites menendezii, Kraeuselisporites tendatus, Kraeuselisporites volkheimerii, Raistrickia
paganciana, Raistrickia rotunda, and Spinozonotriletes hirsutus, and is represented in the upper part of the Cortaderas Formation.
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Geobios, 39(6): 785-790., Jan 1, 2006
Upper Paleozoic sphenopsids from western Gondwana are little known. New finds were made from the ... more Upper Paleozoic sphenopsids from western Gondwana are little known. New finds were made from the Upper Carboniferous of the San Juan
province (Argentina). The specimens include vegetative and fertile characters that allow the definition of a new genus and species: Gondwanites
subtilis. They are characterized by slender branches bearing whorls of very thin, simple or divided leaves. Simple fertile organs are borne in
whorls just below the verticel of leaves. The presence of dichotomized leaves and bractless fertile organs in the new taxon suggests its probable
primitive condition.
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Ameghiniana, 42(2):481-488. , Jan 1, 2005
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Papers by Valeria Perez Loinaze
angiosperms in South America. Whereas the age of the upper part of the Group, namely the Punta del
Barco Formation, has been recently dated at 114.67 0.18 Ma, the rest of the unit still lacks precise
dating. In this contribution a CA-TIMS UePb zircon age of 118.23 0.09 Ma for a tuff interlayered with
fossiliferous rocks of the Anfiteatro de Ticó Formation (lower part of the Baqueró Group) is reported. This
age constrains the duration of deposition of the Baqueró Group to approximately 4 Ma and provides new
evidence for the age interpretation of the previously described angiosperm flora and associated pollen
assemblages from this unit, until now interpreted as early Aptian or possibly Barremian in age. The
Aptian age of the Baqueró Group allows a better comparison between the paleofloras from this southernmost
region.
of the Argentinian Precordillera. The glacial deposits of the lower part of the Carboniferous Quebrada Larga Formation
are divided in three stratigraphic intervals, all of them confined to a paleovalley carved into the granitic
and high-grade metamorphic basement. The lower section is composed of different types of massive and stratified
diamictite interpreted to record reworking of previously deposited poorly sorted glacial sediments. The middle
section comprises shale with dropstones, lenticular beds of diamictite and large-scale cross-bedded sets of
sandstone and conglomerate. These rocks represent a more advanced stage of deglaciation that comprises the
following succeeding steps: 1) amelioration of the climatic conditions, melting of glaciers, fluvial erosion,
2) the formation of a water body (onset of the fjord system) and 3) a later progradation of Gilbert-type deltas.
Diamictite is missing in the upper section, which is chiefly formed by cross-bedded sandstone and conglomerate
deposited in braided fluvial plains. A quantitative analysis of palynological assemblages through the sequence
allowed a reconstruction of the dynamics of the vegetation developed during the filling of the paleovalley. The
presence of monosaccate pollen grains supports an age not older than Serpukhovian and the recognition of the
characteristic species of the Raistrickia densa–Convolutispora muriornata Biozone reinforces a late Serpukhovian–
Bashkirian age for the assemblages.
Paganzo Basin lacking detailed palynological studies. Twelve samples from the midsection, deposited in a coastal
marine environment in the area of Cerro Veladero (La Rioja Province) allowed us to characterize their palynological
content. All associations recovered are dominated by pollen grains, with a important percentage of taeniate
pollen. A detailed comparison is made with other associations from Argentina and Brazil. The presence of several
species such as Protohaploxypinus and Vittatina together with Pakhapites fusus, Weylandites magmus and
Converrucosisporites confluens Morphon sustains its correlation with the Pakhapites fusus - Vittatina subsaccata
Biozone that defines the earliest Cisuralian in Argentina.
margins of Gondwana. These floras represent an extinct biome thatwas subject to increasing regional volcanism.
In combination with the presence of shallow water bodies, this biome provided suitable environments for the
preservation of imprints and compressions of foliage together with permineralized trunks and palynofloras.
Eight facies associations were identified in nine sections, characterizing the evolution of lacustrine and fluvial
environments under intense volcanic activity. In addition, three depositional sequences were defined, with the
purpose of establishing a chronostratigraphic framework to which the positions of the fossiliferous levels identified
in the different sections can be referred. A 206Pb/238U age of 114.67±0.18Ma fromthe upper depositional
sequence constrains the succession as no younger than the late Aptian and probably represents an interval of
4–5 Myr, during which the vegetation was affected by increasing biotic stress conditions. A qualitative analysis
of the palynological assemblages and plant remains allowed a reconstruction of the dynamics of the vegetation
developed during the deposition of the Baqueró Group. Volcanic activity appears to have had relatively moderate
effects on the biota, at least at the Order level. Nevertheless, low species richness is observed toward the top of
the Baqueró Group, reflecting an increase in adverse environmental conditions. The possible interpretations of
the assemblages identified as biozones or, in contrast, biofacies related to changeable environmental conditions
are discussed herein.
of the Guandacol Formation at the Huaco area, central Paganzo Basin, Argentina. Forty-nine spore species are assigned to twenty-seven genera and twenty-one pollen species are assigned to ten genera, however few acritarchs were identified. Biostratigraphic ranges of species suggest an age no older than late Serpukhovian for the section studied. This age is also supported by radiometric data that indicate an early Bashkirian age at the top of the Guandacol Formation. The palynofloras consistmostly of endemic spore species, and provide new evidence for delimiting the Subzone Aof the Raistrickia densa-Convolutispora muriornata Biozone in Argentina. Close correlation is
suggested with palynological associations belonging to thewidespread glaciation occurred during the Serpukhovian-early Bashkirian in South America and Australia.
the basal levels of the Kachaike Formation exposed at the Puesto El Moro Creek, southwest of Santa Cruz
Province, Argentina. Forty-five spore species and 25 pollen taxa (including six angiosperms) have been
identified. The palynological assemblages of the upper levels of Río Mayer Formation are dominated by
pteridophytic spores, while Classopollis is a common element. In the Kachaike Formation, the angiosperm
pollen grains are more diverse and abundant than in the underlying unit, and Cheirolepidiaceae pollen
continues to dominate. The presence of scarce angiosperm pollen, represented by Clavatipollenites sp.,
allows reference of the assemblage recorded in the upper levels of the Río Mayer Formation to the Aptian
Antulsporites-Clavatipollenites Zone. In addition, the lower levels of the Kachaike Formation are referred
to the late Aptianeearly Albian, based on the presence of Asteropollis asteroides, Pennipollis peroreticulatus,
Clavatipollenites sp. and scarce tricolpate pollen. From the three major stages of the early
angiosperm evolution in southern South America that have been previously recognized, the palynoflora
of the upper levels of the Río Mayer Formation can be referred to Stage I (late BarremianeAptian),
whereas the assemblages recognized in the Kachaike strata are comparable to Stage II (latest Aptiane
earliest Albian).
Basin, Argentina. The geological setting and stratigraphic provenance of the samples is provided. Forty-nine spore, twenty-three pollen
and two algal species are identified. Some species are recognized for the first time from this unit, such as: Brevitriletes levis, B. leptoacaina,
Lundbladispora areolata, Peppersites ellipticus, Psomospora detecta, Rattiganispora apiculata and Retusotriletes nigritelus. These assemblages are
referred to Subzone A of the Raistrickia densa-Convolutispora muriornata Biozone, late Serpukhovian–early Bashkirian in age. Palynological
samples from the Tupe Formation at the same locality were studied in order to compare the composition of both units, which present
a palynological composition similar to the associations recovered from the Guandacol Formation. Spelaeotriletes ybertii is restricted to the
palynological assemblages of the Tupe Formation studied herein. It is noteworthy that both units lack taeniate pollen. Some species restricted
at this locality to the Guandacol Formation, have a wider stratigraphic distribution elsewhere. The only species from this unit that seems to
have biostratigraphic significance is Tricidarisporites gutii. A new species of trilete spores is proposed, i.e., Cyclogranisporites cuerdae sp. nov.
from the Tupe Formation.
characterize the Early Cretaceous vegetation of Argentina. The age of the upper part of the Group, known
as Punta del Barco Formation, has been a topic of several discussions in the past. The type locality of this
stratigraphic unit exposes fossiliferous tuffs together with muddy tuffs and tuffaceous sandstones beds.
However, there have been no reliable age constraints for the fossil assemblages. 206Pb/238U analyses of
zircon crystals yielded an age of 114.67 0.18 Ma. This age control makes possible an improved analysis
and comparison of the floras in the southern region.
eastern Paraguay) is presented here. The borehole penetrated the San Miguel Formation, the basal lithostratigraphic
unit of the Independencia Group. This palynoflora represents the westernmost palynological record reported from
Upper Paleozoic sequences along this basin margin at this latitude. This diverse spore-pollen flora includes several
age marker taxa, viz. Verrucosisporites insuetus, Lueckisporites spp., Lunatisporites variesectus, Striatosporites
heyleri, Weylandites lucifer, and Tornopollenites toreutos, as well as Reduviasporonites chalastus. The assemblages
from the Mallorquín-1 well are assignable to the Lueckisporites virkkiae Zone from the Brazilian sector of the
Paraná Basin, thus suggesting a Late Cisuralian-Guadalupian age for the section studied and its correlation with
the Brazilian Palermo and Irati Formations. Moreover, palynostratigraphic regional correlation can be established
with the Tornopollenites toreutos Biozone (northern Brazil), the Striatites and Lueckisporites-Weylandites Biozones
(Argentina) and the Striatoabieites anaverrucosus-Staurosaccites cordubensis Biozone (Uruguay). The presence
of abundant taeniate pollen also suggests similarities with palynofloras from South Africa and Australia.
in this paper. The older one corresponds to diamictites identified in the upper member of the Cortaderas Formation
(Visean, Río Blanco Basin). The glacial sequence consists of shales, dropstone-bearing shales massive matrixrich
diamictites, massive clast-rich diamictites, and stratified diamictites, all of them interpreted as deposited in
distal glaciomarine settings. Palynological remains recovered from shales interstratified with diamictites were
referred to the late Visean Reticulatisporites magnidictyus-Verrucosisporites quasigobbettii Biozone. Younger
glacial deposits were studied at the base of the Guandacol Formation (Paganzo Basin) where are made up by
clast-poor massive diamictites, clast-rich massive diamictites, stratified diamictites, thinly-bedded dropstonebearing
diamictites, rhythmites, dropstone-bearing shales, and barren of dropstone shales. The whole sequence
is interpreted as deposited in low-relief proximal glaciomarine environments (morainal banks). The abundant
palynological assemblages found in the glacial interval were included in the subzone A of the Raistrickia densa-
Convolutispora muriornata Biozone which is considered Serpukhovian-early Bashkirian in age.
Palynological remains found in the Cortaderas Formation suggest that the beginning of the Glacial 2 event in
Gondwana (according to Isbell’s chronological proposal for glacial and interglacial stages) should be considered
late Visean while the end, according to the assemblages recovered from the Guandacol Formation, was not
younger than early Bashkirian. Moreover, sedimentological and stratigraphic data suggest the existence of a short
interglacial period between the Cortaderas and Guandacol glacial events.
Argentina, has yielded six well-preserved palynological assemblages. Fifty-nine species were determined:
37 spores, 19 pollen grains, and 3 algae. Thirty-two of these species have not been recorded so far from the
Malanzán Formation, and all pollen species are illustrated for the first time. These assemblages are referred
to Sub-Biozone A of the Raistrickia densa-Convolutispora muriornata Biozone, Serpukhovian in age.
Moreover, the abundance of monosaccate pollen grains might constrain the Malanzán Formation to the
late Serpukhovian.
Cortaderas Formation in the Río Blanco Basin, northwestern Argentina. In this second contribution, twenty-
eight from a total of seventy-eight spore species are described. A new species of trilete spores is proposed:
Densosporites scalabrinii sp. nov. Worldwide geographic and stratigraphic records of taxa are
analysed. The Cortaderas Formation is dated as late Viséan in age based on the presence of species of potential
stratigraphic relevance, such as Reticulatisporites magnidictyus Playford and Helby, Verrucosisporites
quasigobbettii Playford and Helby and Rugospora australiensis (Playford and Helby) Jones and Truswell and
the absence of pollen grains. The samples collected in the uppermost level of this unit, contain some of
spores typical of the Upper Carboniferous of Argentina and Brazil, although pollen grains are still absent.
Cortaderas Formation in the Río Blanco Basin, northwestern Argentina. The geological setting and stratigraphic
provenance of the samples is provided. In this first part, fifty-two species are described from a total
of seventy-eight species of spores recognized. Five new species are proposed: Verrucosisporites incompositus
sp. nov., Verrucosisporites perbrevis sp. nov., Anapiculatisporites exiguus sp. nov., Anapiculatisporites
expolitus sp. nov. and Dibolisporites insolitus sp. nov. Previous worldwide geographic and stratigraphic
records of taxa are detailed.
magnidictyus-Verrucosisporites quasigobbettii (MQ) Interval Biozone. The base of the biozone is defined by the range bases of
Apiculiretusispora microseta, Dibolisporites disfacies, Reticulatisporites magnidictyus, Rugospora australiensis, and Verrucosisporites
quasigobbettii. The upper limit of the MQ Interval Biozone is marked by the appearance of monosaccate pollen. Two distinct associations
are recognized; Association A is characterized by the range bases of the diagnostic species, and the presence of a group of long-ranging
species. Association B is characterized by the range bases of Anapiculatisporites austrinus, Anapiculatisporites kekiktukensis, Apiculatisporis
variornatus, Crassispora kosankei, Cristatisporites menendezii, Kraeuselisporites tendatus, Kraeuselisporites volkheimerii, Raistrickia
paganciana, Raistrickia rotunda, and Spinozonotriletes hirsutus, and is represented in the upper part of the Cortaderas Formation.
province (Argentina). The specimens include vegetative and fertile characters that allow the definition of a new genus and species: Gondwanites
subtilis. They are characterized by slender branches bearing whorls of very thin, simple or divided leaves. Simple fertile organs are borne in
whorls just below the verticel of leaves. The presence of dichotomized leaves and bractless fertile organs in the new taxon suggests its probable
primitive condition.
angiosperms in South America. Whereas the age of the upper part of the Group, namely the Punta del
Barco Formation, has been recently dated at 114.67 0.18 Ma, the rest of the unit still lacks precise
dating. In this contribution a CA-TIMS UePb zircon age of 118.23 0.09 Ma for a tuff interlayered with
fossiliferous rocks of the Anfiteatro de Ticó Formation (lower part of the Baqueró Group) is reported. This
age constrains the duration of deposition of the Baqueró Group to approximately 4 Ma and provides new
evidence for the age interpretation of the previously described angiosperm flora and associated pollen
assemblages from this unit, until now interpreted as early Aptian or possibly Barremian in age. The
Aptian age of the Baqueró Group allows a better comparison between the paleofloras from this southernmost
region.
of the Argentinian Precordillera. The glacial deposits of the lower part of the Carboniferous Quebrada Larga Formation
are divided in three stratigraphic intervals, all of them confined to a paleovalley carved into the granitic
and high-grade metamorphic basement. The lower section is composed of different types of massive and stratified
diamictite interpreted to record reworking of previously deposited poorly sorted glacial sediments. The middle
section comprises shale with dropstones, lenticular beds of diamictite and large-scale cross-bedded sets of
sandstone and conglomerate. These rocks represent a more advanced stage of deglaciation that comprises the
following succeeding steps: 1) amelioration of the climatic conditions, melting of glaciers, fluvial erosion,
2) the formation of a water body (onset of the fjord system) and 3) a later progradation of Gilbert-type deltas.
Diamictite is missing in the upper section, which is chiefly formed by cross-bedded sandstone and conglomerate
deposited in braided fluvial plains. A quantitative analysis of palynological assemblages through the sequence
allowed a reconstruction of the dynamics of the vegetation developed during the filling of the paleovalley. The
presence of monosaccate pollen grains supports an age not older than Serpukhovian and the recognition of the
characteristic species of the Raistrickia densa–Convolutispora muriornata Biozone reinforces a late Serpukhovian–
Bashkirian age for the assemblages.
Paganzo Basin lacking detailed palynological studies. Twelve samples from the midsection, deposited in a coastal
marine environment in the area of Cerro Veladero (La Rioja Province) allowed us to characterize their palynological
content. All associations recovered are dominated by pollen grains, with a important percentage of taeniate
pollen. A detailed comparison is made with other associations from Argentina and Brazil. The presence of several
species such as Protohaploxypinus and Vittatina together with Pakhapites fusus, Weylandites magmus and
Converrucosisporites confluens Morphon sustains its correlation with the Pakhapites fusus - Vittatina subsaccata
Biozone that defines the earliest Cisuralian in Argentina.
margins of Gondwana. These floras represent an extinct biome thatwas subject to increasing regional volcanism.
In combination with the presence of shallow water bodies, this biome provided suitable environments for the
preservation of imprints and compressions of foliage together with permineralized trunks and palynofloras.
Eight facies associations were identified in nine sections, characterizing the evolution of lacustrine and fluvial
environments under intense volcanic activity. In addition, three depositional sequences were defined, with the
purpose of establishing a chronostratigraphic framework to which the positions of the fossiliferous levels identified
in the different sections can be referred. A 206Pb/238U age of 114.67±0.18Ma fromthe upper depositional
sequence constrains the succession as no younger than the late Aptian and probably represents an interval of
4–5 Myr, during which the vegetation was affected by increasing biotic stress conditions. A qualitative analysis
of the palynological assemblages and plant remains allowed a reconstruction of the dynamics of the vegetation
developed during the deposition of the Baqueró Group. Volcanic activity appears to have had relatively moderate
effects on the biota, at least at the Order level. Nevertheless, low species richness is observed toward the top of
the Baqueró Group, reflecting an increase in adverse environmental conditions. The possible interpretations of
the assemblages identified as biozones or, in contrast, biofacies related to changeable environmental conditions
are discussed herein.
of the Guandacol Formation at the Huaco area, central Paganzo Basin, Argentina. Forty-nine spore species are assigned to twenty-seven genera and twenty-one pollen species are assigned to ten genera, however few acritarchs were identified. Biostratigraphic ranges of species suggest an age no older than late Serpukhovian for the section studied. This age is also supported by radiometric data that indicate an early Bashkirian age at the top of the Guandacol Formation. The palynofloras consistmostly of endemic spore species, and provide new evidence for delimiting the Subzone Aof the Raistrickia densa-Convolutispora muriornata Biozone in Argentina. Close correlation is
suggested with palynological associations belonging to thewidespread glaciation occurred during the Serpukhovian-early Bashkirian in South America and Australia.
the basal levels of the Kachaike Formation exposed at the Puesto El Moro Creek, southwest of Santa Cruz
Province, Argentina. Forty-five spore species and 25 pollen taxa (including six angiosperms) have been
identified. The palynological assemblages of the upper levels of Río Mayer Formation are dominated by
pteridophytic spores, while Classopollis is a common element. In the Kachaike Formation, the angiosperm
pollen grains are more diverse and abundant than in the underlying unit, and Cheirolepidiaceae pollen
continues to dominate. The presence of scarce angiosperm pollen, represented by Clavatipollenites sp.,
allows reference of the assemblage recorded in the upper levels of the Río Mayer Formation to the Aptian
Antulsporites-Clavatipollenites Zone. In addition, the lower levels of the Kachaike Formation are referred
to the late Aptianeearly Albian, based on the presence of Asteropollis asteroides, Pennipollis peroreticulatus,
Clavatipollenites sp. and scarce tricolpate pollen. From the three major stages of the early
angiosperm evolution in southern South America that have been previously recognized, the palynoflora
of the upper levels of the Río Mayer Formation can be referred to Stage I (late BarremianeAptian),
whereas the assemblages recognized in the Kachaike strata are comparable to Stage II (latest Aptiane
earliest Albian).
Basin, Argentina. The geological setting and stratigraphic provenance of the samples is provided. Forty-nine spore, twenty-three pollen
and two algal species are identified. Some species are recognized for the first time from this unit, such as: Brevitriletes levis, B. leptoacaina,
Lundbladispora areolata, Peppersites ellipticus, Psomospora detecta, Rattiganispora apiculata and Retusotriletes nigritelus. These assemblages are
referred to Subzone A of the Raistrickia densa-Convolutispora muriornata Biozone, late Serpukhovian–early Bashkirian in age. Palynological
samples from the Tupe Formation at the same locality were studied in order to compare the composition of both units, which present
a palynological composition similar to the associations recovered from the Guandacol Formation. Spelaeotriletes ybertii is restricted to the
palynological assemblages of the Tupe Formation studied herein. It is noteworthy that both units lack taeniate pollen. Some species restricted
at this locality to the Guandacol Formation, have a wider stratigraphic distribution elsewhere. The only species from this unit that seems to
have biostratigraphic significance is Tricidarisporites gutii. A new species of trilete spores is proposed, i.e., Cyclogranisporites cuerdae sp. nov.
from the Tupe Formation.
characterize the Early Cretaceous vegetation of Argentina. The age of the upper part of the Group, known
as Punta del Barco Formation, has been a topic of several discussions in the past. The type locality of this
stratigraphic unit exposes fossiliferous tuffs together with muddy tuffs and tuffaceous sandstones beds.
However, there have been no reliable age constraints for the fossil assemblages. 206Pb/238U analyses of
zircon crystals yielded an age of 114.67 0.18 Ma. This age control makes possible an improved analysis
and comparison of the floras in the southern region.
eastern Paraguay) is presented here. The borehole penetrated the San Miguel Formation, the basal lithostratigraphic
unit of the Independencia Group. This palynoflora represents the westernmost palynological record reported from
Upper Paleozoic sequences along this basin margin at this latitude. This diverse spore-pollen flora includes several
age marker taxa, viz. Verrucosisporites insuetus, Lueckisporites spp., Lunatisporites variesectus, Striatosporites
heyleri, Weylandites lucifer, and Tornopollenites toreutos, as well as Reduviasporonites chalastus. The assemblages
from the Mallorquín-1 well are assignable to the Lueckisporites virkkiae Zone from the Brazilian sector of the
Paraná Basin, thus suggesting a Late Cisuralian-Guadalupian age for the section studied and its correlation with
the Brazilian Palermo and Irati Formations. Moreover, palynostratigraphic regional correlation can be established
with the Tornopollenites toreutos Biozone (northern Brazil), the Striatites and Lueckisporites-Weylandites Biozones
(Argentina) and the Striatoabieites anaverrucosus-Staurosaccites cordubensis Biozone (Uruguay). The presence
of abundant taeniate pollen also suggests similarities with palynofloras from South Africa and Australia.
in this paper. The older one corresponds to diamictites identified in the upper member of the Cortaderas Formation
(Visean, Río Blanco Basin). The glacial sequence consists of shales, dropstone-bearing shales massive matrixrich
diamictites, massive clast-rich diamictites, and stratified diamictites, all of them interpreted as deposited in
distal glaciomarine settings. Palynological remains recovered from shales interstratified with diamictites were
referred to the late Visean Reticulatisporites magnidictyus-Verrucosisporites quasigobbettii Biozone. Younger
glacial deposits were studied at the base of the Guandacol Formation (Paganzo Basin) where are made up by
clast-poor massive diamictites, clast-rich massive diamictites, stratified diamictites, thinly-bedded dropstonebearing
diamictites, rhythmites, dropstone-bearing shales, and barren of dropstone shales. The whole sequence
is interpreted as deposited in low-relief proximal glaciomarine environments (morainal banks). The abundant
palynological assemblages found in the glacial interval were included in the subzone A of the Raistrickia densa-
Convolutispora muriornata Biozone which is considered Serpukhovian-early Bashkirian in age.
Palynological remains found in the Cortaderas Formation suggest that the beginning of the Glacial 2 event in
Gondwana (according to Isbell’s chronological proposal for glacial and interglacial stages) should be considered
late Visean while the end, according to the assemblages recovered from the Guandacol Formation, was not
younger than early Bashkirian. Moreover, sedimentological and stratigraphic data suggest the existence of a short
interglacial period between the Cortaderas and Guandacol glacial events.
Argentina, has yielded six well-preserved palynological assemblages. Fifty-nine species were determined:
37 spores, 19 pollen grains, and 3 algae. Thirty-two of these species have not been recorded so far from the
Malanzán Formation, and all pollen species are illustrated for the first time. These assemblages are referred
to Sub-Biozone A of the Raistrickia densa-Convolutispora muriornata Biozone, Serpukhovian in age.
Moreover, the abundance of monosaccate pollen grains might constrain the Malanzán Formation to the
late Serpukhovian.
Cortaderas Formation in the Río Blanco Basin, northwestern Argentina. In this second contribution, twenty-
eight from a total of seventy-eight spore species are described. A new species of trilete spores is proposed:
Densosporites scalabrinii sp. nov. Worldwide geographic and stratigraphic records of taxa are
analysed. The Cortaderas Formation is dated as late Viséan in age based on the presence of species of potential
stratigraphic relevance, such as Reticulatisporites magnidictyus Playford and Helby, Verrucosisporites
quasigobbettii Playford and Helby and Rugospora australiensis (Playford and Helby) Jones and Truswell and
the absence of pollen grains. The samples collected in the uppermost level of this unit, contain some of
spores typical of the Upper Carboniferous of Argentina and Brazil, although pollen grains are still absent.
Cortaderas Formation in the Río Blanco Basin, northwestern Argentina. The geological setting and stratigraphic
provenance of the samples is provided. In this first part, fifty-two species are described from a total
of seventy-eight species of spores recognized. Five new species are proposed: Verrucosisporites incompositus
sp. nov., Verrucosisporites perbrevis sp. nov., Anapiculatisporites exiguus sp. nov., Anapiculatisporites
expolitus sp. nov. and Dibolisporites insolitus sp. nov. Previous worldwide geographic and stratigraphic
records of taxa are detailed.
magnidictyus-Verrucosisporites quasigobbettii (MQ) Interval Biozone. The base of the biozone is defined by the range bases of
Apiculiretusispora microseta, Dibolisporites disfacies, Reticulatisporites magnidictyus, Rugospora australiensis, and Verrucosisporites
quasigobbettii. The upper limit of the MQ Interval Biozone is marked by the appearance of monosaccate pollen. Two distinct associations
are recognized; Association A is characterized by the range bases of the diagnostic species, and the presence of a group of long-ranging
species. Association B is characterized by the range bases of Anapiculatisporites austrinus, Anapiculatisporites kekiktukensis, Apiculatisporis
variornatus, Crassispora kosankei, Cristatisporites menendezii, Kraeuselisporites tendatus, Kraeuselisporites volkheimerii, Raistrickia
paganciana, Raistrickia rotunda, and Spinozonotriletes hirsutus, and is represented in the upper part of the Cortaderas Formation.
province (Argentina). The specimens include vegetative and fertile characters that allow the definition of a new genus and species: Gondwanites
subtilis. They are characterized by slender branches bearing whorls of very thin, simple or divided leaves. Simple fertile organs are borne in
whorls just below the verticel of leaves. The presence of dichotomized leaves and bractless fertile organs in the new taxon suggests its probable
primitive condition.