Ana Karina Scomazzon | Universidade Federal do Rio Grande do Sul (original) (raw)

Papers by Ana Karina Scomazzon

Research paper thumbnail of Associações naturais de conodontes Mesogondolella spp., Grupo Itararé, Cisuraliano da Bacia do Paraná

NATURAL ASSOCIATIONS OF MESOGONDOLELLA SPP. CONODONTS, ITARARÉ GROUP, CISURALIAN OF PARANÁ BASIN.... more NATURAL ASSOCIATIONS OF MESOGONDOLELLA SPP. CONODONTS, ITARARÉ GROUP, CISURALIAN OF PARANÁ BASIN. Conodonts are primitive chordates
which lived during the Paleozoic up to their complete extinction at the Triassic. Exclusively marine, they are widely used in biostratigraphic
studies and in studies about vertebrates’ evolution, nowadays, in a new bias, with the discoveries of natural associations of multi-element that
helps to better understand the evolutionary mechanisms of the first vertebrates and the paleobiology of this group. Researchers from the Earth
and Life Museum of the Paleontological Center in the Contestado University (CENPALEO) found tens of ramiform elements near Mafra, southern
Brazil, which macroscopically were similar with porifera spicule, common in the outcrops of the region. After a more detailed analysis, these elements
were identified as conodonts feeding apparatuses, in general complete and well-preserved. This article describes the feeding apparatuses
of conodonts of the first occurrence of conodonts in the Paraná Basin. They represent gondolelids conodonts belonging to the Mesogondolella
genus, a well-known Cisuralian marker. It is also discussed the faunas of these primitive chordate, according to the natural associations found in
the Lontras Shale, Itararé Group, Paraná Basin.

Research paper thumbnail of Taphofacies of Lower-Middle Pennsylvanian marine invertebrates from the Monte Alegre and Itaituba formations, part of the outcropped marine sequence of the Tapaj os Group (Southern Amazonas Basin, Brazil) e regional palaeoecological models

One of the most relevant characteristics of the Pennsylvanian shallow-water carbonates of the Ama... more One of the most relevant characteristics of the Pennsylvanian shallow-water carbonates of the Amazonas Basin is its diverse and well preserved invertebrate fossiliferous assemblages. In order to better understand the origin of these fossil concentrations, taphonomic data were obtained along well exposed areas of the uppermost part of the Monte Alegre Formation and basal part of the Itaituba Formation, which, based on conodonts, fusulinids and palynomorphs is of Atokan age. The taphonomic data focused on invertebrate organisms were supported by petrographic analysis. The understanding of the stacking pattern of the strata in the studied section allowed the identification of five type taphofacies, which contributed in the development of regional palaeoecological models, expressed as block-diagrams. These characterize the distribution of the environmental parameters, the composition of the faunal associations and the distribution and amplitude of the taphonomic processes that created the taphonomic signatures of the bioclastic elements throughout the supratidal to lower intertidal/deep subtidal depositional environments pertinent to the studied depositional environment. The regional palaeoecological models here presented are related to the particularities of the depositional environments of the studied rocks and are exclusive for the characterization of this intracratonic basin set influenced by high frequency climatic variations. Lithofacies, biofacies and taphofacies associations also reflect depositional conditions pertinent to the studied regional context, differing from the elements observed in modern intracratonic contexts analogous to the one studied, from different sedimentary basins around the world. Therefore, invertebrate taphonomy, supported by the analysis of sedimentary facies, fulfills the purposes recommended in this work, demonstrating its potential as a tool for palaeoecological analysis in the Penn-sylvanian outcropping section in the southern platform of the Amazonas Basin.

Research paper thumbnail of Conodont biostratigraphy and paleoecology of the marine sequence of the Tapajos Group, Early-Middle Pennsylvanian of Amazonas Basin, Brazil

Research paper thumbnail of Conodont color alteration index and upper Paleozoic thermal history of the Amazonas Basin, Brazil

The conodont color alteration index (CAI) was determined in elements from core samples of the Fra... more The conodont color alteration index (CAI) was determined in elements from core samples of the Frasnian
Barreirinha Formation (one well) and of the PennsylvanianePermian Tapajos Group (twenty three wells
and one limestone quarry) in the Amazonas Basin. The thermal history of the basin is analyzed using the
CAI value distribution represented in maps and stratigraphic sections through correlation schemes, and
in conjunction with previously published data. The pattern of palaeotemperatures for CAI values of 1.5e3
is coincident with organic matter maturation under a sedimentary overburden providing diagenetic
conditions in the oil/gas window. Locally, conodonts show metamorphism (CAI value of 6e7) in relation
to the intrusion of diabase bodies in beds including high geothermal gradient evaporites. Microtextural
alteration on the surface conodonts commonly shows several types of overgrowth microtextures
developed in diagenetic conditions. Locally, recrystallization in conodonts with a high CAI value is
congruent with contact metamorphism in relation to Mesozoic intrusions. The CAI values of 1.5 or 2
observed close to the surface in several areas of the basin may be interpreted in relation to a high thermal
palaeogradient derived from the magmatic episode or/and to the local denudation of the upper part of
the Paleozoic succession prior to this thermal event.

Research paper thumbnail of Frasnian conodonts at high palaeolatitude (Amazonas Basin, north Brazil)

Palaeogeography, Palaeoclimatology, Palaeoecology, 2015

Research paper thumbnail of First occurrence of Ellisonia, Gondolella and Ubinates (Conodonts) in Itaituba Formation, Pennsylvanian of Amazonas Basin, Brazil

Gaea - Journal of Geoscience, 2010

Research paper thumbnail of Biochronostratigraphy (conodonts and palynology) from a selected strata of the Itaituba Formation (Pennsylvanian of the Amazonas Basin) at Itaituba, Pará State, Brazil

Research paper thumbnail of Bioestratigrafia e paleoecologia com base em conodontes em uma seção de carbonatos marinhos do Pensilvaniano inferior, Formação Itaituba, borda sul da Bacia do Amazonas, Brasil

Research paper thumbnail of CONODONT BIOSTRATIGRAPHY OF THE LOWER ITAITUBA FORMATION (ATOKAN, PENNSYLVANIAN), AMAZONAS BASIN, BRAZIL

Research paper thumbnail of Diplognathodus occurrence in the Itaituba Formation, Amazonas Basin, Brazil

Revista Brasileira De Paleontologia - REV BRAS PALEONTOLOGIA, 2005

Research paper thumbnail of Carboniferous Biochronostratigraphy of the Amazonas Basin, Brazil, Based on Conodonts

Research paper thumbnail of Associações naturais de conodontes Mesogondolella spp., Grupo Itararé, Cisuraliano da Bacia do Paraná

NATURAL ASSOCIATIONS OF MESOGONDOLELLA SPP. CONODONTS, ITARARÉ GROUP, CISURALIAN OF PARANÁ BASIN.... more NATURAL ASSOCIATIONS OF MESOGONDOLELLA SPP. CONODONTS, ITARARÉ GROUP, CISURALIAN OF PARANÁ BASIN. Conodonts are primitive chordates
which lived during the Paleozoic up to their complete extinction at the Triassic. Exclusively marine, they are widely used in biostratigraphic
studies and in studies about vertebrates’ evolution, nowadays, in a new bias, with the discoveries of natural associations of multi-element that
helps to better understand the evolutionary mechanisms of the first vertebrates and the paleobiology of this group. Researchers from the Earth
and Life Museum of the Paleontological Center in the Contestado University (CENPALEO) found tens of ramiform elements near Mafra, southern
Brazil, which macroscopically were similar with porifera spicule, common in the outcrops of the region. After a more detailed analysis, these elements
were identified as conodonts feeding apparatuses, in general complete and well-preserved. This article describes the feeding apparatuses
of conodonts of the first occurrence of conodonts in the Paraná Basin. They represent gondolelids conodonts belonging to the Mesogondolella
genus, a well-known Cisuralian marker. It is also discussed the faunas of these primitive chordate, according to the natural associations found in
the Lontras Shale, Itararé Group, Paraná Basin.

Research paper thumbnail of Taphofacies of Lower-Middle Pennsylvanian marine invertebrates from the Monte Alegre and Itaituba formations, part of the outcropped marine sequence of the Tapaj os Group (Southern Amazonas Basin, Brazil) e regional palaeoecological models

One of the most relevant characteristics of the Pennsylvanian shallow-water carbonates of the Ama... more One of the most relevant characteristics of the Pennsylvanian shallow-water carbonates of the Amazonas Basin is its diverse and well preserved invertebrate fossiliferous assemblages. In order to better understand the origin of these fossil concentrations, taphonomic data were obtained along well exposed areas of the uppermost part of the Monte Alegre Formation and basal part of the Itaituba Formation, which, based on conodonts, fusulinids and palynomorphs is of Atokan age. The taphonomic data focused on invertebrate organisms were supported by petrographic analysis. The understanding of the stacking pattern of the strata in the studied section allowed the identification of five type taphofacies, which contributed in the development of regional palaeoecological models, expressed as block-diagrams. These characterize the distribution of the environmental parameters, the composition of the faunal associations and the distribution and amplitude of the taphonomic processes that created the taphonomic signatures of the bioclastic elements throughout the supratidal to lower intertidal/deep subtidal depositional environments pertinent to the studied depositional environment. The regional palaeoecological models here presented are related to the particularities of the depositional environments of the studied rocks and are exclusive for the characterization of this intracratonic basin set influenced by high frequency climatic variations. Lithofacies, biofacies and taphofacies associations also reflect depositional conditions pertinent to the studied regional context, differing from the elements observed in modern intracratonic contexts analogous to the one studied, from different sedimentary basins around the world. Therefore, invertebrate taphonomy, supported by the analysis of sedimentary facies, fulfills the purposes recommended in this work, demonstrating its potential as a tool for palaeoecological analysis in the Penn-sylvanian outcropping section in the southern platform of the Amazonas Basin.

Research paper thumbnail of Conodont biostratigraphy and paleoecology of the marine sequence of the Tapajos Group, Early-Middle Pennsylvanian of Amazonas Basin, Brazil

Research paper thumbnail of Conodont color alteration index and upper Paleozoic thermal history of the Amazonas Basin, Brazil

The conodont color alteration index (CAI) was determined in elements from core samples of the Fra... more The conodont color alteration index (CAI) was determined in elements from core samples of the Frasnian
Barreirinha Formation (one well) and of the PennsylvanianePermian Tapajos Group (twenty three wells
and one limestone quarry) in the Amazonas Basin. The thermal history of the basin is analyzed using the
CAI value distribution represented in maps and stratigraphic sections through correlation schemes, and
in conjunction with previously published data. The pattern of palaeotemperatures for CAI values of 1.5e3
is coincident with organic matter maturation under a sedimentary overburden providing diagenetic
conditions in the oil/gas window. Locally, conodonts show metamorphism (CAI value of 6e7) in relation
to the intrusion of diabase bodies in beds including high geothermal gradient evaporites. Microtextural
alteration on the surface conodonts commonly shows several types of overgrowth microtextures
developed in diagenetic conditions. Locally, recrystallization in conodonts with a high CAI value is
congruent with contact metamorphism in relation to Mesozoic intrusions. The CAI values of 1.5 or 2
observed close to the surface in several areas of the basin may be interpreted in relation to a high thermal
palaeogradient derived from the magmatic episode or/and to the local denudation of the upper part of
the Paleozoic succession prior to this thermal event.

Research paper thumbnail of Frasnian conodonts at high palaeolatitude (Amazonas Basin, north Brazil)

Palaeogeography, Palaeoclimatology, Palaeoecology, 2015

Research paper thumbnail of First occurrence of Ellisonia, Gondolella and Ubinates (Conodonts) in Itaituba Formation, Pennsylvanian of Amazonas Basin, Brazil

Gaea - Journal of Geoscience, 2010

Research paper thumbnail of Biochronostratigraphy (conodonts and palynology) from a selected strata of the Itaituba Formation (Pennsylvanian of the Amazonas Basin) at Itaituba, Pará State, Brazil

Research paper thumbnail of Bioestratigrafia e paleoecologia com base em conodontes em uma seção de carbonatos marinhos do Pensilvaniano inferior, Formação Itaituba, borda sul da Bacia do Amazonas, Brasil

Research paper thumbnail of CONODONT BIOSTRATIGRAPHY OF THE LOWER ITAITUBA FORMATION (ATOKAN, PENNSYLVANIAN), AMAZONAS BASIN, BRAZIL

Research paper thumbnail of Diplognathodus occurrence in the Itaituba Formation, Amazonas Basin, Brazil

Revista Brasileira De Paleontologia - REV BRAS PALEONTOLOGIA, 2005

Research paper thumbnail of Carboniferous Biochronostratigraphy of the Amazonas Basin, Brazil, Based on Conodonts