Abstract
The Araguaia Plain has extensive areas of savannah scattered forest fragments similar to circular depressions. These features, in addition to serving as corridors, could be associated with important features such as karsts, closed-water connection structures and ecological-type formations. To identify this relationship and contribute to the understanding of its genesis, this study has as its main objective the morphometric analysis of doliniform functions in the Araguaia Plain. Through the geoenvironmental characterization of the study area; digital facility models – SRTM; interpretation of Sentinel 2-A satellite images from 2019 to 2020; and calculation of morphometric variables: area, perimeters, activity, altitude, length and density, Kernel circularity index. A total of 24,023 doliniform features associated with green/healthy vegetation were identified in a Coverage Area of 114,900 km2, Concentrated Majoritariate in the Brazilian municipalities of Lagoa da Confusão -Tocantins; Pium-Tocantins and Cocalinho-Mato Grosso. The features showed circular superiority areas up to 10 km2, circular activity indexes at 0.5 and up to 1 and 1.5, indicating a predominance of circular shapes on slopes of 3% in the NE orientation. Based on the results, it can be verified that these features present sinkholes, as they may be under the influence of patterns associated with some processes, denoting in some processes the existence of a covered karst
Keywords
Mapping; Sinkholes; Karst; Forest fragments
Resumo
A Planície do Araguaia apresenta extensas áreas de savanas com dispersos fragmentos florestais localizados sobre depressões circulares. Estas feições além de servirem como importantes corredores ecológicos, poderiam estar associadas a formações cársticas do tipo dolinas, estruturas fechadas de conexão das águas superficiais e subterrâneas. Para identificar esta relação e contribuir o entendimento da sua gênese, este estudo tem como objetivo principal o mapeamento e análise morfométrica de feições doliniformes na Planície do Araguaia. Por meio da caracterização geoambiental da área de estudo; modelos de elevação digital – SRTM; interpretação de imagens do satélite Sentinel 2-A do período de 2019 a 2020; e cálculo das variáveis morfométricas: área, perímetro, declividade, altitude, coeficiente de alongamento, índice de circularidade e densidade de Kernel. Foram identificadas 24.023 feições doliniformes associadas à vegetação verde/sadia em área de abrangência de 114.900 km2, concentradas majoritariamente nos municípios de Lagoa da Confusão – TO, Pium – TO e Cocalinho – MT. As feições apresentaram áreas de até 10 km2, índices de circularidade superiores a 0,5 e coeficientes de alongamento entre 1 e 1,5, indicando uma predominância de formas circulares em declividades de até 3% na orientação NE. Com base nos resultados, pode-se inferir que estas feições apresentam formas de dolinas, as quais podem estar sob influência de controles estruturais e associadas a processos cársticos, denotando em alguns lugares a existência de um carste encoberto.
Palavras-chave:
Mapeamento; Dolinas; Carste; Fragmentos florestais
INTRODUCTION
Doliniform features are depressions in the terrain with slightly steep slopes in a circular or oval shape caused by the subsidence of the soil. These features can occur in the form of lagoons, sinkholes or delves with or without vegetation. (SCRAGE; UAGODA, 2017).
Doliniform forest fragments popularly known as “ipucas” or “impucas” occur in extensive savannah areas in the Araguaia Plain and represent the main characteristic of the regional landscape (BRASIL, 1981aBRASIL. Projeto RADAMBRASIL. Folha SC. 22. Tocantins: Geologia, geomorfologia, pedologia, vegetação e uso potencial da terra. Ministério das Minas e Energia. Secretaria Geral. Rio de Janeiro, p. 524. 1981a.; MARTINS et al., 2006MARTINS. A.K.E. et al. Relações solo-geoambiente em áreas de ocorrência de ipucas na Planície do Médio Araguaia - Estado de Tocantins. Revista Árvore. v. 30, n. 2 p. 297-310. 2006 https://doi.org/10.1590/S0100-67622006000200017
https://doi.org/10.1590/S0100-6762200600...
). However, the origin of these features has not been fully understood in the geomorphological and geological aspect, most studies of these features are associated with phytosociological (disciplinary) or environmental (interdisciplinary) characterization (MANCHOLA et al., 2021MANCHOLA et al. Abordagem interdisciplinar dos conceitos relacionados a depressões doliniformes na Planície do Araguaia, Brasil. Revista Gaia Scientia, v. 15, n. 2, p. 24-44. 2021. https://doi.org/10.22478/ufpb.1981-1268.2021v15n2.52098
https://doi.org/10.22478/ufpb.1981-1268....
).
These features function, in the floodplain, as important ecological corridors for endemic species in the transition area of the Cerrado and Amazonian biomes (ROCHA et al., 2014ROCHA, R. G. et al. Seasonally flooded stepping stones: emerging diversity of small mammal assemblage in the Amazonia-Cerrado ecotone, central Brazil. Zoological Studies, vl. 53. n. 1, p. 1-10. 2014. https://doi.org/10.1186/s40555-014-0060-0
https://doi.org/10.1186/s40555-014-0060-...
), a range considered as the largest tropical ecotone in the world (TORELLO-RAVENTOS et al., 2013TORELLO-RAVENTOS. M. et al. On the delineation of tropical vegetation types with an emphasis on forest/savanna transitions. Plant Ecology & Diversity, v. 6, n. 1, p. 101-137. 2013. https://doi.org/10.1080/17550874.2012.762812
https://doi.org/10.1080/17550874.2012.76...
).
In addition to their ecological importance, these features also occur in the region in the form of dolines, surface forms of the karst system generated by the dissolution of carbonate rocks, but their lithostratigraphic characterization lacks more detailed studies on the local geological profile that corroborate the possible karst genesis of these depressions (HARDT, 2005HARDT, R. Considerações geomorfológicas sobre o carste de Cocalinho - MT. Anais do XXVIII Congresso Brasileiro de Espeleologia. p. 66-76. Sociedade Brasileira de Espeleologia. 2005. Disponível em: http://www.cavernas.org.br/anais28cbe/28cbe_066-076.pdf . Acesso em: 2 jun. 2022.
http://www.cavernas.org.br/anais28cbe/28...
; MORAIS, 2017MORAIS, F. Classificação morfológica das dolinas da região de Lagoa da Confusão - TO. In: Anais do 34º Congresso Brasileiro de Espeleologia. Ouro Preto-MG: Sociedade Brasileira de Espeleologia. p. 283-287. 2017. Disponível em: https://www.cavernas.org.br/wp-content/uploads/2021/07/34cbe_283-287.pdf Acesso em: 1 mai. 2022.
https://www.cavernas.org.br/wp-content/u...
). Dolines are considered essential units of exokarst relief, as they function as a connection between surface and underground water flows (FORD; WILLIAMS, 2007FORD. D e WILLIAMS P. Karst Hydrogeology and Geomorphology. 2 ed. West Sussex, England: John Wiley & Sons. 2007. https://doi.org/10.1002/9781118684986
https://doi.org/10.1002/9781118684986...
). The occurrence of these karst depressions in areas of intense anthropogenic alteration accelerates the dissolution processes and enhances the risks of contamination of aquifers, the collapse of structures or buildings and increased erosion processes (GUTIÉRREZ et al., 2014GUTIÉRREZ, F., et al. A review on natural and human-induced geohazards and impacts in karst. Earth-Science Reviews, 2014. v. 138, p. 61-88. https://doi.org/10.1016/j.earscirev.2014.08.002
https://doi.org/10.1016/j.earscirev.2014...
).
The first geomorphological studies to characterize doliniform features along the Araguaia Plain date back to 1981, and were carried out by the RADAMBRASIL project, described in Sheets SB-22, SC-22 and SD-22. In these, closed circular or oval depressions, seasonally flooded (temporary ponds from rainwater), are described on soils of the Gley Low Humic type with a high content of organic material that favor the emergence of Gallery Forest fragments. Such features are also characterized as patches of vegetation in the savannah landscape of the Cerrado (dity field), formations considered the most representative of the Flood Accumulation Areas - Faa (BRASIL, 1981aBRASIL. Projeto RADAMBRASIL. Folha SC. 22. Tocantins: Geologia, geomorfologia, pedologia, vegetação e uso potencial da terra. Ministério das Minas e Energia. Secretaria Geral. Rio de Janeiro, p. 524. 1981a.; 1981bBRASIL. Projeto RADAMBRASIL. Folha SD. 22. Goiás: Geologia, geomorfologia, pedologia, vegetação e uso potencial da terra. Ministério das Minas e Energia. Secretaria Geral. Rio de Janeiro, p. 639. 1981b.).
The aforementioned project also highlights the difference between lake systems with circular, oval or straight features in the Fluvial Plain (Apf) that are associated with the water dynamics of the Araguaia River. These lakes are formed by alluvial deposits resulting from vertical accretion processes of sandy sediments in marginal dikes, paleochannels or in abandoned meanders of the main channel and tributaries (BRASIL, 1981aBRASIL. Projeto RADAMBRASIL. Folha SC. 22. Tocantins: Geologia, geomorfologia, pedologia, vegetação e uso potencial da terra. Ministério das Minas e Energia. Secretaria Geral. Rio de Janeiro, p. 524. 1981a.).
These circular depressions in the Araguaia floodplain were also identified in exploratory missions by French and Brazilian researchers in the region of Cocalinho – Mato Groso - Brazil (southwest of the Plain), near the das Mortes river (a tributary of the Araguaia river). In this region, karst features such as sinkholes were identified in the form of lakes up to 1 km long and 5 m deep, in addition to delves with high speleological potential (SOUBIES; GUYOT, 1995SOUBIES, F.; GUYOT, J. L. Compte Rendu de Mission dans la Région du Rio das Mortes (Mato Grosso) du 5 au 8 Septembre 1995. ORSTOM Brasília. 1995.).
In this way, the identification and subsequent planning of sustainable use of areas prone to the occurrence of sinkholes can prevent potential economic, environmental and social damage. Therefore, it is necessary to map its morphometric characteristics, geological structure and spatial dispersion (WU et al., 2016WU. Q. et al. Automated delineation of karst sinkholes from LiDAR-derived digital elevation models. Geomorphology. v. 266, p. 1-10. 2016. https://doi.org/10.1016/j.geomorph.2016.05.006
https://doi.org/10.1016/j.geomorph.2016....
).
Due to the environmental importance of the Araguaia Plain and based on the hypothesis that the doliniform forest formations under the name of ipuca and impuca are similar to sinkholes in their shape. This work intends to contribute, from the geomorphological point of view, to the understanding of its morphostructure, through the mapping of doliniform features and the analysis of the most used morphometric parameters in studies of karst depressions.
Characterization of the study area
The Araguaia Plain is located in the central portion of Brazil, covering parts of the states of Pará, Tocantins, Mato Grosso and Goiás and occupies an area of approximately 64,761 km2 (Figure 1).
Its hydrography is constituted by the Araguaia river basin, considered the main drainage network of the Brazilian savannah, with an average annual flow of 6,420 m3/s, in which the Formoso and Javaés rivers stand out as the main tributaries, with average flows between 110 and 680 m3/s, respectively, in the state of Tocantins; and the das Mortes river in the western portion with an average flow of 899 m3/s in the state of Mato Grosso (LATRUBESSE; TEVAUX, 2002; AQUINO et al., 2009AQUINO. S.; LATRUBESSE, E. M.; DE SOUZA FILHO, E. E. Caracterização hidrológica e geomorfológica dos afluentes da Bacia do Rio Araguaia. Revista Brasileira de Geomorfologia. v. 10. n. 1, 2009. https://doi.org/10.20502/rbg.v10i1.116
https://doi.org/10.20502/rbg.v10i1.116...
).
The Araguaia basin is characterized by the presence of lakes, ponds and abandoned meanders formed, in part, by the seasonal flooding that occurs in the rainy season from November to May with annual precipitation between 1,400 and 2,200 mm/year (CARVALHO; ATRUBESSE, 2004CARVALHO. T. M.; LATRUBESSE, E. M. Aplicação de modelos digitais do terreno (MDT) em análises macrogeomorfológicas: o caso da bacia hidrográfica do Araguaia. Revista Brasileira de Geomorfologia. v. 5. n. 1, 2004. https://doi.org/10.20502/rbg.v5i1.34
https://doi.org/10.20502/rbg.v5i1.34...
; VALENTE; LATRUBESSE, 2012VALENTE, C. R.; LATRUBESSE, E. M. Fluvial archive of peculiar avulsive fluvial patterns in the largest Quaternary intracratonic basin of tropical South America: the Bananal Basin, Central-Brazil. Palaeogeography, Palaeoclimatology, Palaeoecology, vol. 356, p. 62-74, 2012. https://doi.org/10.1016/j.palaeo.2011.10.002
https://doi.org/10.1016/j.palaeo.2011.10...
).
The groundwater resources in this area are related to the deposition of Quaternary sediments distributed along the Araguaia Belt. Of these, the most representative corresponds to the porous Araguaia-Bananal aquifer, which represents 85% of the entire Araguaia Plain with flows that vary between 1 and 10 m3/h depending on the rainfall regime (ANA, 2013; CPRM, 2016CPRM. Projeto de Disponibilidade Hídrica do Brasil - Carta Hidrogeológica - Escala 1:1.000.000, Folha Sd.22 Goiás. 2016).
These morphoclimatic characteristics together with the low slope (less than 7%) and reduced surface runoff (predominance of flattened forms) provide the occurrence of extensive zones of fluvial accumulation and sedimentation processes by vertical accretion, favoring the formation of fluvial plains that vary from 200 to 220 m altitude and slope equal to or less than 5% consisting predominantly of grassy fields on Plinthosols with low water percolation and expressive plinthic horizon (BARBOSA et al., 2011BARBOSA, D. C. et al. Estrutura da vegetação lenhosa em dois fragmentos naturais de florestas inundáveis (impucas) no Parque Estadual do Araguaia, Mato Grosso. Revista Árvore, Viçosa-MG, v. 35, n. 3, p. 457-471, 2011. https://doi.org/10.1590/S0100-67622011000300009
https://doi.org/10.1590/S0100-6762201100...
; BAYER; ZANCOPÉ, 2014BAYER. M.; ZANCOPÉ, M. H. Ambientes sedimentares da planície aluvial do rio Araguaia. Revista Brasileira de Geomorfologia. v. 15, n. 2. 2014. https://doi.org/10.20502/rbg.v15i2.414
https://doi.org/10.20502/rbg.v15i2.414...
; EMBRAPA, 2018EMBRAPA. Sistema brasileiro de classificação de solos. Embrapa Solos: 5 Ed, rev. e ampl. Brasília-DF, 2018.).
The relief forms of the Araguaia Plain are associated with an agradational system of deposition of Quaternary sediments classified into two dominant geomorphological units, Flood Plains – Fa and Fluvial Plains – Fp (Figure 1).
Floodplains are characterized by converging planes of sandy or clayey sediments with reduced surface runoff that are subject to flooding during the rainy season, which partly favors the emergence of a dispersed lacustrine system with lakes associated with savannah vegetation or closed depressions disassociated from the direct influence of the main channel (BRASIL, 1981aBRASIL. Projeto RADAMBRASIL. Folha SC. 22. Tocantins: Geologia, geomorfologia, pedologia, vegetação e uso potencial da terra. Ministério das Minas e Energia. Secretaria Geral. Rio de Janeiro, p. 524. 1981a.; 1981bBRASIL. Projeto RADAMBRASIL. Folha SD. 22. Goiás: Geologia, geomorfologia, pedologia, vegetação e uso potencial da terra. Ministério das Minas e Energia. Secretaria Geral. Rio de Janeiro, p. 639. 1981b.).
On the other hand, the Fluvial Plains are formed by the fluvial dynamics of the main channel and, according to Latrubesse and Stevaux (2002)LATRUBESSE, E. M.; STEVAUX, J. C. Geomorphology and environmental aspects of the Araguaia fluvial basin, Brazil. Zeitschrift für Geomorphologie. Supplementband. n. 129, p. 109-127. 2002., can be subdivided into three geomorphological units:
I – Impeded flow plain: swampy regions occasionally flooded and dammed (back swamp) with slightly undulating topography and distant from the main channel. They feature expressive lakes associated with medium to large vegetation;
II – Paleomeander Plain: Topographically positioned between the impeded flow plain and the plain of islands, it is characterized by intense depositional flood processes, favoring the development of sinuous thalwegs on the banks of the main channel in a spiral, elongated or half-moon lagoons.
III – Plain with added islands/bars: irregular and narrow surface, supported by a sandy platform, positioned parallel to the main channel and characterized by its high capacity for receiving sediments from the Araguaia River.
Regard to the rocky substratum of the Araguaia Plain, this is mostly characterized by Holocene alluvial deposits, which accompany the drainage network, composing a mosaic of Quaternary morphosedimentary structures from the Holocene and Upper Pleistocene, located to the north, between the Amazonian Craton and the Araguaia Belt; and to the south, by extensive Cenozoic covers of the Bananal Sedimentary Basin (BIZZI et al., 2003BIZZI, L. A., et al. Geologia, tectônica e recursos minerais do Brasil. Texto, Mapas e SIG. Brasília, CPRM, Serviço Geológico do Brasil. 2003.; CPRM, 2008CPRM. Geologia do Estado de Goiás e do Distrito Federal. Programa geologia e mineração - Geração e Disponibilização de Informações Geológicas e do Potencial Mineral de Goiás. Goiânia, 2008.).
In the northern sector of the plain, between the cities of Conceição do Araguaia - PA and Caseara - TO, there are outcrops of crystalline and Neoproterozoic rocks, associated with the Couto Magalhães Formation, Tocantins Group, consisting of phyllites, slates, quartz and limestones (IBGE, 2008aIBGE - Instituto Brasileiro de Geografia e Estadística. Carta de Geologia do Estado do Pará. Escala 1:1.800.000. Diretoria de Geociência. 2008a.).
In the central region, in the segment that includes the entire Bananal Island, the Quaternary formations cover most of the area, extending for approximately 800 km between the cities of Caseara, Totantins and Registro do Araguaia – Goiás. They present a tectonic alignment parallel to the flow of the Araguaia river in the north-south direction (NS), showing a certain structural control in their orientation (BRASIL, 1981aBRASIL. Projeto RADAMBRASIL. Folha SC. 22. Tocantins: Geologia, geomorfologia, pedologia, vegetação e uso potencial da terra. Ministério das Minas e Energia. Secretaria Geral. Rio de Janeiro, p. 524. 1981a.). Alignments in the NS direction were also identified in the central region of the Plain in lithostructural characterization studies using satellite images, where foliations oriented in this direction are associated with recent formations of “Neoproterozoic deformation events” in the Araguaia belt (LEANDRO et al., 2011LEANDRO et al. Sensoriamento remoto aplicado a análise estrutural da faixa Araguaia-região de Guaraí-TO. Anais XV Simpósio Brasileiro de Sensoriamento Remoto. p. 3589-3596. 2011. Disponível em: http://marte.sid.inpe.br/col/dpi.inpe.br/marte/2011/07.20.14.50/doc/p1343.pdf. Acesso em: 8 jun. 2022.
http://marte.sid.inpe.br/col/dpi.inpe.br...
). Its lithology is constituted predominantly by Cenozoic coverings of sandy sediments belonging to Holocene alluvium and; by sand-clay packages of varied colors with an advanced stage of lateralization of the Bananal Formation (IBGE, 2008bIBGE - Instituto Brasileiro de Geografia e Estadística. Carta de Geologia do Estado do Tocantins. Escala 1:1.800.000. Diretoria de Geociências. 2008b.; AQUINO et al., 2009AQUINO. S.; LATRUBESSE, E. M.; DE SOUZA FILHO, E. E. Caracterização hidrológica e geomorfológica dos afluentes da Bacia do Rio Araguaia. Revista Brasileira de Geomorfologia. v. 10. n. 1, 2009. https://doi.org/10.20502/rbg.v10i1.116
https://doi.org/10.20502/rbg.v10i1.116...
).
In addition to the Cenozoic covers, outcrops of the Couto Magalhães Formation of the Tocantins Group are also identified in some portions of the flood plain, consisting of detritus-laterite covers, limestone intercalations and sericitic quartzites (BRASIL, 1981aBRASIL. Projeto RADAMBRASIL. Folha SC. 22. Tocantins: Geologia, geomorfologia, pedologia, vegetação e uso potencial da terra. Ministério das Minas e Energia. Secretaria Geral. Rio de Janeiro, p. 524. 1981a.). Paixão and Gorayeb, (2014)PAIXÃO, M. A. P.; GORAYEB, P. S. S. Metalogênese da Faixa Araguaia. In: SILVA, M. G. et al. Metalogênese das províncias tectônicas brasileiras, p. 468-488. Belo Horizonte: CPRM. 2014., prospecting mineral deposits in the central sector of the Araguaia Plain, add that the Tocantins Group is characterized by presenting slates, metasilithites, metacorses and metagrauvacas, phyllites, metarenites and metalimestones.
In the southern sector, in the segment located on the border between the states of Tocantins and Goiás, the Cenozoic alluvial deposits of the Bananal Basin predominate, consisting mainly of clayey-silitic-sandy and fluvial-lacustrine sediments (LACERDA FILHO et al., 2004). In the extreme southwest, in the higher areas related to a portion of the Araguaia Depression, metavolcanic and metasedimentary rocks from the Neoproterozoic are also found, on silicate, iron and carbonate rocks (SOUSA et al., 2019SOUSA et al., Evolução geológica do domínio interno da Faixa Paraguai na região de Nova Xavantina, leste de Mato Grosso. Geociências, v. 38. n. 4, p. 837-851, 2019. https://doi.org/10.5016/geociencias.v38i4.13581
https://doi.org/10.5016/geociencias.v38i...
). In this sense, Lima et al. (2008)LIMA et al. Avaliação de Rochas Calcárias e Fosfatadas para Insumos Agrícolas do Estado de Mato Grosso. Cuiabá: CPRM; METAMAT, p.178, 2008. point out that the outcrop of carbonate rocks in the south of the Araguaia plain is evidenced by the intense exploitation of limestone in the municipality of Nova Xavantina, in the state of Mato Grosso indicating the high occurrence of dolomites, calcitic marbles, calcarenites, calcisiltites and clayey metamargas belonging to the Cuiabá Group.
Due to its geographical location, the Araguaia Plain has a high diversity of species, as it is located in a transition zone between the Amazon and Cerrado biomes, providing contact between different ecological communities and the occurrence of endemic species and species adapted to flooding regimes from the seasonal alluvial semideciduous forest, cerradão and savannah park phytophysiognomies. This particularity of the region characterizes the region as an important area of environmental preservation, in which the Cantão State Park, the Araguaia National Park, the Araguaia Indigenous Park (Avá-Canoeiro, Iny Karajá, Javaé and Tapirapé peoples) stand out; and the Pimentel Barbosa and Wedezé Indigenous Lands of the Xavante people (ASSIS et al., 2022ASSIS. P. C., et al. Unidades de Conservação e sua efetividade na proteção dos recursos hídricos na Bacia do Rio Araguaia. Sociedade & Natureza. v. 34. 2022. https://doi.org/10.14393/SN-v34-2022-60335
https://doi.org/10.14393/SN-v34-2022-603...
).
MATERIALS AND METHODS
Methods
To map the doliniform features, a mosaic of Sentinel 2-A satellite images from the period from 2019 to 2020 in the months of July to October with low cloud cover and contemplating the entire inner perimeter of the Araguaia Plain was used. With these images, it was possible to determine the vegetation associated with the depressions through the supervised classification of the composition of the color bands B8 (infrared near 10 m resolution), B11 (shortwave infrared of 20 m resolution) and B4 (red of 10 m resolution).
The identification of doliniform features was carried out considering all circular shapes of the electromagnetic spectrum greater than 500 m2 resulting from the combination of bands (B4, B8, B11) and supervised classification associated with bodies of water and healthy green vegetation. The validation of the shape was compared to Google Earth images to ratify the meanings of the shapes (Figure 2).
A Digital Terrain Model was generated to observe the altimetry characteristics and confluences of the watercourses in the region through an SRTM image (Shuttle Radar Topography Mission) with a resolution of 30 m. Hypsometric, slope and orientation maps of the slopes were prepared with the objective of analyzing the direction of the slopes and predominant forms that could influence the orientation of the doliniform features.
For the processing of raster images, as well as vector edition, preparation of morphometric calculations such as width, length, area, perimeter and orientation, the free software QGIS 3.4, Georose 0.5 and R Language and Environment for Statistical Computing 4.1.3 were used.
The extraction of the topographic dimensions of the doliniform depressions, in the horizontal profile, was carried out using the minimum bounding rectangle method. From these data, the most common coefficients of morphometric analysis of sinkholes were calculated, such as area, perimeter, width (W - width), length (L - length), elongation coefficient (ELG - Elongatedness), circularity index (C - Circularity Index), Nearest Neighbor Distance (DNI), feature orientation, and Kernel Density (BONDESAN et al., 1992BONDESAN et al. Morphometric analysis of dolines. International Journal of Speleology. v. 21. n. 1, p. 1. 1992. https://doi.org/10.5038/1827-806X.21.1.1
https://doi.org/10.5038/1827-806X.21.1.1...
; DENIZMAN, 2003DENIZMAN. C. A. N. Morphometric and spatial distribution parameters of karstic depressions, Lower Suwannee River Basin, Florida. Journal of Cave and Karst Studies, v. 65, n. 1, p. 29-35. 2003.; GAO et al., 2005GAO et al. Karst database implementation in Minnesota: analysis of sinkhole distribution. Environmental Geology. v. 47, n 8, p. 1083-1098. 2005. https://doi.org/10.1007/s00254-005-1241-2
https://doi.org/10.1007/s00254-005-1241-...
; BASSO et al., 2013BASSO. A., et al. Morphometric analysis of sinkholes in a karst coastal area of southern Apulia (Italy). Environmental Earth Sciences. v. 70, n. 6, p. 2545-2559. 2013. https://doi.org/10.1007/s12665-013-2297-z
https://doi.org/10.1007/s12665-013-2297-...
).
RESULTS
24,023 doliniform features were identified in an area of occurrence equivalent to 114,900 km2. Of these, the features located close to the city of Lagoa da Confusão – Tocantins, Brazil, associated with green/healthy vegetation, presence of water in areas of confluence greater than 800 m2 and low slope (Figure 3A) were validated in the field.
Spatial distribution of doliniform features in the Araguaia Plain. (A) Location of doliniform features in relation to the Araguaia Plain and area of occurrence; (B) Kernel Density Map of the occurrence of features.
By verifying the density of the doliniform features using the Kernel density map, it was possible to identify that the regions with the highest concentration (hotspots) correspond to the municipalities of Cocalinho, Luciara, Ribeirão Cascalheira, in the state of Mato Grosso; and Lagoa da Confusão and Pium, in the state of Tocantins (Figure 3B).
Of the 24,023 doliniform features identified in the area of occurrence, the main morphometric parameters were extracted and the highest frequency percentages were calculated (Table 1 and Figure 4).
Relative frequency of the main morphometric characteristics of the doliniform features in the Araguaia Plain.
The mean, minimum and maximum values of the morphometric parameters (Table 1) showed that there is a wide variability in the dimensions of doliniform features, with areas from 864 m2 to 10.03 km2. The largest ones (above 1 km2) correspond to lake features, such as Lagoa dos Magalhães, 3 km long, located in the municipality of São Felix do Araguaia, state of Mato Grosso; and the 2.5 km long Lagoa da Confusão in the municipality of Lagoa da Confusão, Tocantins.
Most features have an average size of 50,000 m2 for the area; 725 m perimeter; and width and length of 177 and 255 m, respectively. These values were also identified in works of morphometric analysis of lacustrine systems in the mid-Araguaia, during the dry period, and may increase in size by up to 100% during the flood period, depending on the degree of connectivity with the main channel and the drainage density of the channels from the plain (MORAIS et al., 2005MORAIS. R. P., et al. Morfometria de sistemas lacustres da planície aluvial do médio rio Araguaia. Acta Scientiarum. Biological Sciences. v. 27, n.3, p. 203-213. 2005. https://doi.org/10.4025/actascibiolsci.v27i3.1278
https://doi.org/10.4025/actascibiolsci.v...
).
With regard to shape, it was observed that more than 60% of the identified doliniform features have dimensions of less than 43,370 m2 with perimeters from 100 to 1000 meters (Figure 4C), axes (width and length) between 178 m (Figure 4A) and 335 m (Figure 4B). These features are mostly located in regions with slopes between 0 and 3% (Figure 4F) and at altitudes between 176 and 212 m (Figure 4E) with circularity indices between 0.8 and 1 (Figure 4G); and elongations between 1 and 1.5 (Figure 4H). Shapes with roundness and elongation indices close to 1 indicate, according to Basso et al., (2013)BASSO. A., et al. Morphometric analysis of sinkholes in a karst coastal area of southern Apulia (Italy). Environmental Earth Sciences. v. 70, n. 6, p. 2545-2559. 2013. https://doi.org/10.1007/s12665-013-2297-z
https://doi.org/10.1007/s12665-013-2297-...
and Denizman (2003)DENIZMAN. C. A. N. Morphometric and spatial distribution parameters of karstic depressions, Lower Suwannee River Basin, Florida. Journal of Cave and Karst Studies, v. 65, n. 1, p. 29-35. 2003., predominantly circular or oval features.
The average length of 206.42 m, circularity indices greater than 0.5; predominance of circular shapes (95.15% of features), were also identified in studies of morphometric analysis of doliniform features in the region of Lagoa da Confusão - TO, corroborating the predominance of circular or oval shapes identified in the Araguaia Plain (NASCIMENTO; MORAIS, 2012NASCIMENTO, P.; MORAIS, F. Análise morfométrica em Ipucas em carste encoberto na Depressão do Médio Araguaia, estado do Tocantins. In: Simpósio Nacional de Geomorfologia, 2012, Rio de Janeiro. Anais... Rio de Janeiro: SINAGEO. v. 9, p. 1-6. 2012.).
The orientation of all identified doliniform features showed a high variation of directions, of which the East-West orientation (Figure 5) showed greater proportions, indicating a tendency for some features to be aligned with the same surface flow direction of the Araguaia tributaries.
Regarding the spatial arrangement of the features, it was observed that their dispersion presents a random distribution throughout the study area (Figure 1), with distances varying between 76.44 m and 1,2476.36 m (Table 1). By identifying the random distribution and the distance from the nearest neighbor (DNI), the spatial distribution index (R) was estimated through the average observed distance (686.27 m); the expected average distance (820.94 m) and area of the Araguaia Plain (64,761 km2), corresponding to 0.83, which represents, according to GAO et al. (2005), aGAO et al. Karst database implementation in Minnesota: analysis of sinkhole distribution. Environmental Geology. v. 47, n 8, p. 1083-1098. 2005. https://doi.org/10.1007/s00254-005-1241-2
https://doi.org/10.1007/s00254-005-1241-...
tendency towards grouping (Clustering) of the features identified in the Araguaia Plain.
Principal component analysis (PCA) of the main morphometric variables identified for the doliniform features of the Araguaia Plain (area, slope, elevation, distance from the nearest neighbor (DNI), elongation coefficient (ELG); circularity index (C), Orientation of features).
The principal component analysis represented 76.4% of the morphometric data of the doliniform features, showing a high correlation between the slope and elongation coefficient (ELG) variables associated with orientations: northeast (NNE); east-northeast (ENE) and north-northeast (NNE), demonstrating a possible tendency for elongated or oval features to be under great influence of the topographical or structural conditions of the terrain, predominantly oriented in the northeast (NE) direction.
On the other hand, an inverse correlation was observed between the slope variable and the circularity index (C), corroborating the influence of the terrain on the occurrence of circular doliniform shapes associated with low slopes, mostly oriented in the East-West direction (EW), predominant orientation also identified in Figure 5, indicating a possible tendency for most of the circular shapes to be aligned in the same direction as the surface flows of the main channel of the Araguaia River.
It was observed, therefore, that there was a predominance of circular or oval features with areas from 864 to 10,038,442 m2, oriented in the NE direction for the oval features and EW direction for the circular features. These directions, based on the results obtained in the PCA, may be associated with the convergence of surface flows to the main channel (EW) or by structural controls in the NE direction, related to the position of the Tocantins Group.
DISCUSSION
The hypotheses about the karst origin of the features identified in Cocalinho - MT was corroborated years later by Hardt (2005)HARDT, R. Considerações geomorfológicas sobre o carste de Cocalinho - MT. Anais do XXVIII Congresso Brasileiro de Espeleologia. p. 66-76. Sociedade Brasileira de Espeleologia. 2005. Disponível em: http://www.cavernas.org.br/anais28cbe/28cbe_066-076.pdf . Acesso em: 2 jun. 2022.
http://www.cavernas.org.br/anais28cbe/28...
through the geomorphological characterization of the karst relief of the Serra de Calcário, in floodplain areas of the plain, In this study, carbonate outcrops were identified in the form of limestone hills, karst towers, caves, springs, sinkholes and dissolution and collapse uvalas with kilometric dimensions and depths of up to 5 m. Most of these features were identified parallel to Serra de Calcário and tectonically conditioned by faults in the WSW-ENE direction.
This orientation was also verified in this study, through principal component analysis (PCA), as well as in works of morphometric analysis of doliniform features in the municipality of Lagoa da Confusão, Tocantins, where average lengths of 206.42 m were identified; density of 2.25 features per km2 and tendency of the longest axis in the NE-SW direction (NASCIMENTO; MORAIS, 2012NASCIMENTO, P.; MORAIS, F. Análise morfométrica em Ipucas em carste encoberto na Depressão do Médio Araguaia, estado do Tocantins. In: Simpósio Nacional de Geomorfologia, 2012, Rio de Janeiro. Anais... Rio de Janeiro: SINAGEO. v. 9, p. 1-6. 2012.). The Araguaia National Park Management Plan also shows a large number of circular depressions in the form of lagoons aligned parallel to the faults, in the vicinity of the Bananal Plain and the Formoso river, suggesting a probable structural control for this area (IBAMA, 2001IBAMA. Parque Nacional do Araguaia - Plano de Manejo. Ministério do Meio Ambiente, Brasília. 429 p. 2001.).
Tectonic controls and the parallelism of the doliniform features with the faults and fractures, oriented in the ENE direction, could give evidence of the possible karst origin of the doliniform features. However, some studies in the Araguaia Plain associate its genesis either to the formation of lacustrine systems by dissolution or to natural processes of recomposition of native vegetation.
The association of doline-type karst forms with forest formations is evidenced in the environmental diagnosis proposed by Martins et al. (2002)MARTINS I. C. M., et al. Diagnóstico ambiental no contexto da paisagem de fragmentos florestais naturais “ipucas” no município de Lagoa da Confusão, Tocantins. Revista Árvore. v. 263, p 299-309. 2002 https://doi.org/10.1590/S0100-67622002000300005
https://doi.org/10.1590/S0100-6762200200...
, which characterizes the forest fragments called “ipucas”, located in the Flood Plain, in the Tocantins region, in the municipality of Lagoa da Confusão. In the Mato Grosso portion, these forest fragments are also identified in the form of dolines, however, called “impucas” (MARIMON et al., 2012MARIMON B. S., et al. Florística dos campos de murundus do Pantanal do Araguaia, Mato Grosso, Brasil. Acta Botanica Brasilica. v. 26, n.1, p 181-196. 2012 https://doi.org/10.1590/S0102-33062012000100018
https://doi.org/10.1590/S0102-3306201200...
).
The “ipucas” are vegetation fragments with a predominance of shrubby and subshrubby species and some medium-sized tree individuals adapted to flood flows. (Calophyllum brasiliense, Vochysia sp, and Sclerolobium sp.), classified as Seasonal Alluvial Deciduous Forests and located on depressions in shallow soils with a high content of organic matter and fine materials such as silt and clay under the high influence of the water table. These forest formations have areas between 50,000 and 2,460,000 m2 and circularity indices between 0.1 and 0.85 (MARTINS et al., 2002MARTINS I. C. M., et al. Diagnóstico ambiental no contexto da paisagem de fragmentos florestais naturais “ipucas” no município de Lagoa da Confusão, Tocantins. Revista Árvore. v. 263, p 299-309. 2002 https://doi.org/10.1590/S0100-67622002000300005
https://doi.org/10.1590/S0100-6762200200...
).
It should be noted that these forest fragments called “ipucas” or “impucas” are of vital importance in the context of the ecology of the Araguaia landscape, as they function both as temporary habitats for endemic species and as ecological corridors for amphibians and birds in the Cerrado and Amazon ecosystems (PINHEIRO; DORNA, 2009PINHEIRO R. T; DORNA T. Distribuição e conservação das aves na região do Cantão, Tocantins: ecótono Amazônia/Cerrado. Biota Neotropica, v.9 n.1. 2009. https://doi.org/10.1590/S1676-06032009000100019
https://doi.org/10.1590/S1676-0603200900...
; ROCHA et al., 2014ROCHA, R. G. et al. Seasonally flooded stepping stones: emerging diversity of small mammal assemblage in the Amazonia-Cerrado ecotone, central Brazil. Zoological Studies, vl. 53. n. 1, p. 1-10. 2014. https://doi.org/10.1186/s40555-014-0060-0
https://doi.org/10.1186/s40555-014-0060-...
; KURZATKOWSKI et al., 2015KURZATKOWSKI D., et al. Effects of flooding on trees in the semi-deciduous transition forests of the Araguaia floodplain, Brazil. Acta Oecologica, n. 69 p 21-30. 2015. https://doi.org/10.1016/j.actao.2015.08.002
https://doi.org/10.1016/j.actao.2015.08....
; LOPES et al., 2017LOPES. M.H., et al. Expressões da Natureza no Parque Nacional do Araguaia: Processos geoecológicos e diversidade da vida. Historia Ambiental Latinoamericana y Caribeña (HALAC) revista de la Solcha. v. 7 n.2 p 65-100. 2017. https://doi.org/10.32991/2237-2717.2017v7i2.p65-100
https://doi.org/10.32991/2237-2717.2017v...
).
From a geomorphological point of view, not all “ipucas” or “impucas” should be associated with sinkhole-type karst features, as such forest fragments also occur in abandoned meanders and paleochannels of the Araguaia Fluvial Plain, a fact proven by the highly elongated, sinuous and rectilinear; as well as circularity indices below 0.5.
The proposed genesis of these forest formations (ipucas), in a circular shape, was related to subsidence processes in hydromorphic soils, seasonally saturated such as Plinthosols and Gleysols with pH between 4.1 and 6.8 and high amount of organic matter in their interior. The subsidence of these features was theoretically associated with two processes: the lowering of the water table and the transformation of clayey-sandy sediments by ferrolysis; and the formation of dolines by karst processes of dissolution of limestones of the Tocantins Group (MARTINS et al., 2006MARTINS. A.K.E. et al. Relações solo-geoambiente em áreas de ocorrência de ipucas na Planície do Médio Araguaia - Estado de Tocantins. Revista Árvore. v. 30, n. 2 p. 297-310. 2006 https://doi.org/10.1590/S0100-67622006000200017
https://doi.org/10.1590/S0100-6762200600...
).
The proposal for the genesis of forest formations associated with sinkholes based on karst processes can be complemented based on evidence of karst structures identified in the municipality of Lagoa da Confusão, Tocantins, where limestone-dolomitic outcrops of the Tocantins Group, in the form of 30 m high mogotes, have karrens, sinkholes and a complex system of conduits and galleries identified in the Casa de Pedra cave (PONTALTI; MORAIS, 2010).
From another perspective, the genesis of these doliniform depressions in the form of lakes, located in the municipality of Aruanã (northwest of Goiás) is described through processes of mobilization of fine sediments on the surface, causing the detachment of the lateritic crust on the saprolite of the crystalline rock (CARVALHO; LATRUBESSE, 2008CARVALHO. T. M.; LATRUBESSE, E. M. Geomorfologia do Estado de Goiás e Distrito Federal. Goiânia: Secretaria de Indústria e Comércio. 127 p. Boletim Goiano de Geografia. v. 27, n.3, p 169-172. 2008.). This process would generate small and rounded lacustrine features, conditioned by a set of fractures that allow the alignment in the NE-SW and NW-SE directions, revealing an evident tectonic control over the features in the stage of coalescence (VIEIRA, 2002VIEIRA, Pedro Alves. Caracterização das unidades geomorfológicas Geoambientais da Planície do Bananal. Dissertação de Mestrado. Goiânia: Universidade Federal de Goiás/IESA, p. 124. 2002.).
However, this process may also be related to the formation of karst depressions when considering: the high seasonal oscillation of the water table throughout the year on the carbonate substrate underlying the Holocene sedimentary layer of the Araguaia Plain. In this regard, Caramanna et al. (2008)CARAMANNA et al. A review of natural sinkhole phenomena in Italian plain areas. Natural Hazards, v. 45, n. 2, p. 145-172. 2008. https://doi.org/10.1007/s11069-007-9165-7
https://doi.org/10.1007/s11069-007-9165-...
identified dissolution processes in circular karst depressions of the deep piping type in Italian plains characterized by a thick Quaternary alluvial lateritic cover (impermeable or semi-permeable) of up to 100 m, superimposed on an underlying carbonate substrate in the widespread presence of faults (Figure 7).
Generation model of doliniform features in flat areas with carbonate substrate underlying alluvial sedimentary deposits. (a) recharge area with outcrops of carbonate rocks. (b) discharge area, where deep piping sinkholes can occur over plains with alluvial deposits.
This phenomenon of deep piping occurs when the drastic oscillation of the water table, due to periods of heavy rains and prolonged droughts, increases the rise of groundwater over the carbonaceous (faulted) rock, creating small cavities and conduits by dissolution. These conduits increase the ascending endorheic flow, allowing water erosion of cohesive debris from the upper layers by physical-chemical processes, with the removal of less resistant granules occurring, and dissolution, in an acid medium, acts on the cement located in the intergranular contacts of the siliciclastic rock, changing its consistency (sandstone), favoring the downward displacement of non-cohesive sediments (hourglass effect), forming conical and circular depressions on the surface in the fault plane (CARAMANNA et al., 2008CARAMANNA et al. A review of natural sinkhole phenomena in Italian plain areas. Natural Hazards, v. 45, n. 2, p. 145-172. 2008. https://doi.org/10.1007/s11069-007-9165-7
https://doi.org/10.1007/s11069-007-9165-...
; CARDARELLI et al., 2013CARDARELLI. E. et al. Detection and imaging of piping sinkholes by integrated geophysical methods. Near Surface Geophysics. v. 12, n 3, p. 439-450. 2013. https://doi.org/10.3997/1873-0604.2013051
https://doi.org/10.3997/1873-0604.201305...
; VERESS, 2020VERESS. M. Karst types and their karstification. Journal of Earth Science, v. 31, n. 3, p. 621-634. 2020. https://doi.org/10.1007/s12583-020-1306-x
https://doi.org/10.1007/s12583-020-1306-...
).
The occurrence of the possible carbonate substrate underlying the alluvial deposits of the Araguaia Plain was described through geophysical studies with vertical electrical soundings-SEV, at depths of up to 42.6 m, in the region of Lagoa da Confusão, Tocantins. In this location, upper saturated (clay) and semi-saturated (sand-clay) sedimentary layers superimposed on a possible carbonate layer with resistivity values associated with limestone dolomites were identified (PEREIRA; MORAIS, 2012PEREIRA, G. C.; MORAIS, F. Geofísica aplicada ao estudo dos fluxos subsuperficiais no entorno da Lagoa da Confusão-TO. Revista Geonorte, vol. 3. n. 5, p. 1475-1483. 2012.).
FINAL REMARKS
By mapping the doliniform features, it was possible to observe that the area of occurrence of these features exceeds the geological unit of the floodplain, covering an area of 114,900 km2, equivalent to 46.6% more than the initially designated area.
The highest concentrations of features, identified through the Kernel density map, are located in the municipalities of Cocalinho – Mato Grosso, Luciara – Mato Grosso, Ribeirão Cascalheira – Mato Grosso, Lagoa da Confusão – Tocantins and Pium – TO.
With regard to the generating agent of the doliniform features, there are some indications pointing to the formation of depressions with forest formations resulting from the dissolution of covered karst, such as: the occurrence of a quaternary depositional system predominantly flattened and strongly modeled by the high seasonal water load; limestone outcrops of the Tocantins Group in the area where the features occur; structural control indicated by the NE directions of the features and; predominance of circular shapes covered by healthy green vegetation with the constant presence of water. However, to corroborate these hypotheses, geophysical studies capable of identifying the underlying lithologies at depths greater than 50 m or geological soundings that contribute to the understanding of the genesis of these features are necessary.
REFERÊNCIAS
- AQUINO. S.; LATRUBESSE, E. M.; DE SOUZA FILHO, E. E. Caracterização hidrológica e geomorfológica dos afluentes da Bacia do Rio Araguaia. Revista Brasileira de Geomorfologia v. 10. n. 1, 2009. https://doi.org/10.20502/rbg.v10i1.116
» https://doi.org/10.20502/rbg.v10i1.116 - ANA Sistemas Aquíferos - Catálogo de Metadados da Agencia Nacional de Água e Saneamento Básico - Sistemas Aquíferos do Brasil, em escala 1:1.000.000. Gerência de Aguas Subterrânea 2013. Disponível em: https://metadados.snirh.gov.br/geonetwork/srv/api/records/3ec60e4f-85ea 4ba7-a90c-734b57594f90. Acesso em: 20 nov. 2022
» https://metadados.snirh.gov.br/geonetwork/srv/api/records/3ec60e4f-85ea 4ba7-a90c-734b57594f90. Acesso em: 20 nov. 2022 - ASSIS. P. C., et al. Unidades de Conservação e sua efetividade na proteção dos recursos hídricos na Bacia do Rio Araguaia. Sociedade & Natureza v. 34. 2022. https://doi.org/10.14393/SN-v34-2022-60335
» https://doi.org/10.14393/SN-v34-2022-60335 - BARBOSA, D. C. et al. Estrutura da vegetação lenhosa em dois fragmentos naturais de florestas inundáveis (impucas) no Parque Estadual do Araguaia, Mato Grosso. Revista Árvore, Viçosa-MG, v. 35, n. 3, p. 457-471, 2011. https://doi.org/10.1590/S0100-67622011000300009
» https://doi.org/10.1590/S0100-67622011000300009 - BASSO. A., et al. Morphometric analysis of sinkholes in a karst coastal area of southern Apulia (Italy). Environmental Earth Sciences v. 70, n. 6, p. 2545-2559. 2013. https://doi.org/10.1007/s12665-013-2297-z
» https://doi.org/10.1007/s12665-013-2297-z - BAYER. M.; ZANCOPÉ, M. H. Ambientes sedimentares da planície aluvial do rio Araguaia. Revista Brasileira de Geomorfologia v. 15, n. 2. 2014. https://doi.org/10.20502/rbg.v15i2.414
» https://doi.org/10.20502/rbg.v15i2.414 - BRASIL. Projeto RADAMBRASIL. Folha SC. 22. Tocantins: Geologia, geomorfologia, pedologia, vegetação e uso potencial da terra. Ministério das Minas e Energia. Secretaria Geral. Rio de Janeiro, p. 524. 1981a.
- BRASIL. Projeto RADAMBRASIL. Folha SD. 22. Goiás: Geologia, geomorfologia, pedologia, vegetação e uso potencial da terra. Ministério das Minas e Energia. Secretaria Geral. Rio de Janeiro, p. 639. 1981b.
- BIZZI, L. A., et al. Geologia, tectônica e recursos minerais do Brasil Texto, Mapas e SIG. Brasília, CPRM, Serviço Geológico do Brasil. 2003.
- BONDESAN et al. Morphometric analysis of dolines. International Journal of Speleology v. 21. n. 1, p. 1. 1992. https://doi.org/10.5038/1827-806X.21.1.1
» https://doi.org/10.5038/1827-806X.21.1.1 - CARVALHO. T. M.; LATRUBESSE, E. M. Aplicação de modelos digitais do terreno (MDT) em análises macrogeomorfológicas: o caso da bacia hidrográfica do Araguaia. Revista Brasileira de Geomorfologia v. 5. n. 1, 2004. https://doi.org/10.20502/rbg.v5i1.34
» https://doi.org/10.20502/rbg.v5i1.34 - CARVALHO. T. M.; LATRUBESSE, E. M. Geomorfologia do Estado de Goiás e Distrito Federal. Goiânia: Secretaria de Indústria e Comércio. 127 p. Boletim Goiano de Geografia v. 27, n.3, p 169-172. 2008.
- CARDARELLI. E. et al. Detection and imaging of piping sinkholes by integrated geophysical methods. Near Surface Geophysics v. 12, n 3, p. 439-450. 2013. https://doi.org/10.3997/1873-0604.2013051
» https://doi.org/10.3997/1873-0604.2013051 - CARAMANNA et al. A review of natural sinkhole phenomena in Italian plain areas. Natural Hazards, v. 45, n. 2, p. 145-172. 2008. https://doi.org/10.1007/s11069-007-9165-7
» https://doi.org/10.1007/s11069-007-9165-7 - CPRM. Geologia do Estado de Goiás e do Distrito Federal. Programa geologia e mineração - Geração e Disponibilização de Informações Geológicas e do Potencial Mineral de Goiás. Goiânia, 2008.
- CPRM. Projeto de Disponibilidade Hídrica do Brasil - Carta Hidrogeológica - Escala 1:1.000.000, Folha Sd.22 Goiás. 2016
- DENIZMAN. C. A. N. Morphometric and spatial distribution parameters of karstic depressions, Lower Suwannee River Basin, Florida. Journal of Cave and Karst Studies, v. 65, n. 1, p. 29-35. 2003.
- EMBRAPA. Sistema brasileiro de classificação de solos. Embrapa Solos: 5 Ed, rev. e ampl. Brasília-DF, 2018.
- FORD. D e WILLIAMS P. Karst Hydrogeology and Geomorphology 2 ed. West Sussex, England: John Wiley & Sons. 2007. https://doi.org/10.1002/9781118684986
» https://doi.org/10.1002/9781118684986 - GAO et al. Karst database implementation in Minnesota: analysis of sinkhole distribution. Environmental Geology v. 47, n 8, p. 1083-1098. 2005. https://doi.org/10.1007/s00254-005-1241-2
» https://doi.org/10.1007/s00254-005-1241-2 - GUTIÉRREZ, F., et al. A review on natural and human-induced geohazards and impacts in karst. Earth-Science Reviews, 2014. v. 138, p. 61-88. https://doi.org/10.1016/j.earscirev.2014.08.002
» https://doi.org/10.1016/j.earscirev.2014.08.002 - HARDT, R. Considerações geomorfológicas sobre o carste de Cocalinho - MT. Anais do XXVIII Congresso Brasileiro de Espeleologia. p. 66-76. Sociedade Brasileira de Espeleologia. 2005. Disponível em: http://www.cavernas.org.br/anais28cbe/28cbe_066-076.pdf . Acesso em: 2 jun. 2022.
» http://www.cavernas.org.br/anais28cbe/28cbe_066-076.pdf - IBAMA. Parque Nacional do Araguaia - Plano de Manejo. Ministério do Meio Ambiente, Brasília. 429 p. 2001.
- IBGE - Instituto Brasileiro de Geografia e Estadística. Carta de Geologia do Estado do Pará Escala 1:1.800.000. Diretoria de Geociência. 2008a.
- IBGE - Instituto Brasileiro de Geografia e Estadística. Carta de Geologia do Estado do Tocantins Escala 1:1.800.000. Diretoria de Geociências. 2008b.
- IBGE - Instituto Brasileiro de Geografia e Estadística. Malha Municipal (dados vetoriais) Disponível em: https://www.ibge.gov.br/geociencias/organizacao-do-territorio/malhas-territoriais/15774-malhas.html Acesso em: 10 mar. 2022.
» https://www.ibge.gov.br/geociencias/organizacao-do-territorio/malhas-territoriais/15774-malhas.html - KURZATKOWSKI D., et al. Effects of flooding on trees in the semi-deciduous transition forests of the Araguaia floodplain, Brazil. Acta Oecologica, n. 69 p 21-30. 2015. https://doi.org/10.1016/j.actao.2015.08.002
» https://doi.org/10.1016/j.actao.2015.08.002 - LATRUBESSE, E. M.; STEVAUX, J. C. Geomorphology and environmental aspects of the Araguaia fluvial basin, Brazil. Zeitschrift für Geomorphologie. Supplementband n. 129, p. 109-127. 2002.
- LACERDA FILHO, et al. Geologia e Recursos Minerais do Estado de Mato Grosso Brasília: Programa Integração, Atualização e Difusão de Dados de Geologia do Brasil. Convênio CPRM/SICME-MS, MME, p. 235. 2004.
- LOPES. M.H., et al. Expressões da Natureza no Parque Nacional do Araguaia: Processos geoecológicos e diversidade da vida. Historia Ambiental Latinoamericana y Caribeña (HALAC) revista de la Solcha v. 7 n.2 p 65-100. 2017. https://doi.org/10.32991/2237-2717.2017v7i2.p65-100
» https://doi.org/10.32991/2237-2717.2017v7i2.p65-100 - LEANDRO et al. Sensoriamento remoto aplicado a análise estrutural da faixa Araguaia-região de Guaraí-TO. Anais XV Simpósio Brasileiro de Sensoriamento Remoto. p. 3589-3596. 2011. Disponível em: http://marte.sid.inpe.br/col/dpi.inpe.br/marte/2011/07.20.14.50/doc/p1343.pdf Acesso em: 8 jun. 2022.
» http://marte.sid.inpe.br/col/dpi.inpe.br/marte/2011/07.20.14.50/doc/p1343.pdf - LIMA et al. Avaliação de Rochas Calcárias e Fosfatadas para Insumos Agrícolas do Estado de Mato Grosso Cuiabá: CPRM; METAMAT, p.178, 2008.
- MANCHOLA et al. Abordagem interdisciplinar dos conceitos relacionados a depressões doliniformes na Planície do Araguaia, Brasil. Revista Gaia Scientia, v. 15, n. 2, p. 24-44. 2021. https://doi.org/10.22478/ufpb.1981-1268.2021v15n2.52098
» https://doi.org/10.22478/ufpb.1981-1268.2021v15n2.52098 - MARIMON B. S., et al. Florística dos campos de murundus do Pantanal do Araguaia, Mato Grosso, Brasil. Acta Botanica Brasilica v. 26, n.1, p 181-196. 2012 https://doi.org/10.1590/S0102-33062012000100018
» https://doi.org/10.1590/S0102-33062012000100018 - MARTINS I. C. M., et al. Diagnóstico ambiental no contexto da paisagem de fragmentos florestais naturais “ipucas” no município de Lagoa da Confusão, Tocantins. Revista Árvore v. 263, p 299-309. 2002 https://doi.org/10.1590/S0100-67622002000300005
» https://doi.org/10.1590/S0100-67622002000300005 - MARTINS. A.K.E. et al. Relações solo-geoambiente em áreas de ocorrência de ipucas na Planície do Médio Araguaia - Estado de Tocantins. Revista Árvore v. 30, n. 2 p. 297-310. 2006 https://doi.org/10.1590/S0100-67622006000200017
» https://doi.org/10.1590/S0100-67622006000200017 - MORAIS, F. Classificação morfológica das dolinas da região de Lagoa da Confusão - TO. In: Anais do 34º Congresso Brasileiro de Espeleologia. Ouro Preto-MG: Sociedade Brasileira de Espeleologia. p. 283-287. 2017. Disponível em: https://www.cavernas.org.br/wp-content/uploads/2021/07/34cbe_283-287.pdf Acesso em: 1 mai. 2022.
» https://www.cavernas.org.br/wp-content/uploads/2021/07/34cbe_283-287.pdf - MORAIS. R. P., et al. Morfometria de sistemas lacustres da planície aluvial do médio rio Araguaia. Acta Scientiarum. Biological Sciences v. 27, n.3, p. 203-213. 2005. https://doi.org/10.4025/actascibiolsci.v27i3.1278
» https://doi.org/10.4025/actascibiolsci.v27i3.1278 - NASCIMENTO, P.; MORAIS, F. Análise morfométrica em Ipucas em carste encoberto na Depressão do Médio Araguaia, estado do Tocantins. In: Simpósio Nacional de Geomorfologia, 2012, Rio de Janeiro. Anais... Rio de Janeiro: SINAGEO. v. 9, p. 1-6. 2012.
- PAIXÃO, M. A. P.; GORAYEB, P. S. S. Metalogênese da Faixa Araguaia. In: SILVA, M. G. et al. Metalogênese das províncias tectônicas brasileiras, p. 468-488. Belo Horizonte: CPRM. 2014.
- PINHEIRO R. T; DORNA T. Distribuição e conservação das aves na região do Cantão, Tocantins: ecótono Amazônia/Cerrado. Biota Neotropica, v.9 n.1. 2009. https://doi.org/10.1590/S1676-06032009000100019
» https://doi.org/10.1590/S1676-06032009000100019 - PEREIRA, G. C.; MORAIS, F. Geofísica aplicada ao estudo dos fluxos subsuperficiais no entorno da Lagoa da Confusão-TO. Revista Geonorte, vol. 3. n. 5, p. 1475-1483. 2012.
- PONTALTI, A. L.; MORAIS, F. Evolução geomorfológica da gruta Casa de Pedra, Lagoa da Confusão - TO. In: VIII Simpósio Nacional de Geomorfologia, III Encontro Latino Americano de Geomorfologia, I Encontro Ibero-Americano de Geomorfologia e I Encontro Ibero-Americano do Quaternário, 2010, Recife. Anais... Recife: UFPE, p. 13. 2011.
- ROCHA, R. G. et al. Seasonally flooded stepping stones: emerging diversity of small mammal assemblage in the Amazonia-Cerrado ecotone, central Brazil. Zoological Studies, vl. 53. n. 1, p. 1-10. 2014. https://doi.org/10.1186/s40555-014-0060-0
» https://doi.org/10.1186/s40555-014-0060-0 - SOUSA et al., Evolução geológica do domínio interno da Faixa Paraguai na região de Nova Xavantina, leste de Mato Grosso. Geociências, v. 38. n. 4, p. 837-851, 2019. https://doi.org/10.5016/geociencias.v38i4.13581
» https://doi.org/10.5016/geociencias.v38i4.13581 - SOUBIES, F.; GUYOT, J. L. Compte Rendu de Mission dans la Région du Rio das Mortes (Mato Grosso) du 5 au 8 Septembre 1995 ORSTOM Brasília. 1995.
- SCHRAGE. T. J.; UAGODA, R. E. S. Distribuição espacial de depressões na bacia do alto rio Preto (GO, DF, MG) e suas relações com controles geológicos e pedogeomorfológicos. Revista Brasileira de Geomorfologia v. 18. n. 2, 2017. http://dx.doi.org/10.20502/rbg.v18i2.805
» https://doi.org/10.20502/rbg.v18i2.805 - TORELLO-RAVENTOS. M. et al. On the delineation of tropical vegetation types with an emphasis on forest/savanna transitions. Plant Ecology & Diversity, v. 6, n. 1, p. 101-137. 2013. https://doi.org/10.1080/17550874.2012.762812
» https://doi.org/10.1080/17550874.2012.762812 - VALENTE, C. R.; LATRUBESSE, E. M. Fluvial archive of peculiar avulsive fluvial patterns in the largest Quaternary intracratonic basin of tropical South America: the Bananal Basin, Central-Brazil. Palaeogeography, Palaeoclimatology, Palaeoecology, vol. 356, p. 62-74, 2012. https://doi.org/10.1016/j.palaeo.2011.10.002
» https://doi.org/10.1016/j.palaeo.2011.10.002 - VERESS. M. Karst types and their karstification. Journal of Earth Science, v. 31, n. 3, p. 621-634. 2020. https://doi.org/10.1007/s12583-020-1306-x
» https://doi.org/10.1007/s12583-020-1306-x - VIEIRA, Pedro Alves. Caracterização das unidades geomorfológicas Geoambientais da Planície do Bananal Dissertação de Mestrado. Goiânia: Universidade Federal de Goiás/IESA, p. 124. 2002.
- WU. Q. et al. Automated delineation of karst sinkholes from LiDAR-derived digital elevation models. Geomorphology. v. 266, p. 1-10. 2016. https://doi.org/10.1016/j.geomorph.2016.05.006
» https://doi.org/10.1016/j.geomorph.2016.05.006
Publication Dates
-
Publication in this collection
29 May 2023 -
Date of issue
2023
History
-
Received
25 Oct 2022 -
Accepted
28 Feb 2023 -
Published
27 Mar 2023