O AQUÍFERO FRATURADO CRISTALINO EM UM SETOR DO AGRESTE PARAIBANO

In the State of Paraíba the semi-arid climate and the geology of igneous and metamorphic rocks dominate, imposes serous limitations concerning the storage of groundwater. This work aimed to evaluate the fractured aquifer in Agreste Paraibano environment. This region stands out from the regional context of scarcity and plays an important role in the supply of water in periods without rain. This work evaluated 180 wells located in the fractured aquifer, encompassing 9 municipalities. All the studied well was from the Groundwater Information System (SIAGAS) database of Geological Service of Brazil (CPRM). The lithological, flow and salinity data of the waters were integrated with information on rainfall, vegetation cover and topography. In the central portion of the area (Alagoa Nova, Areia and Pilões) the greater productivity of the wells is accompanied by predominantly sweet waters. This scenario is possibly due to the higher incidence of rainfall in the sector and the presence of a thicker mantle of weathering, associated with the presence of the sedimentary rocks of the Serra dos Martins Formation.

RELAÇÕES ENTRE CISALHAMENTO, MAGMATISMO E ANATEXIA: EXEMPLO DA ZONA DE CISALHAMENTO CRUZEIRO DO NORDESTE, PROVÍNCIA BORBOREMA, BRASIL

The Borborema Province, northeastern Brazil, exhibit an extensive framework of shear zones in spatial proximity with syn-tectonic magmatism that makes it a perfect place to understand their relationship. In the eastern portion of this province an important dextral shear zone, that divides into two terranes, was originated during an escape tectonics after an oblique collision after a tectonic transport to NW. The recrystallization of quartz and feldspar shows a remarkable increase towards the shear zone, interpreted as a temperature increase during deformation. Thermodynamic modelling coupled with field relationship shows that high strain migmatitic textures such as stromatic structure was formed at ~650 °C and ~0.9 GPa prior to the shear development. Whereas low strain migmatites with schollen texture was formed at ~750 °C and ~0.7 GPa. We propose that the presence of melt during an oblique collision facilitated the emplacement of shear structures due to a thermal anomaly during the emplacement of syn-tectonic plutons.

FIRST RECORD OF OSTRACODS IN THE ESTIVA FORMATION (PERNAMBUCO BASIN, UPPER CRETACEOUS), NORTHEAST OF BRAZIL

The present work deals with the first record of ostracods in the Estiva Formation, Pernambuco Basin (Cupe, 1 LABIO-PE1 borehole). The Pernambuco Basin extends throughout the southern coast of the state of Pernambuco and is limited by the Pernambuco Shear Zone, in the north and by the Maragogi High, in the south. The Estiva Formation consists of continental shelf carbonates dated as Upper Cretaceous. The analysis and interpretation of the data were performed through literature review, stratigraphic data surveys, and sampling. The methodology used for the treatment of the samples consisted of the following steps: collection, weighing and fragmentation of the samples; washing and drying of the calcined materials; and screening and picking of the carbonatic microfossils. Rare ostracods were found, probably belonging to the brackish genus Fossocytheridea Swain & Brown, 1964. The recognition of the ostracod fauna and its paleoecology aims to contribute to the understanding of the Pernambuco Basin evolution.

GEOLOGIA DE SUPERFÍCIE E ASPECTOS ESTRUTURAIS DA REGIÃO DE RIO TINTO, FAIXA COSTEIRA DA BACIA DA PARAÍBA

This work presents a geological 1:50.000 mapping survey for the Rio Tinto region, located in the coastal zone of Paraíba Basin, Miriri Sub-bacia. The mapping was supported by interpretation of satellite imagery, analysis of well lithologs, thin sections, and morphometric patterns. Basement rocks outcrops in approximately 10% of the study area, represented by Neoproterozoic granitoids. About 90% of the region is covered by Miocene-Pleistocene deposits and Quaternary sediments of the Barreiras, post-Barreiras formations, and coastal sandy and mangrove sediments, Pleistocene terraces, and Holocene eluvial-colluvial sediments. Analysis of cartography data and radar images showed that the relief is dominated by small plateaus and valleys formed by the Quaternary erosion of Barreiras Formation deposits, controlled by reactivation of the structural framework of the coastal zone. The Mamanguape River follows the homonymous fault, which trends ENE-WSW. The secondary drainage is also controlled by faults trending ENE-WSW, NW-SE, and N-S. Correlation of lithologs showed the occurrence of grabens and horsts formed during the late structural evolution of the coastal zone of the basin.

O DEVONIANO NO ESTADO DO MATO GROSSO DO SUL, BRASIL: NOVA ÁREA DE DISTRIBUIÇÃO E PRESENÇA DE TÍPICA FAUNA MALVINOCÁFRICA

Devonian strata are widely known for the eastern edge of the Paraná Basin, particularly in the state of Paraná. However, studies are still scarce on the northwestern border, especially in the state of Mato Grosso do Sul. During the studies, around 120 geological and paleontological sites in the region were identified, and some discrepancies were identified in the distribution maps of the Devonian units (Campos Gerais / Chapada Group) in that state. This paper presents a review on the Devonian strata distribution in Mato Grosso do Sul state, as well a survey of paleontological works in the region of occurrence of the climax Malvinokaffric fauna (Pragian-early Emsian) in order to increase the discussion about the genesis of Devonian deposits. This fauna, combined with other stratigraphic evidences, corroborates a non-compartmentalization of the Paraná Basin for this age. The hypothesis of a tectonism concomitant with the deposition of the Ponta Grossa Formation (=lower Chapada II Group) is raised, mainly to the top of the unit, corroborated by a progradational context followed by a depositional hiatus during the middle Emsian at the end of the Eifelian in the area. It is possible that the Campo Grande Arch only acquired geomorphological expressiveness during the middle Emsian which would be attested by the absence of strata dated as late Emsian / Eifelian in croping areas in the state.

ASPECTOS SEDIMENTOLÓGICOS E GEOQUÍMICOS DO TESTEMUNHO ANP 1040, DO TALUDE CONTINENTAL DA PORÇÃO OESTE DO ESTADO DO CEARÁ

The ANP 1040 core analyzed was collected at a depth of 1900 m in the Equatorial Atlantic Ocean, around 100.8 km from the coastline of the municipality of Itapipoca, Ceará. Particle size analyzes, geochemistry by X-ray fluorescence, calcium carbonate, organic matter and total nitrogen contents were performed. The data show that the ANP 1040 core contains the mud, sandy mud and muddy facies, composed of bioclastic sediments classified as limestone. The decrease of the marine influence on the sedimentation was observed in the intermediate interval of the core because it presented high levels of Ti/Ca and Fe/Ca ratios. In addition, this interval was correlated to high values of mud, organic matter, and low percentage of carbonate content. The high values of these ratios (Ti/Ca and Fe/Ca) are related to an increase of the continental sedimentary contribution, denoting a period of a greater precipitation in the region, indicating a humid tropical climate that increased the flow of the continental drainages and, consequently, the supply of terrestrial sediments to the continental slope. In addition, the high values of the Ti/Al ratio at the base of the core are related to a supply of eolian sediments, while low values of Ti/Al at the top of the core indicated a fluvial source. This work contributes to the knowledge of the Quaternary Geology of the Icaraí sub-basin, Ceará Basin, Brazilian Equatorial Margin.

DEFINIÇÃO ESTRATIGRÁFICA DA FORMAÇÃO MISSÃO VELHA, BACIA DO ARARIPE

The Missão Velha Formation corresponds to the fluvial deposits through the Jurassic-Cretaceous interval in the Araripe Basin, deposited under the context of the Afro-Brazilian Depression in the West Gondwana Early Rift Stage. The Missão Velha Formation stands out in the Araripe Basin mainly due to the occurrence of an assembly of silicified coniferous trunks. Although the Missão Velha Formation and the Dom João Stage deposits, in general, do not present diagnostic features of tectonism and active magmatism, a series of investigations in the last decade challenged the obviousness, seeking to understand the conditions of the early rift, through new comparative and interpretative methods. Under the sight of these new data and in order to facilitate communication between the authors, the present work proposes an objective delimitation and definition of the unit through the analysis of its state of the art and delimitation, tectonoestratigraphic conditions, and its geological and paleontological settings. The unit presents an internal unconformity and its lower and upper sequences present a distinction in the paleocurrents patterns that change from S-SE to NW, respectively; the facies association change from riverbeds with interdigitated floodplain deposits to high-energy braided channels deposits with the presence of silicified trunks. The assignment of the silicified trunks to the Dadoxylon-Araucarioxylon taxon should be discouraged, since this denomination is outdated accordingly the rules of the International Code of Botanical Nomenclature.