Lineaments Research Articles

Lithostructural control of the relief in the eastern sector of the Parnaíba sedimentary basin (Ibiapaba Plateau), Northeast Brazil

Cartographic updates of the geological area between the Parnaíba and Borborema Provinces made it possible to provide details in the interpretation of the lithostructural control of the Ibiapaba Plateau and surroundings. The article aims to interpret regional morphostructural aspects based on bibliographic review, fieldwork and GIS interpretations. The area is characterized by an asymmetrical plateau with a continuous glint-type escarpment (≈800 m), supported by Paleozoic sandstones overlying the Precambrian basement. In the surroundings, flat surfaces predominate (≈200m), whose morphologies vary according to the lithologies. From a structural point of view, the Transbrasilian Lineament (LT) constitutes the main regional tectonic divide, influencing the behavior of the escarpment and the reverse. In lithological terms, the sandstones and conglomerates of the Serra Grande Group stand out, responsible for maintaining the top of the plateau, the Cabeças Formation and lateritic coverings, which support small tabular plateaus within the sedimentary basin, in addition to the granitoids, quartzites and orthogneisses that support residual reliefs in the basement. Considering a regional geomorphological evolution associated with Cretaceous uplifts of rift and post-rift phases, the detailing of lithostructural aspects is fundamental to explain the relationship of differential erosion in the current regional morphology.

Fuzzy-based multiple decision method for landslide susceptibility and hazard assessment: A case study of Tabriz, Iran

Due to the complexity of the causes of the sliding mass instabilities, landslide susceptibility and hazard evaluation are difficult, but they can be more carefully considered and regionally evaluated by using new programming technologies to minimize the hazard. This study aims to evaluate the landslide hazard zonation in the Tabriz region, Iran. A fuzzy logic-based multi-criteria decision-making method was proposed for susceptibility analysis and preparing the hazard zonation maps implemented in MATLAB programming language and Geographic Information System (GIS) environment. In this study, five main factors have been identified as triggering including climate (i.e., precipitation, temperature), geomorphology (i.e., slope gradient, slope aspect, land cover), tectonic and seismic parameters (i.e., tectonic lineament congestion, distribution of earthquakes, the unsafe radius of main faults, seismicity), geological and hydrological conditions (i.e., drainage patterns, hydraulic gradient, groundwater table depth, weathered geo-materials), and human activities (i.e., distance to roads, distance to the municipal areas) in the study area. The results of analyses are presented as a landslide hazard map which is classified into 5 different sensitive categories (i.e., insignificant to very high potential). Then, landslide susceptibility maps were prepared for the Tabriz region, which is categorized in a high-sensitive area located in the northern parts of the area. Based on these maps, the Bozgoosh-Sahand mountainous belt, Misho-Miro Mountains and western highlands of Jolfa have been delineated as risk-able zones.

Investigação geotécnica de taludes rochosos por meio da análise estrutural: estudo de caso da BR-116, Rio Grande do Sul

A BR-116, localizada no nordeste do estado do Rio Grande do Sul, atravessa a Escarpa da Serra Geral, composta de derrames ácidos e básicos da Formação Serra Geral. Diversos movimentos de massa são observados na rodovia, relacionados com a queda e os deslizamentos de blocos dos taludes rochosos. Como hipótese, pretendeu-se verificar se as famílias de fraturas tectônicas regionais causam os movimentos de massa nos taludes da BR-116. O objetivo desta pesquisa foi aperfeiçoar os métodos de investigação geotécnica, correlacionando a Geologia Estrutural com a estabilidade de taludes rochosos. Entre os métodos utilizados estão o sensoriamento remoto e a análise de lineamentos estruturais, a análise estrutural geométrica e a análise geotécnica dos maciços rochosos (identificação de possíveis planos de ruptura e cálculo de seus fatores de segurança). Os resultados dos lineamentos estruturais regionais indicam o predomínio da direção ENE, seguida pelas direções subordinadas NE e WNW. Em relação às fraturas de alto ângulo analisadas em campo, caracterizou-se um máximo com direção N50-70E, similar ao observado regionalmente. A interpretação do diagrama de movimentos de massa indica que 75% dos movimentos que podem ocorrer na BR-116 seriam causados por deslizamentos em cunha, e o restante são planares, com predomínio de descontinuidades de alto ângulo. A direção máxima dos lineamentos (N70-90E) pode causar movimentos em seis dos sete taludes estudados, e o segundo máximo (N60-80W) condiciona deslizamentos em quatro dos sete pontos. Essa evidência mostra que as estruturas provenientes dos lineamentos regionais são as que mais podem gerar movimentos de massa.

Assessment of groundwater potential zones in the basaltic terrain: a case study from in and around Gondar town, North West Ethiopia using remote sensing and GIS technologies

Geospatial technology has wide applications within the groundwater resource assessment studies. Satellite images are increasingly being used in groundwater exploration due to their utility in distinguishing numerous geo-system options. The present study has been disbursed in and around Gondar, Ethiopia. The groundwater potential zones were depicted from the six geo-system parameters like lithology, lineament density, geomorphology, slope, land use/land cover, and drainage density using weighted overlay analysis methodology. Integration of the above mentioned geo-systems has been performed in GIS platform using weighted overlay analysis. Totally different categories of thematic maps are assigned weights supported influence on groundwater hydrology (through intensive literature review), and eventually, factor ranks area were assigned. The ultimate map indicates the potentiality values of groundwater prevalence within the study area, that was classified into 3 categories—high, moderate and low. a total of 24% of the study area fall in low groundwater potential zone, 42%in moderate potential zones and 34%of the realm in the high potential zone. Keywords : Groundwater potential zones, remote sensing, GIS, Gondar, Ethiopia.

Qualitative aeromagnetic interpretation over Ikogosi Warm Spring, southwestern Nigeria

In this paper, lineaments of Ikogosi warm spring and its environs have been delineated using qualitative methods. Boundary structures or lineaments between magnetic units were delineated using the first horizontal derivative map and skeletonization of derivative-based data. Also, the residual anomaly contour map was digitized into ten profiles, profiles’ plots were made and used for interpretation. Dominant lineaments suspected were elongated features trending North East-South West direction and are housed by the shallow basements beneath the study area and surroundings.

Proust’s Disenchantments, the “Repoetization” of Experience, and the Lineaments of the Visible

This paper investigates the role of literature and, in particular, Proust in Merleau-Ponty’s late works’ rehabilitation of the ontology of the sensible. First, I trace Proust’s role in Phenomenology of Percpetion, contrasting it with the somewhat more paradigmatic status as a model it plays in the late works. Second, I compare this with the role of the novel as partial myth in Schelling, who also played an essential role in Merleau-Ponty’s refiguration of the sensible. I briefly trace his examination of the historical or “sociological meaning” of literature through works of the fifties, beginning with his Collège de France candidacy proposal and continuing through his examination of the rationality of modern disenchantment (Entzauberung) or dépoétization in the Adventures of the Dialectic. Finally, discussing the late analysis of Proust against this backdrop, I conclude with considerations concerning the relevance of Merleau-Ponty’s overall analysis of Proust both in his thought and contemporary literary criticism and philosophy more generally. Cet article examine le rôle de la littérature et, en particulier, celui de Proust, dans la réhabilitation ontologique du sensible qui se trame dans les derniers écrits de Merleau-Ponty. En premier lieu, je retracerai le rôle de Proust dans la Phénoménologie de la perception, en l’opposant au statut quelque peu plus paradigmatique, comme s’il s’agissait d’un modèle, qu’il joue dans le dernier Merleau-Ponty. Deuxièmement, je comparerai cela avec la fonction du roman conçu comme un mythe incomplet chez Schelling, qui a aussi joué un rôle essentiel dans la reconfiguration du sensible chez Merleau-Ponty. Je décrirai brièvement son analyse de la « signification sociologique » ou historique de la littérature à travers des oeuvres des années ’50, en me penchant, d’abord, sur sa candidature au Collège de France, et, ensuite, sur son étude de la rationalité du désenchantement moderne (Entzauberung) ou dépoétisation dans les Aventures de la dialectique. Finalement, en examinant les dernières analyses de Proust à partir de ces prémisses, je conclurai avec des considérations sur l’intérêt de l’ensemble de l’analyse que Merleau-Ponty fait de Proust à la fois pour sa pensée, pour la critique littéraire contemporaine et, plus généralement, pour la philosophie.Il presente articolo indaga il ruolo della letteratura e, in particolare, di Proust nella riabilitazione ontologica del sensibile negli ultimi scritti di Merleau-Ponty. In primo luogo, si delinea il ruolo di Proust nella Fenomenologia della percezione, contrapponendolo, in qualche modo, allo statuto paradigmatico di modello che l’autore riveste nei lavori dell’ultimo Merleau-Ponty. In secondo luogo, si confronta questo con il ruolo del romanzo come mito parziale in Schelling, che pure ha giocato una parte essenziale nella rifigurazione del sensibile in Merleau-Ponty. Si articolerà brevemente il significato storico o sociologico della letteratura attraverso gli scritti degli anni Cinquanta, a partire dalla proposta di candidatura di Merleau-Ponty al Collège de France e proseguendo mediante il suo esame della razionalità del disincanto moderno (Entzauberung) o depoetizzazione ne Le avventure della dialettica. Infine, esaminando l’ultima lettura di Proust a partire da queste analisi, propongo una considerazione riguardo alla rilevanza complessiva dell’autore della Recherche nella riflessione di Merleau-Ponty e, più in generale, nella critica letteraria e nella filosofia contemporanee.

Recognition and Mapping of Structural Guides for Barytes Mineral Exploration in Parts of Kadapa District using Remote Sensing and GIS

Identification and mapping of structural criteria of a region reveals information about the occurrence of ore deposits of igneous and metamorphic origin. Remote Sensing and GIS data helps in detection of such structural features, like faults, lineament, folds, etc. These are important guides for exploration of ore mineral and groundwater. Kadapa district hosts important ore minerals of igneous and metamorphic origin like Barytes, asbestos, gold, galena, steatite etc. Barytes is exploited in the district since a long past. Present study is taken up to prepare structural map along the existing Barytes mines in the district using geospatial techniques like Remote Sensing and GIS, with an intension to identify new Barytes mineralized locations through these structural guides. The structural data of any region provides a quick payback with faster, more accurate mineral identification for gold, silver, diamonds, iron, nickel, copper, uranium, aluminum, Barytes, and also provide rock and mineral relationship in search for ore deposits during exploration. Structural criteria, is an important measure in mineral exploration of certain mineral deposits that are confined by geographic, geological and tectonic features. Mainly the occurrence of ore deposits is dependent on neighboring lithology and structural deformation of the location area. Endogenous mineral deposits like tin, muscovite, lithium, tungsten, gold, beryl, gemstones etc. are associated with intermediate and acid rocks like syenite; granite, granodiorite. etc., and deposits of copper, nickel, cobalt, silver, arsenic and apatite are formed in basic rocks like gabbro, norite, diorite, etc. Due to false nature of ore bodies and their varied controls of mineralization the techniques used for mineral exploration such as remote sensing followed by ground and airborne geophysical surveys, stream sediment, litho-geochemical surveys and core drilling have been used for regional and detailed surveys. The aspect that indicate the mineralisation are known as localizers. If these indicators can be identified on satellite data/imagery then the mineral explorations can be much faster with increased efficiency. Keywords: Multispectral, LISS-III Satellite Imagery, SOI Toposheet remote sensing, GIS Cite this Article Ramachandra M., Raghu Babu K., Pradeep Kumar B. et al. Recognition and Mapping of Structural Guides for Barytes Mineral Exploration in Parts of Kadapa District using Remote Sensing and GIS. Journal of Remote Sensing & GIS . 2018; 9(3): 30–36p.

Reativações pós-silurianas do Lineamento Transbrasiliano na porção sul da Bacia do Parnaíba

O Lineamento Transbrasiliano (LTB) apresenta direção NE-SW. Cerca de 900 km desse sistema interceptam o substrato da Bacia do Parnaíba (BPar), inferido, a partir de dados geológicos e geofísicos, como uma zona de cisalhamento plástica transcorrente dextral. Este trabalho objetivou abordar a assinatura estrutural e os marcadores estratigráficos associados às reativações do LTB na região sul da bacia, ao leste de Palmas (TO). No embasamento cristalino, um estágio tardio do LTB se expressa como uma zona dúctil-frágil também de cinemática dextral de idade ediacarana-cambriana, no NW do Ceará. Nas unidades litoestratigráficas da BPar são distinguidos eventos de reativação em regime frágil ou hidroplástico. Na região de estudo, um evento mais antigo registra cinemática transcorrente sinistral expressa principalmente como bandas de deformação e falhas com direção NE, combinadas a estruturas dilatacionais (incluindo juntas e falhas normais) ou conjugadas/antitéticas de rejeito direcional ou oblíquo, com orientações que variam de NNE a NNW, todas observadas nos litotipos das Formações Sambaíba e Pedra de Fogo, bem como nas mais antigas. Ao sudeste de Alto Parnaíba (MA) são observadas evidências de atividade tectônica sindeposicional durante o Permiano superior. Um segundo conjunto de estruturas composto por falhas normais associadas a uma distensão N/NNW, impressas nos corpos básicos de idade eojurássica da Suíte Mosquito, que, por sua vez, é capeada por depósitos com seixos das vulcânicas, correlacionados à Formação Corda. Um terceiro conjunto de estruturas, caracterizado por falhas normais ou oblíquas com direção NE, registra distensão NW, sendo associada ao evento de rifteamento da Margem Leste brasileira, durante o Cretáceo Inferior. Finalmente, um quarto evento, de ocorrência restrita, envolve distensão NE e está registrado em arenitos correlacionados ao Grupo Urucuia, implicando uma idade máxima neocretácea.

Crecimiento urbano y potenciales conflictos entre usos del suelo en el municipio de Luján (Provincia de Buenos Aires, Argentina). Modelado espacial 2016-2030

El impacto de la urbanizacion sobre el uso del suelo rural es una tematica de gran relevancia actual, principalmente cuando se analizan las regiones en la cuales este proceso influye en la actividad productiva primaria y en las condiciones naturales que brindan importantes servicios ambientales. En Argentina, la ecorregion Pampa Ondulada (Region pampeana) es una de las principales zona agroproductivas del mundo. En ella existe un notable crecimiento urbano a traves del Gran Buenos Aires y ciudades de tamano intermedio. El presente trabajo, mediante la utilizacion del analisis espacial cuantitativo con Sistemas de Informacion Geografica, modela hacia futuro (2016-2030) el crecimiento urbano en el Partido de Lujan y su impacto en las zonas de aptitud agroproductiva y de conservacion ambiental. Los resultados obtenidos pueden considerarse una herramienta de gran importancia para la toma de decisiones espaciales en la definicion de lineamientos en la planificacion regional de los usos del suelo.

An Exploration for the Analysis of Ground Water Possibility in Case Based Recommendation System using Hybrid Cuckoo Search and Artificial Honey Bee Algorithm

Groundwater Possibility Exploration is one of the prime problems in human life. Human and other social species are directly or indirectly dependent on water resources. But with increasing population and instant changing environmental conditions, groundwater resources are also becoming less day by day. One approach of manual exploration can be used but that is most laborious and time consuming task. So, there is need of some autonomous approach with which we can find the more groundwater resources without digging the bore well. This paper presents an autonomous approach in case based recommendation system using hybrid cuckoo search and artificial honey bee algorithm for groundwater possibility detection. The proposed concept is structured in the manner to have the input in the form six attributes of slope, geology, landuse, lineament, soil & landform and give output in the form of low, intermediate and high possibility. In this method, case based reasoning used in the manner to retrieve the previous knowledge of use cases. The cases are actually the host bird’s nest and input is cuckoo’s egg. CS originates from the behaviour of certain species of cuckoo which lay eggs in other birds nest in parasitic manner. If cuckoo’s egg adapts the behaviour of host nests it will exist otherwise the host bird will discard cuckoo’s egg. The minimum similarity value is calculated using ABC algorithm. CBR life cycle further uses the information from this metaphor. The overall method is evaluated using the parameters of sensitivity, specificity and accuracy.

Stratigraphic revision and structure of Sierra Plomosa, Chihuahua

New geological mapping and U-Pb dating of detrital zircons and volcanic rocks permit stratigraphic revision and interpretation of pre- Late Permian deformation in the Sierra Plomosa area, located 95 km east of the city of Chihuahua and at comparable distance to the southwest of the border town Ojinaga. The Plomosas area forms the central part of a north-northwest trending uplifted block ranging from Placer de Guadalupe at the north, to the cerro Carrizalillo at the south. Along this elevated block, Precambrian crystalline basement rocks are exposed, as well as lower Paleozoic rocks belonging to the southern platform of Laurentia and upper Paleozoic to lower Mesozoic clastic and volcaniclastic rocks. The main structures in the area are north-northwest trending folds and thrust faults showing a west-southwest vergence or tectonic transport, being the age of this deformation, necessarily pre-Late Permian, given the occurrence of an erosional and angular unconformity between strongly deformed pre-Permian strata and less deformed Permian-Triassic clastic and volcaniclastic deposits which contain Archean (3,022–2,513Ma), Paleoproterozoic (2,461–1,601Ma), Mesoproterozoic (1,592–1,013Ma), Neoproterozoic (994–546Ma) and Paleozoic (533–252Ma) detrital zircon populations, with maximum depositional ages calculated between 252 and 244 Ma and isolated concordant zircons as young as 227 to 223 Ma. In the middle part of the permo-triasic succession, a Permian rhyolitic flow or ignimbrite was previously reported on the basis of a lead alpha age, however, during the present research this rock yielded an Early Jurassic age of 183.3+2.2/–2.7 Ma. On the basis of petrographic features and field relations, the rhyolite is interpreted as an ash flow tuff or ignimbrite, similar to other rhyolitic flows observed in the area. Such flows are concordant to bedding and several clasts of this rock are present in strata overlying the rhyolite. All Paleozoic rocks, including the top of the Permian and Lower Triassic, underlie clastic and volcaniclastic Jurassic rocks of shallow marine origin. In the area was also documented an erosional, locally angular unconformity which separates a Lower Jurassic unit from a Middle (?) to Upper Jurassic unit with previously reported Late Jurassic fauna in the upper part of the succession. Limestone layers in the upper part of the Jurassic succession, are recrystallized as marbles, especially in the area of the Plomosas mine, where both the metamorphism of these limestones and the presence of stratabound ore bodies of lead and zinc seem to be related to thrusting with a tectonic transport to the southwest and northwest, that placed very fractured Permian sandstones and siltstones over the Upper Jurassic rocks. The faulting is possibly associated with transpression along the so-called Plomosas lineament and transcurrent faulting, described as a left lateral shear of the basement whose regional trace lies along the eastern front of the sierra. Finally south of the Sierra Plomosa, in the northeast trending Sierra de Santo Domingo Carboniferous and Permian limestone are thrust over Jurassic sandstones and shale. This thrust fault also cuts a rhyolitic dyke of probable Oligocene age and can be considered as a very late laramide shortening contractive structure, possibly related to transpressive deformation along the Plomosas lineament and its interaction with the uplifted Cerro Carrizalillo block 15 km to the South of Plomosas.

Relationship Analysis between Lineaments and Epicenters using Hotspot Analysis: The Case of Geochang Region, South Korea

Relationship Analysis between Lineaments and Epicenters using Hotspot Analysis: The Case of Geochang Region, South Korea

The Lineaments of Islam: Studies in Honor of Fred McGraw Donner edited by Paul M. Cobb

The Lineaments of Islam: Studies in Honor of Fred McGraw Donner edited by Paul M. Cobb

Las principales concepciones psicoantropológicas como referente para la actividad profesional del psicólogo

En este artículo se presentan los lineamientos generales de 5 modelos teóricos provenientes de la Psicología que en la actualidad se utilizan para describir al hombre. Estos son los modelos: Conductista, Psicoanalista, Humanista, Materialista, Cognitivo y Cognitivo Emocional. En todos los casos se presentan a los principales representantes, se señalan los antecedentes históricos de cada modelo y el tipo de explicación que desarrolla. Finalmente se presenta la bibliografía especifica para cada modelo.

Modern geodynamically active zones in the Central East European Craton

To identify the modern geodynamic processes in the structures of the East European Craton (EEC), the complex approach is used. The results of visual and automated deciphering of the LANDSAT satellite images are analyzed combined with the data of preci� sion measurements for horizontal components of motion rates of GPS reference points. The approach used allowed us to consider the modern activity of geo� logical structures and to distinguish the zones of higher geodynamic instability. To analyze the morphostructures and geodynamic setting of the studied territory, we constructed a space� tectonic scheme of the central EEC using the LESSA software packet [1] and data on the deep structure of the Earth’s crust [2] (Fig. 1). In the scheme, the sys� tems of extended lineaments of different directions are marked; these lineaments shape the integrated struc� tural pattern describing the complex geological evolu� tion of the region. Deep faults in the basement are often expressed on the surface as localized deforma� tions and clustered cracking zones. The rheological properties of sedimentary rocks predetermine the “scatter” of boundaries (faults) between the basement blocks [3]. The orientation of extended lineaments and linea� ment forms in the central EEC reflects the block struc� ture of the basement and partially reveals the buried structures that were activated at the neotectonic stage. Figure 1 shows that the major lineaments are oriented in the SW–NE and SE–NW directions and are related with the primary regmatic division of the crust trans� formed by tectonic processes. Sublatitudinal and sub� meridional lineaments are of secondary value [4]. The distinguished extended Moscow–Ryazan lineament zone of SE–NW strike consists of a series of subparal� lel extended lineaments and corresponds to the transi� tion zone boundary at the layer of sedimentary cover

Recognition of potential sources of strong earthquakes in the Caucasus region using GIS technologies

The petroleum infrastructure, which is intensively developing in the Black Sea-Caspian region, can be significantly damaged by natural disasters, such as strong earthquakes. It is obvious that information about the potential sources of strong earthquakes is the most important for elaboration of the measures pro� viding seismic safety and preventing large scale envi� ronmental catastrophes. We have considered the mountainfolded zone of the Caucasus characterized by a heterogeneous geo� logical structure, which combines the Alpine moun� tain systems of the Greater and Lesser Caucasus with the young Rioni and Kura intermontan basins divided by the Dzirula crystalline massif. The aim of the present work is to recognize the intersections of linea� ments on which earthquakes of М ≥ 6.0 can occur. The problem is solved with the help of pattern recognition algorithms applied to a scheme of the lineamentand� block structure of the Caucasus (Fig. 1). It turn, the scheme of lineaments was obtained by the method of morphostructural zoning (MSZ) and reflects the recent hierarchical block structure of the region. Resulting from the MSZ, 237 intersections of lin� eaments have been delineated in the Caucasus. These intersections in aggregate were the objects of recogni� tion in the region. The task is to subdivide these inter� sections into classes of high and low seismicity, relative to the threshold magnitude М0 = 6.0. For this purpose, the pattern recognition technique is used. Earlier, the intersections of lineaments, where М ≥ 5.5 earth� quakes can occur, were identified for the Greater (1) and Lesser Caucasus (2) independently.

The Synthetic Processing of the Remotely Sensed Geological Lineaments and Geochemical Data to Extract the Significant Lineaments in the Terms of Gold-ore Exploration

The Synthetic Processing of the Remotely Sensed Geological Lineaments and Geochemical Data to Extract the Significant Lineaments in the Terms of Gold-ore Exploration

Satellite geometry of faults and fractures and its relationship with porphyry deposits in northern parts of Dahaj-Sardoiyeh belt, south of Iran

Dehaj-Sarduiyeh area is located in the central Iranian volcano-sedimentary complex, southwest of the Kerman province. The study area, in the southern part of this complex, is located with the copper mineralization which is mainly of porphyry type and is associated with extensive hydrothermal alteration. This area has a great potential as far as tertiary porphyry copper deposits are concerned. To provide guides for exploration of porphyry copper mineralization at a district scale, we examine the spatial association between known 16 copper deposits and fracture in the area. Analysis of the lineaments interpreted out of ETM + (band8) data is recognized as another method for locating porphyry type copper mineralization. There is a close correlation between photolineament factor values and the known copper mineralization in the area.

Study of crustal thickness and Poisson ratio of the North China Craton

The crustal thickness and physical properties of the North China Craton (NCC) are important for understanding the destruction of NCC. We collected waveforms of teleseismic events which occurred from August 2007 to March 2009 from 323 broadband seismic stations deployed in the NCC region. In order to obtain reliable receiver functions, the broadband seismograms of 93 teleseismic earthquakes occurred in the epicentral distance range from 30 degree to 95 degree with magnitudes M6. 5 to M8. 5 were collected. Based on these data, we calculated the receiver functions for each of the seismic stations, and inverted for the distributions of crustal thickness and Poisson ratio for the NCC with fine spatial coverage. There are three characteristics of the crustal thickness and the Poisson ratio: (1) Crustal thinning process not only occurs in the east part of NCC, but also extends to the North South Gravity Lineament. (2) Crustal thinning also occurs in the rifts and basins surrounding the Ordos block, and the Poisson ratio in the surrounding rifts is higher than that inside of the Ordos block. In some rifts the Poisson ratio is as high as 0. 3. (3) The crustal thickness of NCC is negatively correlated to the topography, which is in consistence with Airy isostasy, which may imply that the NCC crust is experiencing a slow process of destruction and isostasy. While the isostasy degree is much lower in the central west and north east part of NCC.

Analysis of the Lineaments Extracted from LANDSAT TM Image of the Area around Okemesi, South-Western Nigeria

Lineament analysis of the area around Okemesi were carriedout using a remotely sensed LANDSAT THEMATIC MAPPER ( LANDSAT TM ) imagery of scale 9.2km to delineate groundwater productive zones in the areas around okemesi, based on the frequency and density of lineaments on the lithologies that make up the area. 260 lineaments comprising 157 on the quartzite, 82 on the granite and 21 on the schist and migmatite were extracted from the image with their corresponding directions and lengths. The results show that the highest pecentage lineament density (17.20%) occur on the quartzite at 041° -050° azimuth and having the longest lineament length of 46.47km. This is closely followed by the granite with (20.73%) of the lineament density occuring at 041° -050° azimuth, while the schist and the migmatite and the gneiss which constitute the other rocks on the imagery also have the lowest density of lineaments (19.20%) occuring at 120 0 -130 0 azimuth and the shortest lineament length of 9.75km. The lineaments on the granites are intersected and long, while those on the quartzites are shorter and mostly in E-W direction. The overall results show a polymodal distribution of lineament lengths and frequencies on the quartzites, granites than the schists. Other lithologies, such as gneisses and migmatites, have fewer lineaments because of their ductile nature.