Lithological Aspects Research Articles

O POTENCIAL DA ROCHAGEM NO NORDESTE DO PARÁ PARA O CULTIVO DE MANDIOCA

The technology, called rochagem (stonemeal), is a recent and sustainable technical solution, increasingly used for the recovery and refertilization of agricultural areas with impoverished soils, using rock dust. In the Northeast of Pará – NEPA, cassava has great economic and social importance, and this region is the largest producer of cassava in Brazil. The great regional limit for the growth of this agricultural activity, in terms of productivity, is the nature of its soils and the human action of intensive and not very rational agricultural practices. To face this situation, in addition to detailing a little more what is Rocha do Solo and Remineralization, we consider geological and lithological aspects of the region in focus, aiming at the potential of sustainable cultivation of the culture. The edaphic parameters evaluated indicate its high geodiversity, which could provide the regional soils with all the macro and micronutrients necessary for their refertilization and, thus, the development of cassava. Keywords: Cassava culture; manioc culture; rockfill; sustainability.

A new approach automatic separation of the Bouguer gravity anomaly, using a new concept for 2D-semi-inversion of the sphere-shaped model

ABSTRACT The present research represents a new, fast and easy-to-apply semi-inversion technique for the direct separation of the Bouguer gravity anomaly to its corresponding depths or thicknesses of the prior known rock formations from a borehole (as a control point). As well as the possibility of tracing these formations on the profile points to the Bouguer gravity map according to their density contrasts with basement rock. The proposed method is based on the fact that the sum of the gravitational effect at a point on the Earth’s surface is equal to the sum of the subsurface gravity effects arising from the points of masses of the causal bodies along the vertical line between the Earth’s surface and the basement rocks. In this method, two sedimentary basin models were built based on the distribution of densities from a prior known borehole. Assuming that the depths of the pointed tops of these rock formations can be replaced by the centres of sphere bodies (or point masses) as causative sources of gravitational effect and by the use of a simple algorithm, it was possible to calculate the depths of the rock formations and trace them on the profile, using a new concept called the zero-offset gravity measurement. In this concept, the measuring gravity is vertically above the centre of the sphere-shaped body as it represents the causative source, and its depths are equal to the radius of the sphere body. The present method was assessed on hypothetical models and synthetic data and applied to two real data in field cases which vary in geological and lithological aspects. The first assessed location is Abu Roash Dome Area, southwest Cairo, Egypt, and the second location is the Mors Salt Dome, North Jutland, Denmark.

MORPHOSCOPIC EVALUATION OF SANTO ANTÔNIO RIVER SEDIMENTS IN SERRA DA CANASTRA NATIONAL PARK - MG AND SURROUNDINGS

The sedimentary morphoscopy studies is an important tool to characterize grains of a given channel with studies of sphericity, roundness and parental material, from their results, which can influence the relief sculpture. The purpose of this research is to understand the distribution and characterization of sediments collected in the Santo Antônio River Basin, located in the Serra da Canastra National Park – MG and surroundings, in order to evaluate the dynamics of sediment transport that occur in this space. Through textural analysis and the study of the genetics of the samples collected in the river channels, they are the result of dynamic processes that collaborate for the sculpting of the regional relief. These channels carry sediments, which were collected in a total of 51 points and, for each sampling point, 50 discontinuous grains with three different diameters were evaluated: 0.600mm; 0.850mm; 1.70mm. In all, approximately 7,650 grains were evaluated. Enabling the quali-quantification of the grains on their sphericity, roundness and the lithological aspect of the material. From the analyzes carried out with the granulometry method by sieving and observation by a precision portable digital type magnifier, monocular, 1000x magnification with a 2.0 megapixel camera. The results point to a greater number of sediments with low sphericity, roundness of the very angular to angular type, with predominance of material of geological aspect such as quartz, laterite and mica.

Mudstone dominated lacustrine deltaic: Lower Cretaceous Damoguaihe Formation, Hailaer Basin, China

Classic Gilbert-type deltas (GTDs) of both lacustrine and marginal marine settings are usually dominated by coarse-grained sandstone and conglomerate, along with gravity-follow deposits. Like other types of deltas, the sediments of GTDs have been traditionally divided into delta plain, delta front and prodelta belts that transit basin-ward from flat-lying topset through inclined foreset to tangentially-flat bottomset accumulations, respectively. The major difference between GTDs and other types of river-, tide- or wave-dominated deltas is the relative coarser and steeper foreset accumulations of the GTDs. The Early Cretaceous Damoguaihe Formation of the Hailaer Basin was deposited in a lacustro-deltaic system. Outcrop, seismic and well-data analyses provide stratal geometric pattern that resembles Gilbert-type deltaic setting but with foresets atypical to the GTDs. The formation preserves two fundamental characteristics: oblique-tangential stratigraphic pattern depositional setting and mudstone-dominated foreset lithology which does not fit the description of foresets of common Gilbert-type deltas. Thus, we envisage that the Lacustro-deltaic successions of the Damoguaihe Formation represent atypical Gilbert-type accumulations. We present here depositional properties that are key to hydrocarbon exploration, and whether volumetrically-significant sand bodies occur within the Damoguaihe Formation as it has been discussed in previous studies. This study endeavors to provide detailed lithologic description of the Damoguaihe Formation and its depositional setting as atypical Gilbert-type delta dominated by mudstone instead of the relatively well-documented sandstone dominated types. This study also sheds light on potential exploration risks that can be posed by fine-grained lithologic aspects of the formation, particularly in frontier areas where little data are available.

Correlation and sequence stratigraphic interpretation of the lithostratigraphic Snake Cave Interval: Implications for hydrocarbon reservoir prospectivity between the southeast Blantyre and northwestern Neckarboo Sub-basins, Darling Basin, southeastern Australia

Correlation and sequence stratigraphic interpretation was conducted on the upper Lower through upper Middle Devonian sandstones of the Snake Cave Interval succession between the southeast Blantyre and northwestern Neckarboo sub-basins across the central Darling Basin. This article necessitated the definition and use of many sedimentary lithotypes related to different facies associations and depositional environment criteria for the purpose of establishing the sequence stratigraphy to aid hydrocarbon exploration of the studied areas. The data set used a combination of wireline logs, core/cutting data and analysis of the paleo-environments of sedimentary facies from three wells. The sedimentological analysis showed that the Snake Cave Interval section presents three different facies associations, which are visible in both vertical and lateral successions, and are characterised as: meandering and braided fluvial facies associations with minor fluvio-shallow lacustrine complex facies associations. The Snake Cave Interval section in the studied areas is consistently defined by six third-order depositional sequences informally named SCS1, SCS2, SCS3, SCS4, SCS5 and SCS6 in the Nyngynderry-1 and Mount Emu-1 exploration wells, and the Kewell East-1 stratigraphic well. All the stratal patterns in the internal sequence stratigraphic units are asymmetric and marked by lowstand, transgressive and highstand systems tracts separated by sequence boundaries, maximum flooding surfaces and transgression surfaces with unique gamma-ray log response characteristics calibrated by particular lithologic aspects. These are all incorporated within the sequence stratigraphic approach to hydrocarbon reservoir prediction. The stratigraphic architecture of the third-order depositional sequences presented here in our study has implications for the hydrocarbon potential of sandstone reservoirs in the southeastern Darling Basin including the Snake Cave Interval succession targets.

Groundwater quality : comparing alluvial plain and tertiary volcanic in tropical region

Sustainable water resources are the most important issue related to the effects of land use change. However, aspects of geomorphology and lithology have not been studied by researchers before. This study aims to analyze the characteristics of groundwater systems associated with lithology and geomorphology. The method used in this study was a survey. Data retrieval is done during the long dry season (tropical region), and the normal dry season in regions with different land forms and lithology. Analyze the data by comparing groundwater samples with physical water quality. The results showed that in tertiary volcano areas there is a decrease in the quality of groundwater physically during the long dry season, while in alluvial plains there is no physical decrease in water quality. The decrease in water quality occurs during the long dry season. The decrease in groundwater quality is influenced by the dry season, the litology of quarland volcanic rocks, and the shape of tertiary volcanic landform.

Lithological characteristics and formation conditions of lower jurassic limestones occuring in the Patil mountain (south-western Crimea)

Background. In this article, we investigate an outcrop of the Lower Jurassic limestones of the Eskiorda suite located on the northern slope of the Bodrak River basin in the south-western Crimea.Aim. The outcrop under study is mentioned in the majority of monographs devoted to the geology of the Crimean Mountains. Although the palaeontology of this assemblage has been sufficiently studied, its lithological aspects require elucidation. We carried out a series of lithological studies to identify the composition, structure and formation conditions of this limestone assemblage.Materials and methods. A macroscopic study of the outcrop was conducted followed by a detailed lithological study of collected limestone samples using a polarising microscope.Results. The conducted microscopic analysis revealed three structural types: organogenic-detrital, detrital and oolitic-organogenic-detrital limestones. The dominant component in the composition was fragments of echinoderms, mainly crinoids. Among other components were — in descending order — brachiopods, gastropods, foraminifera, remains of green algae, sponges, ostracods, ammonites and radiolarians, whose total content did not exceed 10%. Cinoid fragments were round to a various degree. The limestone fragments (intraclasts) were characterised by organogenic-clastic and pelitomorphic structures with an organogenic sludge, occasionally containing fine-sandy and silty quartz admixtures. Oolitic-organogenic-detrital limestones were almost entirely composed of crinoid fragments, some of which represented oolith cores. A specific feature of the limestones under study is their significant hardness resulting from the cementation of the structural components predominantly with crustification cement of several generations.Conclusions. The obtained results allowed us to draw conclusions about the formation conditions of the studied rocks. The limestones were formed in shallow water under the action of waves on the sediment in zones of constant currents. The hydrodynamic action on the sediment led to the formation of intraclasts. The early lithification of the sediment contributed to the formation of a hard seabed, on which subsequent generations of echinoderms settled, lived and died, forming an accumulative carbonate body.

Geological and geomorphic exploration and formation mechanism of the Shilin Geopark in Zecha, Gansu Province

Zecha Shilin Geopark is located in Luqu County, Gansu Province, where the landform completely preserves the characteristics of alpine karst, with typicality and rarity. In order to reveal its natural scientific value, promote the development of natural resources and landscape protection, through field geological survey, taking Luqu County regional geology as the background, the karst landform types of Zecha Shilin Geopark are introduced, which are mainly plateau stone forest, a line of sky as the highlight, and small karst cave as the auxiliary. Then, the formation mechanism of karst landform in the park is analyzed from four aspects of geological structure, lithology, hydrological climate, and biological factors. It is of certain significance to improve the scientific research of karst series geological relics in high-altitude areas. At the same time, the ecological transformation of alpine karst has a good demonstration effect on the control of karst desertification in South China.

ESTRUTURAÇÃO REGIONAL PRÉ-CRETÁCICA DA IBIAPABA, NOROESTE DO ESTADO DO CEARÁ

A Ibiapaba apresenta lacunas em sua história natural e, por conseguinte, há a necessidade de um maior conhecimento sobre sua geomorfologia. Uma etapa importante para o preenchimento dessa lacuna passa pelo conhecimento da estruturação dos substratos geológicos dos relevos que a compõem, na região noroeste do estado do Ceará. Mais do que influenciar, os aspectos litológicos, tectônicos e cronoestratigráficos, mesmo antigos, influenciam e, por vezes, até condicionam o arranjo geomorfológico em escala regional, o que ocorre na Ibiapaba. Sendo assim, o objetivo principal desse trabalho é analisar os condicionamentos geológicos da estruturação regional de idade pré-cretácica na geomorfologia da Ibiapaba em sua porção setentrional, região noroeste do estado do Ceará. Metodologicamente foram utilizados os pressupostos teóricos da ciência geomorfológica, com ênfase na análise morfoestrutural. Tecnicamente, o contingente metodológico se apoiou nas etapas de gabinete, com detalhados e criteriosos levantamentos bibliográfico e cartográfico, na realização de levantamentos de campo e na análise integrada de todos os dados na etapa de laboratório, com ênfase nos mapeamentos temáticos da Ibiapaba e região. Os resultados alcançados permitem fazer uma análise dos condicionantes geológicos de idade pré-cretácica para o quadro geomorfológico da Ibiapaba, condição básica para o conhecimento do relevo e seus aspectos evolutivos.

Nitrogen isotope compositions of the Upper Triassic Chang 7 Shale, Ordos Basin, North China: Implications for depositional redox conditions

Nitrogen isotope (δ 15 N) analysis has been used to evaluate depositional redox conditions in well-preserved sedimentary systems; however, fewer N-isotope studies have been performed to reconstruct the redox conditions in lacustrine shales. In this paper, we report the δ 15 N data from the Upper Triassic Chang 7 Shale of the Ordos Basin, North China. Sedimentary δ 15 N values are significantly higher in the Chang 7 3 and the lower part of the Chang 7 2 submembers (Zone A; average = 9.4 ± 1.3‰) than in the upper part of the Chang 7 2 and the Chang 7 1 submembers (Zone B; average = 5.4 ± 1.5‰). Previous geochemical measurements (i.e., U and TOC/P) of both zones show wide redox variation, however, the average values of these redox proxies are relatively higher in Zone A than those of Zone B. Combined with lithological aspects of the Chang 7 Shale, our study suggest that Zone A was mainly deposited under suboxic bottom water conditions, whereas Zone B deposits accumulated within an oxygenated water column. Stable organic carbon isotopes (δ 13 C org ) and total nitrogen (TN) values of the two zones display little variation that could be attributed to changing organic matter sources and/or post-depositional alteration of δ 15 N. Thus, we suggest that variations in δ 15 N throughout the Chang 7 Shale primarily reflect differences in depositional redox conditions and δ 15 N values of the shale that can provide important details regarding the depositional history of unconventional resource plays. • Provide the first δ 15 N records of the Chang 7 Shale, Ordos Basin. • Differences in δ 15 N are primarily influenced by water column redox conditions. • Organic-rich intervals accumulated under suboxic conditions. • Tectonic events drove redox changes during deposition.

Analysis and validation of two mathematical models of acoustic impedance in well logs: An example in Namorado oilfield, Campos basin, Brazil

This paper is concerned with the reliability of two different models to compute acoustic impedances in the Namorado oilfield, Campos Basin, Brazil. The acoustic impedance is a physical property related to the interaction of a seismic pulse and the components of the rock. This interaction is useful to understand lithological aspects of the studied area. Numerous models have been proposed in the literature with undesirable results. Particularly for Namorado oilfield, there is few models to estimate acoustic impedances in a reliable framework, specially for lack of log data. To achieve this purpose, we use a petrophysical expression that directly estimates acoustic impedances without the need of density logs. In addition, we also discuss empirical expressions to compute compressional velocities using other log data. To validate both models, we calculate the observed acoustic impedance directly from the elastic theory and also present 2-D maps of impedances for the whole Namorado oilfield. The results show that both models are good for low values of impedance, despite of the overall sub-estimation of the acoustic impedance by the petrophysical model. The empirical model presents more dispersive estimations of acoustic impedance when faced with the observed impedance. With this paper, we are intended to present more possibilities for the poor data coverage of Namorado oilfield.

Risk Assessment of Water Inrush in Tunnel through Water-Rich Fault

A fuzzy comprehensive evaluation method based on gray theory is proposed to assess the risk of water inrush in tunnels through water-rich fault. The Grey-Fuzzy method consists of two parts: one is the single factor evaluation matrix which is created by evaluation index and the risk grade membership function, the other one is the weight of each evaluation index set by using the norm gray correlation degree. Five influence factors (fault dip, groundwater level, RMR, permeability and strata inclination) are selected as evaluation indices from the aspects of stratum lithology, geological structure and hydrogeological condition. The orthogonal numerical simulation test is applied to obtain the quantitative evaluation index of geological structure. Finally, the established risk evaluation method of water inrush was applied to the water diversion tunnel project of Longjinxi. The evaluation results can match the reality situation in tunnel construction.

Литолого-генетический аспект формирования отложений тирской свиты на территории Непского свода

Литолого-генетический аспект формирования отложений тирской свиты на территории Непского свода

Geomorphic and lithologic control on bedrock channels in drainage basins of the Western Arabian Peninsula

Hypsometric curves, their integrals and channel profiles have long been used as effective indicators of stages in topographic evolution. This work presents the geomorphic and lithologic aspects of the drainage basins in the Western Arabian Peninsula by analysing basin hypsometry and channel longitudinal profile steepness and concavity indices in order to understand the erosion regimes. A total of 36 drainage basins in the region were analysed in a geographic information system (GIS) environment with a 30-m ASTER Global Digital Elevation Model. Hypsometric curves display shapes resembling from S-shaped to concave curves. Hypsometric integral (HI) shows generally low values in the study area and varies between 0.13 and 0.5, with a mean of 0.27. From the main set of 36 drainage basins defined, three sets of sub-basins were derived for each Strahler order ranging from 4 to 6. Their HI varied between 0.08 and 0.66 with an average HI of 0.33. Then, the HI for each basin order was plotted against the distance from the central location of each basin from south to north. Results reveal that basin hypsometry is independent of spatial variation and spatial scale. Also no clear relations were found between HI and basin area and shape. Further, HI and hypsometric curves were analysed in terms of lithological control on landforms. Results indicate that basin hypsometry is sensitive to lithological variation in the study area. At the largest scale, the HI values can be divided into two populations. More evenly distributed erosion in crystalline rocks and relatively uneven erosion in volcanic rocks are suggested from the results. Channel longitudinal profile steepness and concavity indices provide the distribution of anomalously steep channels and also reflect variations in the locus and rate of differential erosion. High steepness and low concavity in a basin underlain by volcanic rocks and a reverse trend in crystalline rocks confirm the observation from the results of basin hypsometric analysis.

Seismic spectral decomposition and inversion for buried channels delineation: a case study from the Asmari Reservoir, southwestern Iran

Dense data sampling in 3D seismic surveys provides a clear image from subsurface layers, but it may fail in the cases where the thickness of a layer is below seismic resolution (e.g. thin beds and channels). Seismic spectral decomposition and inversion are among methods that can help us to delineate and study the sub-seismic resolution features. This paper shows how the buried channels of the Asmari formation in an oil field located in southwest Iran were delineated and are studied using seismic spectral decomposition and inversion. The Gabor wavelet transform was used to divide seismic frequency spectra into eight bands out of which three frequency bands with central frequencies of 24, 29, and 35 Hz have been selected for RGB blending for its perfectness in exposing the channels. Several distinct channels were detected at 15ms interval below the top of the Asmari formation. The P-impedance data coincide with the findings further giving information on lithological aspects. Detailed delineation of the channels became possible by using the Matching Pursuit Decomposition (MPD) method. In order to delineate sub-seismic resolution features, spectral decomposition is used to transform time-domain seismic data into the frequency domain and then the special elements corresponding to these subsurface features are enhanced with spectral blending.

Plant diversity in the Kamthi Formation of India: A Review

Plant megafossils recorded from the Kamthi Formation of India have been assessed in the present communication. The formation is mainly exposed in the Mahanadi, Godavari and Wardha basins and has been critically analysed on the basis of its megafloral and palynological contents, and the lithological aspects by earlier workers who variously assigned its age as late Permian, early and late Triassic. An endeavour has been made here to compile all the known plant fossil records from the Kamthi Formation for better understanding of its floral and biostratigraphical significance. Known records of the plant megafossils from the Kamthi Formation reveal dominance of the Glossopteris flora and paucity of the Dicroidium floral elements suggesting a transition between late Permian and early Triassic.

The Rhodope Zone as a primary sediment source of the southern Thrace basin (NE Greece and NW Turkey): evidence from detrital heavy minerals and implications for central-eastern Mediterranean palaeogeography

Detrital heavy mineral analysis coupled with a regional geological review provide key elements to re-evaluate the distribution of the Rhodope metamorphic zone (SE Europe) in the region and its role in determining the evolution of the Thrace basin. We focus on the Eocene–Oligocene sedimentary successions exposed in the southern Thrace basin margin to determine the dispersal pathways of eroded crustal elements, of both oceanic and continental origins, as well as their different contributions through time. Lithological aspects and tectonic data coupled with geochemistry and geochronology of metamorphic terranes exposed in the area point to a common origin of tectonic units exposed in NW Turkey (Biga Peninsula) with those of NE Greece and SE Bulgaria (Rhodope region). The entire region displays (1) common extensional signatures, consisting of comparable granitoid intrusion ages, and a NE-SW sense of shear (2) matching zircon age populations between the metapelitic and metamafic rocks of the Circum-Rhodope Belt (NE Greece) and those of the Camlica–Kemer complex and Cetmi melange exposed in NW Turkey. Detrital heavy mineral abundances from Eocene–Oligocene sandstones of the southern Thrace basin demonstrate the influence of two main sediment sources mostly of ultramafic/ophiolitic and low- to medium-grade metamorphic lithologies, plus a third, volcanic source limited to the late Eocene–Oligocene. Detrital Cr-spinel chemistry is used to understand the origin of the ultramafic material and to discriminate the numerous ultramafic sources exposed in the region. Compositional and stratigraphic data indicate a major influence of the metapelitic source in the eastern part (Gallipoli Peninsula) during the initial stages of sedimentation with increasing contributions from metamafic sources through time. On the other hand, the western and more external part of the southern Thrace margin (Gokceada, Samothraki and Limnos) displays compositional signatures according to a mixed provenance from the metapelitic and metamafic sources of the Circum-Rhodope Belt (Camlica–Kemer complex and Cetmi melange). Tectonic restoration and compositional signatures provide constraints on the Palaeogene palaeogeography of this sector of the central-eastern Mediterranean region.

Using Electrical Resistivity Tomography (ERT) as a tool in geotechnical investigation of the substrate of a highway

Abstract Geological and geotechnical engineering field tests, like structure drillings and dynamic (DPL, DPSH) or static probing (CPT), are considered for a fundamental source of information about soil and water environments. Since Eurocode 7 has been introduced, it has become more common to use also dilatometers (DMT) or pressure meters (PMT). Results obtained using all the mentioned tests are always of a discrete nature - information is provided in certain points in the field. However, they determine the basis for creating spatial models of geological structure and geotechnical condi- tions of a substratum. The range and number of investigations conducted (including drilling, probing and laboratory tests) influence precision, in which a geological structure is identified and thus, also affect probability of compatibility between spatial model and real geological conditions of a substratum. In the paper, results of non-invasive electrical resistivity tomography (ERT) method are presented, comprising 2-dimensional image of a soil medium resistance. Electrical resistance is a parameter that reflects diversification of a soil medium, considering its lithological aspect. In addition, when combined with drilling results, it can be used to accurate determination of boundaries between soil layers. Carrying out of ERT tests in the field during expressway construction contributed to identification of weak, low-strength soils like organic soils (peat, aggradated mud) and of soft consistency cohesive soils. These kinds of soil are the main cause for unacceptable deformations appearing in the new road engineering structure.

Landsat ETM+ imaging for mineral potential mapping: application to Avaj area, Qazvin, Iran

The Avaj area is located in the northwestern part of Iran, on the boundary between the Orumieh-Dokhtar and Sanandaj-Sirjan geological zones. It corresponds to two different geological sub-zones:Abe-Garm, to the north, which is related to the volcanic belt of Orumieh-Dokhtar; and the Razan sub-zone, to the south, which is related to the Sanandaj-Sirjan zone. Lithological aspects of different rock units indicate the presence of four distinct volcanic groups of andesite, basalt, tuff, and dacite. The present research utilizes various Landsat Enhanced Thematic Mapper Plus (ETM+) image-processing techniques, including false colour composite images, colour composite ratio images, and standard principal component (PC) image analysis on six bands and colour composite selective PC images, filtering and supervised classification. Nonetheless, colour composite selective images may be the most reliable method for enhancement of areas with hydrothermal alteration. All the techniques used clearly show the pervasive alteration of kaolinite-argillite in the area. These alterations are mainly related to the andesite, and tuffs have the same trend as fault directions.

U-Pb zircon geochronology of northern metamorphic massifs in the Biga Peninsula (NW Anatolia-Turkey): new data and a new approach to understand the tectonostratigraphy of the region

Metamorphic massifs of the Biga Peninsula can be divided into two approximately ENE–WSW-trending belts. It is believed that these two belts represent two different tectonic zones separated by a NE-trending Alpine ophiolitic suture. The Sakarya Zone lies to the S–SE of this Alpine suture, and consists of the Kazdağ metamorphic complex which is tectonically overlain by the Permo-Triassic Karakaya Complex. The metamorphic rocks, as an Alpine edifice located N–NW of the suture, have been assigned to the Rhodope and Serbo-Macedonian massifs of Bulgaria and Greece. The northern metamorphic belt is represented by the Karadağ Massif in the west, which has been evaluated as a different unit from the others, the Karabiga Massif in the east and the Çamlıca Massif between them. All three massifs are mapped in detail in light of previous studies and LA–ICP–MS U-Pb zircon dating was applied to stratigraphically compare them. Contrary to previous studies, our data indicate that the basement metamorphic associations in these three areas show similar characteristics concerning their stratigraphical and lithological aspects and also spatial distribution of their outcrops. U-Pb LA–ICP–MS dating of zircons from the three individual metamorphic massifs yielded the following data: maximum sedimentation ages of the protolith of mica schists in the range of 559 ± 17 to 582 ± 30 Ma; crystallisation age of the protolith of metavolcanic rocks of 577 ± 20 Ma; and crystallisation age of the protolith of eclogites at 565 ± 9 Ma. These ages clearly show that the metamorphic units of the northern massifs are comparable to each other. Also, the U-Pb zircon concordia diagrams from these three metamorphic massifs show remarkably similar patterns. In addition to the similar maximum sedimentation ages for all mica schists with crystallisation ages of the protoliths of the metabasic rocks, there are two major complex tectono-thermal overprints (episodic lead loss events), at c. 330–300 Ma (Variscan?) and c. 100–10 Ma (Alpine and late Alpine?), respectively. Field mapping and analytical data indicate that the basement rocks of the northern massifs in the Biga Peninsula have a correlative Late Ediacaran to Early Cambrian stratigraphic range. In part, Permian strata unconformably overlie basement rocks in the Karadağ Massif. Both tectono-thermal events are demonstrated by coeval episodic lead loss of many zircons in all samples from all areas. Finally, the results of this research do not support an Alpine suture between the two metamorphic belts of the Biga Peninsula. Therefore, the geological evolution of the region might require reevaluation.