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1

Structure of the crust and lithospheric mantle beneath the central main Ethiopian rift

Kassa Muluken, Alemu Abera, Muluneh Ameha

Acta Geophysica

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2022

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Vol. 70, no 5

1979--1999

EN

We use the complete Bouguer anomaly (CBA) derived from GGMplus 2013 to model the lithosphere–asthenosphere boundary (LAB) depth, LAB temperature, lithospheric mantle density and crustal/lithospheric mantle structure of the central main Ethiopian rift (CMER) and surrounding regions. The regional Bouguer anomaly is estimated by using a 200-km cutoff wavelength low-pass filter, and the resulting anomaly map is inverted using Parker–Oldenburg method to generate the depth to the LAB. The result shows that the LAB depth values fluctuate between 38.8 and 78 km in the region. The LAB temperature is estimated based on the results of the LAB depth in the CMER and surrounding regions. The LAB temperature estimates range between 1267 and 1287 °C in the region. The lithospheric mantle density in the study area varies from 3240 to 3295 kg/m3 , as estimated using empirical equations. Relatively low lithospheric mantle densities are determined to occur beneath the Yerer-Tullu-Wellel Volcanotectonic Lineament and Boru-Toru Structural High. 3D gravity models computed for the study area show thickening of the bottom interfaces of the top layer, upper and lower crystalline basement depths when going from the rift toward the western and eastern plateaus. This crustal thickening is evidenced by the associated low CBA (approximately−285 mGal) observed over the plateaus.

2

Crustal velocity structure in Borneo Island using receiver function inversion

Syuhada Syuhada, Pranata Bayu, Anggono Titi, Ramdhan Mohamad, Zulfakriza Zulfakriza, Febriani Febty, Prasetio Aditya D., Dewi Cinantya N., Hasib Mohammad, Sulaiman Albertus

Acta Geophysica

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2022

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Vol. 70, no 6

2529--2553

EN

Borneo is an island situated in a tectonically complex region and characterised by multiple arcs and continental blocks accreted during the Mesozoic and early Cenozoic. We analyse receiver functions of teleseismic events from 12 seismic stations around the island. In general, these stations sample a variety of geological environments, including Meratus Complex, Eastern Borneo, South–Western Borneo, North–Western Borneo, and Sabah Zones. We then derive the shear wave velocity models from the inversion of receiver functions using the stochastic non-linear approach. Inversion results indicate that the island is covered by sedimentary layers with thickness ranging from 1 to 3 km thick. The inversion solutions for most stations also show that the crustal thickness varies between 26 and 36 km around the region. The variation in the average crustal Vp/Vs values obtained for each seismic station addresses the geological diversity of the study area. Furthermore, the lowvelocity zone with high and low Vp/Vs in the lower crust observed beneath some seismic stations may be associated with the tectonic evolution and development of Borneo Island. The results inferred from our inversion are generally consistent with other previous geological and geophysical studies conducted in this region.

3

Crustal Structure Along Sunda-Banda Arc Transition Zone from Teleseismic Receiver Functions

Syuhada S., Hananto N. D., Abdullah C. I., Puspito N. T., Anggono T., Yudistira T.

Acta Geophysica

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2016

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Vol. 64, no. 6

2020--2050

EN

We analyzed receiver function of teleseismic events recorded at twelve Indonesian-GEOFON (IA-GE) broadband stations using nonlinear Neighbourhood Algorithm (NA) inversion and H-k stacking methods to estimate crustal thickness, Vp/Vs ratios and S-wave velocity structure along Sunda-Banda arc transition zone. We observed crustal thickness of 34-37 km in Timor Island, which is consistent with the previous works. The thick crust (> 30 km) is also found beneath Sumba and Flores Islands, which might be related to the arc-continent collision causing the thickened crust. In Timor and Sumba Islands, we observed high Vp/Vs ratio (> 1.84) with low velocity zone that might be associated with the presence of mafic and ultramafic materials and fluid filled fracture zone. The high Vp/Vs ratio observed at Sumbawa and Flores volcanic Islands might be an indication of partial melt related to the upwelling of hot asthenosphere material through the subducted slab.

4

Lithospheric structure of the Arabian Shield from joint inversion of P- and S-wave receiver functions and dispersion velocities

Al-Amri A. M.

Acta Geologica Polonica

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2015

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Vol. 65, no. 2

227--243

EN

New velocity models of lithospheric thickness and velocity structure have been developed for the Arabian Shield by three tasks: 1) Computing P-Wave Receiver Functions (PRFs) and S-Wave Receiver Functions (SRFs) for all the broadband stations within the Saudi seismic networks. The number of receiver function waveforms depends on the recording time window and quality of the broadband station. 2) Computing ambient noise correlation Green’s functions for all available station pairs within the Saudi seismic networks to image the shear velocity in the crust and uppermost mantle beneath the Arabian Peninsula. Together they provided hundreds of additional, unique paths exclusively sampling the region of interest. Both phase and group velocities for all the resulting empirical Green’s functions have been measured and to be used in the joint inversion. 3) Jointly inverted the PRFs and SRFs obtained in task 1 with dispersion velocities measured on the Green’s functions obtained in task 2 and with fundamental-mode, Rayleigh-wave, group and phase velocities borrowed from the tomographic studies to precisely determine 1D crustal velocity structure and upper mantle. The analysis of the PRFs revealed values of 25 - 45 km for crustal thickness, with the thin crust next to the Red Sea and Gulf of Aqaba and the thicker crust under the platform, and Vp/Vs ratios in the 1.70 – 1.80 range, suggesting a range of compositions (felsic to mafic) for the shield’s crust. The migrated SRFs suggest lithospheric thicknesses in the 80-100 km range for portions of the shield close to the Red Sea and Gulf of Aqaba and near the Arabian Gulf. Generally, the novelty of the velocity models developed under this paper has consisted in the addition of SRF data to extend the velocity models down to lithospheric and sub-lithospheric depths.

5

Topography of the Moho and earth crust structure beneath the East Vietnam Sea from 3D inversion of gravity field data

Nguyen N.T., Nguyen T.H.

Acta Geophysica

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2013

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Vol. 61, no. 2

357--384

EN

The Moho depth, crustal thickness and fault systems of the East Vietnam Sea (EVS) are determined by 3D interpretation of satellite grav- ity. The Moho depth is calculated by 3D Parker inversion from residual gravity anomaly that is obtained by removing the gravity effects of sea- floor and Pre-Cenozoic sediment basement topographies from the free air anomaly. The 3D inversion solution is constrained by power density spectrum of gravity an omaly and seismic data. The calculated Moho depths in the EVS vary from 30-31 km near the coast to 9 km in the Central Basin. A map of the lithosphere extension factor in the Cenozoic is constructed from Moho and Pre-Cenozoic sediment basement depths. The fault systems constructed by the maximum horizontal gradient approach include NE-SW, NW-SE, and N-S oriented faults. Based on the interpretation results, the EVS is sub-divided into five structural zones which demonstrated the different characteristics of the crustal structure.

6

Models of the Earth’s crust from controlled-source seismology – where we stand and where we go?

Malinowski M.

Acta Geophysica

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2013

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Vol. 61, no. 6

1437--1456

EN

Controlled-source seismology (CSS) is the primary source of information regarding the fine structure of the lithosphere. The aim of this paper is to provide an overview of the methods that are commonly used to derive Earth models from CSS data with the focus on the wide-angle reflection/refraction method. Some outlook on the future of the CSS is presented with the special emphasis on the full-wavefield based methods like full-waveform inversion, which brings high level of objectivity into modeling, as well as significantly increases spatial resolution. It is stressed that the researchers should be aware of the limitations of how the elastic parameters transcribe into the actual rock properties which should stimulate them to go beyond the simple P-wave modeling and to build multiparameter Earth models based either on the seismic data or constrained by additional geophysical fields in order to derive sound geological interpretation of their models.

7

Crustal thickness and poisson’s ratio variations across the northwest Himalaya and eastern Ladakh

Hazarika D., Kumar N., Yadav D.

Acta Geophysica

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2013

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Vol. 61, no. 4

905--922

EN

Crustal thickness and PoissonPoisson's ratios are estimated across the northwest (NW) Himalaya and eastern Ladakh applying H-k stacking method on receiver functions of teleseismic earthquakes recorded at 16 broadband seismological stations. The results show significant lateral variation of crustal thickness from the Lesser and Higher Himalaya (~50 km thick) to Ladakh (~80 km thick) through the Indus Tsangpo Suture Zone (ITSZ). The Indian Moho is continuously traceable across the ITSZ which is consistent with the underthrusting of the Indian plate beyond the surface collision boundary. The estimated Poisson's ratio is intermediate in the Tethyan Himalaya (0.269-0.273) and high beneath Ladakh (0.280-0.303), indicating the effect of aqueous fluid/partial melt present in the crust.

8

Badania struktury skorupy ziemskiej na obszarze Europy Centralnej, ze szczególnym uwzględnieniem Transeuropejskiej Strefy Szwu, metodami głębokich profilowań sejsmicznych

Guterch A.

Wiadomości Naftowe i Gazownicze

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2012

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R. 15, Nr 9 (173)

4--9

EN

The complex tectonic history of Central Europe (Fig. 1a) reflects the break-up of a Neoproterozoic supercontinet(s) (Rodinia/Pannotia) to form the fragment Baltica and the subsequent growth of continental Europe beginning with the Caledonian orogeny. Caledonian and younger Variscan orogenesis involved accretion of Laurentian and Gondwanan terranes to the riftet margin of Baltica. (East European craton, EEC) during the Paleozoic. From Central Poland northward, the region also experienced volcanic activity during the Permian and tectonic inversion during the Alpine orogeny, which in the south continues today. The Trans-European Suture Zone (TESZ) is a term used to refer to the suite of sutures and terranes that formed adjacent to the rifted margin of Baltica, and these features extend from the British Isles to the Black Sea region (Fig. 1a and 2). Understanding the structure and evolution of the TESZ region is one of the key tectonic challenges in Europe north of the Alps. The TESZ is far more complex than a single suture but in a broad sense is the boundary between the accreted terranes and Baltica. The TESZ includes the Teisseyre-Tornquist Zone (TTZ), which has several definitions. Here, we will use the term TTZ to refer to a structural zone associated with the southwestern edge of the EEC. Beginning in 1997, Central Europe, between the Baltic and Adriatic Seas, has been covered by an unprecedented network of seismic refraction experiments (Fig. 1b). These experiments - POLONAISE’97, CELEBRATION 2000, ALP 2002, and SUDETES 2003 - have only be possible due to a massive international cooperative effort. International Consortium consisted of 35 institutions from 16 countries in Europe and North America - Austria, Belarus, Canada, Croatia, Czech Republic, Denmark, Finland, Germany, Hungary, Lithuania, Poland, Russia, Slovakia, Slovenia, Turkey and the United States. The majority of the recording instruments was provided by the IRIS/ PASCAL Instrument Center and the University of Texas at El Paso (USA), the Geological Survey of Canada and other countries. For example, in the CELEBRATION experiment, the total number was 1230 stations ands 147 shot points located along seismic lines of a total length of about 9000 km. A large number of seismic sources and stations in all experiments means that besides 2 - D approach along profiles (Fig. 3 and 4), also 3 - D approach (Fig. 5 and 6) could be implemented in data interpretation. Total length of seismic profiles in all experiments is about 20 000 km (Fig. 1b).

9

The structure of the crust in TESZ area by kriging interpolation

Majdański M.

Acta Geophysica

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2012

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Vol. 60, no. 1

59-75

EN

A precise 3D model of the crust is necessary to start any tectonic or geodynamic interpretation. It is also essential for seismic interpretations of structures lying below as well as for correct analysis of shallow structures using reflection seismics. During the last decades, a number of wide-angle refraction experiments were performed on the territory of central and eastern Europe (POLONAISE’97, CELEBRATION 2000, SUDETES 2003), resulting in many high quality 2D models. It is an interesting and complicated transition zone between Precambrian and Palaeozoic Platforms. This paper presents 3D model of the velocity distribution in the crust and upper mantle interpolated from 2D models of the structure along 33 profiles. The obtained model extends to a depth of 50 km and accurately describes the main features of the crustal structures of Poland and surrounding areas. Different interpolation techniques (Kriging, linear) are compared to assure maximum precision. The final model with estimated uncertainty is an interesting reference of the area for other studies.

10

Upper lithospheric structure in the central Fennoscandian shield: Constraints from P- and S-wave velocity models and Vp/Vs ratio distribution of the BALTIC wide-angle seismic profile

Janik T.

Acta Geophysica

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2010

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Vol. 58, no. 4

543-586

EN

The paper presents an analysis of the crust and upper mantle structure in the central Fennoscandian shield based on new P- and S-wave 2D velocity models of the BALTIC wide-angle reflection and refraction profiles. Using reprocessing of the old data, new P- and S-wave velocity models and V p /V s ratio distribution were developed. Moving from SW to NE, the thickness of the crust varies strongly, from ∼36 km to extremely thick, 58-64 km, crossing Wiborg rapakivi massif, Saimaa and Outokumpu areas, and Eastern Finland complex. Based on the lateral variations of V p , V p /V s and thickness of the crust, three main blocks of the crust and upper mantle were distinguished from SW to NE: southwestern, associated with Wiborg rapakivi massif; the central, having the highest thickness of the crust; and the northeastern, not well documented, with Archaean basement.

11

Lithospheric structure of the western part of the East European Craton investigated by deep seismic profiles

Grad M., Janik T., Guterch A., Środa P., Czuba W.

Geological Quarterly

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2006

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Vol. 50, No. 1

9-22

EN

The Palaeoproterozoic collision of Archaean Fennoscandia, Volgo-Uralia and Sarmatia, viewed as a large composite of terranes, each with an independent history during Archaean and Early Proterozoic time, formed the East European Craton. This paper summarizes the results of deep seismic sounding investigations of the lithospheric structure of the southwestern part of the East European Craton. On the basis of the modern EUROBRIDGE’94–97, POLONAISE’97 and CELEBRATION 2000 projects, as well as of data from the Coast Profile and from reinterpreted profiles VIII and XXIV, the main tectonic units of Fennoscandia and Sarmatia are characterized. The crustal thickness in the whole area investigated is relatively uniform, being between 40 and 50 km (maximum about 55 km). For Fennoscandia, the crystalline crust of the craton can be generally divided into three parts, while in Sarmatia the transition between the middle and lower crust is smooth. For both areas, relatively high P-wave velocities ( 7.0 km/s) were observed in the lower crust. Relatively high seismic velocities of the sub-Moho mantle (~8.2–8.3 km/s) were observed along most of the profiles. The uppermost mantle reflectors often occur ca. 10 to 15 km below the Moho. Finally, we show the variability in physical properties for the major geological domains of Fennoscandia and Sarmatia, which were crossed by the network of our profiles.

12

Lithospheric structure of the TESZ in Poland based on modern seismic experiments

Guterch A., Grad M.

Geological Quarterly

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2006

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Vol. 50, No. 1

23-32

EN

This paper presents the results of seismic investigations on the structure of the lithosphere in the area of the Trans-European Suture Zone (TESZ) in Poland that is located between the southwestern margin of the East European Craton (EEC) to the north-east, the West and Central European Palaeozoic Platform (PP) to the south-west and the Carpathians to the south. Based on results of the modern POLONAISE’97 and CELEBRATION 2000 projects, as well as older profiles, models are presented for the configuration and extent of different crustal types. In the investigated area, the EEC has a relatively uniform crustal thickness of 40 to 50 km with its three-layered crystalline crust displaying P-wave velocities of 6.1–6.4, 6.5–6.8 and 6.9–7.2 km/s in the upper, middle and lower parts, respectively. The Variscan consolidated crust is covered by 1–2 km thick sediments and consists of two layers with velocities of 5.6–6.3 and 6.5–6.65 km/s. In the Carpathians, sediments reaching to depths of some 20 km and are characterized by velocities of <5.6–5.8 km/s, whilst the underlying two-layered crystalline crust displays velocities of 6.0–6.2 and 6.5–6.9 km/s. The crust of the TESZ can be divided into the Małopolska, Kuiavia and Pomerania blocks that are overlain by up to 9–12 km thick sediments having velocities <5.4 km/s. In the area of the TESZ, the upper part of the consolidated crust has to depths of 15–20 kmrelatively low velocities of <6.0 km/s and is commonly regarded as consisting of deformed and slightlymetamorphosed Early Palaeozoic sedimentary and volcanic series. In this area the middle and lower crust are characterized by velocities in the range of 6.3–6.6 km/s and 6.8–7.2 km/s, respectively, that are comparable to the EEC. Based on the dense network of seismic profiles the map of the depth toMoho is given for the area of Poland. Uppermost mantle reflectors occur about 10 to 15 km below the Moho whereas the deepest reflectors are recorded at depths of 90 km. Future investigations ought to aim at an integrated geological-geophysical program, including deep near-verical reflection-seismic profiling and ultimately the drilling of deep calibration boreholes.

13

Crustal structure of the Trans-European Suture Zone in Central Poland - reinterpretation of the LT-2, LT-4 and LT-5 deep seismic sounding profiles

Grad M., Guterch A., Polkowska-Purys A.

Geological Quarterly

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2005

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Vol. 49, No. 3

243--252

EN

The paper gives a reinterpretation of data from three deep seismic sounding profiles-LT-2, LT-4 and LT-5 - acquired in 1974-1979 between the Precambrian East European Craton (EEC) and the Palaeozoic Platform (PP) in Central Poland. Good quality seismic records in the distance interval from 50-90 to 200-280 km were the input data for the modelling of the crustal and uppermost mantle structure. Clear first arrivals and later phases of waves reflected/refracted from the crustal and the Moho boundaries were interpreted using a two-dimensional (2-D) ray tracing technique. In general, the crustal thickness along the three profiles varies from 30-35 km in the Palaeozoic platform area, to 42-44 km in the Polish part of the EEC, being 35-40 km in the transition zone between the PP and the EEC. In the transition area, the P-wave velocity is very low (Vp < 6.0 km/s) down to depths of 15-18 km, indicating that a very thick succession of sedimentary, metamorphosed or volcanic origin rocks is present there. All three 2-D models of the crust are discussed together with results obtained 20-30 years ago, particularly taking into account the difference in interpretation methods and new computation possibilities. Jointly with recent seismic studies along the profiles LT-7 and TTZ, as well as the POLONAISE'97 profiles P1-P4, the reinterpreted old profiles provide a collection of crustal models of the TESZ in Poland.

14

Huge contrasts of the lithospheric structure revealed by new generation seismic experiments in Central Europe

Guterch A., Grad M., Keller R. G.

Przegląd Geologiczny

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2004

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Vol. 52, nr 8/2

753-760

EN

Beginning in 1997, Central Europe, between the Baltic and Adriatic Seas, has been covered by an unprecedented network of seismic refraction experiments (Fig.1A). These experiments — POLONAISE’97, CELEBRATION 2000, ALP 2002, and SUDETES 2003—have only been possible due to a massive international cooperative effort. International Consortium consisted of more than 30 institutions from 16 countries in Europe and North America—Austria, Belarus, Canada, Croatia, Czech Republic, Denmark, Finland, Germany, Hungary, Lithuania, Poland, Russia, Slovakia, Slovenia, Turkey, and the United States. The majority of the recording instruments was provided by the IRIS /PASCAL Instrument Center and the University of Texas at El Paso (USA), the Geological Survey of Canada, and other countries. For example, in the CELEBRATION experiment, the total number was 1230 stations and 147 shot points located along seismic lines of a total length of about 9000 km. A large number of seismic sources and stations in all experiments means that besides 2-D approach along profiles, also 3-D approach could be implemented in data interpretation. Total length of seismic profiles in all experiments is about 20,000 km.

15

Tektoniczne uwarunkowania rowu lubelskiego (późny dewon-karbon)

Narkiewicz M.

Przegląd Geologiczny

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2003

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Vol. 51, nr 9

771-776

PL

Koncepcja "pasywnej synkliny" (Antonowicz i in., 2003) jako alternatywy dla rowu lubelskiego budzi poważne wątpliwości. Znacznie bardziej prawdopodobne jest istnienie rowu tektonicznego, interpretowanego przez wielu autorów od lat 70. ubiegłego wieku. Inwersję tej jednostki w najpóźniejszym karbonie poprzedził rozwój wydłużonych depocentrów w dewonie późnym i późnym wizenie-westfalu. Od środkowego franu do famenu zarówno strefa Kocka jak i strefa obecnego uskoku Kazimierz-Ursynów funkcjonowały jako krawędzie depozycyjne, z którymi związane są duże gradienty miąższościowe i facjalne. W karbonie strefa Kocka przynajmniej okresowo stanowiła ważną granicę obszarów o zróżnicowanej subsydencji i depozycji. Natomiast południowo-zachodnia krawędź depozycyjna rowu znajdowała się prawdopodobnie 20-30 km na SW od jego obecnej (tektonicznej) granicy. Mogła się ona pokrywać z nieciągłością skorupową, interpretowaną na podstawie danych sejsmicznych i grawimetrycznych. Związek genetyczny z orogenem waryscyjskim polegał nie tyle na bezpośrednim przenoszeniu na Lubelszczyznę naskórkowych nasunięć zgodnie, np. z modelem appalachijskim, co na głęboko zakorzenionych blokowych ruchach pionowych i przesuwczych w strefie platformowego przedpola, w reakcji na kompresję na aktywnej krawędzi płyty. Odrzucenie koncepcji "pasywnej synkliny" i przyjęcie modelu rowu lubelskiego, w podwójnym (depozycyjnym i tektonicznym) sensie ma poważne konsekwencje dla strategii poszukiwań naftowych. M.in. umożliwia predykcję rozmieszczenia ważnych górnodewońskich facji macierzystych, a także rzutuje na przewidywane modele pułapek strukturalnych.

EN

The idea of a "passive syncline " (Antonowicz et al, 2003) as an alternative to the well-established concept of the Lublin Graben raises serious doubts. Development of the structural unit in the latest Carboniferous was preceded by establishment of elongated depocenters in the Late Devonian and late Visean-Westphalian, most probably in a changing pull-apart regime. From the middle Frasnian to Famennian both flanks of the graben, i.e. the Kock Fault Zone and the present Kazimierz-Ursynów Fault zone acted as depositional edges with associated pronounced fades and sediment-hickness gradients. During the Carboniferous the Kock Zone constituted at least intermittently an important boundary between areas with different depositional and subsidence histories. On the other hand, the south-western depositional edge of the basin was probably located 20-30 km SW of the present graben boundary. It could have been related to the crustal discontinuity interpreted after seismic and gravimetric data. A genetic relationship between the graben origin and the Variscan orogen to the west did not involve transmission of thin-skinned thrusts like e.g. in the Appalachian model. Rather, it consisted of deep-rooted vertical and strike-slip movements of the eastern orogenic foreland in response to compression at the active plate margin. Rejection of the "passive syncline " model and at the same time confirmation of the Lublin Graben concept (in both depositional and structural sense) has important consequences for petroleum prospection. Among others, it allows prediction of important petroleum source-deposits of the upper Frasnian-lower Famennian, and constrains predicted structural-trap models.

16

Holy Cross Mts. area - crustal structure, geophysical data and general geology

Dadlez R.

Geological Quarterly

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2001

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Vol. 45, No 2

99-106

EN

At the start of international seismic experiment CELEBRATION 2000 an attempt at the compilation of the present geophysical and geological data in the Holy Cross Mountains and their surroundings has been made. Five geological units of the first order and four their dividing fault zones have been distinguished in the area studied: uplifted part of the Precambrian Craton (A), Lublin Unit (B), Radom-Łysogóry Unit (C), Kielce-Nida Unit (D), and Upper Silesian Massif (E). They are separated by fault zones: Kock Fault Zone (1) between A and B, Kazimierz Fault Zone (2) between B and C, Holy Cross Fault (3) between C and D, Cracow-Lubliniec Fold Zone (4) between D and E. The first and last units bordering the area are not discussed in this paper. Units B and C are built on the cratonic crust up to 54 km thick. Unit C is composed of poorly correlated mosaic of crustal blocks with crust 35-45 km thick. Fault zones 1 and 3 coincide with crustal fractures while zone 2 has not its counterpart in crustal structure.

17

Crustal structure of the East European Craton along the POLONAISE'97 P5 profile

Czuba W., Grad M., Luosto U., Motuza G., Nasedkin V.

Acta Geophysica Polonica

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2001

|

Vol. 49, nr 2

145-168

EN

The large scale seismic experiment POLONAISE'97 (POlish Lithospheric Onsets-An International Seismic Experiment) was carried out in May 1997 in Poland, Lithuania and Germany. Its main purpose was to investigate the structure of the crust and the uppermost mantle in the region of the Trans European Suture Zone. This paper covers the interpretation of seismic and gravity data along the NW-SE trending, 180km long profile P5 located on the East European Craton. The recordings were of a high quality with seismic energy clearly visible along the whole profile. We have not found waves refracted below the upper crust in first arrivals. The PmP wave can usually be correlated at distances starting from 80-100 km. The crystalline crust consists of three parts: the upper, middle and lower crust with P-wave velocities of 5.9-6.3, 6.5-6.85 and 7.0-7.2 km/s, respectively. We have delineated a high velocity body with the P-wave velocity in the range of 6-6.75 km/s in the upper crust in the NW part of the profile. The Moho depth is 42 km at the NW end of the profile dipping to the SE to 44 km with an undulating shape. We have found a floating reflector within the lower crust in the NW part of the profile and a reflecting upper mantle boundary in the central part of the profile at a depth of about 54 km. Sufficient S-wave data was available to estimate the Vp/Vs ratio for each layer, being 1.75 in the high velocity body, 1.67 in the upper crust, 1.70 in the middle crust and 1.76 in the lower crust.

18

Nowa generacja programów badań głębokich struktur litosfery: eksperymenty sejsmiczne POLONAISE'97 i CELEBRATION 2000 w Europie Środkowej

Guterch A., Grad M.

Przegląd Geologiczny

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2000

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Vol. 48, nr 12

1085-1095

PL

Duży sejsmiczny eksperyment POLONAISE '97 został zrealizowany w maju 1997 r. na obszarze Polski w strefie transeuropejskiego szwu i złożonych struktur związanych z basenem polskim. W badaniach wzięły udział zespoły geofizyczne z Polski, Danii, USA, Litwy, Niemiec, Finlandii, Szwecji i Kanady. Badania przeprowadzono na dużą skalę wzdłuż profili sejsmicznych o łącznej długości około 2000 km, z udziałem 613 stacji sejsmicznych, które wykonały rejestrację fal sejsmicznych wzbudzonych w 64 punktach strzałowych. Jednym z ważniejszych rezultatów badań było stwierdzenie wybitnej asymetrii między maksymalną miąższością pokrywy osadowej w rowie polskim (16-20 km) i skorupowym korzeniem (o50 km) związanym z TESZ/TTZ. Inny wielki eksperyment sejsmiczny nazwany CELEBRA TION 2000 był wykonany w Europie Środkowej w czerwcu 2000 r., na obszarze południowej i wschodniej Polski, Słowacji, Węgier, Austrii, Czech, SE Niemiec oraz częściowo na Białorusi i w Rosji. Sejsmiczny eksperyment CELEBRATION 2000 został zlokalizowany na obszarze południowo-wschodniego obrzeżenia Baltiki (wschodnioeuropejski kraton), południowej części TESZ, struktur inwersyjnych TESZ, orogenu karpackiego, basenu panońskiego i masywu czeskiego. Prace zostały sfinansowane przez międzynarodowe konsorcjum 28 instytucji z 13 krajów z Europy i Ameryki Północnej. Z 1200 aparatur sejsmicznych, które zostały użyte do rejestracji, zdecydowaną większość dostarczyły Centrum Aparaturowe IRIS/PASCAL w Waszyngtonie i Uniwersytet Teksański w El Paso w USA. Pozostałe aparatury sejsmiczne dostarczyły Kanadyjska Służba Geologiczna, uniwersytet w Kopenhadze w Danii, Instytut Badań Ziemi w Gebze w Turcji i inne organizacje z pozostałych krajów. Całkowita długość profili sejsmicznych wynosi około 9000 km. Wzdłuż profili sejsmicznych zlokalizowano 147punktów strzałowych.

EN

A large seismic experiment, the POLONAISE '97 project, was conducted in Poland during May 1997 and targeted the deep structure of the Trans European Suture Zone (TESZ) and the complex series of upper crustal features associated with the Polish Basin. It included contributions from the geophysical communities in Poland, Denmark, the USA, Lithuania, Germany, Finland, Sweden and Canada. This large lithospheric seismic experiment deployed 613 instruments to record 64 shots along five profiles with a total length of about 2000 km. One of the most important result is a very distinct asymmetry between the maximum thickness of the sedimentary cover in the Polish Trough (16-20 km) and the crustal root (a50 km) associated with TESZ/TTZ. Another large scale experiment named CELEBRATION 2000 was carried out in Central Europe during June 2000 in the territory of Southern and Eastern Poland, Slovak Republic, Hungary, Austria, the Czech Republic, SE Germany, and partly in Belarus and Russia. The CELEBRATION 2000 seismic experiment is located in the area of the southern portion of the TESZ region, the margin ofBaltica (East European Craton), inversion structures along the TESZ, the Carpathian orogenic belt, the Panonian Basin and the Bohemian Massif. Funding for the CELEBRATION 2000 experiment was made by the International Consortium consisted of 28 institutions from 13 countries in Europe and North America. The majority of the recording instruments was provided by IRIS/PASCAL Instrument Center and the University of Texas atEl Paso in the USA, the Geological Survey of Canada, the University of Copenhagen in Denmark, the Earth Research Institute in Gebze (Turkey) and others. The total number was 1200 stations and 147 shot points located along seismic lines of a total length of about 9000 km.