About 1600 joint fractures were measured in tillites of the Upper Hecla Hoek Formation on the southern shore of Bellsund. Measurements were collected in 12 areas between the Renardbreen and Tjörndalen. Ray diagrams and contour diagrams of joint fractures, and contour diagrams of joint fractures after rotation to pre-folding position were made for each area. The preliminary analysis of diagrams indicates 2 conjugated joint sets: ca. 60°—120° and 0°—30°. This joint system is probably older than folding and was originated under ENE—WSW to NE—SW stress.
The Lidfjellet thrust is the most prominent tectonic structure in the Lidfjellet-Řyrlandsodden fold zone, which stretches NNW-SSE along the western coast of Sřrkapp Land in Spitsbergen. This paper provides a reinterpretation of the Lidfjellet structure, with particular reference to lithostratigraphy of the autochthonous and overthrust sequences involved, and to the position of the thrust surface. Geological and palynologicalal data indicate that the sequence attributed previously to the Lower Cretaceous Helvetiafjellet Formation of the autochthonous cover represents in fact the Carboniferous (Viséan) Sergeijevfjellet Formation forming the lower part of the overthrust unit. The youngest deposits involved in tectonic structures of the Lidfjellet-Řyrlandsodden fold zone are of Upper Jurassic age.
Palaeomagnetic investigation of the Upper Carboniferous clastic Hyrnefjellet Formation from opposite limbs of the Hyrnefjellet Anticline in southern Spitsbergen (Svalbard Archipelago) uncovered two components of NRM. Direction C1 (D = 224.6°; I = –27.9°; κ = 22.40; α95% = 5.6°) is of prefolding origin and most probably of near-primary origin. High Tb spectra above 575°C indicate hematite as the carrier of C1. Acquisition of the C1 component may be related to an early diagenetic crystallization of hematite, not excluding a detrital origin of the NRM. A paleopole calculated for the C1 component (F = 23.3°N; L= 147.7°E) falls into the Late Devonian–Early Carboniferous sector of APWP for Baltica. This result suggests that Svalbard remained in the present day orientation with respect to Baltica since the Carboniferous time. A second component with intermediate unblocking temperatures, determined in the Hyrnefjellet Formation deposits, is labelled C2. Its mean orientation for in situ position is D = 11.2°; I = 69.2° (κ = 44.05; α95% = 6.3°), thus being similar to Late Mesozoic directions for Baltica. After 100% tectonic correction for tilting of anticline limbs and axis, the C2 component orientation is D = 265.7°; I = 59.7°, thus being distant from any directions for Baltica. Detailed analysis suggest that the C2 component is most probably of synfolding origin, and it was formed during the Tertiary Alpine Tectonic Event.
Geological investigations of the 4th Polish Geodynamic Expedition to West Antarctica, summer 1990/91, covered the following topics: volcanological studies and mapping at Deception Island; stratigraphic, palaeonotological and sedimentological studies, and mapping of Tertiary glacial and glacio-marine strata on King George Island; sedimentological and mesostructural studies, and mapping at Hurd Peninsula, Livingston Island; and palaeontological sampling of Jurassic (Mount Flora Formation) and Trinity Peninsula Group deposits at Hope Bay, Trinity Peninsula.
Geological investigations of the 3rd Polish Geodynamic Expedition to West Antarctica, 1987—1988, covered the following topics: sedimentological and mesostructural studies of the Trinity Peninsula Group (?Carboniferous — Triassic) at Hope Bay, Cape Legoupil and Andvord Bay, Antarctic Peninsula, and at South Bay. Livingston Island (South Shetland Islands); late Mesozoic plant-bearing terrestrial sediments at Hope Bay; Antarctic Peninsula Volcanic Group, Andean-type plutons and systems of acidic and basic dykes (Upper Cretaceous and ?Tertiary) at Trinity Peninsula and around Gerlache Strait (Arctowski Peninsula, Anvers and Brabant islands); basalts and hyaloclastites within Tertiary glacigenic successions of King George Island; volcanic succession of the Deception Island caldera.
The aim of this study was to identify thoroughly the geological structure of the Choszczno Anticline for potential CO2 storage. The paper presents the interpretation of seismic materials for a selected seismic profile reprocessed into a section of reflection coefficients characterized by increased recording resolution as compared to the wave image. Particular attention was paid to the geological complexes associated with the Jurassic reservoir formations suitable for carbon dioxide storage within the anticline. The correlation of the identified layers reflects the lithology and structure of the rock series. It allows determination of the thicknesses of the series and changes within them, and enables linking the individual layers with the lithologic units, based on geological data. The study refers to the whole Zechstein-Mesozoic succession of the Choszczno Anticline, with special emphasis on these series, in which there are potential reservoir formations for CO2 storage. The interpretation has significantly expanded the amount of data provided in standard seismic documentations. While assessing the suitability of the formations for CO2 storage, special attention should be paid to the tectonic disturbances within the Komorowo Formation, especially in the top part of the Choszczno structure. The Reed Sandstone bed is more continuous in this respect. The obtained results seem to suggest wider application of reprocessing of seismic materials into effective reflection coefficients to study the geological structure, also for other structures.
Modern space measurement techniques like SLR, DORIS, VLBI and GNSS are used to study the tectonic plates. The determination of plate motion parameters (Φ, Λ, ω) from various geodetic measurements is outlined. This paper is the third part of our studies on estimating geodetic and geodynamic parameters; it regards an accuracy analysis of the determined Φ, Λ, ω parameters which describe motions of the tectonic plates using Very Long Base Interferometry (VLBI) technique. Prior to this, SLR and DORIS space measurement techniques were examined by authors. The study is based on the velocities of station positions, as included in a realization of the International Terrestrial Reference System– ITRF2008 forVLBI technique, published by the International Earth Rotation and Reference Systems Service (IERS). This model is made subject to an analysis in association with the APKIM2005 model. Six big plates, namely: Eurasian (EUAS), African (AFR), Australian (AUS), North American (NOAM), Pacific (PACF) and Antarctic (ANTC) were analysed. The results obtained in this analysis were compared with our previous estimations based on DORIS and SLR techniques and estimated according to the APKIM2005 model. Generally, all our three solutions based on SLR, DORIS and VLBI measurement techniques were found to be consistent.
The Szamotuły Graben covers the southernmost part of the Permo-Mesozoic Poznań–Szamotuły Fault Zone. Along this regional discontinuity there are several salt structures, including the Szamotuły diapir, over which an extensional graben formed in the Paleogene and Neogene. The graben is located north of Poznań in central- western Poland, and is NW–SE-trending, ~20 km long, 3–5.5 km wide, and up to 160 m deep. It is filled with Lower Oligocene and Neogene sediments, including relatively thick lignite seams. Data from boreholes allow the assignment of the graben-fill sediments to appropriate lithostratigraphic units. Furthermore, analysis of changes in the thickness of these units provides evidence for periods of accelerated graben subsidence or uplift relative to its flanks. As a result, two distinct stages of tectonic subsidence and one inversion in the Paleogene–Neogene evolution of the Szamotuły Graben have been distinguished. Thus, relatively significant subsidence occurred in the Early Oligocene and the middle Early–earliest Mid-Miocene, while slight inversion took place in the middle part of the Mid-Miocene.
The area of NW Wedel Jarlsberg Land south of Bellsund (Spitsbergen), between Dunderbukta in the west and the Berzeliustinden mountain group in the east, consists of five fault-bounded blocks: (1) the Renardbreen Block (Middle–Late Proterozoic basement rocks), (2) the Chamberlindalen Block (Late Proterozoic basement rocks), (3) the Martinfjella Block (Late Proterozoic through Early Ordovician basement rocks), (4) the Berzeliustinden Block (Late Proterozoic and Early Ordovician basement rocks covered by Late Palaeozoic–Tertiary platform deposits), (5) the Reinodden Block (Late Palaeozoic and Mesozoic rocks). The paper presents an outline of lithostratigraphy (Middle/Upper Proterozoic–Lower Ordovician: Hecla Hoek Succession) and architecture of the Caledonian basement in which several thrust-sheets and thrust-folds have been recognized. It also discusses some aspects of Tertiary overthrusting, faulting and rotation with affected the basement rocks and remodelled its Caledonian architecture.
The lithospheric transect South Shetland Islands (SSI) — Antarctic Peninsula (AP) includes: the Shetland Trench (subductional) and the adjacent portion of the SE Pacific oceanic crust; the South Shetland Microplate (younger magmatic arc superimposed on continental crust); the Bransfield Rift and Platform (younger back-arc basin); the Trinity Horst (older magmatic arc superimposed on continental crust); the Gustav Rift (Late Cenozoic) and James Ross Platform (older back-arc basin). Deep seismic sounding allowed to trace the Moho discontinuity at about 30 km under South Shetlands and at 38—42 km in the northern part of Antarctic Peninsula (Trinity Horst), under typical continental crust. Modified crust was recognized under Bransfield Strait. Geological interpretation based on deep seismic refraction and multichannel reflection soundings, and surface geological data, is presented.