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Geochronologia skał wulkanicznych centralnej i południowej części Wyspy Króla Jerzego (Szetlandy Południowe, Zachodnia Antarktyka)

Pańczyk M.

Przegląd Geologiczny

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2013

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Vol. 61, nr 2

117--119

EN

New isotopic and paleomagnetic studies of volcanic rocks from the central and southern part of the King George Island and Penguin Island were carried out. The combination of three dating methods: single grain U-Pb dating of separated zircons, whole-rock 40Ar-39Ar dating and magnetostratigraphy allow distinguishing five magmatic activity phases: the oldest, late Cretaceous (Campanian), early to middle Eocene (about 53–43 Ma), late Eocene (about 37–35 Ma), late Oligocene (about 28–25 Ma) and, the youngest, late Pliocene to Holocene.

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Geochronology of selected andesitic lavas from the King George Bay area (SE King George Island)

Pańczyk M., Nawrocki J.

Geological Quarterly

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2011

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Vol. 55, No. 4

323-334

EN

Volcanic rocks from the Lions Rump area, which are the basement for a sequence of glaciomarine sediments of the Polonez Cove Formation, and lava flows from the Turret Point–Three Sisters Point area were sampled for thermogeochronological and palaeomagnetic investigations. Generally, andesitic lavas from King George Bay area consist mainly of clinopyroxene (Ti-augite) orthopyroxene (hyperstene) and plagioclase phenocrysts. The groundmass comprises mostly plagioclase laths, clinopyroxene, titanomagnetite and rare orthopyroxene crystals. However, the modal content, size, shape and distribution of phenocrysts are variable and specific for each sample. The Ar-Ar plateaus ages calculated for lavas from the Lions Rump area are very homogenous and point to middle Eocene age (Lutetian, ~44.5 Ma). The similar and consistent ages for volcanic basement for that area excluded the thesis about separate tectonic evolution of the Warszawa and Kraków blocks at least since the middle Eocene. The lavas from Turret Point and Three Sister Point are younger and were emplaced during the late Eocene (Bartonian/Priabonian: 37.3 š0.4 Ma and Priabonian: 35.35 š0.15 Ma, respectively). The results of isotopic investigations are consistent with magnetic polarities of the rocks indicating that the samples from the Lions Rump area are coeval with the lower part of the C20 polarity chron whereas the sample from Turret Point can be correlated with the upper part of the C17 polarity chron

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Admiralty Bay, King George Island (Soth Shetland Islands, West Antarctica): A geological monograph

Birkenmajer K.

Studia Geologica Polonica

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2003

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Vol. 120

5-73

EN

Admiralty Bay is the largest fjord system on King George Island, South Shetland Islands (West Antarctica). Exposures along its coasts, and on nunataks, give a good insight into geological history of the area, spanning more than 90 Ma, from Late Cretaceous to Recent. King George Island is located in the middle of the South Shetland Islands arc. To the north, it borders on the South Shetland subduction trench, part of Drake Passage, to the south - it is divided from crustal block of Antarctic Peninsula by a young rift and basin of Bransfield Strait. The island consists of four tectonic blocks/terranes bounded by longitudinal strike-slip faults of Tertiary age. Three of these blocks, the Barton Horst (axial), the Warszawa Block (southern, downthrown with respect to the Barton Horst), and the Kraków Block (southernmost, downthrown with respect to the Warszawa Block, bordering on Bransfield Rift) are present at Admiralty Bay. Geological successions of stratiform volcanic/sedimentary and intrusive (hypabyssal and plutonic) rocks markedly differ between these tectonic blocks/terranes, suggesting considerable horizontal displacements between them along longitudinal strike-slip faults. Geological age of stratiform and intrusive magmatic successions is there generally well established on radiometric dating. Terrestrial strata yielded numerous fossil plant assemblages of Late Cretaceous and Early Tertiary ages. In the Admiralty Bay area, there occur also the westernmost exposures of Oligocene marine/glaciomarine strata, whose principal outcrops are located further east. The paper is a monograph of the Admiralty Bay area, the geological map of which, 1:50,000 scale (Pl. I), and geological cross-sections (Pl. II), are attached under a separate jacket. The monograph gives an outline of geological research on King George Island since its beginnings in the 19th century, a concise description of the Upper Cretaceous through Lower Oligocene rock successions within each tectonic block/terrane, and of Quaternary strata, forms and events.

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Geology and Petrography of a Large Porphyritic Andesite Dyke at Paradise Harbour, Danco Coast, West Antarctica

Birkenmajer K., Lorenc M.

Bulletin of the Polish Academy of Sciences. Earth Sciences

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2003

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Vol. 51, nr 2

161-171

EN

A large porphyritic dyke exposed at Porphyry Ridge, Paradise Harbour, Danco Coast (northern Antarctic Peninsula, West Antarctica), consists of albitized andesite. Together with other hypabyssal intrusions (dyke swarm) and plutonic intrusions (granite-granodiorite-gabbro - mainly sills), it belongs to the Late Cretaceous Andean Intrusive Suite (AIS) which post-dates a monotonous, some 2000 m thick, Early Cretaceous basaltic-andesitic volcanic pile (Antarctic Peninsula Volcanic Group - APVG). The volcanic effusions (APVG) and the successive plutonic and hypabyssal intrusions (AIS) had formed in response to subduction of the SE Pacific oceanic crust under continental crust of Antarctic Peninsula.

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Sedimentary Features of a Tertiary Lahar on King George Island, South Shetland Islands, West Antarctica

Birkenmajer K., Gradziński R., Porębski Sz.

Bulletin of the Polish Academy of Sciences. Earth Sciences

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2002

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Vol. 50, nr 1

81-97

EN

A coarse diamictite (agglomerate) up to 34 m thick consisting mainly of angular basaltic lava clasts occurs within Tertiary terrestrial stratiform volcanic succession at Admiralty Bay, King George Island (South Shetland Islands, West Antarctica). At some sites, it interfingers with coeval basaltic lava flows. The coarse diamictite is interpreted as a lahar developed from low-maturity debris flows triggered either by volcanic eruptions or by less of stability by water-saturated weathering covers. Diamictites with predominantly rounded clasts, and sandstone -the products of short-lived short-distance reworking and sorting by running water, are subordinate.

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Retreat of Ecology Glacier, Admiralty Bay, King George Island (South Shetland Islands, West Antarctica), 1956-2001

Birkenmajer K.

Bulletin of the Polish Academy of Sciences. Earth Sciences

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2002

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Vol. 50, nr 1

15-29

EN

Ecology Glacier at Admiralty Bay (South Shetland Islands, West Antarctica) has been in a state of continuous retreat at least since 1956/7. The retreat was slow between 1956/7 and 1988/9, amounting to 4-4.5 m/yr it rapidly accelerated in the past decade (1989-1999) - up to 30 m/yr; a semi-enclosed lagoon opened in front of the retreating glacier. Retreat of the glacier's northern lobe between 1978/9 and 2000/l, bas exposed its bottom moraine (boulder clay), occasionally with fluted pattern, and numerous striated roches moutonnees, moreover kame fields that once formed in open ice crevasses. At the beginning, the north-easternmost part of this ice lobe retreated stepwise, leaving behind five successive push-moraine ridges.

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Sulphide and oxide ore mineralization at Reptile Ridge, Adelaide Island, West Antarctica

Birkenmajer K., Doktor M., Piestrzyński A.

Bulletin of the Polish Academy of Sciences. Earth Sciences

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1999

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Vol. 47, nr 2-3

135-153

EN

Metalliferous sulphide and oxide mineralization was studied at Reptile Ridge, Adelaide Island, West Antarctica. It occurs in metavolcanics and metaquanzites of the Antarctic Peninsula Volcanic Group (APVG: Upper Jurassic - Lower Cretaceous) and, to a lesser degree, in adamellite-granodiorite pluton of the Andean Intnisive Suite (AIS: probably Cretaceous). The mineralization zone had developed along a NNE-SSW-striking fault which displaces the volcanics (APVG) and the pluton (AIS). Among sulphides, pyrite, pyrrhotite, sphene and chalcopyrite are the most common. The oxides are represented mainly by magnetite, haematite, haemoilmenite and rutile. Two phases of pneumatolytic-hydrothermal mineralization were recognized in the metaquartzites (APVG): (1) the first phase produced Fe-Ti mineral association in form of veins and fills of intergranular spaces; (2) the second phase produced Fe-Cu sulphide mineralization mainly as fills of intergranular spaces.

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Ujemny trend rocznych sum opadowych na Stacji im. H. Arctowskiego (Wyspa Króla Jerzego, Szetlandy Pd., Antarktyka Zach.)

Marsz A. A.

Problemy Klimatologii Polarnej

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1998

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nr 8

63--77

EN

The paper treats variabiliry of annual precipitation sum registred at the Arctowski Station for the 1978-1996 time period. The annual sum of precipitation show a big variability, its to possible to distinguish three periods in their course. For the period 1978-1985 mean annua1 precipitation sum amounted 560 mm (δn = 26 mm), for the next period (1986-1989) precipitation sum was characterised by a very strong variability (min = 377, max = 630 mm) mean precipitation sum amounted 472 mm,where δn = 95.4 mm. For the last, third period (1990-1996) mean precipitation sum amounted 456 mm (o n = 26.1 mm) (tab. l, fig. 1). Occurrence of strong periodicty every 6.0, 2.0, 4.50, 2.57 and 9.0 years has been found for the course of annual precipitation sum (fig. 2). Also, the spectrum analysis of a course of monthly precipitation sum in March (maximum of precipitation) and August (minimum of precipitation) has been led. Analysis showed the existence strong common periodicity (for annual and month sum: maximum and minimum) every 2.00, 3.60 and 6.00 years. Analysis of amplitudes and phases of periodicity do not explain the occurrence of so big variability of observed precipitation sum. The strong negative trend of annual precipitation sum, significant from the statistic point of view occurs here (fig. 3, formula l). Negative trends were also found in: the course of mean monthly precipitation sum for 8 from 12 monts of a year (the strongest and significant in February), in the course of number of days with measurable precipitation, in the mean annual twenty-four-hours precipitation sum. The negative trend of precipitation sum at Arctowski Station is not conformable to signalised (Ackley S., Bentley C., Foldvik A., Clarke A., King J, Priddle J. 1996.) positive trend of precipitation sum, which appears on the west coast of the Antarctic Peninsula. The examination of relation between precipitation sum at the Arctowski Station with walues of SOI shows, that the strongest relations between annual and maximum precipitation sum in a given year appears with one year delay (SOI of the previous year - precipitation of the present year), whereas in case of minimum sum the strongest relation appears with three years defay (tab. 2). The significant relation between monthly precipitation sum at the Arctowski Station and values of SOI appears in January and February (fig. 4, the strongest correlation with values of SOI are the end of winter and spring of the previous year). The negative trend of SOI correspond with the negative annual precipitation sum at the Arctowski Station. The observed environmental results, which confirms decrease of precipitation sum at the Arctowski Station has been shortly discussed (decrease of fields of permanent snow, disapperance of lakes and seasonal streams, drying of seashore terraces, hastening of ablation of glaciers ice from a surrounding glaciers, hastening of deglaciation processes).

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Głębokie zimowe inwersje temperatury na nadmorskiej terasie okolic Stacji im. H. Arctowskiego (wyspa Króla Jerzego, Szetlandy Pd., Antarktyka Zach.)

Kruszewski K.

Problemy Klimatologii Polarnej

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1998

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nr 8

47--62

EN

Paper presents results of investigations on temperature inversions, carried out during XIX Antarctic Expedition PAS in 1995, Temperature values taken from thermograph readings at Arctowski Station (3 m asl) and Point Thomas (173 m asl, situated 850 m, WNW from Station) were used to find periods of time with temperature inversions, Seven cases, analysed in this paper. Were selected as deep inversions (mean temperature gradient counted from hourly values was higher than 1°C/100 m), All presented inversions were radiation type, accompanied by calms and relatively small total nebulosity, except three cases, when nebulosity was the effect of inversion Influence of local orographic conditions on deepening temperature inversions is strong, but the main factor for it's forming is anticyclonic situation in the region of South Shetland Islands (accompanied by calms) and sea ice conditions. All analysed inversions were fonned during months with fast ice cover existence in Admiralty Bay and very close ar close ice fields on Bransfield Strait. In other ice conditions deep temperature inversions were not recorded, Minimum air temperatures at Arctowski Station recorded in July, August and September 1995 were measured during inversions. Maximum difference in air temperature between Point Thomas and Arctowski Station was recorded on July 22 (l4°C), These cases let to make conclusion, that probably all extremely low temperatures recorded during severe winters at Arctowski Station were measured in inversion conditions.

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Quaternary geology at Potter Peninsula, King George Island (South Shetland Islands, West Antarctica)

Birkenmajer K.

Bulletin of the Polish Academy of Sciences. Earth Sciences

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1998

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Vol. 46, nr 1

9-20

EN

The succession of Quaternary deposits and morphological forms at Potter Peninsula. Maxwell Bay, King George Island (South Shetland Islands, West Antarctica) includes: (1) raised residual gravel and remains of marine abrasion surfaces, 97-118 m a.s.l. (Pleistocene); (2) marine (fjord-bottom) silty and sandy beds with bivalve shells (radiocarbon-dated at early Holocene); (3) highest raised marine terraces, 40-50 m a.s.l. (early Holocene); (4) older moraines - the Punta Batiza glaceir advance stage (mid-Holocene); (5) high raised marine terraces, 22-25 m a.s.l. (late Holocene); (6) low raised marine terraces, 7.5-12 m a.s.l., and raised marine beaches, 2-16 m a.s.l. (late Holocene); (7) younger moraines, outwash cones, kame terraces etc. - the Potter Cove glacier advance and retreat stages (latest Holocene). The Holocene isostatic land uplift at Potter Peninsula, is calculated at about 50 m.

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Geology of Volcanic Rocks (?Upper Cretaceous-Lower Tertiary) at Potter Peninsula, King George Island (South Shetland Islands, West Antarctica.

Birkenmajer K.

Bulletin of the Polish Academy of Sciences. Earth Sciences

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1998

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Vol. 46, nr 2

147-155

EN

Stratiform basaltic/basaltic-andesite lavas (a minimum 50m thick), with red agglomerate and tuff interlayers (up to 10m thick), are the oldest rocks recognized at Potter Peninsula, King George Island (South Shetland Islands, West Antarctica). They resemble volcanic-volcaniclastic rocks of the Paradise Cove Group (King George Island Supergroup) from Admiralty Bay, King George Island, K-Ar-dated at Upper Cretaceous. Hypabyssal intrusions of basalt and andesite at Potter Peninsula represent two hases: (1) plugs and stills at Stranger Point are closely interrelated with the stratiform volcanic complex, and could be of Cretaceous age; (2) a large basalt (resp. hypersthene-augite andesite) plug of Three Brothers Hill, K-Ar-dated at Lower Tertiary, and two systems of vertical basaltic/andesitic dykes (Admiralty Bay Gp), cut the stratiform volcanic complex. The older dykes strike NW-SE. The younger dykes, striking NNE-SSW to N-S, often follow vertical Tertiary faults transversal to the island axis. These transversal faults cut also the Three Brothers Hill plug.

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Geology of tertiary volcanic rocks at Turred Point and Mersey Spit, King George Island (South Shetland Islands, West Antarctica)

Birkenmajer K.

Bulletin of the Polish Academy of Sciences. Earth Sciences

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1998

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Vol. 46, nr 3-4

223-234

EN

Three Lower Tertiary volcanic complexes occur at the Turred Point-Mersey Spit promotory on King George Island (South Shetland Islands, West Antarctica. The first complexis represented by a pile of thick andesitic-basaltic lava flows attributed to the Mazurek Point Formation. The second complex consist of andesite breccias which from vertical cutting the lavas. The third complex is represented by vertical andesite plugs and dykes cutting the lavas and the vent braccias.

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Geology of Gerlache Strait, west Antarctica. II. Wiencke Island to Brabant Island

Birkenmajer K.

Bulletin of the Polish Academy of Sciences. Earth Sciences

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1998

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Vol. 46, nr 3-4

167-190

EN

Four major fault-boundedc tectonic blocks are recognized in the Gerlache Strait area, West Antarctica: (A) the Danco Coast Block; (B) the Brabant Island Block; (C) the Neumayer Channel Block; and (D) the Anvers-Melchior Islands Block. The blocks differ from each other in the succession and age of rocks: (A) metasediments of the Trinity Penisula Group (TPZG:? Upper Permian-Triassic). Uncorfarmably covered by a thich basaltic-andesitic effusive complex (Antarctid Penisula Volamic Group, APVG: Lower Cretaceous), intruded by granitic trough gabbroic plutons (Andean Intrusive Suite, AIS-I: Berriasian-Cenomanian) and by hypabyssal dykes and sillsof several generations (AIS-2: ?Upper Creataceous and /or Tertiary);(B) basaltic-andesitic effusive complex (APVG: ?Lower Cretaceous), intruded by a granodiorite aill (AIS-1) and by hypabyssal dykes of several generations (AIS-2), unconformably covered by /Late Tertiary volcanics; (C) Early Tertiary granite-granodiorite pluton, intruded by hypabyssal dykes of several generations, eroded and weathered, covered by strainform ? Late Tertiary volcanics; (D) effusive complex (?APVG), followed by granitoid and hybrid intrusions apparently representing there successive phases, of Late Paleocene, Eocene/Oligocene boundary, and Early Miocenes ages, intruded by several systems of hypabyssal dykes.