Bauxites : Feedbacks of System Earth at Greenhouse times

The sedimentary record is an inexhaustible repository of information on global climates. The study of the documents of past climate changes may help to understand not only the causes and presumable effects of the current change, but also to reveal the often complex and subtle mechanisms regulating the system. Ferrallitic soils and soil-derived sediments (=bauxites) are generally considered as best climate-indicators on dry-land. Their frequency distribution through geologic time shows pronounced positive anomalies coincident with greenhouse periods of the Earths’ history. It is proposed that intense ferrallitic weathering instead of being simply the passive product of the greenhouse could be also one of the negative feedbacks of the system counteracting warming by contributing to the pump-down of greenhouse gases from the atmosphere and this way to help to decelerate both the carbon-cycle and the hydrological-cycle. The mass-transfer of oxygen from the atmosphere to the lithosphere is tentatively considered as an additional negative feedback acting to slow down oxidative weathering on land. It is suggested that the study of bauxites and correlative anoxic sediments in the oceans should be used to reveal details of the above complex regulation mechanism

Bakonyi felsőkréta dinoszauruszlelőhelyek földtani és őslénytani vizsgálata = Upper Cretaceous dinosaur localities (Bakony Mts, Hungary): geology and palaeontology

Megtörtént a lelőhely szisztematikus feltárása és megindult a leletek preparálása, meghatározása, leltározása. A begyűjtött anyag többezer izolált csontot és fogmaradványt, állkapocstöredékeket, csigolyákat, végtagcsontokat, és négy részleges csontvázat tartalmaz. A faunát halak, kétéltűek, gyíkok, krokodilok, ankylosauria dinoszauruszok, pteroszauruszok és madarak alkotják. A legteljesebb összefüggő csontváz alapján leírt Hungarosaurus tormai új taxon. Ugyancsak új taxon a Bakonydraco galaczi (pteroszaurusz). A begyűjtött fauna bár hasonlít a többi európai dinoszaurusz lelőhely faunájához, részleteiben azoktól eltér: nem tartalmaz sem Sauropoda, sem Hadrosaurida dinoszauruszokat. Ennek valószínű oka, hogy a hazai fauna kora santoni, tehát idősebb a többi európai késő-kréta faunáknál, az említett két csoport pedig csak a késő-kréta még későbbi szakaszában érte el az egykori szigetvilágot. Az üledékképződési környezetet elágazó folyó kis-esésű, a feltételezett deltához közeli alluviális síkságaként azonosítottuk. A folyó távoli, nem-karbonátos térszínről érkezett. A leletek többsége egy az egykori ártérbe vágódó sekély, mederágat kitöltő iszapos törmelékfolyás üledékéből, a csontvázak a mederág lefűződésével kialakult holtág finomszemcsés kitöltéséből kerültek elő. A csontok piritesedése a korai diagenezis során az üledéket átitató szulfát-gazdag pórusvizre (delta-közelség) utal. | Systematic collecting, preparation, and identification of fossils recovered from the Late Cretaceous Csehbánya Formation was undertaken. Several thousands of isolated bone and teeth remains, fragments of jaws, vertebrae and limbs and four partially preserved skeletons were recovered. The fauna consists of fish, amphibians, lizards, crocodiles, dinosaurs (Ankylosauria), pterosurs and birds. The most complete skeleton, described as Hungarosaurus tormai is a new taxon. Likewise new is a pterosaur Bakonydraco galaczi. The fauna, though similar to other European dinosaur findings, is also different from those. It does not contain Sauropods or Hadrosaurids, either. The reason for this is probably the older age of the Hungarian site. The above two taxa have reached the ancient archipelago probably only in the Campanian when the Iharkut locality has already submerged. The depositional environment was the alluvial plain of a low-gradient anastomosing river coming form a distant non-carbonate area and gradually passing into a hypothethic delta plain. Bone fragments and teeth were recovered from a channel cross-cutting the alluvial plain and filled by sediments deposited from a cohesive muddy debris-flow. Skeletons, on the other hand, were recovered from a thick dark-coloured laminated mud filling up the obviously abandoned former channel. Pyritization of the bones suggests that early diagenesis took place in contact with sulphate-rich fluids

KARST FEATURES AND RELATED SOCIAL PROCESSES IN THE REGION OF THE VIKOS GORGE AND TYMPHI MOUNTAIN (NORTHERN PINDOS NATIONAL PARK, GREECE)

Due to unfavourable natural conditions (poor soils, lack of water, special relief conditions), karst terrains have always been relatively sparsely populated, and they have been seriously affected by recent depopulation processes. However, the creation of national parks on karst terrains and the recent increase of (geo)tourism may influence and even turn these population trends. Our study examines the validity of this statement in the context of Vikos Gorge and Tymphi Mountain (NW Greece). Geological and geomorphological values are presented first, including Vikos Gorge, the glaciokarst landscape of Tymphi and the particular spherical rock concretions. Digital terrain analysis is used to obtain scientifically based, reliable morphometric parameters about Vikos Gorge, and it is found that the maximum gorge depth is 1144 m, the maximum width is 2420 m, and the maximum of depth/width ratio is 0.76. Thereafter, rural depopulation trends are examined and it is found that this region (Zagori) is seriously affected by depopulation. It is observed that there are differences among settlements, and a relative stabilization of population is sensible in only few settlements around Vikos Gorge, which are linked to tourism. As for nature protection, while at the beginning conflicts were perceptible among management and local people, now new conflicts are emerging between growing tourism and nature protection goals.Key words: gorge morphometry, glaciokarst, spherical concretions, rural depopulation, geotourism, national park.Kraške oblike in s krasom povezane družbene spremembe na območju soteske Vikos ter v gorovju Timfi (narodni park Severni Pindi, Grčija)Zaradi neugodnih naravnih razmer, kot so manj rodovitna prst, pomanjkanje vode in svojstvena oblikovanost površja, je kraško površje od nekdaj relativno redko poseljeno, v zadnjem obdobju pa je podvrženo tudi procesom odseljevanja. V zadnjem času je vse več tudi geoturizma in z njim povezanega ustanavljanja geoparkov, ki trend depopulacije lahko tudi obrnejo. Pričujoča študija se nanaša na vrednotenje omenjenih procesov na primeru doline Vikos in gorovja Timfi (SZ Grčija). Najprej so predstavljene geomorfološke in geološke značilnosti območja, kjer so izpostavljene značilnosti soteske Vikos, glaciokras gorovja Timfi in za to območje značilne okrogle skalne konkrecije. Digitalni model višin je bil namenjen morfometrični analizi soteske Vikos. Ta je pokazala, da je njena največja globina 1144 m, največja širina 2420 m, največje razmerje med globino in širino pa 0,76. V nadaljevanju so analizirane značilnosti odseljevanja s podeželja, katerim je najbolj podvrženo območje Zagori. Demografski vzorci kažejo na razlike med posameznimi naselji, kjer je število prebivalcev stabilno le v nekaterih naseljih v bližini turistično zanimive soteske Vikos. Z ustanovitvijo parka so se pojavili tudi konflikti. V začetku so se navzkrižja interesov pojavila med lokalnim prebivalstvom in upravljavci, sedaj pa se konflikt pojavlja ob istočasnem naraščanju turizma in želji po varovanju narave.Kjučne besede: morfometrija soteske, glaciokras, okrogle konkrecije, depopulacija podeželja, geoturizem, narodni park.

Szárazulati és tengeralatti üledékhézagok elkülönítése a Dunántúli-középhegység alsó- és középső-kréta rétegsoraiban = Distinction of subaerial and submarine gaps in the Lower and Middle Cretaceous successions of the Transdanubian Range

Alkalmazott vizsgálati módszerek: Szelvényezés és mintavételezés Vékonycsiszolat-készítés és vizsgálat Mikrofauna vizsgálat (vékonycsiszolat, oldási maradék) Makrofaunavizsgálat: zöldalga, ammonitesz, telepes korall Egyéb vizsgálat: kőzetszövet és mikrofácies, katódlumineszcencia, termikus és röntgendiffrakciós, fő és nyomelem, oxigén és szénizotóp, nehézásvány Vizsgált Tatai Mészkő fedőjű üledékhézagos előfordulások: Alsó-Hajag, Felső-Hajag, Bakonybél, Som-hegy; Lókúti-domb tető; Zirc-borzavári úti kőfejtő; Olaszfalu, Eperjes; Bakonycsernye, Tűzköves-árok, Mór, Éles-kő; Vértessomló, Szarvaskút; Tata, Kálvária-domb. Tési Agyagmárga fedőjű vizsgált üledékhézagos előfordulások: Lókút, temetői feltárás; Zirc, Istenesmalmi-kőfejtő; Zirc, faluvégi kőfejtő; Mór, Lófar-völgy Az üledékhézagok Szárazulati: Karsztosodás, vadózus cement a feküben, allit ásványok a fedőben, kaolinit dúsulás, szárazföldi eredetű mikroméretű szervesanyag, folyóvízi, tavi fedőüledék, transzgressziós bázisüledék, Változás a stabilizotóp összetételben , lumineszcencia képesség romlása. Tengeralatti: Bioeróziós nyomok felszínen, lokális tanúüledék, mélyvízi sztromatolit, tengeri fosszíliával, jelentős elemdúsulás, szárazföldi ásványok hiánya, a szárazfölditől eltérő elemdúsulás, átülepített, roncsolt tengeri mikrofauna Meghatároztuk a Tatai, és a Tési Formációval fedett üledékhézagok tér és időbeli elterjedését. A Tatai Mészkő fedőjű üledékhézagok tengeralattiak, a Tési Agyagmárga fedőjűek szárazulatiak. | Methods of investigation used: Depicting columnar sections and sampling in the field Preparation and study of thin sections Palaeontological investigations: microfossils, Dasycladales, ammonites, colonial corals Other investigations: Microfacies and texture, Cathodeluminescense microscopy, Thermal and X-ray diffraction, Major and trace elements, Oxygene and carbon isotopes, Heavy minerals Studied sections under Tata Limestone: Alsó-Hajag, Felső-Hajag, Som-hegy, Bakonybél, Top of Lókút Hill; Zirc-Borzavár quarry; Eperjes, Olaszfalu; Tűzköves Ravine, Bakonycsernye; Éles-kő, Mór; Szarvaskút,Vértessomló; Kálvária Hill,Tata. Studied sections under under Tés Clay: Eastern end, Lókút; Istenesmalom, Zirc; quarry at the northern rim of, Zirc; Lófar Valley, Mór. Characterization of gaps Continental: Karstification, vadose cement allite minerals in the cover beds concentration of kaolinite terrestrial microscopic organic matter fluvial and lake sediments transgressional basal beds change in the concentration of stabile isotops decreasing of luminescence ability. Submarine: Bioerosional traces local test sediment deep-water stromatolite with marine fossils concentration of elemnts different from the subaerial one lack of minerals of terrestrial origin reworked marine microfossils. Gaps below the Tata Limestone are submarine in origine, while those below the Tés Clay are all subaerial. Gaps covered by either the Tata Limestone or the Tés Clay are deliniated both geographically and in time

Geobody architecture of continental carbonates: “Gazda” travertine quarry (Süttő, Gerecse Hills, Hungary)

The Gazda quarry is one of the largest outcrops of the present-day Süttő travertine complex that is situated close to the town of Süttő (Hungary), in the Pannonian Basin. Sedimentological and petrographical analyses show that the Gazda travertine body is built out of phytohermal, wavy laminated, massive and flat laminated travertine lithofacies representing reed mound, slope, lacustrine and palustrine depositional environments, respectively. Based on petrographic analyses, the following three main textural features were recognized that allow to describe the most common microscopic features: (1) micrite textures; (2) micritic coatings and crusts; and (3) different types of clasts. Each major lithofacies is characterized by a particular association of these textural types. The geometry of the travertine beds follows the antecedent land-surface, a NE-SW striking pre-Pleistocene valley. It is proposed that in this valley travertine precipitation took place along a gently sloping terrain. The Gazda travertine system was fed by at least two groundwater-springs. One of them was located NE of the quarry from which waters were flowing along the axis of the valley. The other source was located to the East of the Gazda quarry and waters joined the main water-course along the valley. Closest to the confluence, a phytohermal mound developed with lateral slope and eventual pond depositional systems. Onlapping and interfingering with the flat laminated lithofacies indicate alternating activity of the two springs. Fractures observed in the quarry are mainly related to postdepositional gravitational sliding, however, neotectonic forces resulting in SE–NW tension also played a role in the formation of the fractures. Stable oxygen and carbon isotope analyses show that water temperature was approximately 25°C. Petrographic studies indicate that only syn-diagenetic processes affected the precipitates. Therefore the original stable oxygen isotope signatures, characteristic of the depositional environment, were preserved. Detailed sedimentological and geochemical study of the Gazda travertine complex allowed small-scale facies characterization providing information about the ancient depositional environment and the heterogeneous nature of these carbonates