ѕроекты ћѕ√ , одобренные Ќаучным советом ѕрограммы в 2003 году
Full Title: Late Westphalian terrestrial biotas and palaeoenvironments of the Variscan Foreland and adjacent intramontane basins
Proposers: Dr Christopher Jonathan Cleal (United Kingdom), Dr Stanislav Olustil (Czech Republic), Prof. Yanaki Tenchov (Bulgaria), Prof. Erwin Zodrow (Canada)
This project will investigate late Westphalian (Pennsylvanian) palaeoecological changes that took place across the Variscan Foreland and Mountains, during a critical time in the Palaeozoic evolution of Europe and Eastern North America. The Variscan Orogeny affected large parts of this region, as Gondwana and Laurasia collided during the Late Carboniferous. The resulting tectonic activity disrupted the lowland swamp habitats that had occupied much of the Variscan foreland, as well as causing the development of intramontane basins within the adjoining Variscan Mountains. However, our understanding of the environments in these basins is still limited. What were the relative elevations of the different basins? What were their relative subsidence-rates and sedimentation-rates? What was the rate of down-draw of carbon in each basin and what was the effect, if any, on global climatic change?
Plants are known to be one of the most sensitive environmental indicators of terrestrial habitats and so the palaeobotanical record is an ideal tool with which to investigate this problem. The project aims to develop an integrated palaeofloristic database for each of the main late Westphalian and earliest Stephanian coal basins in this area. By bringing together palaeobotanical and palynological specialists from the various countries where these coal basins occur, it is intended to develop for the first time an agreed taxonomy for the plant macro- and microfossil species. A floristic distributional database will be developed using this consistent taxonomic nomenclature, and will be investigated by multivariate statistical analysis. It will also include estimations of species abundance, which will help with judging endemic or provincial species. This floristic evidence will be integrated with sedimentological evidence of depositional regimes in the various basins. The resulting synthesis will provide the most complete environmental picture to date of these Variscan-affected habitats, and will have important consequences for our understanding of the evolution of the Variscan Orogeny.
Marine deposits are virtually absent from these sequences, and so there is effectively no evidence from marine faunas. Terrestrial faunas of this age are generally rare and of uncertain value for palaeoenvironmental interpretation. The only significant exceptions are insects and spiders, whose remains occur reasonably abundantly in the Upper Carboniferous of the Variscan Foreland and Mountains. The project will therefore attempt to incorporate these groups into the biogeographical database.
Full Title: Depth Images of the EarthТs Crust Ц СinnerТ space, the continents and their margins
Proposers: Dr B. J. Drummond (Australia), Prof. L. D. Brown (United States), Prof. F. A. Cook (Canada), Dr O Oncken (Germany), Dr G. S. Fuis (United States), Prof. R. W. Hobbs (United Kingdom), Prof. Songlin Li (China), Dr D. M. Finlayson (Australia)
This IGCP project will bring together the strengths in a number of major geoscience research institutions and international associations to make available to a worldwide scientific, educational and public audience, the best examples of images of the interior of the EarthТs crust and upper mantle across a variety of representative structural provinces from all parts of the globe. This aim may be seen as part of a wider objective to foster the spread and application of geoscience knowledge to issues related to the pursuit of international social, economic and cultural goals and sustainable development.
The last three decades have seen an explosion in the quantity and quality of seismic images of the EarthТs crust. These images give us a detailed insight into the geological structures and tectonic processes that shape the crust. They are therefore relevant to natural resource exploration, the distribution and management of groundwater resources and the study and mitigation of natural hazards such as earthquakes. They define the processes that control the evolution of the landscape and soils.
However, most deep seismic images have been generated to study geology at the regional scale. This project will provide the catalyst for and the means by which the results of the separate regional programmes will be brought into a global scientific framework, in order to tease out common scientific results that do not arise from the individual programmes. Most Earth science theory flows from an understanding of the geology at the surface of the Earth. This project will generate collaboration to show and make accessible research images of type depth sections across representative orogenic belts, rifts, continental margins, etc. Most of the results available today are from developed nations. In making the results accessible in a global scientific context, they will be available and have meaning to researchers and educators in developing nations, which have no opportunity to fund their own seismic imaging programmes.
Previous attempts at such correlations have failed to make an impact because of the effort required to publish and distribute the seismic images and their interpretations in consistent formats. Some compilations are only at hand in scientific journals and to those with high-level specialist computer facilities. Some are contained in specialist atlases that would be difficult or impossible for the researchers in developing countries to access. This can now be overcome by distributing the results in common digital format via the World Wide Web. Formats will be chosen to also ensure access by the general public. Distribution by the WWW ensures that the results will be available almost everywhere immediately. The results will therefore be designed to bridge the gap between scientific effort and the public interest and give the public a real insight into the nature of the major geological processes in the outer 50-70 km of the Earth that directly affect their lives.
Full Title: Deltas in the Monsoon Asia-Pacific Region (DeltaMAP): Late Quaternary Development and Recent Changes Due to Natural and Human Influences
Proposers: Dr Steven Goodbred Jr (United States) and Dr Yoshiki Saito (Japan)
The project will lead its studies in the area of the Monsoon Asia-Pacific Region (MAP) Ц from China to Pakistan, and Oceania. The subject of the analysis will be the Mega riverine delta systems in Huanghe (Yellow), Changjiang (Yangtze), Mekong, Irrawaddy, Ganges-Brahmaputra, and Indus. The studies will also enclose the large riverine delta systems in Zhujiang (Pearl), Song Hong (Red), Chao Phraya, Salween, Mahakam, Digul, Fly, Godavari, Cauveri, and others; medium and small riverine delta systems Ц many systems (over 20), particularly in Oceania, Western India, Taiwan, and Japan. The project impetus will affect immense human populations in the MAP region - about 0.5 billion people living in or directly influenced by deltas; approx. 2.5 billion people affecting river delta catchments. The project also has a large geohazard potential Ц river flooding, river avulsion, drought, cyclones, storm surges, tsunamis, sea-level rise, coastal erosion, saltwater intrusion, earthquakes, and arsenic contamination. It also has a potential of rapid growth for research and discovery in the MAP region because the rivers and deltas of the region were historically understudied.
Full Title: Monsoon Evolution and Tectonics-climate Linkage in East Asia and its Marginal Seas During the Late Cenozoic
Proposer: Ryuji Tada (Japan)
Uplift of the Himalayas and Tibetan Plateau (HTP), and the consequent changes in atmospheric circulation pattern and draw down of atmospheric CO2 through enhanced chemical weathering are considered as the principal causes of strengthening of the Asian monsoon and global cooling. In addition, the opening of East Asian marginal seas may have contributed to global cooling through their influence on eustatic sea levels, the global carbon cycle, and global surface- and deep-water circulation patterns. However, causative relationships among the events are still unclear. Thus, it is crucial to put the timing and evolution process of the HTP uplift, East Asian marginal seas, and Asian monsoon within the same chronostratigraphic framework, and examine their interrelationships in order to test models for tectonics-climate linkage and Cenozoic global cooling. The project proposes to conduct a group effort to (a) correlate continental and marine climatic and tectonic records, (b) examine their interrelations, and (c) explore the linking mechanism(s) between tectonics and climate in East Asia and its marginal seas during the Late Cenozoic. Through these studies, it is hoped to create a new model on the tectonics and climate linkage in East Asia and their impact on global climate, and elaborate a strategy to test the model by utilizing international sediment sampling programmes such as IODP, ICDP, and IMAGES.
Full Title: Neoproterozoic to Early Palaeozoic Palaeogeographic, Palaeoclimatic, Palaeobiologic and Tectonomagmatic Events within the Framework of South-West Gondwana
Proposers: Dr Claudio Gaucher (Uruguay), Prof. Dr Daniel Poirй (Argentine), Prof. Dr Paulo C. Boggiani (Brazil), Dr Andreas Braun (Germany), Prof. Dr Hartwig Frimmel (South Africa) and Dr Gerard J. B. Germs (South Africa)
The Neoproterozoic to Early Palaeozoic was a time of biological innovation related to profound changes in tectonics, climate and chemistry of the oceans and atmosphere. South-West Gondwana is one of the key regions to understand these changes and also one of the least studied ones.
Full Title: Sustainable Use of Platinum Group Elements in the 21st century: Risks and Opportunities
Proposers: James E. Mungall (Canada), Markku Iljina (Finland), Cesar Ferreira-Filho (Brazil)
The proposed project will involve research and data collection along four dominant themes: - PGE resource inventory in each participating country - deposit-scale controls on PGE deposition - large-scale metallogenetic controls on formation of PGE mineralisation provinces - PGE in the environment - dispersion, mobility, bio-availability of PGE
The objectives of the project are to allow participants from individual countries to assess their national or regional PGE resources, including known and potential reserves, as a complement to ongoing efforts to generate a global PGE resource inventory. Efforts will be made to transfer knowledge and techniques of PGE exploration to geoscientists worldwide. Research by participants will continue to improve our understanding of PGE as tracers of geochemical processes and of the mechanisms of formation of major deposits of the PGE. At the same time we will contribute to an increasingly balanced look at how PGE use affects the environment, and how adverse effects might be reduced or mitigated.
Full Title: Dating Caspian Sea Level Change
Proposers: Prof. Dr S. B. Kroonenberg, Netherlands (project leader) and Prof. Dr S. Leroy United Kingdom (deputy project leader)
The causes of Pleistocene and Holocene Caspian sea level changes are very complex, ranging from tectonic, climatic to anthropogenic. Current research suggests that the recent short-periodical changes may reflect fluctuations in continentalЦscale precipitation forced by the North Atlantic Fluctuation (NAO). Past Caspian Sea level might therefore give clues to palaeoprecipitation over a vast part of Eurasia and might be a proxy for NAO in the past. However, dating of Caspian Sea level in the Late Pleistocene and the Holocene has been unusually difficult owing to a variety of reasons, and large discrepancies exist between results from different research teams. The purpose of the project is to bring the relevant research groups together, to compare and analyse existing data sets and to design plans for an international dating programme.
Project No 482/489 Ц Geodynamics of the East African Rift System / Geophysical Characteristics and Evolution of the South-Western Branch of the East African Rift System
Full Title: Dynamic Evolution, Resource Potential and Environmental Impact of the East African Rift System / South-Western Branch of the East African Rift System: Geophysical Characteristics, Structural Evolution and Sedimentary Geology: Implications for Modelling Nascent Rifts
Proposers: Ass. Prof. Genene Mulugeta (Sweden)/ Dr E.A. Atekwana (United States), Dr M.P. Modisi (Botswana), Dr M.N. Sebagenzi, (Congo DR), Dr J.-J Tiercelin (France)
No. 482 This is a collaborative and multidisciplinary project to address the geodynamic evolution, resource potential and hazard impact of the East African Rift System (EARS). The scientific objectives focus on the synthesis, integration and correlation of available and ongoing (field, laboratory and theoretical) research pertaining to EARS, merged into a unified framework for the understanding of its geodynamic evolution. It will examine critically and in detail some of the dynamic links between deep-seated and shallow processes leading to rifting, factors controlling magmatism as well as sedimentary basin formation. The findings will then be integrated into a clearer and more directly applicable form, by focusing on some specific yet unanswered fundamental questions; such as: How are rift structures influenced and respond to changes in lithospheric structure and rheology? What are the dynamic consequences of plume/lithospheric interaction? What controls the changes in magma volumes and composition along the EARS? How does the dynamics of rifting affect resources? What are the causes and consequences of environmental hazards?
This new IGCP project is intended to generate an international and a truly multidisciplinary co-operation. By bringing together scientists from different disciplines, it plans to stimulate dialogue and facilitate communication among researchers in Eastern Africa and throughout the world. The rationale is that by mobilising intellectual and instrumental resources, such a pooling would provide a sound basis for solving truly fundamental geo-scientific problems necessary for development. Although many countries in Eastern Africa share one of the longest rift systems in the world, research activities at various institutions are undertaken in isolation. Not one country in the region has access to modern facilities and devices that are needed to study these features at a regional or sub-continental scale. Thus, we propose a new project that involves the sharing of facilities and training of a new generation of young interacting geo-scientists. In the proposed project emphasis will be given to the contribution of geo-sciences to development. The ultimate goal is to improve the quality of life in Eastern Africa through capacity-building, sustainable use of natural resources as well as mitigation of hazards. This is the motivation for this new IGCP project.
No. 489 While the studies of rift basins through projects such as the IGCP 400 have significantly increased our understanding of the process of rifting and passive margin development, most documented continental rifts in the world represent quite advanced stages of crustal extension. What are missing in this sequence of passive margin evolution are studies of the geologic and tectonic processes occurring during the earliest stages of rift creation.
Thus, the initial process of continental break-up remains an enigma in the earth sciences, largely because there are few areas worldwide where we can study the process as it is occurring, in near real-time. The project aims to study a region in the very early (incipient) stages of continental break-up: the south-western branch of the East African Rift system. Our aim is to understand fault development and kinematics, sedimentation patterns, structural styles, and the role of antecedent structures (inheritance) and basin evolution during this initial stage of continental break-up. Additionally, the southern tip of the south-western branch of the EARS hosts the Okavango Delta, supporting a very delicate ecosystem and a fresh water reservoir. Neotectonic activity has strong influence on the drainage and geomorphology of the delta providing a delicate balance between the faults, hydrology, sedimentation, and the ecosystem of the delta. The Okavango Delta has, over thousands of years, undergone changes in the flooding patterns due to tectonic activity related to rifting, in addition to climatic variations. One of the various geological aspects that have never been quantified in the evolution of the Okavango Delta is the heat flow pattern. Studies are needed to determine the linkage between neotectonics and the past flooding patterns within the Delta. Such studies will provide vital information essential for understanding the flooding behaviour over the Delta and for predicting future flooding patterns. This can enhance existing hydrologic models on which future management plans of the Delta can be based.
The main goal of this project, consistent with IGCP objectives is to create a trans-national African research linkage which will stimulate and enhance collaboration with developed countries with the aim of accomplishing the following objectives: (1) To map the geological structures of the South-Western branch of the EARS using Landsat, aeromagnetic, and gravity data enabling a determination of fault distribution and preliminary estimation of the thickness of the sediments in the rift basins; (2) compile a set of detailed micro-earthquake data using seismometers operating or which operated in the region through several unconnected projects (e.g. Kaapvaal craton, Botswana, Namibia, Zambia and Zimbabwe earthquake monitoring stations). This will allow us to constrain the focal mechanisms of earthquakes and relate them to active faults bounding the rift basins in order to reconstruct the fault kinematics at the regional scale; (3) compile seismic reflection data from ongoing studies within some of the basins; these data will be provided by the teams involved in this IGCP project; (4) correlate sedimentological studies from cores within the various basins to constrain the sedimentation patterns during the earliest stage of continental rifting, in terms of tectonics and palaeoclimate; (5) compile hydrologic data allowing to understand the controls of neotectonic activity as well as abrupt changes in climate conditions on drainage development during the earliest stage of continental rift development.
Full Title: Cratons, metacratons and mobile belts; keys from the West African craton boundaries: Eburnian versus Pan-African signature, magmatic, tectonic and metallogenic implications
Proposers: Nasser Ennih (Morocco), Jean-Paul Liйgeois (Belgium)
Cratons are characterized by a rigid behaviour during younger subsequent orogenesis. The strong rheological contrast with surrounding mobile belts induces loci favouring in particular magmatism and mineralisation. Also, the craton boundaries may be only partly affected, showing characteristics and behaviour intermediate between a craton in the strict sense and a mobile belt; this intermediate behaviour has been called a 'metacraton' (Abdesalam et al, 2002). Metacratons are not often recognized and remain poorly understood, as they do not fit the classical models.
West Africa is an excellent place to tackle this problem: a large part of this area is constituted by the Eburnian (ca. 2 Ga) West African craton (WAC) surrounded by Pan-African (0.8-0.55 Ga) mobile belts, with no Mesoproterozoic event at all. This major break in age, and the absence of complications caused by intervening orogenies, is a major advantage when seeking to distinguish between craton building events (Eburnian) and the younger destabilization events (Pan-African).
However, surveys in the West African region vary in their detail and the geological research in different countries has been and is still generally conducted by independent and separate groups, which results in problems and inconsistencies of lithostructural correlations. The 19th session of the Colloquium of African Geology, which was held in Morocco through the Chouaпb Doukkali University from 19-22 March 2002 provided an opportunity for scientists working in the WAC and surrounding areas to compare their observations and ideas. This showed the major scientific potential and need for correlation studies along the boundaries of the WAC.
This work should also have consequences for Rodinia and Gondwana reconstructions. Indeed, WAC palaeopositions are not known between 2000 Ma and the Phanerozoic because of the absence of rocks during this period of time. On its boundaries (provided they are recognized and demonstrated), more events occurred and rocks probably suitable for palaeomagnetic studies are present, such as the ca. 788 Ma dolerite dyke swarm in the Anti-Atlas region.
This project aims to study and correlate the tectonostratigraphic terranes along the margins of this WAC craton, to determine the nature of the boundary between the Palaeoproterozoic and Neoproterozoic terranes, as well as between the Neoproterozoic and Palaeozoic terranes, to define the role of the shear zones during accretional events, and of the magmatism around continental margins, and to decipher the thermal evolution and geochronology of key lithologies and characteristic mineral deposits. The African countries which might be directly involved in the project are: Morocco, Algeria, Mali, Niger, Mauritania, Guinea, Burkina Faso, Ghana, Togo, Benin, Cфte d'Ivoire.
Full Title: Au-Ag-telluride-selenide deposits in Europe and in developing countries (and new methodologies for their investigation)
Proposers: Dr Habil Nigel John Cook (Norway), Dr Kari Kojonen (Finland)
The project will NOT be aimed at pan-regional scale problems of metallogen or the influence of geodynamics, deep structures and regional tectonics at the orogenic scale. Rather, the project shall be a vehicle for scientists working on the processes involved in the genesis of tellurium and selenium-enriched Au-(Ag) deposits, who wish to correlate, compare and contrast their observations and conclusions. The project will offer potential for interaction between ore mineralogists and geologists, as well as ore fluid geochemists, all of who are working at the orefield mine, or microscopic scales. We are aware of an apparent gap between scientists working in the laboratory, either on experimental or micro-analytical aspects of deposit mineralogy, and those working in the field documenting and modelling currently exploited ores. The aim is to build an IGCP project that can encourage the cross-fertilisation needed to obtain maximum use of resources for the collective good.
Despite the differing manifestations of ores containing Au (± Ag), comparable ore-forming processes can be recognised across geological time and deposit type. We would aim therefore, in this project, to bring together scientists who are involved with, or who are developing innovative qualitative and quantitative methodologies for the study of these types of mineralisation. This range of activities encompasses research on all aspects of ore distributions, mineral associations and paragenesis, physical and chemical conditions of formation, character and source of ore-forming fluids, chemical and mechanical processes of ore concentration. Participation is open to scientists working on research of both pure and applied aspects, and we particularly welcome researchers from the field of ore beneficiation.
The project is aimed at correlation of human understanding of geological processes causing accumulations of gold (± silver) over space and time, the mineralogy of these deposits and the internal and external controls on the mineralogical distributions. Although the programme will be based on deposits in Europe and adjacent areas (Urals, Greenland, Turkey, Middle East, North Africa), it is not intended to geographically restrict the project to these areas alone. Comparison and analogy with other productive and potential regions worldwide will play an important role in the project as will exchange of ideas, education and training of scientists in traditional and modern investigative techniques.
The project would involve scientists from all continents and as many countries as possible, including especially developing countries. Among the goals would be agreement on an internationally accepted set of definitions and terminologies. Activities within the project can be considered as successors to a number of meetings held across Europe in the 1980s and 1990s, and also, to some extent, activities within parts of the GEODE programme (which concludes in 2003). Even though the GEODE projects had focused primarily on macro-scale aspects of ore deposit evolution, we would hope that the spirit and networks of international collaboration already in place (e.g. in Fennoscandian and Ukrainian Shields or South-East Europe) could be harnessed in the proposed project.
Products of the project will include symposia/fieldtrips/short courses/workshops (either as part of existing scientific meetings or arranged separately), field guides, monographs and other written publications, a website. Most importantly, the project is designed to allow scientists to exchange knowledge and information. Research themes are:
Ore mineralogy / paragenesis of gold-bearing systems
'Exotic' trace mineral associations as tracers for behaviour of precious metal-carriers and fluid paths during gold deposition. Predictability of tellurides, selenides and accompanying sulphosalts in gold-bearing ores
Role of Bi and/or As precipitates as gold scavengers in high-temperature deposits (Au skarns; metamorphogenic sulphide ores, remobilisation)
Relationships between Fe/Ti oxides in metamorphosed terranes as potential tracers for sulphidation/oxidation reactions and gold deposition
Links between Sb-bearing sulphosalts and fluorine enrichment in host rock; possible indication of high-sulphidation environments in metamorphosed deposits. Au-tellurides Ц modelling of oxidation state of fluids
Crystal-growth processes and depositional environments; morphologies of native gold
Metasomatism/behaviour of gold, tellurium and selenium in skarn and porphyry systems (epithermal transition)
Devolatilisation and secondary boiling in magmatic-hydrothermal systems: tracers for abrupt changes in fluid parameters with impact to Au extraction; comparison between Au in porphyry, skarns and epithermal massive sulphides
Mineralogical indicators of genetic evolution and physical-chemical environments of Au deposits. Speciation in extended magmatic hydrothermal systems, tracers for zonation/fluid evolution. Implications as prospecting tools
Comparison between 'simple' hydrothermal systems and, for example, complex stratovolcano or volcano-sedimentary complexes: implications for environment of gold deposition
Styles of hydrothermal alterations in gold deposits: inferences for gold enrichment in sulphide/oxide deposits (e.g. iron oxideЦcopperЦgold deposits)
3D modelling of Au areas; role of host rock in focusing and channelling ore-bearing fluids.
Full Title: The Role of Holocene Environmental Catastrophes in Human History
Proposers: Suzanne Leroy (United Kingdom) and Iain Stewart (United Kingdom)
The project focuses on the inter-disciplinary investigation of Holocene geological catastrophes, which are of importance for civilizations and ecosystems. Presently, there is no nationally or internationally equivalent group dealing with this topic. Joining the efforts of the several international organizations such as IUGS, INQUA, UNESCO, and IGBP will create a new synergy. The project is concerned with environmental events since the beginning of the Holocene (the last 11,500 calendar years) excluding therefore the influence of the glacial-interglacial cycles. Three time scales will be considered: (1) the Holocene when major natural hazards are mostly known from sedimentary records; (2) the last 5-4000 years for which we have written documents; (3) the last couple of centuries with instrumental records. Importantly, the project will examine how quickly ecosystems and civilisations are able to recover from catastrophic events. With the growing recognition that major natural events can have abrupt global impacts, this project is a timely opportunity to assess the sensitivity of modern society to extreme natural threats. The project will involve the geoscience community, but also biologists, archaeologists, historians, meteorologists and astrophysicists.
Full Title: Early Vertebrate biogeographic data as tests of current palaeogeographic models during the Middle Palaeozoic, and its interaction with atmosphere composition, climate change, and extinction events
Proposers: Dr ZHU Min (China) and Dr Gavin Young (Australia)
The project is to enhance the exchange of ideas and data among scientists globally, through a series of web-based forum, workshops and field trips. The main aim is to apply a complex and highly organized global dataset - the distributions in space and time of Early/Lower vertebrates - to provide more rigorous controls on the timing of connections and barriers implied by competing palaeogeographic hypotheses that incorporate extensive equatorial oceans during the Middle Palaeozoic, and to provide a framework for understanding the global diversification of terrestrial ecosystems during the 'Age of Fishes' (Devonian Period), and its interaction with atmosphere composition, climate change, and extinction events. The scope is primarily Devonian, but will include research in earlier and later times. The project is a successor to IGCP projects 328, 406. It will extend the results of 411 and 421, and link with IUGS Sub-commissions (Silurian, Devonian and Carboniferous).
Full Title: The Rise and Fall of the Vendian Biota: Palaeoenvironmental, Palaeoclimatic and Plate Tectonic Controls on the Preservation and Biodiversity of the Vendian Biota with a Comparison of Gondwana and Northern Assemblages
Proposers: Prof. Mikhail Fedonkin (Russia), Prof. Patricia Vickers-Rich (Australia), Dr Jim Gehling (Australia)
As so eloquently pointed out in the introduction to IGCP Project 478, the Proterozoic and early Phanerozoic, especially "the Neoproterozoic-Early Palaeozoic saw the occurrence of some of the most significant events in Earth history" which included a glaciation on a global scale, dramatic changes in the composition of oceans and atmosphere, marked changes in continental configuration and, from the point of view of IGCP 493, the appearance and great increase in biodiversity of metazoans culminating in the appearance of a variety of hard tissue skeletons that marks the end of the Proterozoic and beginning of the Phanerozoic.
This project, which is intimately linked with IGCP 478, and which can take advantage of a number of field conferences and symposia already in train under the umbrella of IGCP 478, is particularly interested in investigating the precise timing of Proterozoic events, the effects that these changing environments, climates, global chemistry and palaeogeogrphy had on the development and diversification of animals which culminated in the spectacular Vendian faunas, best represented along the Winter Coast of the White Sea in Russia and in the Flinders Range of South Australia.
This project aims to locate additional material from areas with a sparse Vendian biotic record (South America in particular), but with marked palaeobiogeographic interest, to closely compare their settings (sedimentology, carbon and oxygen isotope signatures, palaeogeographic positions) with those of the best known Vendian biotas. This project aims to allow the proposers to gain further experience with those less biodiverse Vendian assemblages in Namibia, South America and with other older assemblages such as those in the Bangamall Basin of Western Australia and the Western United States, where some of the oldest probable records of multicellular organisms have been reported. In doing so, the proposers wish to bring researchers from other areas to examine and gain experience with the two most biodiverse assemblages in Australia and Russia, to involve students in this interaction, in the hope of markedly increasing the amount of material from some of the lesser known locales and refining the dating of all of these locales.
Parellel to our investigations concerning the megascopic multicellular biota, the work of several associates of this project will be investigating the geochemistry of the sediments for clues to changing climate and ocean chemistry and the involvement of microfauna in the deposition of major ore bodies of mid to late Proterozoic age.
Project No. 494 Ц Dysoxic to Oxic Change in Ocean Sedimentation During the Middle Cretaceous: A Study of the Tethyan Realm - Young Scientists Project
Full Title: Dysoxic to Oxic Change in Ocean Sedimentation During the Middle Cretaceous: A Study of the Tethyan Realm
Proposers: Dr Xiumian Hu (P. R. China), Dr Krzysztof Bak (Poland), Dr Jens Wendler (Germany), Dr Natalyia Tur (Russia)
The aim of this project is to gain knowledge about the oceanographic conditions, which caused occasional changes from dysoxic/anoxic deep-sea sedimentation into oxic. Such changes particularly occurred during the middle Cretaceous. From the Valanginian up to Early Aptian organic carbon - enriched black shales are intercalated with deep-water carbonates in the Tethys, and become more common from the Faraoni Horizon (about 126 Ma) to the Selli Horizon (OAE 1a, 120-119 Ma). From the Selli level to the Bonarelli level (OAE2, 93.5 Ma), deep ocean deposits are generally non-calcareous organic rich black shales. Beginning after the Selli Horizon red beds were deposited at certain locations. Preliminary results indicate that the Aptian-Cenomanian oceanic red beds (mainly red carbonate and clay) not only occur in Italy (Central Apennines and Southern Alps), but also are present in the Austrian Alps, the Slovakian and Polish Carpathians, and in Southern Russia. Due to the limited exploration of the Tibetan Plateau so far mid-Cretaceous marine red beds have not been discovered in this area.
After OAE2, in the Upper Cretaceous, the character of deep-sea deposits dramatically changed and oceanic deposits are red beds that indicate a major change in environmental conditions in the deep sea from anoxic to oxic. The existing IGCP project 463 concentrates on these Upper Cretaceous red beds while the Young Scientists Project IGCP 494 will focus on a detailed study of the onset of red beds deposition in the Middle Cretaceous. The observed switch from anoxic to oxic represents a major change in the location of hydrocarbon source rocks, which during Middle Cretaceous times were the deep oceanic basins. However, in the Late Cretaceous when red beds were deposited, very little organic carbon was buried in the deep oceanic basins. This overturn requires major changes either in the location of the carbon reservoir, or changes in the content of CO2 in the atmosphere, which in turn is reflected by the palaeoclimate. As the sediments inherited imprints of Palaeoclimatic, Palaeoceanographic and tectonic change this project will study the conditions, which could lead to the oscillations from dysoxic to oxic depositional setting during the Middle Cretaceous.
The project will concentrate on the study of different successions, which represent not only an excellent palaeolatitude transect through the Western Tethys, but also different bathymetrical sedimentary successions, and a longitudinal transect (Alps-Himalayas) to develop a database that will include stratigraphical, sedimentological, geochemical, and chronostratigraphical information. This project will focus on the transitions from black shales to oceanic red beds, especially at two well-defined stratigraphic levels - at the transition from the Selli level to the younger Aptian red beds, and at the transition from the Bonarelli level to the post-Cenomanian red beds. The study will be multidisciplinary using sedimentological/palaeontological, and advanced geochemical analyses that include stable isotope measurement, and organic and inorganic geochemistry. The relationships between occurrences of oceanic red beds and black shales, palaeoceanographic processes, palaeoclimate changes, palaeogeographical changes, igneous and tectonic events will be analysed aiming at a better understanding of the causes of changes in the burial rates, the amount of organic carbon and the content of oxygen in the world oceans during Middle Cretaceous time.
/ Проекты: действующие:
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