Introduction to the Geological Map of Asia and Europe

ThenewlycompiledGeologicalMapofAsiaandEurope(1.5000000)wasoneoftheimportantmapsoftheMinistryofGeologyandMineralResources(MGMR)ofChinaforsubmittingtothe30thInternationalGeologicalCongress.ItwascompiledbytheinstituteofGeology,CAGS.ThemapincludesthewholeAsianandEuropeanterritories,covering50.71millionkm~2,withalengthof3.5mand2.5minwidth.Themainresearchresultsandgreatprogressshownonthemapareasbelow.1.Thegeographicalmap,basedonwhichthegeologicalmapwascompiled,hashighprecisioninmathematics…     

Cretaceous–Tertiary structures and kinematics of the Serbomacedonian metamorphic rocks and their relation to the exhumation of the Hellenic hinterland (Macedonia, Greece)

 The kinematic pattern and associated metamorphism of the predominant ductile deformation and the subsequent deformational stages of the Serbomacedonian metamorphic rocks and granitoids are presented in terms of peri-Tethyan tectonics. A systematic record of structural and metamorphic data gives evidence of a main top-to-ENE to ESE ductile flow of Cretaceous age (120–90 Ma) associated with a crustal stretching and unroofing. A subordinate WSW to WNW antithetic sense of movement of the tectonic top is observed in places. The associated metamorphic conditions are estimated at 4.5–7.5 kbar and 510–580  °C. During Eocene to Miocene times these fabrics were successively deformed by low-angle extensional D_e ductile shear zones with top-to-NE and SW sense of movement and brittle shear zones of similar kinematic pattern, suggesting a transition from ductile to brittle deformation. D_e deformation was accompanied during its later stages by NW/SE-directed shortening. We also discuss the relation of this Cretaceous–Tertiary deformation of the Serbomacedonian metamorphic rocks with the Eocene to Miocene ductile, top-to-southwestward crustal shear of the adjacent Rhodope crystalline rocks. We regard the Serbomacedonian and the Rhodope metamorphic rocks to represent related metamorphic provinces, the most recent exhumation and cooling history of which is bracketed between the Eocene and Neogene. Received: 8 December 1998 / Accepted: 19 April 1999     

Geochemistry of О, Н, C,S, and Sr isotopes in the water and sediments of the Aral basin

The paper presents original authors' data on the O, H, C, S, and Sr isotopic composition of water and sediments from the basins into which the Aral Sea split after its catastrophic shoaling: Chernyshev Bay (CB), the basin of the Great Aral in the north, Lake Tshchebas (LT), and Minor Sea (MS). The data indicate that the δ¹⁸О, δD, δ¹³C, and δ³⁴S of the water correlate with the mineralization (S) of the basins (as of 2014): for CB, S = 135.6‰, δ¹⁸О = 4.8 ± 0.1‰, δD = 5 ± 2‰, δ¹³C (dissolved inorganic carbon, DIC) = 3.5 ± 0.1‰, δ³⁴S = 14.5‰; for LT, S = 83.8‰, δ¹⁸О = 2.0 ± 0.1‰, δD =–13.5 ± 1.5‰, δ¹³C = 2.0 ± 0.1‰, δ³⁴S = 14.2‰; and for MS, S = 9.2‰, δ¹⁸О =–2.0 ± 0.1‰, δD =–29 ± 1‰, δ¹³C =–0.5 ± 0.5‰, δ³⁴S = 13.1‰. The oxygen and hydrogen isotopic composition of the groundwaters are similar to those in MS and principally different from the artesian waters fed by atmospheric precipitation. The mineralization, δ¹³С, and δ³⁴S of the groundwaters broadly vary, reflecting interaction with the host rocks. The average δ¹³С values of the shell and detrital carbonates sampled at the modern dried off zones of the basins are similar: 0.8 ± 0.8‰ for CB, 0.8 ± 1.4‰ for LT, and –0.4 ± 0.3‰ for MS. The oxygen isotopic composition of the carbonates varies much more broadly, and the average values are as follows: 34.2 ± 0.2‰ for CB, 32.0 ± 2.2‰ for LT, and 28.2 ± 0.9‰ for MS. These values correlate with the δ¹⁸O of the water of the corresponding basins. The carbonate cement of the Late Eocene sandstone of the Chengan Formation, which makes up the wave-cut terrace at CB, has anomalously low δ¹³С up to –38.5‰, suggesting origin near a submarine methane seep. The δ³⁴S of the mirabilite and gypsum (11.0 to 16.6‰) from the bottom sediments and young dried off zone also decrease from CB to MS in response to increasing content of sulfates brought by the Syr-Darya River (δ³⁴S = 9.1 to 9.9‰) and weakening sulfate reduction. The ⁸⁷Sr/⁸⁶Sr ratio in the water and carbonates of the Aral basins do not differ, within the analytical error, and is 0.70914 ± 0.00003 on average. This value indicate that the dominant Sr source of the Aral Sea is Mesozoic–Cenozoic carbonate rocks. The Rb–Sr systems of the silicate component of the bottom silt (which is likely dominated by eolian sediments) of MS and LT plot on the Т = 160 ± 5 Ma, I₀ = 0.7091 ± 0.0001, pseudochron. The Rb–Sr systems of CB are less ordered, and the silt is likely a mixture of eolian and alluvial sediments.     

U-Pb Zircon Dating of the Granitic Conglomerates of the Hutuo Group： Affinities to the Wutai Granitoids and Significance to the Tectonic Evolution of the Trans-North China Orogen

1 Introduction The North China Craton (NCC) is considered to be the oldest and largest cratonic block in China. Recent studies to gain understanding of basement architecture of the NCC has led to its division into the Western and Eastern Blocks, separated by a N-S trending Paleoproterozoic Trans-North China Orogen (TNCO) (Fig. 1; Zhao et al., 1998, 1999a, 2000a, 2001a; Wilde et al., 2002). Although there is now abroad consensus that the final assembly of the NCC was completed by th…     

Refinement of the structure of ζ-Nb2O5 and its relationship to the rutile and thoreaulite structures

Summary The crystal structure of -Nb₂O₅, space groupC2/c, a 12.740(2),b 4.8830(6),c 5.5609(6)Å, 105.02(1)°, Z 4, has been refined toR 1.6% for 457 observed reflections (MoK). The coordination polyhedron of the niobium atom is a distorted octahedron; the crystal structure consists of two-octahedron-thick, rutile-like layers separated by crystallographic shear (CS) planes. Relative to the rutile structure, these planes are indexed (101) and adjacent layers are related by the CS vector <a/6b/2c/2>. Members of the thoreaulite-foordite series have topologically identical two-octahedron-thick (101) sheets; however, here the CS vector Zusammenfassung Die Kristallstruktur des -Nb₂O₅, Raumgruppe C2/c, a 12,740(2),b 4,8830(6),c 5,5609(6) Å, 105,02(1)°,Z 4, wurde mit 457 beobachteten Reflexen (MoK) aufR 1,6% verfeinert. Das Koordinationspolyeder des Niobiumatoms ist ein verzerrtes Oktaeder; die Kristallstruktur besteht aus Rutil-artigen Schichten, die zwei Oktaeder dick sind und von kristallographischen Scher-(CS-)flächen getrennt werden. In bezug auf die Rutilstruktur haben diese Flächen die Indizes (101) und benachbarte Schichten sind durch den CS-Vektor <a/6b/2c/2> verknüpft. Die Glieder der Thoreaulith-Foordit-Reihe haben idente (101)-Schichten einer Dicke von zwei Oktaedern; indessen bewirkt hier der CS-Vektor <a/2> _r gekoppelt mit dem Translationsvektor <1,5c> _r die Einlagerung von tetragonal-antiprismatischen Lücken zwischen benachbarte Schichten.

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A contribution to the crystal chemistry of the voltaite group: solid solutions, Mössbauer and infrared spectra, and anomalous anisotropy

Voltaite is a mineral of fumaroles, solfatares, coal-fire gas vents, and acid-mine drainage systems. The nominal composition is K₂Fe₅ ²⁺Fe₃ ³⁺Al(SO₄)₁₂·18H₂O and the nominal symmetry is cubic, $Fd\overline{3}c$ . The tetragonal (I4₁/acd) superstructure of voltaite is known as the mineral pertlikite. In this study, we investigated 22 synthetic voltaite samples in which Fe²⁺ was partially or completely replaced by Mg, Zn, Mn, or Cd, by single-crystal and powder X-ray diffraction (both in-house and synchrotron). Two samples contained NH₄ ⁺ instead of K⁺. The structure of voltaite is based on a framework defined by kröhnkite-like heteropolyhedral chains which host both M³⁺ and M²⁺ in octahedral coordination. Unit cell dimensions of the end-members scale almost linearly with the size of M²⁺. In the Fe²⁺-Mg-Zn solid solutions, the Fe²⁺-Mg and Fe²⁺-Zn solutions are linear (ideal) in terms of their lattice-parameter variations. The Mg-Zn solid solution, however, is strongly non-ideal. A detailed analysis of the topology of the chains showed that this behavior originates in expansion and contraction of individual M²⁺-O bonds within the chains. In the Mg-Zn solid solution, some of the M²⁺-O bonds expand while none contract. In the other solid solutions, expansion of some M²⁺-O bonds is always compensated by contraction of the other ones. Parts of the nominally cubic crystals are optically anisotropic and their symmetry is found to be tetragonal by single crystal X-ray diffraction measurements. The coexistence of cubic and tetragonal sectors within a single crystal without any detectable difference in their chemical composition is difficult to explain in terms of growth of such composite crystals. Mössbauer and infrared spectra collected on our synthetic crystals conform with previously published data.     

Velocities of Present-Day Horizontal Movements in the Central Sector of the Greater Caucasus according to GPS Observations and Their Relation to Tectonics and the Deep Structure of the Earth’s Crust

The results of the first GPS measurements along the geophysical profile that intersects all major geological structures of the Osetiya region of the Greater Caucasus are presented. The results of the measurements are interpreted in comparison with those of neotectonic studies and data on the deep structure.     

Genesis of the Archean–Paleoproterozoic Tabletop Domain,Rudall Province,and its endemic relationship to the West Australian Craton

The Tabletop Domain of the Rudall Province has been long thought an exotic entity to the West Australian Craton. Recent re-evaluation of this interpretation suggests otherwise, but is founded on limited data. This study presents the first comprehensive, integrated U–Pb geochronology and Hf-isotope analysis of igneous and metasedimentary rocks from the Tabletop Domain of the eastern Rudall Province. Field observations, geochronology and isotope results confirm an endemic relationship between the Tabletop Domain and the West Australian Craton (WAC), and show that the Tabletop Domain underwent a similar Archean–Paleoproterozoic history to the western Rudall Province. The central Tabletop Domain comprises Archean–Paleoproterozoic gneissic rocks with three main age components. Paleo–Neoarchean (ca 3400–2800 Ma) detritus is observed in metasedimentary rocks and was likely sourced from the East Pilbara Craton. Protoliths to mafic gneiss and metasedimentary rocks are interpreted to have been emplaced and deposited during the early Paleoproterozoic (ca 2400–2300 Ma), and exhibit age and isotopic affinities to the Capricorn Orogen basement (Glenburgh Terrane). Mid–late Paleoproterozoic mafic and felsic magmatism (ca 1880–1750 Ma) is assigned to the Kalkan Supersuite, which is exposed in the western Rudall Province. The Kalkan Supersuite provided the main source of detritus for mid–late Paleoproterozoic metasedimentary rocks in the Tabletop Domain. Similarities in the age and Hf-isotope compositions of detrital zircon from these metasedimentary rocks and Capricorn Orogeny basin sediments suggests that a regionally extensive, linked basin system may have spanned the northern WAC at this time. The Tabletop Domain records evidence for two metamorphic events. Mid–late Paleoproterozoic deformation (ca 1770–1750 Ma) was high-grade, regional and involved the development of gneissic fabrics. In contrast, early Mesoproterozoic (ca 1580 Ma) high-grade deformation was localised and associated with more widespread, late-stage, greenschist facies alteration. These new findings highlight that the Tabletop Domain experienced a much higher grade of deformation than previously assumed, with a Paleoproterozoic metamorphic history similar to that of the western Rudall Province.     

The Early Precambrian Rocks,Their Ages,Division and Correlation of the Taihang-Wutai Region, the Yanshan Region and the Eastern Sector of the Yinshan Mountains

According to differences of the protolith formations, the early Precambrian strata in the northern part ofthe North China platform may be divided into the stable stratigraphic region in the west and the mobilestratigraphic region in the east. Based on unconformities, either stratiragphic or tectonic, as well as significantmetamorphic thermal events, the two regions may be stratigraphically defined as follows: 1) the middleArchaean Fuping Supergroup composed of the Chenzhuang and Wanzi Groups (stable areas), and the middleArchaean Qianxi Group (mobile area), whose upper limits are all dated at 2800 Ma; and 2) the upper ArchaeanWutai Supergroup composed of the Longquanguan, Shizui and Taihuai Groups (stable areas), and the upperArchaean Zunhua, Dantazi and Zhuzhangzi Groups (mobile areas). whose upper limits are all dated at 2500Ma. A correlation of the above-mentioned units is also made. The lower Proterozoic Hutuo Group of the sta-ble region is adjusted to comprise the Gaofan, Doucun, Dongye and Guojiazhai Groups. The upper limit of theGaofan Group is placed at 2350 Ma, Dongye 1850 Ma and Guojiazhai (the lower limit of the Changcheng Sys-tem) 1700 Ma.     

Exotic crustal block accretion to the eastern Gondwanaland margin in the Late Cambrian–Tasmania,the Selwyn Block,and implications for the Cambrian–Silurian evolution of the Ross,Delamerian, and Lachlan orogens

Reconstructions of the Cambrian–Silurian tectonic evolution of eastern Gondwanaland, when the Australian Tasmanides and Antarctic Ross Orogen developed, rely on correlation between structural elements in SE Australia and Northern Victoria Land (NVL), Antarctica. A variety of published models exist but none completely solve the tectonic puzzle that is the Delamerian–Lachlan transition in the Tasmanides. This paper summarizes the understanding of Cambrian (Delamerian) to Silurian (Lachlan) geological evolution of the eastern Tasmanides, taking into account new deep seismic data that clarifies the geological connection between Victoria and Tasmania — the ‘Selwyn Block’ model. It evaluates previous attempts at correlation between NVL, Tasmania and Victoria, and presents a new scenario that encompasses the most robust correlations. Tasmania together with the Selwyn Block is reinterpreted as an exotic Proterozoic microcontinental block – ‘VanDieland’ – that collided into the east Gondwanaland margin south of western Victoria, and north of NVL in the Late Cambrian, perhaps terminating the Delamerian Orogeny in SE Australia. Subsequent north-east ‘tectonic escape’ of VanDieland in the Early Ordovician explains the present-day outboard position of Tasmania with respect to the rest of the Delamerian orogen, the origin of the hiatus that separates the Delamerian and Lachlan orogenic cycles in Australia, and how western Lachlan oceanic crust developed as a ‘trapped plate-segment’. The model establishes a new structural template for subsequent Lachlan Orogen development and Mesozoic Australia–Antarctica separation.     

Timing of low-temperature metamorphism and cooling of the Paleozoic and Mesozoic formations of the Bükkium,innermost Western Carpathians,Hungary

K-Ar ages of illite-muscovite and fission track ages of zircon and apatite were determined from various lithotypes of the Bükkium, which forms the innermost segment of the Western Carpathians. The stratigraphic ages of these Dinaric type formations cover a wide range from the Late Ordovician up to the Late Jurassic. The grade of the orogenic dynamo-thermal metamorphism varies from the late diagenetic zone through the anchizone up to the epizone (chlorite, maximally biotite isograd of the greenschist facies). The K-Ar system of the illite-muscovite in the < 2 m grain-size fraction approached equilibrium only in epizonal and high-temperature anchizonal conditions. The orogenic metamorphism culminated between the eo-Hellenic (160-120 Ma) phase connected to the beginning of the subduction in the Dinarides, and the Austrian (100-95 Ma) phase characterized by compressional crustal thickening. No isotope geochronological evidence was found for proving any Hercynian recrystallization. The stability field of fission tracks in zircon was approached using the thermal histories of the different tectonic units. A temperature less than 250°C and effective heating time of 20–30 Ma had only negligible effects on the tracks, whereas total annealing was reached between 250 and 300°C. Apatite fission track ages from the Paleozoic and Mesozoic formations show that the uplift of the Bükk Mountains occurred only in the Tertiary (not earlier than ca. 40 Ma ago). Thermal modeling based on apatite fission track length spectra and preserved Paleogene sediment thickness data proved that the Late Neogene burial of the recently exhumed plateau of the Bükk Mountains exceeded 1 km.     

Ecological Impact of the Introduction to New Zealand of Asian Date Mussels and Cordgrass—The Foraminiferal,Ostracod and Molluscan Record

The ecological impact from the establishment of dense intertidal beds of introduced Asian date mussels (Musculista senhousia) and cordgrass (Spartina alterniflora) in five northern New Zealand estuaries and harbours was documented in 2005–2006, using the fossil record of the shells of foraminifera, ostracods and molluscs in paired sediment cores and surface samples taken from inside and outside selected beds. The most significant changes in faunal composition in all, but the most saline sites, generally occurred in both cores in each pair and could be attributed to the impact of decreased salinity and pH as a result of increased freshwater runoff following clearance of the surrounding forest in the 19th century and urban development in the late 20th century. Establishment of Asian date mussel beds had a greatest impact on the composition of ostracod faunas. At near oceanic salinity, the mussels had completely replaced the native infaunal bivalve fauna, but had little impact on the foraminifera. At more brackish sites, the presence of mussel shells appears to have buffered the calcareous foraminifera from the effects of lowered pH, which had dissolved this component outside the beds. Establishment of cordgrass patches had no impact on ostracod faunas, and little on molluscs except at Kaipara, where introduced Pacific oysters had colonised the cordgrass. Cordgrass had the most impact on the foraminifera. At brackish sites, cordgrass patches had been colonised by agglutinated foraminiferal species different from those that dominate outside. In cordgrass at more saline sites, agglutinated foraminifera have invaded and bloomed at the expense of calcareous Ammonia spp., which dominated outside the patches.     

Prevenance,preservation, and transport of the detrital “coffee grounds” of the Mississippi Delta

Detrital organic fragments or “coffee grounds”, common in the swash zone, and in the lee of barrier islands off the Mississippi Delta consists of up to 40% high-volatile bituminous coal particles of medium to coarse sand size (0.25–1 mm). These coal fragments produce both a well preserved Cretaceous-Paleocene flora and a less well preserved Pottsville (Early Pennsylvanian) flora. This Pottsville flora has close affinities with one described by Kosanke (1950) from the Early Pennsylvanian Illinois Basin coals. If the provenance assignment is correct, these coal particles were transported by the Mississippi River a minimum of 1000 miles from the Interior Coal Province to their present locality in the south Pass area of the Mississippi Delta. However, spillage contamination during a century of barge transport within the Mississippi drainage cannot be ruled out as a possible source for the “coffee grounds” coal.High-volatile coals crop out in the Black Warrior Basin in Alabama to the northeast of the delta. If this is a source of the coal, then an entirely different drainage-transport system would be involved. It would invoke drainage from the Appalachian Province southward, with subsequent longshore current transport, westward — along the Gulf Coast shoreline.Heavy-mineral differences exist between these two sedimentary provinces, with the Appalachian-derived heavy minerals dominated by kyanite, staurolite, and tourmaline; and the Mississippi River Canadian Shield source dominated by amphiboles and pyroxenes. The heavy-mineral assemblage recovered from the “coffee grounds” material is more like those of the Mississippi River Province, and dominated by green hornblende.Vitrinite particles of the coals show no evidence of oxidation rims although they have been in oxygenated waters for an extended period of time during transport. The spore preservation is adequate for specific identification, and is further evidence of minimal oxidation.Coal rank analysis and palynoflora identifications provide a dual approach in reconstructing provenance, transport history, and origin of these detrital organic deposits.     

Natural and anthropic perturbations to the chemical composition of the Colorado River (Tucumán,Argentina)

Economic and urban development in the province of Tucumán is closely associated with its hydrological network. In spite of the regulatory efforts to preserve the quality of the water resources, the lower basins of the majority of the rivers are contaminated with organic effluents derived from sugar-mill and citrus industry. In this paper, the conditions of the Colorado River basin are described. At its headwater, the lithology and geology determine the chemical composition. Calcite and gypsum dissolution and silicate influence water composition, which is slightly perturbed a few kilometers downstream by geothermal waters discharged by a tributary. Close to the discharge into the Salí River, the Colorado River receives a high organic matter load from the highly polluted Calimayo stream, which produces an increase in the organic matter and depletion of dissolved oxygen with redox conditions that promote the reduction of sulfate to sulfide.     

The Experimental Results of Pb and Zn Partitioning between Fluid and Melt, and Their Application to the Research on Metallogeny

Three logarithmic linear equations between D_(Me)~(V/L) and [m_(NaCl)], and the relationship of D_(Me)~(V/L) versus F/Cl or K/Na mole ratios have been established by the experiments of the partitioning of Pb and Zn between granitic silicate melt and aqueous fluid. These results have been used to quantitatively study some essential problems, such as the possibility and degree of Pb-Zn mineralization in the system of granitic magma and hydrothermal fluid, and the influence of the relative contents of alkali and volatiles on the Pb-Zn mineralization in the same system. Some new points have been put forward in this paper.