scholarly journals Palaeogeographical conditions of the formation of the channel alluvium of the high (Susidovychi) terrace of the Dnister River in the Kulakivtsi section (Podillia-Dnister region)

2018 ◽  
pp. 303-323
Author(s):  
Andriy Yatsyshyn ◽  
Andriy Bogucki ◽  
Danuta Olszewska-Nejbert ◽  
Maciej Bąbel
Keyword(s):  
Granulometric Composition ◽  
Small Volume ◽  
Coarse Grained ◽  
Alluvial Deposits ◽  
Petrographic Composition ◽  
Rock Types ◽  
Clay Matrix ◽  
Two Stages ◽  
River Valleys ◽  
The Village

The main lithological characteristics of the channel facies of the Susidovychi terrace, which correspond to the high (situated over the canyon) groups of Dnister terraces, were given. The investigations in the gravel pit at Kulakivtsi proved that the alluvium of the terrace has been formed in two stages. During the first stage, the lower 1.5 thick bed of the alluvium was deposited. The upper one, nearly 4 m thick alluvium bed was formed in the next, second one depositional stage. The stages of the alluvium formation were recorded in the changes of the granulometric and petrographical composition of the alluvium, and of the roundness of the coarse-grained clasts. The transition between these two alluvial beds is outlined by the voluminous intercalations of the sand lenses, and also by a change in the colour of the alluvial deposits. Granulometric composition of the alluvium of the channel facies, in general, changes little in the section. Only in the transition zone from the lower to the upper part of the alluvial deposits, there is a sharp, abrupt increase in the content of gravels and a sharp reduction in the content of boulders. Generally, in the composition of the alluvium two dominant and two subordinate components are clearly identified. The pebble grains and the sandy-clay matrix are the dominant components, whereas the gravel grains and the boulders are less common. Petrographic composition of the coarse-grained fraction of the terrace alluvium proved to be the richest of all the so far investigated sections of the high (situated over the canyon) terraces of the Dnister River (at Kunysivtsi, Ivane-Puste, Repuzhyntsi, and Lysychnyky). The pebbles 40–100 mm in diameter show particularly diverse petrographic composition which includes fragments of nine types of rocks: the four of the Carpathian provenance (sandstone, aleurite, cherts, and quartzite), and the five of the Podillian provenance (red-coloured Devonian sandstone, Albian cherts and sandstone, and lithothamnian and cryptocrystalline chemogenic limestone). More precisely, the richest is the lower part of the alluvial deposits where the fragments of all the nine rock types occur. The upper part of the alluvium is markedly poorer because only the five rock types occur there. Diversity of the petrographic composition of the alluvium decreased by reducing the local Podillian types of rocks, which are represented only by the red-coloured Devonian sandstones. The composition of the Carpathian types of rocks remained unchanged. The detected changes in the granulometric and petrographic composition of the alluvium of the investigated terrace permitted to show that the principal providers of the local (Podillian) debris of rocks was played by the Podillian tributaries of the Dnister River. The Dnister alone transported mainly the Carpathian material and only the small volume of Podillian rocks represented by the debris of the red-coloured Devonian sandstones. It was also found that the accumulation of the alluvial deposits of the Susidovychi terrace in the Kulakivtsi section took place in the conditions of restructuring of the Dnister palaeodrainage system. In the initial stages of this terrace formation, the palaeo-Dnister was directed from the village Dobryvliany further north than today, and it entered into the present-day Tupa River valley at environs of the village Bedrykivtsi. In the vicinity of the village Bedrykivtsi, the palaeo-Dnister was turning sharply eastward and proceeded along the present-day river valleys of Tupa and Seret. In the later stages of the Susidovychi terrace formation, the palaeo-Dnister left the portion of its valley stretching between the villages Bedrykivtsi and Schytivtsi, and it shifted several hundred meters to the south and has stopped practically within its current canyon valley. The desolate portion of its palaeo-valley located between the villages Bedrykivtsy and Kasperivtsi has been inherited by the Tupa River and the lower portion of this palaeo-valley located between the villages Kasperivtsi and Schytivtsi – by the Seret River. Key words: palaeo-Dnister, over the canyon terraces, Susidovychi terrace, alluvium, granulometric composition, petrographical composition, roundness, Carpathian material, Podillian material.

scholarly journals Lithological characteristic of the riverbed alluvium of the sixth terrace of the Dnister–Stryvihor in the Dubrivka section (Forecarpathians)

2015 ◽  
pp. 348-363
Author(s):  
Andriy Yatsyshyn ◽  
Andriy Bogucki
Keyword(s):  
Key Words ◽  
Granulometric Composition ◽  
The Other ◽  
Coarse Grained ◽  
Clastic Material ◽  
Alluvial Deposits ◽  
Petrographic Composition ◽  
Preferred Direction ◽  
Carpathian Foredeep ◽  
Main Components

The main lithological characteristics of riverbed facies of alluvium of the sixth terrace above the floodplain of the Dnister-Stryvihor Rivers (Loyeva level) near Sambir were analysed. The granulometric and petrographic composition of the gravelly-pebble material, its roundness, form and the orientation of grains were characterised. Lithological analyses helped to determine that investigated layer of alluvium are poorly sorted. The three main components of alluvial strata (pebbles, gravel and sand-loamy filler) are present in approximately comparable proportions. Boulders are least common in the composition the alluvium. Coarse material is preferably well and medium rounded. Poorly and very well rounded fragments happen considerably rarely. The preferred direction of transport of fragment materials was Northwest–Southeast. Its direction is approximate to the current of modern Stryvihor. The fragments of the Carpathian rocks (sandstones, siltstones and silicates) dominate in a petrographic composition of coarse-grained alluvial deposits. That means that the Carpathians were the main source of supply of clastic material during the formation of investigated strata of alluvium. The rocks of local origin, which is involved from the bed of alluvium during the cutting of paleoStryvihor in the thickness of pre-Quaternary rocks of the Carpathian Foredeep, were mixed with the fragments of the Carpathian rocks in small amounts. The results of lithological studies show that paleo-Stryvihor accumulated the alluvial strata of Dubrivka section after that time when it had cut into the socle of Torhanovychi terrace up to 8–10 m before the deposition of alluvium. In other words, the preserved fragment of Loyeva level between the villages Torhanovychi and Dubrivka that is on the Dnister-Stryvihor interfluves consists of two terraces of different ages. One of them is a hypsometric higher and older Torhanovychi terrace, which was formed by paleo-Dnister River, and the other one is a hypsometric lower and respectively younger Dubrivka terrace, which was formed by paleo-Stryvihor River. Key words: alluvium, granulometric composition, petrographic composition, roundness of grains, sandstones, siltstones, silicates, gaizes, current of palaeochannel, Loyeva level.

scholarly journals Petrography of aggregates in Luzon, Philippines: Identification of components and deleterious materials

2020 ◽  
Vol 18 (2) ◽  
pp. 1-18
Author(s):  
Maria Ines Rosana Balangue-Tarriela ◽  
Cleodette L. Lagata ◽  
Raymond G. Leuterio ◽  
Ma. Lourdes Caluen-Abad
Keyword(s):  
Volcanic Rocks ◽  
Chemical Properties ◽  
Coarse Grained ◽  
Alluvial Deposits ◽  
Clastic Rocks ◽  
Rock Types ◽  
Transmitted Light Microscopy ◽  
Metro Manila ◽  
Aggregate Composition ◽  
Physical And Chemical

Petrography is one of a series of standard tests used to assess an aggregate’s components, mechanical qualities, durability, chemical stability, and alkali reactivity. In this study, aggregate materials were collected from rock exposures and/or alluvial deposits from four areas near Metro Manila, Philippines: Bulacan, Rizal, Pampanga, and Zambales. Transmitted light microscopy was conducted to identify rock types and characterise physical and chemical properties that may present potential problems when used as aggregate materials. The results show that the aggregates vary in terms of rock types and alteration type. Samples from Bulacan are mostly porphyritic basalt and fine to coarse-grained sandstone with veinlets of silica and carbonate. The presence of cavities and microfractures caused mainly by vesicles from the volcanic rocks was also observed. Rizal aggregates are composed predominantly of chloritized basalts and andesites with minor clastic rocks and tuffs. The aggregates from Zambales are products of erosion of the Zambales Ophiolite, mixed with the lahar deposits from the Pinatubo eruption. On the other hand, Pampanga aggregates are mostly lahar deposits, containing pumice, a poor choice for aggregate composition due to its low hardness, brittleness and vesiculated texture. Aside from the lithological classification, potentially alkali-reactive constituents were also observed in selected samples from the four sampling areas.

The Origins of the Village Revisited: From Nuclear to Extended Households

2002 ◽  
Vol 67 (3) ◽  
pp. 417-433 ◽  
Author(s):  
Kent V. Flannery
Keyword(s):  
Nuclear Family ◽  
Extended Family ◽  
Near East ◽  
Shared Storage ◽  
Nuclear Families ◽  
Second Stage ◽  
Third Stage ◽  
Two Stages ◽  
Extended Households ◽  
The Village

In Mesoamerica and the Near East, the emergence of the village seems to have involved two stages. In the first stage, individuals were distributed through a series of small circular-to-oval structures, accompanied by communal or “shared” storage features. In the second stage, nuclear families occupied substantial rectangular houses with private storage rooms. Over the last 30 years a wealth of data from the Near East, Egypt, the Trans-Caucasus, India, Africa, and the Southwest U.S. have enriched our understanding of this phenomenon. And in Mesoamerica and the Near East, evidence suggests that nuclear family households eventually gave way to a third stage, one featuring extended family households whose greater labor force made possible extensive multifaceted economies.

scholarly journals Properties of cement composites based on limestone depending on their granulometric composition

Vestnik MGSU ◽  
2020 ◽  
pp. 999-1006
Author(s):  
Svetlana V. Samchenko ◽  
Olga V. Alexandrova ◽  
Anton Yu. Gurkin
Keyword(s):  
Composite Materials ◽  
Portland Cement ◽  
Granulometric Composition ◽  
Coarse Grained ◽  
Cement Matrix ◽  
Cement Composites ◽  
Construction Costs ◽  
Initial Strength ◽  
Fine Grained ◽  
Additional Formation

Introduction. The use of limestone in cement compositions as an additional cementing agent solves both environmental and economic problems, namely, reduction of construction costs. In this regard, the study of the properties of the granulometric composition and volumetric content of cement composites, containing limestone, becomes increasingly important. The mission of this research is to optimize the properties of composite materials containing Portland cement and limestone by changing the granulometric composition of flour limestone. Materials and methods. Limestone, having three different Blaine milling fineness values of 250, 300 and 450 m2/kg, was used; its content reached 10, 15, 25 and 35 %. Cement and sand mortars were applied for testing purposes. The influence of the granulometric composition of limestone on the workability and compressive strength of composite cement was determined. Results. The effect of limestone on the limit shear stress becomes more pronounced when the amount of limestone increases to 25 and 35 %. This is most noticeable for limestone with a high content of fine fractions of 5–20 µm. The use of finely milled limestone increases the initial strength of the composite material. By adding 10 and 15 % of such limestone we can increase the strength by 16–20 %, and supplementary 25–35 % of limestone increases strength by 5–8 %. Strength enhancement is due to the reactivity of limestone and formation of calcium hydrocarbon aluminate 3CaO∙Al2O3∙СаСО3∙12H2O, which promotes formation of the crystal framework of the cement matrix. Additional formation of crystalline hydrates in the initial coagulation structure deteriorates the mortar workability, but increases its strength. Conclusions. The use of coarse-grained limestone significantly improves mortar workability, while the use of fine-grained limestone increases its content without reducing its strength. The granulometric composition of ground limestone shall be as close as possible to the granulometric composition of cement for the properties of composite materials containing Portland cement and limestone to be optimized.

scholarly journals Deflation's soil and technogenic pollutants of the near-highway zones of road Lviv–Krakovets

2017 ◽  
pp. 370-381
Author(s):  
Yuliia Chykailo ◽  
Ivan Voloshyn
Keyword(s):  
Chemical Elements ◽  
Alluvial Plain ◽  
Soil Profiles ◽  
Buried Soils ◽  
Beech Forests ◽  
Alluvial Deposits ◽  
Different Depths ◽  
The Village ◽  
Humus Horizons ◽  
Near Highway

In the article is analyzed the soils’ properties in near-highway road strips of M-10 Lviv- Krakovets with width up to 150 m. Within the near-road strips of the highway, have been established 12 experimental polygons under forest, meadow vegetation and agricultural lands. On each polygons from soils profile samples are selected the most common soils: sod-podzolic, formed on fl uvio-glacial and gray-forest soils formed onloess loam. Completed description of soil profiles to depth of 0-100 cm. Part of experimental soils are formed under hornbeam-beech forests (11, 12 polygons) and oak-hornbeam-pine (4, 6, 7, 8 polygons). The researches revealed that in soil profiles at different depths are lie buried in eolian forms of relief (dunes) with different steepness of slopes. The steepness of the walls of the superficial layers of the dunes varies from 10 to 30°. In the research profiles of near-highway soils on the surface of the dunes, fi nd presence of progumed fragments of strips up wide to 2–3 cm. On the territory of the Nadsyanska moraine-zandrova alluvial plain at a distance of 50 m from the roadway (polygon 2, in the valley of the river Shklo, where the grassland vegetation is predominant, the turfy shallow gluten sandy soils are formed on alluvial deposits) discovered two low-power buried humus horizons who inherited a deflationary relief. Their steepness on the surface of the dunes is about 10 °. In polygon 3, the incision is laid in the micro threshold of the ancient relief, where the vegetation is represented by a spruce forest with oak impurities. In the profile of sod-hidden-podzolic sandy soil, on the surface of buried dunes which have steep walls 10-20°, are observed a humus layers . In the polygon 12, which is laid in the southwestern spurs of Roztochya 1,5 km north of the village of Birky in the hornbeam forest, steepness of the walls superficial layers of dunes of western exposition ranges from 10 to 12°. Soil is a clear-gray forest-loamy on loess loamy. In the soil profi les have been identified the following chemical elements: Pb, Zn, Co, Cu, Ni, Mo, Cr, Mn, V, Ba, Sr, Zr, Fe, Ti, Sn. The researches have established that in the territory of the Nadsyanska moraine-zandrovu alluvial plain, and in the southwestern spurs of Roztochchya, widespread buried dune relief. Based on our research, we propose to consider the issue of the allocation of types (subtypes) in soil legends, to investigate the defilations and inter deflation periods of their formation. Key worlds: near-roads strips, soil profile, deflation forms, buried soils, fragments of humus layers.

Dense 3D electrical resistivity tomography to understand complex deep landslide structures

2021 ◽  
Author(s):  
Julien Gance ◽  
Orlando Leite ◽  
Myriam Lajaunie ◽  
Kusnahadi Susanto ◽  
Catherine Truffert ◽  
...  
Keyword(s):  
Electrical Resistivity ◽  
Large Scale ◽  
Electrical Resistivity Tomography ◽  
Surface Deformation ◽  
Reference Model ◽  
Slope Instability ◽  
Complex Objects ◽  
Alluvial Deposits ◽  
Resistivity Tomography ◽  
The Village

<p>Large scale slope instabilities are complex objects controlled by multiple parameters. The underground and superficial structure of the slope plays a major role as it often controls water circulations, potentially causing weathering and damaging processes, and permits the local storage of water masses, causing temporary overload. In addition, the structure of the subsurface often delineates rock-volumes with variable mechanical properties, whose spatial distribution greatly influences the behavior of the slope. This work illustrates how Dense 3D Electrical Resistivity Tomography can provide relevant constraints on these parameters.</p><p>The village of Viella, in France (Hautes-Pyrénées), is affected by strong slope movement since 2018, when a massive rockslide above the village modified the stress conditions of the entire slope and, potentially, the hydrogeological context. As a consequence, some houses and infrastructures are progressively damaged, leading to heavy measures (houses evacuation). This complex, deep-seated (> 80 m), slope instability covers an area of ca. 650 000 m², is primarily composed of altered shists, colluviums, and non-consolidated alluvial deposits, forming several kinematic units with surface velocities in the range [0.5 – 5] mm.month<sup>-1</sup>.</p><p> </p><p>A 3D dense electrical resistivity tomography was realized using the FullWaver system, to characterize the structure and the forcing factors of this unstable slope. 55 V-FullWavers receivers (3 -electrodes, 2 channels sensors) were quasi-evenly distributed over a surface area of 400 x 500 m² with an interval of 90 m, apart from the village area, where no electrode could be grounded. Each V-FullWaver recorded signals through two orthogonal dipoles of 25 m length. Current injections were realized with a high-power transmitter (6 kW, 16 A, 3000 V). 235 injection dipoles were used. The system injected current between a fixed remote electrode (more than 1 km away from the site to increase the investigation depth) and a local mobile electrode, moved all over the investigated area in between the V-Fullwaver receivers, with an interval of approximately 40 m, except in the village area.</p><p> </p><p>The resulting 3D resistivity model presents a high spatial variability until 100 to 150 m depth approximately, that highly relates to the complex strain dynamics of the slope and the hydrogeological observations. It highlights the relation between the most active kinematic compartments and the large-scale structure of the slope.</p><p>It provides a first understanding of the role of local compacted rocks in the buildup of surface deformation but also on the localization of heterogeneities (fissures, scarps) which may relate to water circulation paths.</p><p>. This 3D image of the slope is the first structural reference model for future hydrogeological and geomechanical studies aiming at deducing the possible evolution of the slope.</p>

scholarly journals Petrogenesis and U-Pb and Sm-Nd geochronology of the Taquaral granite: record of an orosirian continental magmatic arc in the region of Corumba - MS

2015 ◽  
Vol 45 (3) ◽  
pp. 431-451 ◽  
Author(s):  
Letícia Alexandre Redes ◽  
Maria Zélia Aguiar de Sousa ◽  
Amarildo Salina Ruiz ◽  
Jean-Michel Lafon
Keyword(s):  
Geochemical Data ◽  
Alkaline Magmatism ◽  
Alluvial Deposits ◽  
Mato Grosso ◽  
Microgranular Enclave ◽  
Magmatic Arc ◽  
Rock Types ◽  
High K ◽  
Continental Magmatic Arc ◽  
Shrimp Zircon

The Taquaral Granite is located on southern Amazon Craton in the region of Corumbá, westernmost part of the Brazilian state of Mato Grosso do Sul (MS), near Brazil-Bolivia frontier. This intrusion of batholitic dimensions is partially covered by sedimentary rocks of the Urucum, Tamengo Bocaina and Pantanal formations and Alluvial Deposits. The rock types are classified as quartz-monzodiorites, granodiorites, quartz-monzonites, monzo and syenogranites. There are two groups of enclaves genetically and compositionally different: one corresponds to mafic xenoliths and the second is identified as felsic microgranular enclave. Two deformation phases are observed: one ductile (F1) and the other brittle (F2). Geochemical data indicate intermediate to acidic composition for these rocks and a medium to high-K, metaluminous to peraluminous calk-alkaline magmatism, suggesting also their emplacement into magmatic arc settings. SHRIMP zircon U-Pb geochronological data of these granites reveals a crystallization age of 1861 ± 5.3 Ma. Whole rock Sm-Nd analyses provided εNd(1,86 Ga) values of -1.48 and -1.28 and TDM model ages of 2.32 and 2.25 Ga, likely indicating a Ryacian crustal source. Here we conclude that Taquaral Granite represents a magmatic episode generated at the end of the Orosirian, as a part of the Amoguija Magmatic Arc.

Liquid immiscibility and the origin of alkali-poor carbonatites

1988 ◽  
Vol 52 (364) ◽  
pp. 43-55 ◽  
Author(s):  
B. A. Kjarsgaard ◽  
D. L. Hamilton
Keyword(s):  
Liquid Immiscibility ◽  
Raw Material ◽  
Coarse Grained ◽  
Rock Types ◽  
Liquid Fractionation ◽  
Ring Complexes ◽  
The Common ◽  
Melt Cooling ◽  
Carbonate Melt ◽  
Common Sequence

AbstractThe work on liquid immiscibility in carbonate-silicate systems of Freestone and Hamilton (1980) has been extended to include alkali-poor and alkali-free compositions. Immiscibility is shown to occur on the joins albite-calcite and anorthite-calcite at 5 kbar. These results make it possible to interpret ocellar structure between calcite-rich spheroids in lamproite or kimberlite host rock as products of liquid immiscibility. The common sequence of rock types found in carbonatite complexes of melilitite-ijolite-urtite-phonolite is interpreted as being the result of both fractional crystallization and liquid fractionation, the corresponding carbonatite composition changing from nearly pure CaCO3 (±MgCO3) progressively to natrocarbonate. A carbonate melt cooling in isolation will suffer crystal fractionation, the residual liquid producing the rarer ferrocarbonatites, etc., whilst the crystal accumulate of calcite (dolomite) plus other phases such as magnetite, apatite, baryte, pyrochlore, etc., are the raw material for the coarse-grained intrusive carbonatites commonly found in ring complexes.

scholarly journals Geological Challenges of Archaeological Prospecting: The Northern Peloponnese as a Type Location of Populated Syn-Rift Settings

2020 ◽  
Vol 12 (15) ◽  
pp. 2450
Author(s):  
Katharina Rusch ◽  
Harald Stümpel ◽  
Walter Gauß ◽  
Silke Müth ◽  
Alexander Sokolicek ◽  
...  
Keyword(s):  
Case Studies ◽  
Coastal Plain ◽  
Urban Areas ◽  
Coarse Grained ◽  
Sea Level Changes ◽  
Alluvial Deposits ◽  
Archaeological Prospection ◽  
Wave Refraction ◽  
Wave Measurements ◽  
Marine Terraces

The Northern Peloponnese is not only home of a series of ancient poleis that are being studied by archaeologists, but it is also located on the southern shoulder of the most active extensional crustal structure in the world; the Corinthian rift. This rift has shaped the Northern Peloponnese as we now see it today since the Pliocene. Normal faulting, the tectonic uplift of syn-rift sediments and sea level changes, has shaped a landscape of steps rising from the coast to the ridges in the hinterland that provides challenging conditions to a geophysical survey. Where we can find coarse grained slope and delta deposits of conglomerate on top of banks of marl on ridges and slopes, the lower marine terraces and the coastal plain as well as valleys show the protective caprock eroded and the marl covered by young alluvial deposits. These materials show only a small contrast in their magnetic properties, which reduces the importance of magnetic mapping for the archaeological prospection in this region. The human utilization of the coastal plain and the urban areas pose additional challenges. These challenges have been overcome through various approaches that are shown in exemplary case studies from Aigeira and Sikyon. Whereas a combination of magnetic mapping and ground-penetrating radar (GPR) works very well on the ridges and along the slopes where we find coarser sediments in addition to the magnetic mapping, it is not suitable in the coastal plain due to the attenuating properties of the alluvial sediment. Here, electrical resistivity tomography (ERT) proved to be very successful in mapping entire parts of a settlement in great detail. Seismic soundings were also sucessfully applied in determining the bedrock depth, the detection of walls and in the question of locating the harbor basin. In the presented six exemplary case studies, the following findings were made: (1) A fortification wall and building foundations at a depth of 0.4–1.2 m on a plateau northwest of the acropolis of Aigeira was found by 400 MHz GPR. (2) A honeycomb-shaped pattern of magnetic anomalies that suggested cavities could be identified as a weathering pattern of conglomerate rocks. (3) A rock basement 2.3 m deep and remains of an enclosing wall of the Aigeira theater area were found by shear wave refraction measurements. (4) Extensive ERT surveys detected several building remains in Sikyon like a potential building and grave monuments as well as several small houses. (5) A silted-up depression in the sediments of the coastal plane located through Love wave measurements, could be taken as evidence for either a silted harbor or a navigable riverbed.

Djadokhta Formation correlative strata in Chinese Inner Mongolia: an overview of the stratigraphy, sedimentary geology, and paleontology and comparisons with the type locality in the pre-Altai Gobi

1993 ◽  
Vol 30 (10) ◽  
pp. 2180-2195 ◽  
Author(s):  
T. Jerzykiewicz ◽  
P. J. Currie ◽  
D. A. Eberth ◽  
P. A. Johnston ◽  
E. H. Koster ◽  
...  
Keyword(s):  
Inner Mongolia ◽  
Sedimentary Facies ◽  
Coarse Grained ◽  
Medium Size ◽  
Alluvial Deposits ◽  
Fossil Assemblage ◽  
Lacustrine Sedimentation ◽  
Theropod Dinosaurs ◽  
Eolian Deposits ◽  
Vertebrate Eggs

Because the Bayan Mandahu redbeds of Inner Mongolia share similar sedimentary facies and fossil assemblages with the Djadokhta Formation of pre-Altai Gobi, the two units are interpreted as stratigraphic correlatives, both of Campanian age. Sedimentary facies indicate that the Bayan Mandahu redbeds were deposited in semiarid, alluvial to eolian environments. An assemblage of fossil vertebrates found in the Bayan Manduhu consists of ceratopsian, ankylosaurian, and theropod dinosaurs; turtles; crocodiles; and small lizards and mammals. Six different kinds of fossil vertebrate eggs are present. The most common fossil vertebrates occur in association with eolian deposits and are interpreted as the remains of autochthonous "faunal" components, many of which died in situ during sandstorm events. In contrast, rare and fragmentary specimens of large dinosaurs occur in coarse-grained alluvial deposits and are interpreted as the remains of allochthonous faunal components. The low diversity of this fossil assemblage and overall small to medium size of its constituents indicate a relatively stressed paleoenvironment, an interpretation which is compatible with our sedimentological conclusions. A diverse trace fossil assemblage is present and includes rhizoliths and endogenic traces. Endogenic traces are well preserved and typically associated with eolian deposits, suggesting that the deposits were at least seasonally damp and cohesive. The opinion that the Late Cretaceous Gobi Basin was a large inland lake, still advocated by some authors, cannot be maintained within the context of our sedimentologic and paleontologic data. In contrast with the perennial lacustrine sedimentation that was characteristic of the underlying Lower to lower Upper Cretaceous units in the Gobi Basin, the Bayan Mandahu redbeds and correlative Djadokhta Formation mark a pronounced shift toward eolian and intermittent lacustrine sedimentation in an increasingly arid climate.

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