Київський національний університет імені Тараса Шевченка
ЛЕСОВІ ПОРОДИ
ЗБІРКА ТЕКСТІВ ТА ГЛОСАРІЙ
Методичні вказівки до навчального курсу
"ІНОЗЕМНА МОВА"
для студентів геологічного факультету
(магістрів V-VI курсів)
спеціальність "Гідрогеологія та інженерна геологія"
Київ
Видавничо-поліграфічний центр
"Київський університет"
2002
УДК 551.79 + 624.131.23
Лесові породи: Збірка текстів і глосарій до навчального курсу
"Іноземна мова" для студентів геологічного факультету
(магістрів V-VI курсів) / Упоряд. І.М. Байсарович, О.Є.
Кошляков - К.: ВПЦ "Київський університет", 2002. - 38 с.
Рецензент  Є.С.Кириченко, канд. геол.-мін. наук, доцент
Затверджено вченою радою
геологічного факультету
27 березня 2002 р.
2
ПЕРЕДМОВА
Збірка текстів і глосарій до навчального курсу "Іноземна мова"
розраховані на студентів (магістрів) та аспірантів геологічного
факультету університету, а також інженерів і науковців, які
займаються перекладом наукових статей в галузі гідрогеології,
інженерної та четвертинної геології. Мета даного видання розширення лексичного запасу і формування навичок ефективного
використання наукових публікацій за фахом, виданих англійською
мовою.
Text No 1. Loess definitions
A number of definitions of the term ''loess'' can be found in the
literature, it being a clastic sediment produced by a range of processes.
The genetic definition of loess is mainly based on the mineral substance,
the grain-size distribution, the origin, the means of transport and
deposition, and the character of diagenesis after sedimentation. A
sustained dust source, adequate wind energy to transport the dust, and a
suitable accumulation site are the fundamental requirements for loess
formation [8, p. 87].
The term "loess'' was first defined by von Leonhard (1823-1824), who
described the yellowish brown, silty deposits along the Rhine valley near
Heidelberg [2]. Lyell (1834, 1847) brought the term into widespread usage
by visiting the Rhine and the Mississippi valleys, observing the
similarities between loess and loess derivatives in both areas along the
loess bluffs [4, p. 110-113, 5, p. 34-39]. The aeolian origin of loess has
been accepted since von Richthofen's (1878) observation and
interpretation of the loess in China. It was generally accepted that the first
brown forest soil or adequate soil is an equivalent of the last interglacial
soil in the loess record of Central Europe [8, p. 201].
A common way of classifying loess and loess-like deposits (e.g., sandy
loess, loess loam, clayey loess, and loess derivates) is by grain size [8, p.
88].
The magnitude of the dust transport from a source area is influenced by
the nature of the prevailing wind systems.
Loess and loess-like materials form extensive sedimentary deposits
covering up to 10% of the earth's surface. Considerable quantities of loesssized terrigenous quartz silt can also be found in ocean sediments and
significant amounts of quartz silt are present throughout the whole
sedimentary record. Although no agreement has yet been reached over
3
what constitutes the truly characteristic features of loess, one of the
simplest definitions is that it is a windblown deposit consisting mainly of
quartz particles in the 20-60 m size range [8, p. 7].
Without a suitable source of silt-sized particles a loess deposit cannot
form. Although little is known about the exact mechanisms involved in the
generation of the silt contained within loess deposits, there has been
considerable debate throughout the 20th century over what types of
environments are the most efficient producers of silt [8, p. 8].
In the loess series the alternations of loess and palaeosol layers are
generally interpreted as consequences of cyclic climatic changes [3, p. 63].
The extensive loess deposits associated with the Central Asian and
North Chinese deserts can be explained by their geographical location
adjacent to High Asia  the most tectonically active region in the world,
where large energy transfers accompanied by the operation of intensive
frost weathering processes. The frost weathering can produce large
amounts of sediments, including silt. These sediments are subsequently
fed into the neighboring deserts by fluvial systems. Although rates of
sediment production and sediment accumulation are considerably lower
within low relief deserts such as the Sahara, significant quantities of silt
are contained within the Nile and Niger sediments and in ocean sediments
[8, p. 14].
Mineral aeolian dust deposits (e.g., loess) potentially provide
important information about climate changes and variations in global
atmospheric circulation patterns.
There is a close association between major river systems and
extensive deposits of loess, and it is now generally agreed that fluvial
systems must play a key role in transporting and redistributing the
sediment involved in the "loess cycle". The major loess deposits of central
and eastern Europe are associated with the Danube, those of North
America with the Mississippi  Missouri river system, the German loess
with the Rhine, and the greatest loess accumulations in China with the
Yellow River [8, p. 12].
The formation of any loess deposit will often be complex and consist of
several silt-producing events and several stages of transport and sediment
reworking. In order to reach a more complete understanding of how and
why any particular loess deposit has formed we need to be able to identify
the sequence of events involved in its formation.
4
Thought questions
- Give a definition of the term "loess" from the genetic point of
view.
- Where are located the most extensive loess deposits?
- What is the main factor that influence on the magnitude of the dust
transport from a source area?
Text No 2. Loess deposits of Africa
The formation of recognisable loess deposit involves at least four
stages. These are (1) silt production event(s); (2) silt transportation; (3)
silt concentration and deposition; and (4) in situ post-depositional
alteration.
Let us discuss the problem of "desert" loess. The concept of two main
sources for loessic silts (a cold or "glacial" and a hot or "desert" source)
can be traced back to the work of Obruchev published in 1911. The
assumption that cold environmental conditions were more conductive to
quartz silt generation than hot environments developed from Tutkovskiy’s
observation in 1899 that loess appeared to be closely associated with the
retreat of the major ice-sheets. It has been further strengthened by the
apparent lack of extensive loess deposits associated with major deserts,
such as the Sahara and Australian deserts [8, p. 8].
When considering silt production within cold climate environments it
has traditionally been assumed that subglacial grinding is the main process
that is sufficiently energetic to convert significant quantities of sand sized,
and larger, quartz particles into silt-sized fragments. Glaciers are certainly
powerful agents of erosion. However, other scientists question the idea
that silt is abundant in tropical soils.
Further challenges to the dominance of glacial and cold climate
geomorphic processes in the generation of silt include:
- the identification of loess deposits in areas that cannot be
explained satisfactorily by glacial processes (Israel, Tunisia,
Nigeria);
- the importance of hot arid environments as source areas for global
dust storms;
- the discovery of terrigenous loess-sized quartz silt in the Atlantic
Ocean up to 100 km off the coast of West Africa;
- reinterpretation of the limits of the Pleistocene glaciation in China
suggesting that this was not as extensive as originally believed [8,
p. 9].
5
Arid regions represent important sources for dust during both glacial
and interglacial periods, and the Sahara Desert is currently a major source
of atmospheric dust. Estimates for the annual transport of dust from the
Sahara range from 260 million tons to 700 million tons. Fine silt and claysized particles (<10  m) with a Saharan origin have been found in the
Caribbean and Florida, while significant amounts of terrigenous loesssized quartz silt have been found within ocean sediments in a zone up to
100km off the west African coast. This seems to indicate that Saharan
Africa is an important source of silt.
Mechanisms such as fluvial comminution, salt weathering and aeolian
abrasion are all capable of operating within the Sahara.
The Sahara covers a large and relatively diverse area able to sustain the
operation of several silt-generating mechanisms. It also contains within it
a variety of land surfaces, including upland areas, low lying salt flats and
shallow saline lakes, wadi, fluvial channel and alluvial fan systems, desert
pavement areas and extensive sand sea and dune systems. Many of these
may play an important role in the generation of the loess-sized silt, and it
is suggested that the silt contained within the associated loess deposits has
been produced by a variety of mechanisms and originates from a diverse
range of sources.
In connection with the debate on silt particle production and ’desert’
loess, one of the key regions to consider is the Sahara Desert. Although
this is possibly the world’s best known hot desert, the loess deposits
associated with it (Fig. 1), such as those of Tunisia, Nigeria, Israel and
Libya, are thin and discontinuous [8, p. 14].
Within the desert upland areas of the Sahara (the Tibesti, Ennedi,
Ahaggar and Air Massifs), predominantly physical weathering
mechanisms, with minor contributions from chemical processes, produce
significant quantities of debris. This debris is delivered to fluvial systems
by overland flow and slope processes. Weathering processes in upland
areas adjacent to the Sahara, the Atlas Mountains and the Ethiopian
Highlands also generate sediments, some of which are transported into
adjacent desert region. Debris may also be generated by chemical
weathering in the humid tropical area south of the Sahara and become
incorporated into northerly flowing perennial river systems. Some of the
material contained within loess deposits of northern Nigeria may have
been released from tropical weathering profiles south of the Lake Chad
Basin and transported north by the Chari-Logone River system [8, p. 15].
6
It has been recognised that alluvial fan and wadi/river channel deposits
represent geomorphologically active surfaces from which sediment can be
readily mobilised by the wind. The material transported in the aeolian
system includes populations based on particle size and distance
transported by the wind. Coarse to medium sand-sized grains can be
transported during sandstorm events for short distances by saltation. Fine
sands and coarse to medium silt grains can be transported for distances of
between 50 and 200 km in short term suspension. In this way, material
generated within arid environments is moved towards and beyond the
desert margins. The size fraction involved in this mode of transport is
critical to the formation of loess deposits, such as those found in Tunisia,
Israel, Libya and Nigeria. Finally, fine silt and clay-sized material can be
transported for long distances in suspension (1000 km) forming large
dust clouds. In this way dust transported from the Sahara can reach the
Caribbean and Northern Europe [8, p. 17].
Fig.1. The approximate location of the main deposits of loess and silt
associated with the Sahara and the principal pathways of aeolian transport
[8, p. 14].
Thought questions
- Explain the role of weathering processes in upland areas adjacent
to the Sahara in generating of sediments and their further
transportation.
7
-
What phenomenon does indicate that Saharan Africa is an
important source of silt?
Which way dust transported from the Sahara can reach the
Caribbean and Northern Europe?
Text No 3. Loess of Asian region
Dust flux from Asia to the North Pacific in the late Quaternary time
The Asian continent and the surrounding oceans are among the classic
areas for research on the upper Pleistocene and Holocene variability of the
flux and accumulation rates of aeolian dust. A comparative study of the
literature on the late Quaternary accumulation of aeolian dust in China,
Japan and the Pacific Ocean shows three different temporal patterns of
dust signals. The main dust sources in Asia, the deserts and desert
margins, contain large amounts of wind-suspensible allochthonous
material. Commonly, an increase in dust accumulation is taken as an
indicator of increased aridity in the interior of Asia. [8, p. 67].
It seems possible to identify three main patterns of dust signals for the
late Quaternary (beginning of the Last Interglacial to the Holocene).
1. The ''Chinese Pattern'' shows dust flux maxima during both stadials
of the Last Glaciation. This signal can be found not only on the
Chinese Loess Plateau, but also in the sediments of Lake Biwa in
central Japan.
2. Similar to the Chinese Pattern, the dust signals from northern Japan
show high values of dust flux during both stadials of the Last
Glaciation. However, during the second stage of the Last
Glaciation significantly higher values can be seen. This is
considered typical of the ''Japanese Pattern''.
3. Some dust archives seem to exhibit a signal with higher aeolian
accumulation rates during Interglacial periods. This pattern, named
the ''North Pacific / Desert Margin Pattern'', cannot be identified as
clearly as the above mentioned patterns. [8, p. 68-69].
Dust sources
Fig.2 and Table 1 show Asian dust source regions that have been
mentioned in the literature. Some dust derives directly from the high
mountain areas such as the Tibetan Plateau (e.g. Clarke, 1995) as well as
from the continental shelf exposed during the lower sea levels during the
Pleistocene glaciations (e.g. Liu et al., 1987). However, there is a general
8
consensus that the main dust sources in Asia are deserts, such as the
Taklamakan, the Gobi / Badain Jaran, or the Tengger desert. This has been
demonstrated by sedimentological, mineralogical, geochemical and
meteorological analyses of dust deposits in China, Tibet, Japan and the
North Pacific [8, p. 70].
Fig.2 Main dust sources in Asia (according to different authors); cf. Table
1. [8, p. 71].
Table 1 - Names of locations shown in Fig.2
№ Region
№
1
Taklamakan Desert
13
2
Western Gansu
14
3
Gobi / Badain Jaran
15
4
Tengger / Ordos
16
5
Tibet
17
6
East Asian Shelf
18
7
Northern China, Mongolia, Siberia 19
8
Southern China
20
9
India
21
10 Japan
22
11 North America
23
12 South America
24
Region
Ob / Irtysch
Mujunkum
Kysylkum
Karakum
Aral Sea
Thar
Ganges
Rub el Khali
Nefud
Mesopotamia
Persian Gulf
Somalia
At present it seems likely that most of the dust originally formed in
mountainous areas with their active periglacial and glacial environments.
From here the particles were transported towards the desert basins [8, p.
71].
Dust transport towards different depositional areas is dependent on
specific meteorological situations. Two main pathways of dust transport
9
and sedimentation are frequently assumed in the literature. As indicated by
the sketch map shown in Fig. 3, long-distance dust transport towards the
Northern Pacific is achieved mainly by the upper-level westerly winds in
spring. Regional dust transport in China is also accomplished by low level
northwesterly winds originating from the Siberian anticyclone in winter
(this is the Eastern Asian winter monsoon) [8, p. 73].
Fig.3. Main dust transporting wind systems in Asia (according to different
authors) [8, p. 73].
Chinese Loess Plateau
In China, loess deposits occupy an area of 440,000 km2, from which
the Loess Plateau with thick loess accounts to 273, 000 km2 in the middle
reaches of the Hunghe River. The Loess Plateau extends northward to
about 400N and southward to about 320N in the southern piedmont of the
Chinglin range [3, p. 141].
During the loess-forming period the climatic conditions were relatively
dry-cold. Within the loess layer, the macroporosity is developed. The
fauna was mainly cavedwellers, rodents. In the Pleistocene the flora was
mainly forest-steppe and steppe plants on the Loess Plateau, because of
lesser precipitation and lower permeability of the soil layers, and thus the
water content was lower than that in other deposits.
The permafrost has developed widely in the broad continental area of
northern China during the Pleistocene glacial stage, when cold weather
prevailed. The southern limit of modern permafrost in northeast China
corresponds approximately to the 0  -20C isotherm. The northern border
10
reaches 48-500 N. The southern boundary of permafrost during Pleistocene
glacial stage could migrate southwards reaching 380 N near Beijing city
and 320 N in the northern pediment of Chinglin range in southern part of
the Loess Plateau. The southern limit of seasonal frozen earth migrated
from 250 N southward to 200 N. The southern boundary of seasonal snow
in winter of glacial reached Taiwan Island and northern coast of the South
China Sea [3, p. 148].
A number of loess profiles along the roadcuts near the Shidongshi
Railway Station, 60 km to the north of Lanzhou city, is well known. This
location is at an altitude about 1000 m on the west Loess Plateau (104 E,
36.5 N). Bedrocks in the loess profiles are Carboniferous and Permian
limestone series, in which the eroded paleotopographic surface became the
buried hills with gentle slopes, which were covered by loess and loess-like
deposits [3, p. 143]. In the upper part of the profiles, the Late Pleistocene
Malan loess is greyish white, unstratified, lithologically uniform, and 20 m
thick or more. Below the Malan loess, there is a suite of loess-like
deposits, which have bended in consistence with the basement relief, and
intercalated with clayey beds. These interbeds display irregular beddings
and varying thickness. They are irregular sediments, usually with
thicknesses from several cm to several mm. The loess is yellow and about
10 m thick. The clay is partly greyish-green.
The most extensive loess deposits (thickness nearly 300 feet) are found
on the Loess Plateau in central China, where the succession of Quaternary
loess units and intercalated paleosols is a more or less continuous record
of changing climatic and environmental conditions. The loess in China
results from a combination of conditions, which have persisted for the last
2.5 Ma, namely the uplift of the Qinghai-Xizang (Tibetan) Plateau and
surrounding ranges, high rates of sediment production and supply to
adjacent basins, a strong northwesterly and westerly wind regime, and the
existence of effective dust traps and mountain barriers downwind of the
source area [8, p. 85].
Loess in China is produced by a range of processes in which those
associated with cold environments and interior plateau and mountain
terrains are most effective, especially, when the silts are concentrated in
conditions conducive to massive deflation (e.g., desert lake basins, large
rivers with highly seasonal regimes).
It is generally believed that the alternation of loess and paleosols in
central China can most reasonably be explained by cyclic variations of the
East Asian monsoon, which in turn is driven by orbital forcing [8, p. 85].
11
Northern Mongolian Plateau
Located in the interior of the Asian continent, the Northern Mongolian
Plateau receives its highest precipitation in the north and almost none in
the south, the mean annual temperature increasing towards the south.
Numerous eolian sections have been reported in the corridor running
from Ulaanbaatar to Lake Baikal, the core region of the SiberianMongolian High Pressure cell. This corridor (shaded area in Fig.4), has a
loess cover and contains the best agricultural lands in Mongolia.
Fig.4. Relief map of Mongolia (Shaded is the loess-covered corridor from
Baikal Lake to Ulaanbaatar) [8, p.78].
The thick eolian sections in the Ulaanbaatar-Baikal corridor area are
exclusively found on north-facing slopes, suggesting that they were
primarily deposited by northerly winds.
A loess/soil section was found at Shaamar. Although only 39 m is
exposed, coring data (by the Mongolian Geological Survey) show that a
further 20 m of loess is buried here.
A meandering river in the Khyaraany area freshly exposed a
sand/loess/soil section. Three orders of laminations were observed in this
section. Sand units alternate with loess units (first order). Specifically, 0400 cm is a sandy unit, 400-800 cm is a silty unit, and 800-1200 cm
another sandy unit [8, p. 78-79].
12
-
Thought questions
Describe Asian dust source regions.
What kind of climatic conditions were there within the Chines
Loess Plateau during the loess-forming period?
The loess sequence of Loess Plateau in China (Shaanxi) is the most
extensive location in the world (thickness is nearly 300 feet) isn't
it?
Text No 4. Loess of Europe
Early glacial climates in Europe were interrupted several times by
major dust storms which deposited thin layers of aeolian dust called
Markers and in many locations terminated temporarily the development of
biogenic soils. Markers were first described in Bohemia and Moravia.
Markers are commonly calcareous. They were interpreted as deposits of
continental-scale dust storms. They were described from numerous sites in
their type area in the Czech Republic, Slovakia and Austria, but apart of
France and Ukraine were also identified in Germany and Moldova [10,
p.47].
By their geographic position, European countries are at the parting of
Mediterranean, boreal, continental and Atlantic influences. These
determine in the present a similar climate to that of an interglacial,
especially in the mean part of that country. However, preferential
influences of one or more of these components during the Pleistocene
have led to significant variations of climate [3, p 152].
On the basis of recent studies scientists suggest that the loess is a
product formed under arid and cold climatic conditions in the Quaternary,
and some paleosols in the loess are representative of the warm and humid
climate. In the whole Quaternary period, the global climate has fluctuated
many times, and some continental ice sheets appeared at high latitudes in
North America and Europe. In the periphery of continental ice sheets
many periglacial processes have occurred extensively in that time [3, p.
141].
Loesses are known in Northern France, Normandy, Belgium, Germany,
Hungary, Poland, Ukraine, Italy and other European countries. Some
Upper Pleistocene profiles in the European loess belt are presented on Fig.
5.
The Maastricht-Belvedere loess- and gravelpit is located NW of the
city of Maastricht near the Belgian-Dutch border. It is situated within the
13
loess belt, some 20 km south of its northern boundary. The pit was carved
into the steep cliff between the lower and middle terrace of the river Maas
[3, p 51].
Fig.5. Some Upper Pleistocene profiles in the European loess belt [8, p.
212].
In the northeast Scotland and Ireland the presence of pockets of
saprolite indicates that glacial erosion may be of limited efficiency within
some high latitude areas [8, p. 8].
Germany
The northern margins of the loess belt in Central Europe were mapped
by the geological survey at the beginning of the 20th century. Until very
recently, it has been assumed that the boundary of the loess is a transition
from contemporaneous sandy to silty sediments as a result of aeolian
sorting. A reexamination of these sequences, however, has shown that the
stratigraphy of the sediments in this marginal region represents multiple
aeolian phases [8, p. 191].
The loess-palaeosol sequences of the Middle Rhine Area provide a
relatively detailed and continuous terrestrial record of climate and
environment change for the past 200,000 years [8, p. 201].
The Nussloch sections are in a Triassic limestone quarry on the east
bank of the Rhine river a few km to the south of Heidelberg and the
confluence with the Neckar (Fig. 5). At loess site in Nussloch the
thickness of loess deposits is 18 m. In this part of the upper valley of the
Rhine river (Upper Rhine Graben), the geomorphological context of the
east bank includes a very broad alluvial plain (30 km wide), separated
14
from the Odenwald hill country by an abrupt slope exposed to the WestNorth-West. During the Weichselian, this particular morphology favoured
the accumulation of thick loess deposits at the junction between the
Odenwald and the east-bank slope of the Rhine Graben. This phenomenon
produced a very particular landscape in which a succession of elongated
"dunes" of loess, 15-20 m thick and 2-4 km long and trending NNW to
SSE were separated by small dry valleys. This very specific morphology
corresponds to that of the ''gredas'' observed in Bulgaria and more
generally in Central Europe [8, p. 211].
Hungary
The thickest exposures of the loess sequence of the Carpathian basin
are found along the Danube sections south of Budapest, partly in
Hungarian and partly in Yugoslavian territory [3, p. 88]. Sequence of the
loess section from lithological, pedological, chronological etc. points of
view can be subdivided into four units: the Dunaujvaros-Tapiosuly loess
series, the Mende-Basaharc loess series, the Paks series, the Dunafoldvar
silt and red clay formation.
In the Hungarian loess exposures young and old loess sequences are
distinguished.
The young loess sequence is about 25-30 m thick, its major part
consisting of typical loess that is porous and rich in CaCO3. In its upper
part of 5 to 10 m only two humic loess horizons (h1, h2) are found. The
lower part is thicker, i.e. about 20 m, here five steppe soils (MF1, MF2,
BD1, BD2, BA) could be identified. Among these several loess bands are
found. The young loess sequence is separated from the older one by the
red-brown forest soil marked by MB [3, p. 43].
The comparison of the mineral composition of the young and old loess
sequences of Hungary is seen in Table 2 [3, p. 49].
The differences between the loess sequences of different ages are as
follows:
- in the young sequences the quantities of each mineral varies
between wider limits;
- in the old loess sequence there are more quartz;
- dolomite is the predominating carbonate mineral of the
younger sequence;
- the total amounts of clay minerals are the same in the two
kinds of loess sequences but kaolinite is characteristic of the
younger and chlorite of the older loess sequences;
15
-
concerning the average values of the other minerals there are
no remarkable differences between the two, i.e. young and old
loess sequences.
Table 2 - Comparison of the mineral composition of the young and old
loess sequences
Minerals
Young loess horizons, Old loess horizons,
% ( L1 - L6)
% (L1 - L6)
quartz
21-40
29-45
feldspars
5-12
7-11
micas
4-17
4-15
illite
14-17
12-18
montmorillonite
6-15
7-13
kaolinite
1-2
0.3-1
chlorite
0-7
2-8
clay minerals
21-41
21-40
dolomite
8-20
10-21 (L5 - L6 = 0)
calcite
0-14
2-15
carbonate minerals
8-34
12-35
pyrite
0-0.5
0-0.2
iron oxy-hydroxide
0-0.3
0-1.5
organic matter
0.2-1
0-0.5
Al- hydroxide
0-0.3
0-0.5
The granulometric and mineralogical investigation of old loess
sequences of the loess exposures of Hungary revealed differences in
mineralogy and granulometry between the upper and lower parts. Based
on the comparison of the same parameters of the young and old loess
sequences it could state, that in the old loess sequence quartz and chlorite
while in the young one dolomite and kaolinite predominate [3, p. 43].
The most completely studied among the loess sequences of the
Carpathian basin is Paks loess (location between Dunakomlod and Paks
cities). The Paks series is dated 125,000 - 1,000,000 years. The Paks loess
exposure (thickness of 50-60 m) with the adjoining loess bluff has a length
of about 3 km and is situated 105-108 km south of Budapest, in the
vicinity of the Hungarian nuclear power-plant.
This old loess characterized by six compact loess horizons of large
CaCO3 concretions, two sand layers and five paleosols. The two
lowermost fossil soils (Paks Double) are reddish brown forest soils of
16
Mediterranean type. Below 3 m thick sandy silt is deposited in the base of
the Paks series (estimated age is 1 million years) [3, p. 96].
Spain
The Granada Basin (Southern Spain) contains several sites that include
Late Pleistocene loess.
In the Late Pleistocene, the pre-existing relief of the Granada Basin
was partly covered by loess (up to 10 m thick) and by commonly
associated slope deposits.
The texture of the loess units in Granada (Table 3) is not significantly
different from that of the re-deposited loess of Middle Europe, whereas the
carbonate contents (up to 60%) are more similar to the Tunisian Matmata
loess [8, p. 243].
Table 3 - Summary of the calcium carbonate, pedogenic iron and grain
size distribution of loess and palaeosols from loess and slope deposits in
the Granada Basin [8, p. 244]
loess
soils from loess soils from slope deposits
CaCO3 (%)
21.4-60.3 12.2-38.6
16.2-39.7
Fed (%)
0.16-0.39 0.28-0.90
0.54-0.92
Sand (%)
2.0-20.3
0.8-21.4
2.5-20.2
Silt (%)
70.2-88.9 71.3-90.8
41.7-59.8
Clay (%)
4.4-27.8
8.1-25.2
24.1-39.0
The loess in the Granada Basin is generally associated with clay-rich
slope deposits, cryoclasts, gelifluction as well as ice wedge fillings so that
it may be categorised as re-deposited loessic material of periglacial origin.
The composition of loess was estimated semi-quantitatively on the
basis of areas under selected XRD peaks. For the determination of the
major and minor elements, the clay fraction was mixed at 7:1 with wax,
ground, and then pressed into tablets and measured with a Siemens SRS
300 [8, p. 243].
Italy
In Northern Italy (Po plain and adjoining Adriatic Basin), the loess
deposits are recorded all along the Alps and Apennine fringes, on karstic
plateaus in the Pre-Alps, on paleosurfaces within the Apennine range, in
the Dalmatian Archipelago, and along Marche coast. Generally the loess
sheets lie on stable surface, and therefore they have been heavily affected
by soil forming processes, which strongly changed their original textural
characteristics. Fresh loesses are preserved in cave fills and in stratigraphic
17
sequences, buried by thick sedimentary cover. The alluvial plain of the Po
has been the main source of the eolian dust. Irrespectively of the deposits
it covers, the loess has a rather homogeneous mineralogical composition.
Loess deposits are systematically associated with Paleolitic artifacts,
which constitute a valuable tool for correlation and dating: early Middle
Pleistocene loess is poorly preserved, while late Middle Pleistocene and
Late Pleistocene loesses are widespread all along the margin of the Po
plain. Lateglacial loess sedimentation is limited to the inner part of the
Alpine range [3, p. 125].
Northern Italy's loess covers vast areas of the margins of the Po basin
as a result of the climatic conditions, which came about during the
Quaternary glacial stages. In fact, during these stages glaciers covered
most of the Alps and encroached upon the margin of the plain, where
highly continental climatic conditions prevailed. These conditions were
intensified by the redoubling of the plain's surface toward S/SE as the sea
receded all the way to the present  100-m isobath. The center of the plain
was occupied by a boreal forest, while in a narrow belt along the
piedmont, there were dry steppe areas, where loess was deposited [3, p.
126].
Ukraine and Poland
Territories of Poland and Ukraine are situated in that part of the
Central-Eastern Europe that was glaciated, at least partially, in different
periods of the Pleistocene. At the same time, periglacial phenomena
occurred almost throughout the whole area of this large region, which
constitutes about 10% of the European continent. Glacial and periglacial
processes were registered in the deposits that provide good evidence of the
Pleistocene cold stages. In this context, loesses covering extensive areas,
especially in Ukraine, are very important. Numerous paleogeographical
records of the Pleistocene warm stages (palaeosols, swamp-lacustrine
organic deposits, fluvial deposits) are also significant [10, p.13].
In the North-East Poland there were two advances in the youngest icesheet (Vistulian Glaciation). The first of them happened in the Middle
Stadial, called ''Swiecie Stadial" in Poland, the second  in the Main
Stadial. In the North-East Poland, the Swiecie Stadial ice sheet covered
the northern part of Kurpie Plain as far as Kolno, Wasosz and
Klimaszewnica, slipped a small ice tongue into the Biebrza River and
Nurka river valleys. [10, p.46].
18
The present Ukrainian Stratigraphical Framework for the Quaternary
was proposed by M.F.Veklitch between 1965 and 1967. It has been
elaborated over the last 30 years by a team of Ukrainian Quaternarists.
The framework is based on the results of multidisciplinary study:
palaeopedology and lithology, (mineralogy and micromorphology
included), palaeontology (therriofaunal, malacological and palynological),
palaeomagnetic studies, TL, 14C and oxygen-isotopic dating. More than
100 key sites in different regions of Ukraine have been investigated to
substantiate the framework (it consists of 10 regional parts and a general
correlation table) [11, p. 8].
The lower boundary of the Pleistocene is placed at 1.8 MA, at the base
of the Berezan loess unit. The Pleistocene consists of 11 main loess units
and 10 main palaeosol units. A till of the Dnieper Glaciation is an
important stratigraphic marker within the loess sequence of the Middle
Dnieper area. It is correlated with Saalian Glaciation of Western Europe.
The Brunches-Matuyama boundary falls in the interval between the
Shyrokyno and Martonosha soil units. There are 5 main loess units and 4
main soil units between the Brunches-Matuyama boundary and the
Dnieper till.
The Martonosha soil unit (mr) consists of two paleosols separated by
loess. In the Middle Dnieper, the Martonosha soils are very distinctive, the
most rich in clay and sesquioxides of iron and aluminium. This is the
cause of the pronounced reddish shade in the soil colour. The Martonosha
soils were formed under a warm climate, similar to a subtropical one, with
abundant but not regular precipitation: wet and dry seasons alternated
during soil formation [11, p. 8].
The Lubny soil unit (lb) includes two main pedocomplexes, each of
which consists of a lower forest soil and upper chernozem-like soil. The
soils were formed under temperate climatic conditions. The two
pedocomplexes are separated by a loess subunit.
The Zavadivka soil unit (zv) consists of two pedocomplexes. The
soils are mainly brown forest soils, though the uppermost ones are
chernozem-like. The soils were formed in the warm-temperate belt.
The Potyagaylivka soil unit (pt) is represented by one pedocomplex
with a lower forest soil and an upper chernozem-like soil. The distribution
of the unit is restricted, probably this is connected with the strong
denudation caused by the Dnieper (Saalian) unit.
The Middle Pleistocene loesses - the Sula (sl), Tyligul (tl), Orel' (or)
and Dnieper (dn) loesses - are distinguished from Upper Pleistocene
19
loesses by more heavy grainsize (up to heavy loams), brownish shades of
colour and intense gleying. The Dnieper loess is most rich in silt particles,
the Sula loess  the richest in clay particles.
Above the Dnieper unit, the two lower soil units  the Kaydaky (kd)
and Pryluky (pl)  consist of a lower forest soil and upper chernozem soil,
and occur in association in sections. On the plateau, they form a single
polygenetic soil. The lower forest soils of both units were formed under a
temperate climate.
The Tyasmyn (ts) loess unit, which separates the Kaydaky and Pryluky
pedocomplexes, is thin (up to 0.5 m) and, in the northern part of Ukraine,
is observed only in palaeodepressions. Though in some sections in the
unglaciated area of Ukraine, the Kaydaky and Pryluky pedocomplexes are
seem to be distinctly separated by loess, the Tyasmyn loess (up to 2 m in
thickness).
In the upper part of the Upper Pleistocene sequence of the Middle
Dnieper area, the loess units strongly predominate over the soil units in
their thickness. The characteristic features of the Uday loess unit (ud) are
its small thickness and high percentage of clay particles.
The Vytachiv soil unit (vt) consists of a pedocomplex from 2-3
interstadial soils with loess interlayers. The soils do not have present-day
analogues. Despite their small thickness, they are enriched in clay and
sesquioxides of iron and aluminium, and are often gleyed.
The upper loess deposits of the Upper Pleistocene are subdivided into
two unequal parts by Dofinivka interstadial soils: the Bug loess unit (bg)
(below)  the thickest of the Pleistocene loesses of Ukraine (up to 18 m)
and the most "typical", with all characteristic loessic features, and the
Prychernomorsk loess unit (pc) (above)  thin (less than 2 m), with a
larger admixture of clay and sand particles than in the silty Bug loess. The
Dofinivka soils (df) are weakly developed turf-carbonate soils. In the
northern part of Ukraine, they are of a very limited distribution, and the
Bug and Prychernomorsk units combine to form a single loess sequence
[11, p.11].
According to the Ukrainian Stratigraphical Framework of the
Pleistocene (Veklitch et al., 1993), there are 4 main loess units and 4
palaeosol units above the Dnieper (Saalian) unit. From bottom to top, the
soil units are Kaydaky (kd), Pryluky (pl), Vytachiv (vt) and Dofinivka
(df), loess units are Tyasmyn (ts), Uday (ud), Bug (bg) and
Prychernomorsk (pc) [10, p.28].
20
Paleolithic sites in Ukraine
As well known, Donbass (South-Eastern Ukraine) is a part of a belt of
the Quaternary loess-soil formation. The Donbass Quaternary loesses
(loess-loams) and palaeosol include not very numerous Paleolithic
remains. More abundant Paleolithic sites are present in the border of socalled Bakhmut-Torets basin, North-West Donbass. The peculiarity of the
Donbass Middle Paleolithic evidences is a very late geological dating (the
Bug loess complex of the Bilokuzmynivka site) which is associated with a
time of the Middle-Upper Paleolithic transition industry or the early Upper
Paleolithic industry. As a rule, the preservation of the Middle Paleolithic
cultural remains is not very good due to a re-deposition processes during
the Late Pleistocene.
In the 90-ies of XX century, the interesting paleontological site has
been found not far from Antratsit town of the Lugansk region. There the
Pleistocene animal bones were piled up in the form of vertical tape,
according to the stream beds. The special type of re-deposition of cultural
remains was connected with specific secondary movements due to both
cryogenic activities and soil fauna activities. As a consequence of this
redeposition, flints moved up (mainly) and down off their primary position
[10, p.43].
The Upper Paleolithic site Mezhyrich is located in the Mezhyrich
village, 18 km to the N of the town of Kaniv (Fig. 6). The site has been
discovered in 1965 and studed by Acad. I. Pidoplichko (Institute of
Zoology of NASU).
The site is located on the low terrace of the Ros’ river. It coincides with
the promontory of the terrace between the valleys of the rivers Ros´ and
Rossava (Ukrainian word ’"Mezhyrich’ means ’between two rivers’). The
terrace is adjacent to a steep slope of plateau dissected by numerous
gullies (’balkas’) and ravines. The site is connected to a proluvial fan of
the large ravine opening into the Ros’ valley.
Glacial and glacio-fluvial sediments of the Dnieper unit (up to 20 m
thick) are widespread on plateau and overlay the Paleogene deposits [11,
p.42].
21
Fig. 6. Mammoth-bone dwelling from the Mezhyrich site, reconstructed
under the supervision of Acad. I. Pidoplichko (a  the entrance, b  the
back). The structure (Dwelling No.1) was about 5 meters across at the
base. Skulls are placed in a semicircular way to form the interior base
wall. The outer and upper part of the wall consisted of 95 mandibles
arranged "chin down". The roof may have been made of hides supported
by a wood frame and held in place by an assortment of bones. The upright
bones in front of the entrance come from the legs of the mammoth. A skull
decorated with designs in red ochre can be seen just behind them [11,
p.45].
22
-
Thought questions
Describe the Paleolithic cultural bed remnants from the
Mezhyrich site in Ukraine.
Where within Europe we can find the loess deposits?
What do you know about the loess deposits in Germany?
Where does located the so-called Paks loess formation?
Describe the loess deposits of Nussloch sections that are in a
Triassic limestone quarry on the east bank of the river Rhine (a few
km to the south of Heidelberg).
Where is Granada basin located?
What are the differences between the loess sequences of different
ages (the young and old Hungarian loess sequences)?
Text No 5. Loess deposits of North American and South American
continents
U.S.A.
During the Ice Age, glaciers advanced down into the mid-continent of
North America, grinding underlying rock into a fine powderlike sediment
called "glacial flour". As temperatures warmed, the glaciers melted and
enormous amounts of water and sediment rushed down the Missouri River
valley. The sediment was eventually deposited on flood plains
downstream, creating huge mud flats. During the winters the meltwaters
would recede, leaving the mud flats exposed. As they dried, fine-grained
mud material called silt was picked up and carried by strong winds. These
large dust clouds were moved eastward by prevailing westerly winds and
were redeposited over broad areas. This process repeated for thousands of
years, building layer upon layer until the loess reached thicknesses of 60
feet or more and became the dominant feature of the terrain [9, p.2].
In westernmost Iowa the Loess Hills rise 200 feet above the flat plains
forming a narrow band running north-south 200 miles along the Missouri
River (Fig. 7.) The steep angles and sharp bluffs on the western side of
the Loess Hills are in sharp contrast to the flat rectangular cropfields of the
Missouri River flood plain. From the east, gently rolling hills blend into
steep ridges [9, p.2].
Loess is German term for loose or crumbly. It is a gritty, lightweight,
porous material composed of tightly packed grains of quartz, feldspar,
mica, and other minerals. Loess is the source of most rich agricultural soils
and is common in the U.S. and around the world. However, Iowa's Loess
23
Hills are unusual because the layers of loess are extraordinarily thick, as
much as 200 feet in some places. The extreme thickness of the loess layers
and the intricately carved terrain of the Loess Hills make them a rare
geologic feature. Shaanxi, China, is the only other location where loess
layers are as deep and extensive. Though much older (2.5 million years)
and much thicker (nearly 300 feet) than Iowa's loess, the Shaanxi loess
hills have been greatly altered by both natural and human activity and no
longer retain their original characteristics [9, p.2].
Fig.7. Loess Hills of Iowa state.
The loess Hills in Iowa are comprised of three major layers. From
oldest to youngest, the layers are known as the Loveland Loess (120,000
to 159,000 years old), the Pisgah Loess (25,000 to 31,000 years old), and
the Peoria Loess (12,50025,000 years old).
Clues in the loess layers help geologists determine the rate at which the
loess was deposited. For example, ripples mean accumulation took place
very quickly. Thin dark bands in the loess indicate the presence of soil and
vegetation, which means little or no deposition was occurring.
Erosion has sculpted the Loess Hills into unusual shapes. The pie-crust
shapes of these hills are the result of extreme erodibility of loess by wind,
water, gravity-induced slipping, and human activity. When dry, loess
particles form stable surfaces. Wet loess, however, is very susceptible to
collapse and erosion because of lack of clay particles, which normally
bond wet soils together.
The Loess Hills of Iowa are extremely fragile. They have one of the
highest erosion rates in the U.S., almost 40 tons/acre/year. Gullies,
although a natural part of this landscape, are a serious problem.
24
Argentina
The Argentinean loess, the most extensive loess region in the Southern
Hemisphere, was described by D'Orbigny in 1842, by Darwin in 1846
during his South American travels, by Ameghino in 1881, and by
Bodenbender in 1894. Although, loessic deposits were found and studied
in the Chaco region (around 300 S), in Santiago del Estro province, in
Formosa and Corrientes provinces, a fuller understanding of the
distribution of loessic materials within the subtropical region of Argentina
has been achieved only in the last few decades [8, p. 247].
The loess thickness (in general from Late Pleistocene to Holocene in
age), outcropping in the eastern Pampas, is about 10-15 m. The thickness
increases westwards, reaching up to 40 m in the southern Buenos Aires
Sierras, as well as in the western Pampa plain and piedmont of the Sierras
de Cordoba. In the pre-Andean subtropical valleys, the Late Pleistocene
loess reaches 20-60 m in thickness. In the western Chaco plain, the Late
Pleistocene and Holocene loess is represented by the Tucuman formation
with average depth of 10-20 m. Towards the central and eastern Chaco
plain, the thickness of the reworked loess decreases, the maximum being
10 m. The Chaco is a large tropical plain located in the interior of South
America, which covers 840,000 km2 in Argentina, Paraguay, and Bolivia
[1, 228].
The visible characteristics of Pampean loess may be summarised, in the
words of Teruggi (1957)[8, p.249], as "light yellow or brown in colour,
sometimes with a reddish or grey tinge; they are devoid of stratification,
stand for a long time in vertical walls, process tubes and rods of calcium
carbonate formed around plant roots and contain remains of vertebrate
fossil''. With minor exceptions, this description matches the sub-tropical
loess of Argentina.
-
Thought questions
Compare the cross-section of loess deposits in Iowa's Hills and
Chinese Loess Plateau.
Which clues in the loess layers do help geologists in determining
the rate of loess deposits formation?
What forces had sculpted the Loess Hills of Iowa into unusual
shapes?
Give the definition of subtropical loess of Argentina.
25
Text No 6. Weathering and Erosion
After tectonics and volcanism have made mountains, chemical decay
and physical breakup join with rainfall, wind, ice, snow, and downward
movements of material over Earth’s surface to wear away those
mountains. This is the course of erosion - the set of processes that loosen
and move soil and rock downhill or downwind. Erosion moves weathered
material from Earth’s surface, carrying it away and depositing it
elsewhere. And as erosion carries away weathered solid material, it
exposes fresh, unaltered rock to weathering [6, p.136]
Weathering is the general process by which rocks are broken down at
Earth’s surface. Weathering produces all the clays of the world, all soils,
and the dissolved substances that are carried by rivers to the ocean.
Weathering takes place in two ways:
- Chemical weathering occurs when the minerals in a rock are
chemically altered or dissolved.
- Physical weathering occurs when solid rock becomes fragmented
by physical processes that do not change its chemical composition
[6, p. 135-136].
Chemical and physical weathering help and reinforce each other. The
faster the decay, the weaker the pieces and the more susceptible to
breakage; the smaller the pieces, the greater the surface area available for
chemical attack and the faster the decay.
The nature of a parent rock affects weathering because (1) different
minerals weather at different rates and (2) the structure of rocks affects
their susceptibility to cracking and fragmentation [6, p. 136].
Granite monuments may remain unbroken and uncracked even after
centuries, though they may show evidence of some chemical weathering.
Other intrusive igneous rocks, like many granites, may be massive,
showing no planes of weakness that contribute to cracking or
fragmentation. In contrast, shale, a sedimentary rock that splits easily
across thin bedding planes, breaks into small pieces so quickly that only a
few years after a new road is cut through a shale, the rock will become
rubble.
Weathering and erosion are closely related interacting processes.
Physical weathering and erosion are closely tied to how wind, water, and
ice work to transport weathered material [6, p. 151].
Physical weathering fractures a large rock into smaller pieces, more
easily transported and therefore more easily eroded than the larger mass
26
was. The first steps in the erosion process are downhill movements of
masses of weathered rock, such as landslides, and transportation of
individual particles by flows of rainwater down slopes. The steepness of
slopes affects both physical and chemical weathering, which in affect
erosion. Weathering and erosion are more intensive on steep slopes and by
their action make slopes gentler.
The sizes of materials formed by physical weathering are closely
related to various erosional processes. As weathered material is
transported, it may again change in size and shape, and its composition
may change as a result of chemical weathering. When transportation stops,
deposition of the sediment formed by weathering begins [6, p. 151].
Not all weathering products are eroded and immediately carried away
by streams or other transport agents. On moderate and gentle slopes,
plains, and lowlands, a layer of loose, heterogeneous weathered material
remains overlying the bedrock.
Physical weathering is not always so dependent on chemical
weathering. There are processes by which unweathered rock masses are
broken up, such as the freezing of water in cracks. And some rocks are
made particularly susceptible to physical weathering by fracturing
produced by tectonic forces as rocks are bent and broken during mountain
building. On the Moon, physical fragmentation works alone, for there is
no water to make chemical weathering possible. On that lifeless terrain,
rocks are broken into boulders and fine dust by the impacts of large and
small meteorites [6, p. 148].
It is now recognized that weathering mechanisms, especially physical
weathering processes such as salt attack and frost shattering, are
particularly important for generation of debris within both hot and cold
desert environments. Within more humid tropical environments chemical
weathering predominates, although these environments are also believed
to be capable of silt generation. The quartz silt contained within tropical,
equatorial and Mediterranean weathering profiles is generated by the
splitting of quartz minerals inherited from the parent rock. Chemical
weathering processes bring about the partial dissolution of quartz grains in
situ. Depending upon climatic conditions or changes in climatic
conditions, the debris released by weathering processes may become
incorporated into fluvial or glacial systems and, to a lesser extent, directly
into aeolian systems. These transporting events can rework and sort
weathering sediments, processes that may involve further comminution. In
fact, the most significant role of weathering within loess systems may not
27
be the direct release of silt particles so much as the supply of debris for
reworking and comminution by erosional processes [8, p. 12].
-
Thought questions
What is weathering and how is it geologically controlled?
What would a world look like if there were no weathering at the
surface?
Text No 7. Methods of Defining the Liquidity Index IL
Not every geotechnical problem requires very precise definition of
geotechnical parameters. Depending on the problem range (structure type,
loading value, structure sensitivity to uneven settlement, complicated or
simple subsoil construction and possible consequences of building
damage) there are assumed several methods of defining the geotechnical
parameters.
For non-cohesive soils the density index Id is a leading parameter,
while for cohesive soils  the liquidity index Il. On the basis of Id and Il it
is easy to define other important values that are necessary for further
calculations. These parameters make the criteria of some more precise
soils division: non-cohesive ones due to density and cohesive ones due to
states [7, p.70].
Let us analyze the methods of defining of the cohesive soil states on
the basis of the liquidity index Il, which strictly depends on the water
content of this soil.
Casagrande's method is the oldest method of defining of the liquid limit
wl and as the consequence  liquidity index Il. This method is still used
in all geotechnical laboratories in the world. It is based on some
conventional boundary water content between the states: liquid limit wl
(boundary water content between very soft state and liquid one) and
plastic limit wp (boundary water content between semi-solid state and stiff
one). The difference between the liquid limit wl and plastic limit wp
makes also a certain parameter Ip. This is an index of plasticity, which is
the characteristic feature for different soil type as far as their cohesion
(content of clayey fraction) is concerned, and physically it shows us how
much water the soil is adsorbing when it turns from the semi-solid state to
the liquid one. Casagrande's method is still used mainly due to possibility
of defining the plasticity index Ip and liquid limit wl, because they make
28
the basis for the further estimation of soils (plasticity diagram according to
Casagrande, activity according to Skempton, estimation of swelling
abilities).
For many years the research have been carried on to introduce a
simpler method of defining the liquidity index Il. The method of
Wasilew's cone was one of the first methods, however, it turned out not to
be easy either. Polish Standard recognises the liquid limit tests by means
of Wasilew's cone as a model, since it conditions the correctness of the
Casagrande's method results to it. Casagrande's device should be verified
on the grounds of Wasilew's method and meets the requirements if the
liquid limits values that are obtained in both methods, satisfy the equation
(1) [7, p.71]:
(1)
 L  0,691 L  4,4
where:
w’L- liquid limit that is defined by Wasilew’s method;
wL- values of liquid limits for the same soils that are defined by the
verified Casagrande device.
The index of plasticity is defined according to the classical formula (2):
IL 
wn  w p
wL  w p
(2)
where:
wn- natural water content of soil, %
wp.- plastic limit, %
wL- liquid limit, %.
-
Thought questions
What methods of defining the liquidity index IL do you know?
What classical formula is traditionally used to define the index of
plasticity?
Text No 8. Stability of Loess Slopes in China
Failure of cementation bonds leading to soil structure collapse and
slope failure is a major problem encountered in loess slopes in the
Lanzhou region of China.
The Lanzhou loess region is situated in the north-eastern extension
zone of the Tibetan Plateau. In this region, a more or less continuous drape
of loess is found with thicknesses generally greater that 50m and
29
frequently reaching 300m. Substantial neotectonic crustal movements,
associated with the Himalayan orogenesis and the consequent deformation
of the Tibetan Plateau, formed an ideal geomorphic system through which
large quantities of silt could transit and accumulate in the Loess Plateau to
the North and East of the Tibetan Plateau.
Widespread slope failures, including large-scale catastrophic mass
movements, have a serious impact on human activities in the Lanzhou
region. Rapid economic development involving urban expansion and road
construction has increased the tendency to slope instability. Internal
hydrology, weathering potential, shear strength and failure behavior
influence loess deformation and the stability of slopes. Variations in the
degree of cementation, packing density, and the direction and frequency of
natural shear zones are to a large extent associated with spatial and
temporal changes in transport and depositional conditions [8, p. 21].
Chinese loess may be subdivided, from oldest to youngest, into three
major stratigraphical units: Wucheng, Lishi and Malan loess.
Representative samples from each of these loess units were taken from the
Dawan and Jiuzhoutai profiles situated southwest of Xigu (western
Lanzhou) and just north of Lanzhou, respectively. The oldest (Wucheng)
loess has a high bulk density (>1.7 Mg/m3), is strongly compacted, has
well developed cementation bonds, and is densely jointed. Lishi loess has
bulk densities ranging from 1.7 Mg/m3 (base) to 1.4 Mg/m3 (top). Malan
loess forms the most widespread surface cover with thicknesses ranging
from 10 to 34 m and a bulk density of less than 1.4 Mg/m3 [8, p. 23].
The loess deposits of North China predominantly comprise crystalline
quartz particles in the silt size range. This imparts to the materials a
generally low plasticity index and low plastic limit. Characteristically, the
plasticity indices of Lanzhou loess fall between 6 and 8%. In some
palaeosols with a greater than average clay content, the plasticity index
(Ip) may reach as much as 14-15%.
A theoretical relationship between pore size distribution and
collapsibility of loess is shown on Figure 8.
For the assessment of the stability of loess slopes it is important to
characterise the material in its undisturbed state, i.e. before failure (or
collapse) occurs and liquefaction (or fluidisation) take place.
30
Fig.8. A theoretical relationship between pore size distribution and
collapsibility of loess [8, p. 24].
Fig.9. Gullies on the Loess Plateau (Shaanxi).
-
Thought questions
Why did the major problem encountered in loess slopes in
Lanzhou region of China exist?
Describe the peculiarities of three major stratigraphical units of
Chinese loess.
What can you say about the loess deposits of North China?
31
GLOSSARY
chemical
decay
acre акр (= 0,4 га)
chemically
altered
admixture домішка
clastic
sediments
aeolian еоловий
clay loam
(eolian)
alluvial fan конус виносу ріки
clayey loess
alluvial алювіальний,
cohesive
річковий
average середня величина,
comminution
середнє
complicated
B
band смуга
confluence
bedding нашарування
crack
bluff крута скеля,
crumbly
урвище,
обривистий берег
boreal північний,
D
арктичний
boulder валун
damage
A
boundary межа, границя
breakage руйнування
C
debris
decay
deflation
Casagrande's метод Касагранде
method
chemical хімічний склад
composition
diagenesis
хімічне
звітрювання
хімічно змінені
уламкові осадочні
породи
суглинок
глинистий лес
зв’язаний (грунт)
подрібнення
складний
злиття річок
тріщина
рихлий
пошкодження,
збитки
уламковий матеріал
руйнування, гниття
вивітрювання
породи, видування,
вітрова ерозія
діагенез
direct прямий,
безпосередній
32
dissolved розчинені речовини
substances
dust пил (пилувата
фракція)
dwelling житло
E
e.g. наприклад
(скорочення від
exempli gratia; лат.)
environment навколишнє
середовище
erodibility еродованість
erosion ерозія
F
feldspar
fine
flint
flood plain
fluvial
польовий шпат
тонко (зернистий)
кремінь
заплава
річковий
G
geli- пов’язаний з
холодом, дією
морозу або
багаторічною
мерзлотою
gelifluction соліфлюкція
glacier глетчер, льодовик
gley глейовий
grain зерно
granulometry
gravityinduced
slipping
greyish-green
grinding
gritty
gully
H
heterogeneous
гранулометрія
просідання або зсув
під дією гравітації
сіро-зелений
подрібнення
піщаний
яр, балка
гетерогенний,
неоднорідний,
різнорідний,
різнотипний, різний
hill пагорб
flux потік, постійний
рух
fragile нестійкий, крихкий
fragmentation подрібнення
freezing замерзання
frost морозне
weathering звітрювання
Holocene голоцен
humic гуміновий
I
interbed прошарок
33
interglacial
period
interlayer
intricate
L
landslide
Late
latitude
layer
lightweight
liquid limit
liquidity
liquidity
index
loading value
loam
loess
loess
derivates
loess-like
loose
lowland
міжльодовиковий
період
прошарок
складний
M
macroporosity макропористість
magnitude величина, розміри
marker маркуючий
горизонт
зсув
mica слюда
пізній
mineral мінеральний склад
composition
широта
mountain гірська місцевість
terrain
шар
mud мул
легкий
O
межа текучості
outcrop відслонення
текучість
overland flow поверхневий
схиловий стік
показник текучості
overland поверхневий стік
runoff
величина
overlying залягаючий зверху
навантаження
суглинок
P
лес, лесові породи
palaeosol, викопний грунт
paleosol
похідні лесових
parent rock материнська порода
порід
лесоподібний
partial частковий,
неповний
вільний,
pattern модель, структура
незв’язаний
низина, долина
perennial непересихаюча
river річка
permafrost вічна мерзлота
34
physical
weathering
piedmont
pit
plain
planes of
weakness
plasticity
index
Pleistocene
porous
powderlike
promontory
фізичне
звітрювання
передгір’я
яма, кар’єр, шурф,
шахта
рівнина
площини
ослаблення
число пластичності
(для глинистих
порід)
плейстоцен
пористий
подібний до муки
мис, виступ
relief рельєф
remains залишки, рештки
rock гірська порода
rod гілка, пагін
rodents гризуни
rubble валун, бут, бутовий
камінь
S
salt flat засолена низина
saltation стрибкоподібне
переміщення
часток у воді і
повітрі
saprolite сапроліт
sediment осадконакопичення
accumulation
sediment осадкоутворення
production
sediment перетворення
reworking осадку
sedimentary осадочна порода
rock
sesqui- півтора
shale глинистий сланець
Q
quarry кар’єр, відкрита
розробка
quartz кварц
Quaternary четвертинний
період
R
rare рідкісний
rate темп, пропорція,
ступінь, відсоток
rectangular прямокутний
redistribution перерозподіл
shallow saline мілководне солоне
lake озеро
shape форма
35
shattering руйнування,
подрібнення
silt мул, наноси, осадок
U
silt-sized мулова розмірна
uneven нестійка будівля
particles фракція
settlement
slope схил
upland височина
slope схилові процеси
V
processes
soil грунт
valley долина
solid твердий
vertebrate хребетний
splitting розколювання,
vertical walls вертикальні стінки
подрібнення
steep крутий
W
steppe areas степ
wadi ваді, сухе русло
susceptible чутливий до…,
Wasilew's конус Васильєва
піддається дії …
cone
swamp- болотно-озерний
water content вміст води
lacustrine
swelling здатність до
weathering звітрювання
ability набухання
westerly західні вітри
T
winds
thickness потужність
westwards на захід
tightly packed щільно упакований
tinge відтінок, слід
turf дерн
36
ПЕРЕЛІК ПОСИЛАНЬ
Episodes.  1999.  Vol.22, N 3 (Sept.).
Leonhard, L.C. von, 1823/24. Charakteristik der Felsarten. 3 Vols.
J. Engelmann Verlag, Heidelberg, 772 pp.
3. Loess and periglacial phenomena: Symposium of the INQUA
Commission on Loess: lithology, genesis and geotechnic definitions
and IGU Commission for Periglacial studies: field and laboratory
experimentation, Normandy-Jersey-Brittany, Caen, August 1986
/Edited by M. Pecsi and H.M. French.  Budapest: Akad. Kiado.
Hungary, 1987.  311 p.
4. Lyell, C., 1834. Observation on the loamy deposits called ''loess'' of
the basin of the Rhine. The Edinburgh New Philosophical Journal
17, p.110 - 113.
5. Lyell, C., 1847. On the delta and alluviual deposits of the
Mississippi, and other points in the geology of North America,
observed in the years 1845, 1846. American Journal of Science 3,
34-39
6. Press Frank, Silver Raymond. Understanding Earth.  New York.
W. H. Freeman and Company, Second ed., 1998.  682 p.
7. Problems of environmental engineering in the Odra river mouth. 
Szczecin: Midmodexim Szczecin Print. Poland, 1999.  327 p.
8. Quaternary International.  2001.  Vols. 76/77  (Feb.-Mar.).
9. Science for a Changing World: Geology of the Loess Hills, Iowa.
U.S.Geological Survey information Handout.Washington: United
States Government Printing Office, 1999.
10. The Ukraine Quaternary Explored: the Middle and Upper
Pleistocene of the Middle Dnieper Area and its importance for the
East-West European correlation. Volume of Abstracts.  Kyiv,
Institute of Geological Sciences NASU., 2001.  110 p.
11. The Ukraine Quaternary Explored: the Middle and Upper
Pleistocene of the Middle Dnieper Area and its importance for the
East-West European correlation. Excursion Guide.  Kyiv,
Institute of Geological Sciences NASU., 2001.  63 p.
1.
2.
37
ЗМІСТ
Передмова
3
Text 1. Loess definitions
3
Text 2. Loess deposits of Africa
5
Text 3. Loess of Asian regions
8
Text 4. Loess of Europe
13
Text 5. Loess deposits of North American and South American 23
continents
Text 6. Weathering and Erosion
26
Text 7. Methods of Defining the Liquidity Index IL
28
Text 8. Stability of Loess Slopes in China
29
Glossary
32
Перелік посилань
37
Зміст
38
38