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X/1/2019
InterdIscIplInarIa archaeologIca
natural scIences In archaeology
homepage: http://www.iansa.eu
Review of Illuvial Bands Origin; What Might the Presence of Dark Brown
Bands in Sandy Infllings of Archaeological Features
or Cultural Layers Mean?
Lenka Lisá
a*
, Aleš Bajer
b
, Klement Rejšek
b
†
, Valerie Vranová
b
, Lenka Vejrostová
c
,
Andrzej Wisniewski
d
, Petr Krištuf
e
a
Institute of Geology CAS, Rozvojova 269, 165 00 Prague, Czech Republic
b
Department of Geology and Pedology, Faculty of Forestry and Wood technology, Mendel University in Brno, Zemědělská 3, 613 00 Brno, Czech Republic
c
Faculty of Science, Charles University, Albertov 6, 128 43 Prague, Czech Republic
d
Institute of Archaeology, University of Wrocław, Szewska 48, 50 137 Wrocław, Poland
e
Department of Archaeology, University of West Bohemia, Sedláčkova 15, 30614 Pilsen, Czech Republic
1. Introduction
The presence of bands within the sedimentary/pedological
record has been of interest to diferent pedologists since the
beginning of the twentieth century. The most common term
for these laminated textural features are illuvial bands, but
names such as pseudofbres, lamellas, laminae, clay-iron
bands or covarvany, are also used in diferent references
(see review, Prusinkiewicz
et al.
, 1998 and Kühn
et al.
,
2011), or, according to the US Soil Survey Staf (1999), a
lamella. A textural feature called a lamella (plural lamellae;
band) can develop as an illuvial horizon with a thickness
of less than 7.5 cm and is intercalated with horizons poor
in clay (Miedema, 1987; Kemp and McIntosh, 1989). Such
accumulations are usually composed of fne-grained, silica-
rich clay attached to a coarser fraction that is composed
of the original soil. Illuvial bands difer in colour (higher
chroma values, redder hues) (Van Reeuwijk and de Villiers,
1985). The transition between bands and the surrounding
matrix is usually wavy and broken. Sometimes these bands
compose a kind of web or network. A concave gefuric
c/f-related (coarse/fne-related) distribution is the typical
micromorphological pattern. Clay coatings cover and bridge
the individual sand grains which is refected in a chitonic
or chito-gefuric c/f-related distribution (Kühn
et al.
, 2011).
Most commonly these bands are described in sandy soils,
Volume X ● Issue 1/2019 ● Pages 19–28
*Corresponding author. E-mail: lisa@gli.cas.cz
ARtICle Info
Article history:
Received: 27
th
June 2018
Accepted: 1
st
May 2019
DOI: http://dx.doi.org/ 10.24916/iansa.2019.1.2
Key words:
illuvial bands
clay-iron accumulations
subsoil lamellae
micromorphology
Neolithic
Palaeolithic
AbStRACt
The presence of lamellae (or bands) often promises an interesting sedimentary archive related to the
occupation or abandonment history of a site. How exactly might such types of bands be interpreted,
and how do their presence change the original primary features preserved within the archaeological
structure? For this review, two archaeological sites are introduced, both distinct in many aspects,
located in diferent climatic regions, but with the presence of bands preserved inside of the infll, as
well as in the locality’s background. One site is related to the Magdalenian/Epigravettian occupation
in south-western Poland, and the second related to the Neolithic occupation in central Bohemia. What
connect these two localities are their permeable sandy background, presence of human occupation, and
the development of the above-described textural features. Sedimentological observations supported
by micromorphology and geochemistry, as well as by magnetic susceptibility, revealed that, in both
localities, the presence of dark brown bands was the result of repeated illuviation due to a kind of
podsolization process not necessarily related to human presence. The illuvial lamellae/bands at the
Kly site probably originated during the Subboreal due to the increased humidity connected with the
presence of the disturbed background of the infll in the ditch. The Sowin site displays, at the very least,
two phases of origin. One of the phases is pre-dated by glacial conditions, and the second is of late
glacial or Holocene origin. The origin of these features in both study sites is due to precipitated water
and the movement of clay down the section, but under their diferent conditions.
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Lenka Lisá, Aleš Bajer, Klement Rejšek, Valerie Vranová, Lenka Vejrostová, Andrzej Wisniewski, Petr Krištuf: Review of Illuvial Bands Origin; What Might the Presence
of Dark Brown Bands in Sandy Infllings of Archaeological Features or Cultural Layers Mean?
20
but their appearance in other soils is not excluded. Several
of the best-developed examples of soils with illuvial bands
described in Holocene (as well as Pleistocene) soils are the
humic podzols of the European Aeolian Sand Belt (Koster,
2009). Gerasimova and Khitrov (2012) classifed similar
soils located in glacifuvial sand in south western Poland.
What is the process whereby the illuvial bands develop?
What role does climate, natural processes, or human infuence
play in the origin of these features? The origin of illuvial bands
is generally not well understood and it remains controversial.
It seems that some “trigger” (increased precipitation – Pelle
et al.
, 2013) activates the movement of clay, which then
stops moving at a certain depth where there is some textural
inhomogeneity (Bouabid
et al.
, 1992). Another possibility
is that the origin is triggered by the precipitation, but these
bands start to form at the limit of the capillary water reach
(Van Reeuwijk and de Villiers, 1985), or on a transition to a
more calcareous zone,
i.e.
at a point of a distinct pH change
(Schaetzl, 1992). Stefanovits (1971) suggested that illuvial
bands are the result of unfavourable conditions triggered
by climate. On the other hand, the same author, as well as
Tsigirintsev (1968) and Ugla and Ugla (1979), propose that
illuvial bands are the result of the impact of forest vegetation.
Their assumption is that the clay movement is activated by
a change of pH that has been triggered by the acid “waste”
from conifer trees. In this scenario, active maintenance of
the vegetation by humans may play a role in the origin or
absence of these features. Another trigger, difering from
those mentioned above, is the local hydrology (see review in
Ibrahim, 2011). Here the underground water is transporting
a quantity of some iron compound that may transform at one
point in time (and place) and thus form the illuvial bands.
The primary sedimentary accumulation of iron, and later
pedological transformation of these accumulations, may
also play a role in the development of these bands (Schaetzl,
2001).
This paper aims to review the possible formation processes
that lead to the origin of illuvial bands and, in addition,
how micromorphology and geochemistry methodological
tools may help with interpreting these formation processes.
What might the main triggers be and what exactly might the
presence of illuvial bands mean for interpretation of human
presence and the environment of a site?
2. Study sites
2.1 Kly
The Kly site is situated at the confuence of the Labe
and Vltava Rivers in central Bohemia (Figure 1A). The
Figure 1.
Lidar-based DTM data expression
on both sites (A – Kly, B – Sowin) together
with their location in central Europe.
0 1000
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Lenka Lisá, Aleš Bajer, Klement Rejšek, Valerie Vranová, Lenka Vejrostová, Andrzej Wisniewski, Petr Krištuf: Review of Illuvial Bands Origin; What Might the Presence
of Dark Brown Bands in Sandy Infllings of Archaeological Features or Cultural Layers Mean?
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background of the site is composed of Cretaceous sand of
Turonian Age covered by the fuvial sandy deposits of the
Labe River. A Neolithic enclosure has been recorded there by
way of an aerial survey. The enclosure is composed of two
ditches and a stockade groove on the inside. The enclosure
defnes the area of a defunct bend in the River Labe and
exceeds its alluvium (food plain) by approximately 5
metres. The outside ditch was interrupted at 10 places and
the inside at 13 places (Gojda
et al.
, 2002). All three lines
of the enclosure were partially excavated by trenches for
the frst time in 1999, and then again in 2015 (Krištůf
et al.
,
2019).
The outer V-shaped ditch is 3.5–4.3 m wide at its top with
a maximum depth of 1.4 m. The inner ditch has a similar
shape. Its width ranges from 3.7 to 4.1 m with a maximum
depth of 1.3 m. The ditches were dug into the sandy subsoil,
resulting in the low stability of their walls. Shortly after the
digging of these ditches, their bottoms were clogged up by
sandy layers. The depth at that moment reached 0.9 m and
0.95 m, respectively, and the ditches had a U-shape profle.
Most of the fndings associated with the enclosure were
found in the layers above this horizon. The most frequent
fndings were large accumulations of daub and fragments of
vessels. The authors managed to reconstruct two tulip-like
beakers and pots. The upper part of the ditches was defnitely
flled up during agricultural cultivation in the Middle Ages or
even the post-medieval Period. In both ditches, besides the
above-described layers, there were also weak dark-brown
layers that occurred at a depth of 0.7–1.3 m and went into
the sandy subsoil. The same situation was observed during
the research work in 1999, when these layers were the only
stratifcation that had been recognized in the ditch’s profle
(Gojda
et al.
, 2002).
The cause-way enclosure near Kly is classifed to an
early phase of the Michelsberg culture on the basis of the
archaeological fndings. This is evidenced mainly by fndings
of Tulip-like beakers of type II (according to Lüning, 1968).
At least one beaker was found in both ditches. The same
beaker type was found during the research work in 1999
(Gojda
et al.
, 2002). Three radiocarbon dates have been
retrieved from this site. Two of them came from the outside
and the other came from the inner ditch. All three dated
samples came from contexts with numerous archaeological
fndings. Both dates from the outer ditch are identical,
5195±40
14
C BP. The date from the inner ditch is slightly
earlier, 5230±30
14
C BP. Formal similarities, archaeological
fndings and radiocarbon dates indicate the simultaneity of
both ditches (Krištůf
et al.
, 2019).
2.2 Sowin
The Sowin site is situated within the central part of the
Niemodlin Plain, which separates the Nysa Kłodzka
Valley from the Ścinawa Niemodlińska Valley, SW Poland
(Figure 1B). The Niemodlin Plain rises ca. 40 metres above
the bottom of the Nysa Kłodzka Valley and ca. 25 metres
above the Ścinawa Niemodlińska Valley (Przybylski and
Badura, 2001). The background of the study site is composed
of relics of a till plain and glacifuvial sediments of the Odra
glaciations (OIS6), partly covered by loess deposits (OIS2)
and sand dunes (Dryas I–III as well as OIS2) with traces
of Upper Palaeolithic settlement. The Late Palaeolithic
record from the Sowin area comprises a number of sites
(Wiśniewski
et al.
, 2009; 2012). Three of them (nos. 7, 9 and
11) have yielded large collections (more than one thousand
stone artefacts). The illuvial bands are a common feature in
all the types of sandy sediments.
In this paper, we will only focus on site 7, which has been
widely recognized. Sowin site 7 has provided data on human
activity corresponding to the Epigravettian and Magdalenian.
The Epigravettian fnds occurred in sandy sediment
overlying sand and gravel of glacial origin. Using OSL
dating, the sediment in which the Epigravettian assemblage
was located had formed in 15,470±860
14
C BP (GdTL2496)
and 16,200±920
14
C BP (GdTL2497); (Wiśniewski
et al.
,
2017). The artefacts were buried by aeolian sand (up to
0.4 m thick). The sandy layer contains a network of fne
desiccation cracks and isolated ice-wedge pseudomorphs as
a result of periglacial processes. The aeolian sand was OSL
dated between 13,830±860 (GdTL2495) to 14,710±900 BP
(GdTL2494). The modern topsoil situated above was 0.3 m
thick. The Magdalenian fnds were recorded in the upper
part of the aeolian sand and in the topsoil. Artefacts below
the ploughing zone had survived in local depressions that
were probably of thaw origin, inherited from the periglacial
period. Spatial analysis and a technological study of this
assemblage allowed us to distinguish two diferent functional
clusters connected with blank (stone tool) production and
the production and use of tools such as burins, endscrapers,
and backed pieces. Ochre was also confrmed in the layer.
The second artefact cluster was situated in the context of
fllings of the periglacial structures such as ice wedges or
desiccation cracks.
3. Methods
Both sites included in this study were evaluated during
archaeological excavations. The presence of illuvial bands
outside the archaeological context was, in the case of the Sowin
site, recorded by a set of cores as well as trenches, and these
bands were also recorded in the straight context of the cultural
layer. To better understand the illuvial band formation, trench
7/IV was chosen for the geochemical evaluation, in spite of
the fact that it was archaeologically sterile. On the other hand,
trench 7/IV provided a lithology where sand covered by loess
was preserved. Micromorphological samples documenting
the bands lithology were taken from trench 7/IV as well
as from the other trenches where only sandy material and
human occupation was documented (7/I, 7/II). Concerning
the stratigraphy of the site, it is suggested that the formation
of trench 7/IV preceded the Epigravettian and Magdalenian
occupation of the area (Wisniewski
et al.
, 2017).
In the case of the ditch infll in Kly, illuvial bands were
recorded mainly inside the ditch, but partly also in its
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IANSA 2019 ● X/1 ● 19–28
Lenka Lisá, Aleš Bajer, Klement Rejšek, Valerie Vranová, Lenka Vejrostová, Andrzej Wisniewski, Petr Krištuf: Review of Illuvial Bands Origin; What Might the Presence
of Dark Brown Bands in Sandy Infllings of Archaeological Features or Cultural Layers Mean?
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