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99
XIII/2/2022
INTERDISCIPLINARIA ARCHAEOLOGICA
NATURAL SCIENCES IN ARCHAEOLOGY
homepage: http://www.iansa.eu
Geochemical Study of Chert Artefacts from Xicotó Rockshelter
(NE Iberia) Archaeological Site. New Data on Neolithic and Mesolithic
Human Occupations
Marta Sánchez de la Torre
1*
, Cynthia Belén González Olivares
1
, Bernard Gratuze
2
,
François-Xavier Le Bourdonnec
3
, Xavier Mangado
1
1
SERP-IAUB. Universitat de Barcelona. 6–8 Montalegre St, 08001 Barcelona, Spain
2
IRAMAT-CEB (UMR 5060). CNRS – Université d’Orléans. 3D Ferrollerie St, 45071 Orléans, France
3
Archéosciences Bordeaux (UMR 6034). CNRS – Université Bordeaux Montaigne – Université de Bordeaux. Esplanade des Antilles, F-33607 Pessac
Cedex, France
1. Introduction
The analysis of lithic raw materials provides essential
information not only about the strategies involved in the
procurement of the rocks used for the production of lithic
assemblages of past human groups, but also on the territorial
use of past communities. Studies of lithic raw materials were
incorporated into archaeological research some decades
ago as means of better understanding the behaviour of past
human populations. In NE Iberia, such studies started during
the 1990s and have increased in the frst years of the 21
st
century. The classic approach to analyse lithic raw materials
involved macroscopic characterisations to determine the
textural and micropalaeontological content, as well as the use
of petrographic analyses to determine mineralogical features
(Mangado, 2005; Ortega, 2002; Terradas, 2001). However,
the classic approach was limited in the case of sedimentary
convergence facies,
i.e.
where two or more diferent
geological formations possess similar characteristics and
diferences cannot be established (Aubry, 1990). In addition,
the petrographic characterisation was a destructive tool,
as a thin section was needed to perform the mineralogical
description of the rock. With the aim of resolving these
limitations and avoiding the use of destructive techniques,
other methodological approaches have been tested in recent
years (Roy-Sunyer
et al.
, 2013; Soto, 2015; Sánchez de la
Torre, 2015). Following this trend, the use of geochemical
tools to determine the origin of the archaeological chert
Volume XIII ● Issue 2/2022 ● Pages 99–115
*Corresponding author. E-mail: martasanchezdelatorre@ub.edu
ARTICLE INFO
Article history:
Received: 19
th
January 2022
Accepted: 4
th
August 2022
DOI: http://dx.doi.org/10.24916/iansa.2022.2.1
Key words:
lithic sourcing
human mobility
geochemistry
chert
Mesolithic
Neolithic
NE Iberia
Pre-Pyrenees
ABSTRACT
Xicotó Rockshelter (Alòs de Balaguer, Lleida, Spain) is located in the eastern Pre-Pyrenean range
in north-east Iberia, in the middle Segre River Basin. Since 2013, archaeological works have been
developed by a team from the Prehistoric Studies and Research Seminar (SERP) at the University
of Barcelona and up to three sedimentary levels have been identifed. The preserved archaeological
remains have allowed determining that the site was occupied during at least two diferent periods: the
Ancient Neolithic and the Middle Mesolithic. The relative chronology given by the archaeological
assemblage has been confrmed by several radiocarbon dates that place the occupations of the site to
be during the VI and VII millennia cal BC. This paper presents the results obtained after the analysis
of lithic raw materials from the entire lithic assemblage. The analysis was performed using the classic
petroarchaeological approach, comprising textural and micropalaeontological descriptions, combined
with the application of geochemical methods, using energy-dispersive X-ray fuorescence (ED-XRF)
and laser-ablation inductively-coupled-plasma mass spectrometry (LA-ICP-MS). The results show that
several rock types were selected for confectioning the lithic tools, among which chert was the preferred.
Diferent types and origins have been identifed, with similar sourcing strategies that involved local and
regional procurement.
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Marta Sánchez de la Torre, Cynthia Belén González Olivares, Bernard Gratuze, François-Xavier Le Bourdonnec, Xavier Mangado:
Geochemical Study of Chert Artefacts from Xicotó Rockshelter (Ne Iberia) Archaeological Site. New Data on Neolithic and Mesolithic Human Occupations
100
artefacts was incorporated a few years ago in NE Iberia
with satisfactory results (Sánchez de la Torre
et al.
, 2017a;
Sánchez de la Torre
et al.
, 2017c; Sánchez de la Torre
et al.
,
2019a).
This paper aims to present the archaeological site of
Xicotó Rockshelter and its history of human occupation; the
characterisation of the recovered lithic raw materials is used
as means of tracing the mobility patterns and the territoriality
of prehistoric people that occupied the site during the Ancient
Neolithic and the Middle Mesolithic periods.
2. Materials and Methods
2.1 Xicotó Rockshelter: the site and the archaeological
levels
The archaeological site of Xicotó Rockshelter (Alòs de
Balaguer, Lleida, Spain) is located in the contact area
between the Catalan Central Depression and the frst Pre-
Pyrenean Mountain Ranges. The site lies at 368 m asl and
up to 100 m above the current Segre riverbed. The rock
shelter possesses a maximum length of 18 m in its E-W
axis and 8 m in the N-S axis. It was discovered in 1996
during a geoarchaeological survey in the Segre river basin
(Bergadà
et al.
, 2007) and it is located 400 m to the east of
the prehistoric site of Parco Cave (Mangado
et al.
, 2014).
A survey to determine the archaeological potential of the site
was undertaken in 1999. During these frst investigations,
4 m
2
were excavated and resulted in several sedimentary
levels possessing archaeological remains being identifed.
Within the archaeological evidence recovered, there were
some faunal remains, pottery and lithic artefacts. In 2013,
the archaeological work was restarted under the direction of
two of us (Xavier Mangado and Marta Sánchez de la Torre)
and still continues today.
As a frst step, further 16 m
2
were opened, increasing the
surface excavation to 24 m
2
in the following years (Figure 1).
Below a mixed level with evidence of human occupation
during the Bronze Age, frst sedimentary package of 40 cm
was identifed, with several hearths and pits. Recovered
archaeological assemblage suggested relative chronology
from the Ancient Neolithic (
e.g.
presence of impressed
pottery and some
double bevel
geometric lithic tools)
(Oms
et al.
, 2019), that was confrmed by a radiocarbon
date from pit 1 (5300–5040 cal BC) (Figure 2). The second
level was recognised below this frst one, possessing
mixed archaeological assemblage about 20 cm in width
with a mixed set of materials moved from levels I and III.
The sedimentary level III, which is still under excavation,
possesses archaeological remains that can be exclusively
related with a human occupation of the site during the
Middle Mesolithic period (Figure 3). The large amount
Figure 1.
Xicotó Rockshelter location (top),
archaeological grid (bottom left) and site
detail area (bottom right).
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IANSA 2022 ● XIII/2 ● 99–115
Marta Sánchez de la Torre, Cynthia Belén González Olivares, Bernard Gratuze, François-Xavier Le Bourdonnec, Xavier Mangado:
Geochemical Study of Chert Artefacts from Xicotó Rockshelter (Ne Iberia) Archaeological Site. New Data on Neolithic and Mesolithic Human Occupations
101
of notched and denticulated chert artefacts, as well as two
radiocarbon dates from charcoals recovered at pit 12 (7050–
6700 cal BP) (see Figure 2), allow us to set that the site was
frequented during the Mesolithic facies known as Notch and
Denticulates. This facies has been defned in the southern
slopes of the Pyrenees by the dominance in the lithic industry
of notched and denticulated tools (Alday, 2006).
2.2 Macroscopic and geochemical approaches
Firstly, a visual and micropalaeontological description of
the entire lithic assemblage was undertaken (2383 samples).
This macroscopic characterisation was carried out using
a binocular microscope Olympus SZ61 (from 6.7 to 45 ×
magnifcation). Images were taken using a coupled Olympus
SC30 camera. As the aim of the study was to analyse both
Figure 2.
Representative lithic industry from levels I (top right) and III (top left) and radiocarbon dates and calibration after OxCal v.4.3.2 (Ramsey, 2017)
with IntCal13 atmospheric curve (Reimer
et al.
, 2013) (bottom).
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IANSA 2022 ● XIII/2 ● 99–115
Marta Sánchez de la Torre, Cynthia Belén González Olivares, Bernard Gratuze, François-Xavier Le Bourdonnec, Xavier Mangado:
Geochemical Study of Chert Artefacts from Xicotó Rockshelter (Ne Iberia) Archaeological Site. New Data on Neolithic and Mesolithic Human Occupations
102
geological and archaeological samples, non-destructive
techniques were prioritised.
The second stage of this analytical approach involved
geochemical analyses to quantify major, minor and trace
components so as to be able to compare the raw materials
of the chert artefacts with those from known geological
outcrops. For this part of the study, 13 chert artefacts from
level III of Xicotó Rockshelter were analysed by energy-
dispersive X-ray fuorescence (ED-XRF) and 36 artefacts
(also from the same level) were studied with laser-ablation
inductively-coupled-plasma mass spectrometry (LA-ICP-
MS). Archaeological tools without cortex and surface
alterations were preferred.
With the aim of comparing results obtained after the
analysis of archaeological samples, geological formations
with cherts having similar characteristics to those of the
Figure 3.
Materials dispersion with the three archaeological levels (A), the main types of rocks (B) and some representative archaeological remains (C).
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Marta Sánchez de la Torre, Cynthia Belén González Olivares, Bernard Gratuze, François-Xavier Le Bourdonnec, Xavier Mangado:
Geochemical Study of Chert Artefacts from Xicotó Rockshelter (Ne Iberia) Archaeological Site. New Data on Neolithic and Mesolithic Human Occupations
103
artefacts from Xicotó were surveyed and sampled. It
involved up to 13 outcrops from 9 geological formations,
with more than 160 samples being selected for geochemical
analyses (Table 1). Only primary outcrops were considered
for this study. To improve analysis time and to avoid surface
alterations, geological samples were prepared in squares of
5 × 5 mm, removing cortex surfaces.
To analyse major and minor elements, energy-dispersive
X-ray Fluorescence (ED-XRF) was employed. Analyses
were done at the Archéosciences-Bordeaux Laboratory,
Pessac, France. Nine element concentrations were quantifed
(Na, Mg, Al, Si, P, K, Ca, Ti, Fe) using an X-ray fuorescence
spectrometer SEIKO SEA 6000 VX (Orange
et al.
, 2017),
using fundamental parameters corrected by the granodiorite
GSP2 from the US Geological Survey (USGS) international
standard (Wilson, 1998). A 3
×
3 mm collimator was
prioritised, and analysis time was set to 400 s for each
measurement condition (3 conditions with air or He
environment and Cr or Pb flter were established). To check
instrument calibration and accuracy, the JCh-1 chert standard
from the Geological Survey of Japan (GSJ) was employed
(Imai
et al.
, 1996). To prove and validate the formula which
was used and to check instrument accuracy, a measurement
with the JCh-1 chert standard was established, with the
standard deviation obtained always being lower than
0.08 w%, validating the accuracy of the formula used
(Sánchez de la Torre
et al.
, 2017b).
To analyse trace elements, we used laser-ablation
inductively-coupled-plasma mass spectrometry (LA-ICP-
MS) at the Ernest Babelon Laboratory, IRAMAT, Orleans,
France. Elements were quantifed using a Thermo Fisher
Scientifc Element XR mass spectrometer associated with
a Resonetics RESOlution M50e ablation device. This
spectrometer has the advantage of being equipped with a dual
mode (counting and analogue modes) secondary electron
multiplier (SEM) with a linear dynamic range of over nine
orders of magnitude, associated with a single Faraday
collector which allows an increase in the linear dynamic
range by additional three orders of magnitude. This feature
is particularly important for laser-ablation analysis of lithic
samples, as it is possible to analyse major, minor and trace
elements in a single run regardless of their concentrations and
their isotopic abundance. The ablation device is an excimer
laser (ArF, 193 nm), which was operated at 7–8 mJ and
20 Hz and only if saturation was observed were conditions
reduced to 10 Hz. A dual gas system with helium (0.65 l/
min) released at the base of the chamber, and argon at the
head of the chamber (1.1 l/min) carried the ablated material
to the plasma torch. Ablation time was set to 40 s: 10 s pre-
ablation to let the ablated material reach the μμspectrometer
and 30 s collection time. Laser spot size was set to 100
μm,
and only reduced to 80 or 50 μm if saturation was detected,
and line mode acquisition was chosen to enhance sensitivity.
Background measurements were run every 10–20 samples.
Fresh fractures were analysed on geological samples to
reduce potential contamination. Priority was given to
characterising large samples; thus, only one ablation line
was carried out per specimen. However, if element spikes
due to the presence of inclusions or heterogeneities were
observed during analysis, results were discarded and a new
ablation location was selected.
Calibration was performed using a standard reference glass
NIST610 which was run periodically (every 10–20 samples)
to correct for drift. NIST610 was used to calculate the
response coefcient (k) of each element (Gratuze, 1999;
Gratuze, 2014), and the measured values of each element
Table 1.
Outcrops and archaeological samples selected for study with the number of samples analysed by each geochemical method.
ACRONYMOUTCROP / SITEFORMATIONAGETYPEED-XRFLA-ICP-MS
ALB1Alberola 1Tartareu-AlberolaOligoceneLacustrine2020
ALB2Alberola 2Tartareu-AlberolaOligoceneLacustrine
16
17
CDFCastelló de FarfanyaCastelltallat FmOligoceneLacustrine5149
PCPuente Candasnos
Aragonian limestonesMioceneLacustrine2320
PERALPeraltilla
Castelltallat FmOligoceneLacustrine2320
ZURI
ZuritaTremp Fm (2)MaastrichtianLacustrine
18
13
FONTFontllongaTremp Fm (1)MaastrichtianEvaporitic
–
19
ALIAlins del MonteTremp Fm (1)MaastrichtianEvaporitic
–
30
CERCérizolsBleu tertiaryDanianEvaporitic
–
17
VSSMVessant Sud Sant MametTremp Fm (1)MaastrichtianEvaporitic
–
21
MONTGMontgaillardFlysch limestonesTuronian-SantonianMarine
–
20
MONTSMontsaunèsNankin FmMaastrichtianMarine
–
20
BUALA
Buala
Marly fysch
Campanian-MaastrichtianMarine
–
20
XICOTÓXicotó Rockshelter
––
Lacustrine1317
XICOTÓXicotó Rockshelter
––
Evaporitic
–
17
XICOTÓXicotó Rockshelter
––
Marine
–
2
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Marta Sánchez de la Torre, Cynthia Belén González Olivares, Bernard Gratuze, François-Xavier Le Bourdonnec, Xavier Mangado:
Geochemical Study of Chert Artefacts from Xicotó Rockshelter (Ne Iberia) Archaeological Site. New Data on Neolithic and Mesolithic Human Occupations
104
were normalised against 28Si, the internal standard, to
produce a fnal percentage. Glass Standard NIST612 was
analysed independently of calibration to provide comparative
data. In all, 30 elements were quantifed (Li, Be, B, Mg, Al,
Si, Ca, Ti, V, Cr, Fe, Ga, Ge, As, Rb, Sr, Y, Zr, Nb, Cs, Ba,
La, Ce, Pr Nd, Sm, W, Bi, Th and U).
3. Results
3.1 Macroscopic characterisations: chert types and
related formations
From the 2383 lithic artefacts that were recovered from
the three sedimentary levels from Xicotó, 1958 were made
Figure 4.
Main lithological groups from
the lithic industry by levels (A), chert types
by levels (B) and macroscopic views of the
diferent groups (bottom).
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Marta Sánchez de la Torre, Cynthia Belén González Olivares, Bernard Gratuze, François-Xavier Le Bourdonnec, Xavier Mangado:
Geochemical Study of Chert Artefacts from Xicotó Rockshelter (Ne Iberia) Archaeological Site. New Data on Neolithic and Mesolithic Human Occupations
105
of chert (82%). Fine-grain metamorphic rocks defned as
hornfelses made up 12% of the assemblage, the remaining
being 6% other metamorphic and igneous rocks like
quartzites and granites. In Level I, the Ancient Neolithic
occupation, chert represented 58% of the set, the rest
largely represented by hornfelses and other rocks (27% and
15%). However, in the Middle Mesolithic occupation from
level III, the presence of chert increased up to 91%, the other
rocks being anecdotic (quartzites 6% and other rocks 3%)
(Figure 4 A). This signifcant diference between levels with
regard to the lithology is probably related to changes in the
typology of the retouched lithic assemblage. Thus, hornfelses
and other metamorphic and igneous rocks are mostly related
with the manufacture of macrotools, whereas chert is mostly
used for confectioning carving artefacts obtained from
fakes by direct percussion. Accordingly, during the Ancient
Neolithic, the production of macrotools is predominant in the
archaeological set (39% of the fnished tools). By contrast, in
the Middle Mesolithic, the macrotools were reduced to 10%,
whereas other typological tools like notches and denticulates
increased (42% of the fnished tools). These tools possess
extensive discontinued deep retouches frequently inverse
or alternate with generally a signifcant presence of cortical
surfaces. The macroscopic observation of the archaeological
cherts has allowed us to determine two main types (1 and
2) and some evidence of other types (A and B), the latter
only being represented by some scarce elements (2 pieces
from type A and 1 from type B), suggesting that these raw
materials were only occasionally procured. The presence
of each chert type by levels is quite homogeneous, type 2
being the most represented in the three sedimentary levels
(Figure 4 B).
Type 1
is represented by 253 artefacts, which means
13% of the set. The distribution of this chert type by levels
is quite homogeneous, representing 14% in level I and 11%
in level III. Macroscopically this chert has a heterogeneous
texture with metal oxides, micritic residues, grains of
detrital quartz and probably organic matter inclusions.
The main micropalaeontological content consists of
sections of
Charophyte algae
and some gastropods. These
cherts originated in a lacustrine sedimentary environment,
with parallels in four diferent geological formations.
A description of the main features of each formation,
follows. More detailed descriptions can be found in Sánchez
de la Torre
et al.
(2017c).
•
The
Tremp formation
(2) (Maastrichtian, Upper
Cretaceous) possesses a level of laminated micritic
limestones with
Charophyte algae
and gastropod
moulds flled with sparite (IGME, e.p.). This formation
contains nodular cherts and outcrops in the Carrodilla
Mountain Range, a Pre-Pyrenean foothill located
between the Cinca River Basin to the west and the
Noguera Ribagorzana River to the east (Zurita outcrop,
ZURI). Cherts have a texture with impurities of mineral
oxides, carbonate residues and probably organic
matter. The main micropalaeontological content is
composed of
Charophyte algae
and gastropods.
•
The
Castelltallat formation
(Rupelian, Oligocene)
largely outcrops in Serra Llarga (IGME, 1998),
a mountain range located in the province of Lleida,
in the contact area between the Pre-Pyrenees and the
Central Depression. Nodular cherts appear within the
stratifed limestone, more than 40 primary outcrops
having been identifed along the Serra Llarga some
years ago (Castelló de Farfanya outcrops, CDF)
(Mangado, 2005). The presence of chert nodules from
this formation has also been noticed several kilometres
to the west of Serra Llarga and close to the Cinca River
(Peraltilla outcrop, PERAL) (Sáez, 1987). Cherts from
this formation have a macroscopic texture with metal
oxides, carbonate remains, detrital quartz and probable
organic matter.
Charophyte algae
and lacustrine
gastropods constitute the main micropalaeontological
content.
•
The
Tartareu-Alberola
cherts (Rupelian, Oligocene)
appear within the lacustrine stratifed limestones
outcropping in the Sant Miquel Mountain Range,
a Pre-Pyrenean Mountain Chain located to the north of
Serra Llarga and limited by the Noguera Ribagorzana
River to the west and the Farfanya River to the east.
Two primary outcrops were identifed during the
surveys (Alberola 1outcrop, ALB1 and Alberola 2
outcrop, ALB2). This chert type has macroscopic
heterogeneous textures with metal oxides and abundant
micritic remains. The micropalaeontological content is
formed of
Charophyte algae
and gastropod sections.
•
The
Aragonian limestone formations
containing
chert nodules (Aquitanian-Vindobondian, Miocene)
outcrops in the Central Depression of the Middle
Ebro Basin (Puente Candasnos outcrop, PC) (IGME,
e.p.
). This chert has homogeneous textures with metal
oxides, carbonate remains, probable organic matter and
some detrital quartz crystals.
Charophyte algae
and
gastropod sections make up the micropalaeontological
content.
Type 2
is formed by 1550 elements, being the most
represented chert type (79% of the set), being similar
the distribution by levels (79% in the Ancient Neolithic
and 81% in the Middle Mesolithic). This raw material
is characterised by the absence of bioclastic content, as it
originated in a hypersaline sedimentary environment. The
textures are quite smooth, with only a few inclusions of
metal oxides and lenticular gypsum pseudomorphs. Parallels
can be macroscopically drawn with cherts from the Tremp
formation, outcropping largely in the central and eastern
southern Pyrenees and the blue cherts from the Danian
outcropping in the northern slopes of the Pyrenees.
The
Tremp formation
(1) largely outcrops in the
southern slopes of the central and eastern Pre-Pyrenees.
Cherts are embedded within the lacustrine limestones from
the Garumnian facies of this formation (IGME, 2006). Chert
outcrops have been located in the Carrodilla Mountain
Range (Alins del Monte outcrop, ALI) and the Montsec
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Marta Sánchez de la Torre, Cynthia Belén González Olivares, Bernard Gratuze, François-Xavier Le Bourdonnec, Xavier Mangado:
Geochemical Study of Chert Artefacts from Xicotó Rockshelter (Ne Iberia) Archaeological Site. New Data on Neolithic and Mesolithic Human Occupations
106
Mountain Range, with several outcrops being defned, from
which two have been selected for this study (Fontllonga
outcrop, FONT and Vessant Sud de Sant Mamet outcrop,
VSSM). Cherts possess a homogeneous texture with some
metal inclusions, the main feature of this chert type being
the absence of micropalaeontological content. In some cases,
lenticular gypsum crystals are identifed.
The
Tertiary
bleu
cherts
(Danian, Paleocene) are
recognised within the limestone formations from the Danian
outcropping in the
Petites-Pyrénées
and the Plantaurel
regions, as well as in the Aurignac massif, in the northern
slopes of the Pyrenean Mountain Chain (Simonnet, 1999)
(outcrop selected for analysis: Cérizols, CER). These cherts
have homogeneous textures without bioclastic content, the
sole inclusion being some metal oxides.
Besides the two main types, other textures were
identifed. The frst one (
type A
) is only represented by
two specimens, both found in the Middle Mesolithic level.
Macroscopically, both samples are characterised by a
heterogeneous texture composed of abundant metal oxides
and detrital quartz crystals, the main micropalaeontological
content being composed of sponge spicules. This chert
type is macroscopically similar with the two chert sources
outcropping in the northern slopes of the Central Pyrenees:
The Montgaillard fysch cherts from the Turonian-Santonian
and the Montsaunès-Buala cherts from the Nankin formation
(Maastrichtian). A summary with the main features of each
formation follows. More detailed descriptions can be found
in Sánchez de la Torre
et al.
(2019b).
The Turonian-Santonian cherts from the
Montgaillard
outcrop (MONTG) originate in the fysch limestones
outcropping primarily in the Dussert quarry, near Montgaillard
town, in the northern central Pyrenees (Barragué
et al.
,
2001). These cherts are macroscopically composed of
a heterogeneous texture with metal oxides and detrital quartz
crystals. The micropalaeontological content is formed of
sponge spicules and some small benthic foraminifera.
The Campanian-Maastrichtian fysch cherts come from
the Buala outcrop (BUALA) outcrop in the old Buala quarry,
near Montgaillard town, in the northern central Pyrenees.
These cherts present a heterogeneous texture with metal
oxides, detrital quartz cristals, sponge spicules, some small
pelagic foraminifera and, in some cases, probable siderolites.
The Maastrichtian cherts from the Nankin Formation
(Montsaunès outcrop) (MONTS) are inserted in the Nankin
formation limestones, outcropping in the northern slope of
the central Pyrenees, near the ancient quarry of Montsaunès
(Montsaunès outcrop, MONTS). These cherts possess
a heterogeneous texture with carbonate relicts, detrital quartz
and metal oxides. The micropalaeontological content is
composed of sponge spicules and some small foraminifera.
The second texture was defned as
type B
and represented
by only a single specimen, found in the transitional level
(level II). Macroscopically it consists of inclusions of
abundant quartz crystals and calcite or dolomite rhombohedral
crystals, and sponge spicules and small foraminifera as the
main micropalaeontological content. This specimen can
directly be related to cherts from the Agua-Salenz formation
(Conacian), outcropping in the southern slopes of the Central
Pyrenees, near the Turbón Massif. However, considering that
this artefact is attributed to the transitional level, we will not
particularly take it into account during the later discussion.
3.2 Geochemical characterisations: connecting
archaeological cherts with specifc outcrops
To try to establish a connection between the diferent chert
types identifed in the archaeological record and specifc
chert outcrops, geochemical methods were employed. The
13 lacustrine chert artefacts from level III were analysed
by ED-XRF to determine major and minor components and
were compared with 151 samples from six chert outcrops
from four geological formations. Only lacustrine samples
were studied using this geochemical approach, as previous
studies revealed that this technique was not discriminant
when analysing other types of chert (Sánchez de la Torre
et al.
, 2017b). While nine oxides were measured within
ED-XRF (Na
2
O, MgO, Al
2
O
3
, SiO
2
, P
2
O
5
, K
2
O, CaO, TiO
2
and Fe
2
O
3
), data relating to Na
2
O and P
2
O
5
was limited as
their values were frequently below the equipment’s detection
limits. Median values and the standard deviation for each
geological outcrop and the values for all the archaeological
samples in w% are presented in Table 2.
The lacustrine cherts recovered at Xicotó possess
similar macroscopic features to the cherts outcropping in
the Tartareu-Alberola unit, the Castelltallat formation, the
Tremp formation (2) and the Aragonian limestones, and with
outcrops from 25 to 100 km from the site. The scatterplot
concerning three of the main components (Fe
2
O
3
, Al
2
O
3
and
SiO
2
) (Figure 5, top) shows that some diferences can be
observed between the diferent geological sources. However,
there is an overlapping area, so results cannot be taken to
be conclusive. Nevertheless, several formations could be
already discarded: the Tartareu-Alberola cherts (Alberola 1
and Alberola 2) as well as the Aragonian cherts (Puente
Candasnos) seem to be far from the main dispersion of the
archaeological samples. In a similar way, the main groups
from the Maastrichtian cherts (Zurita outcrop) and the
Peraltilla outcrop from the Castelltallat formation do not ft
with the samples from Xicotó. Thus, the lacustrine cherts
from Xicotó seem to better ft with cherts from the Castelló
de Farfanya outcrop (Castelltallat formation).
As the ED-XRF results were not conclusive for the
lacustrine cherts and the other chert types had not yet
been studied, we also developed LA-ICP-MS analyses
to quantify the trace elements. Thus 17 lacustrine chert
artefacts, 17 evaporitic chert tools and the two recognised
marine cherts from level III were analysed by LA-ICP-MS
to specifcally determine trace elements and were compared
with up to 286 samples from 13 chert outcrops from nine
geological formations. Up to 30 elements were quantifed
using this method (Li, Be, B, Mg, Al, Si, Ca, Ti, V, Cr, Fe,
Ga, Ge, As, Rb, Sr, Y, Zr, Nb, Cs, Ba, La, Ce, Pr, Nd, Sm,
W, Bi, Th and U). Median values and the standard deviation
for each geological outcrop and the values for all the
image/svg+xml
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Marta Sánchez de la Torre, Cynthia Belén González Olivares, Bernard Gratuze, François-Xavier Le Bourdonnec, Xavier Mangado:
Geochemical Study of Chert Artefacts from Xicotó Rockshelter (Ne Iberia) Archaeological Site. New Data on Neolithic and Mesolithic Human Occupations
107
Figure 5.
Scatterplot for Ln As/W vs Ln W/U representing all the lacustrine geological outcrops (circles) and the lacustrine archaeological samples of
Xicotó (triangle).
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Marta Sánchez de la Torre, Cynthia Belén González Olivares, Bernard Gratuze, François-Xavier Le Bourdonnec, Xavier Mangado:
Geochemical Study of Chert Artefacts from Xicotó Rockshelter (Ne Iberia) Archaeological Site. New Data on Neolithic and Mesolithic Human Occupations
108
archaeological samples in ppm% are presented in Table 3.
According to the LA-ICP-MS results, some trace elements
could be relevant for distinguishing between sources.
Regarding the lacustrine cherts, the values for As, W and U
clearly separate the diferent geological sources, being in this
case the archaeological samples from Xicotó directly related
to cherts from the Castelló de Farfanya outcrop (Figure 5,
bottom).
The evaporitic chert artefacts from Xicotó Rockshelter
were macroscopically similar to the southern Pre-Pyrenean
cherts from the Garumnian facies of the Tremp Formation
(Alins del Monte, Fontllonga and Vessant Sud de Sant Mamet
outcrops) and the northern Pre-Pyrenean
bleu
cherts from the
Danian (Cérizols outcrop). A discriminant analysis (DA)
was run using XLSTAT software (Addinsoft, 2020) to see
if quantifed distinctions were visible at the minor elemental
levels. The DA of the four geological outcrops and the
archaeological samples of Xicotó concerning three specifc
trace elements (Be, B and U values) showed that some
diferences can indeed be immediately observed between
formations. Of the 98.36% of the total variance F1 (77.69%)
and F2 (20.67%) is represented. Both in the presentation of all
the samples (Figure 6, top) and only the centroids (Figure 6,
bottom) it can be highlighted that cherts outcropping in the
northern Pyrenees (Cérizols outcrop) do not ft with the main
dispersion (cluster) of the archaeological samples. The large
number of samples from Xicotó can mostly be related to
cherts from Vessant Sud de Sant Mamet outcrop, according
to the geochemical analysis of specifc trace elements.
Finally, the two chert artefacts found in level III with
macroscopic textures associated to marine cherts were
studied by LA-ICP-MS and compared with geological
samples from the fysch cherts from Montgaillard and
cherts from the Nankin formation (Buala and Montsaunès
outcrops), all of them outcropping in the northern Pyrenees.
The scatterplot concerning specifc trace elements (Ti, Sr
and Th) (Figure 7) clearly separates the three outcrops, the
archaeological samples being placed in the dispersion area of
the Montgaillard group.
4. Discussion
The macroscopic analysis of the lithological assemblage
recovered at the Xicotó Rockshelter site has revealed that
the nature of the rocks was adapted to the functionality of
the artefacts. Thus, during the Ancient Neolithic period,
metamorphic and igneous rocks such as hornfelses and
granites were largely exploited for manufacturing macrotools,
for example, hand mills, mortars and grinding stones.
However, during the Middle Mesolithic period, the presence
of these rocks signifcantly decreased. Unfortunately, the
origin of the hornfelses and other metamorphic and igneous
rocks has not yet been established. However, near to the site
in the Segre riverbed these rocks are nowadays abundant.
Regarding the origin of chert artefacts, type 2, which
is the most abundant chert type found in the two human
occupations, seems to be directly related to cherts from the
Table 2.
Median values and standard deviations (in brackets) for each geological outcrop and values for each archaeological sample with the nine elements
quantifed by ED-XRF in w%.
VariableAl
2
O
3
CaOFe
2
O
3
K
2
OMgONa
2
OP
2
O
5
SiO
2
TiO
2
ALB11.02 (1.22)3.02 (2.92)0.27 (0.37)
0.16 (0.24)
0.31 (0.21)<LOD<LOD95.44 (3.22)
0.04 (0.06)
ALB2
0.75 (0.56)2.88 (2.27)
0.21 (0.15)
0.12 (0.08)
0.44 (0.24)<LOD<LOD95.92 (2.47)0.03 (0.03)
CDF
0.61 (0.55)2.17 (10.62)
0.10 (0.43)0.03 (0.02)0.31 (0.22)<LOD<LOD97.07 (11.24)0.02 (0.04)
PERAL
0.42 (0.13)
2.75 (1.58)
0.09 (0.05)0.05 (0.02)<LOD<LOD<LOD
96.68 (1.55)
0.02 (0.01)
PC
0.41 (0.09)
0.28 (0.38)
0.02 (0.01)0.02 (0.01)
0.08 (0.01)
<LOD<LOD
99.30 (0.36)
0.01 (0.00)
ZURI
0.43 (0.10)
0.28 (0.81)
0.02 (0.01)0.02 (0.01)<LOD<LOD<LOD99.25 (0.79)<LOD
Xicotó-05
0.640.58
0.030.17
0.66
<LOD0.1397.790.01
Xicotó-070.71
0.28
0.050.09
0.38
<LOD0.04
98.44
0.01
Xicotó-08
0.722.320.050.090.32<LOD0.13
96.35
0.01
Xicotó-090.730.370.03
0.16
0.45<LOD0.37
97.89
<LOD
Xicotó-101.520.33
0.08
0.25
0.6
<LOD0.21
96.98
0.02
Xicotó-11
0.651.980.08
0.09
0.38
<LOD
0.1696.64
0.02
Xicotó-14
0.68
2.93
0.06
0.03
0.28
<LOD
0.08
95.940.02
Xicotó-181.08
0.390.10.14
0.58
<LOD0.09
97.61
<LOD
Xicotó-19
0.69
1.090.040.1
0.46
<LOD0.1197.510.01
Xicotó-220.49
0.46
0.02
0.060.28
<LOD0.12
98.56
<LOD
Xicotó-230.910.750.040.140.49<LOD0.1297.550.01
Xicotó-24
0.58
0.710.020.070.03<LOD0.03
98.56
<LOD
Xicotó-26
2.11
0.760.080.26
0.77<LOD<LOD95.990.03
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Marta Sánchez de la Torre, Cynthia Belén González Olivares, Bernard Gratuze, François-Xavier Le Bourdonnec, Xavier Mangado:
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109
Table 3.
Median values and standard deviations (in brackets) for each geological outcrop with the nine elements quantifed by LA-ICP-MS in ppm. Data from archaeological samples can be found in the
Supplementary Raw Data fle.
VariableLiBeBMgAlSiCaTiVCrFeGaGeAs
ALB1
20.67
(9.82)
0.51
(0.29)
41.97
(26.14)
2570.92
(1205.97)
9712.97
(8937.50)
406164.10
(46288.87)
71674.31
(74266.16)
519.14
(423.77)
19.39
(16.60)
13.44
(8.63)
4522.34
(3901.88)
28.72
(39.21)
0.49
(0.12)
11.22
(13.03)
ALB2
18.76
(8.90)
0.40
(0.2)
39.49
(12.37)
2819.19
(1157.20)
7721.62
(4609.65)
417378.93
(26698.20)
58012.88
(44655.41)
504.68
(348.99)
14.39
(8.38)
11.42
(5.56)
3500.53
(1826.71)
24.59
(16.99)
0.52
(0.14)
4.01
(3.29)
ALI
0.88
(1.24)
0.33
(0.13)
25.82
(9.96)
84.39
(184.46)
269.44
(761.81)
465558.38
(1807.01)
1831.27
(1038.42)
51.90
(40.30)
4.26
(13.67)
2.35
(1.60)
335.67
(602.47)
22.29
(102.09)
<LOD
2.38
(2.63)
BUALA18.31
(6.17)
0.13
(0.09)
110.23
(8.86)
72.54
(49.32)
1071.67
(874.76)
460541.83
(4220.74)
1970.71
(681.84)
125.31
(110.66)
7.05
(5.43)
22.75
(12.41)
6379.06
(5526.08)
7.36
(8.64)
0.60
(0.22)
8.91
(8.32)
CDF13.27
(7.31)
0.17
(0.10)
56.50
(12.09)
540.92
(549.82)
2193.91
(2251.09)
450758.81
(23874.27)
20067.27
(36294.54)
169.79
(316.46)
4.67
(5.06)
4.69
(3.06)
1275.34
(1612.18)
12.97
(9.40)
0.48
(0.14)
8.26
(5.31)
CER
4.61
(4.50)
0.10
(0.05)
51.82
(35.29)
36.75
(17.33)
86.57
(57.56)
465523.30
(812.80)
2224.10
(1088.48)
48.64
(20.76)
1.47
(0.86)
2.63
(1.06)
423.16
(357.49)
2.09
(2.98)
<LOD1.77
(1.42)
FONT0.51
(0.50)
0.12
(0.07)
15.23
(15.26)
53.27
(85.14)
150.58
(378.11)
464611.60
(4537.01)
3874.76
(6705.12)
34.79
(35.11)
0.39
(0.63)
2.05
(1.45)
92.28
(164.39)
1.18
(1.16)
<LOD1.30
(0.95)
MONTG12.11
(7.13)
0.06
(0.05)
64.20
(19.49)
170.75
(201.75)
2265.64
(3007.38)
463293.49
(3830.70)
4537.03
(5195.78)
165.10
(91.51)
6.21
(8.41)
13.32
(10.56)
3549.10
(5357.62)
5.58
(2.69)
0.66
(0.19)
5.15
(7.82)
MONTS9.90
(4.15)
0.14
(0.05)
111.15
(22.63)
93.73
(47.67)
1355.81
(698.73)
464669.27
(1681.56)
2623.20
(991.31)
222.65
(145.78)
9.99
(6.99)
15.95
(9.55)
2348.13
(2110.58)
3.44
(1.21)
0.24
(0.06)
7.79
(6.76)
PERAL15.46
(5.67)
0.16
(0.07)
62.91
(9.51)
1346.62
(899.27)
3299.64
(1920.55)
421340.51
(34133.46)
61376.29
(51978.68)
246.92
(170.46)
8.45
(9.76)
7.49
(3.46)
2008.55
(891.10)
32.84
(19.50)
0.50
(0.36)
12.50
(9.48)
PC
7.13
(4.97)
0.23
(0.06)
43.78
(6.91)
173.01
(110.29)
964.58
(617.38)
461255.85
(5484.60)
7145.75
(7511.34)
153.24
(114.02)
2.33
(1.43)
4.65
(3.46)
371.80
(186.27)
2.75
(2.71)
0.36
(0.05)
2.10
(0.66)
VSSM
4.98
(6.67)
0.23
(0.20)
13.45
(12.67)
53.75
(91.50)
107.10
(143.79)
463422.66
(10089.95)
5340.28
(15386.86)
44.34
(32.81)
3.24
(10.65)
2.56
(1.11)
480.36
(772.90)
1.98
(1.20)
0.61
(0.14)
2.15
(2.57)
ZURI
2.53
(1.90)
0.10
(0.09)
37.62
(32.48)
254.65
(253.93)
483.61
(598.21)
457359.04
(15665.83)
13475.12
(23505.41)
96.67
(56.46)
3.24
(3.98)
4.19
(2.05)
708.36
(875.59)
3.59
(1.86)
<LOD
4.48
(4.41)
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Marta Sánchez de la Torre, Cynthia Belén González Olivares, Bernard Gratuze, François-Xavier Le Bourdonnec, Xavier Mangado:
Geochemical Study of Chert Artefacts from Xicotó Rockshelter (Ne Iberia) Archaeological Site. New Data on Neolithic and Mesolithic Human Occupations
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Table 3.
Median values and standard deviations (in brackets) for each geological outcrop with the nine elements quantifed by LA-ICP-MS in ppm. Data from archaeological samples can be found in the
Supplementary Raw Data fle. (
Continuation
)
VariableRbSrYZrNbCsBaLaCePrNdSmWBiThU
ALB1
16.61
(14.54)
293.41
(337.69)
1.32
(1.00)
10.62
(15.76)
1.58
(1.28
1.04
(0.97)
138.56
(224.35)
3.82
(5.27)
7.66
(10.59)
0.78
(0.97)
2.92
(3.45)
0.50
(0.43)
0.40
(0.26)
0.14
(0.12)
1.42
(1.39)
11.14
(9.07)
ALB2
13.67
(8.61)
326.29
(266.04)
2.17
(2.95)
8.81
(13.44)
1.48
(0.91)
0.87
(0.58)
117.61
(119.24)
2.70
(2.53)
5.88
(6.79)
0.61
(0.57)
2.37
(2.32)
0.50
(0.54)
0.26
(0.13)
0.09
(0.05)
1.21
(1.17)
4.43
(5.11)
ALI
0.66
(1.53)
7.82
(21.17)
0.07
(0.14)
0.34
(0.66)
0.19
(0.36)
0.07
(0.13)
100.54
(473.07)
0.12
(0.28)
0.74
(2.34)
0.06
(0.12)
0.12
(0.24)
0.04
(0.06)
4.45
(6.79)
0.24
(0.19)
0.05
(0.11)
58.20
(22.56)
BUALA
1.30
(0.97)
13.51
(8.12)
0.77
(0.60)
4.19
(1.62)
0.41
(0.22)
0.09
(0.09)
30.06
(43.72)
0.74
(0.49)
1.65
(1.07)
0.23
(0.15)
0.85
(0.58)
0.22
(0.15)
3.58
(8.55)
0.16
(0.07)
1.30
(0.58)
0.67
(0.17)
CDF3.40
(4.19)
61.91
(98.82)
0.47
(0.55)
2.75
(7.24)
0.48
(0.74)
0.20
(0.30)
57.07
(48.73)
0.61
(0.99)
1.31
(1.97)
0.15
(0.22)
0.52
(0.69)
0.13
(0.17)
0.57
(2.27)
0.11
(0.12)
0.35
(0.46)
54.04
(28.65)
CER0.35
(0.17)
2.09
(1.24)
0.11
(0.10)
0.30
(0.21)
0.17
(0.22)
0.06
(0.06)
8.36
(10.46)
0.13
(0.09)
0.38
(0.38)
0.08
(0.07)
0.16
(0.12)
0.06
(0.07)
4.32
(6.09)
0.31
(0.37)
0.05
(9.03)
2.97
(2.91)
FONT0.31
(0.56)
3.66
(8.24)
0.06
(0.07)
0.15
(0.18)
0.07
(0.10)
0.07
(0.08)
3.61
(3.83)
0.05
(0.08)
0.12
(0.21)
0.03
(0.03)
0.04
(0.05)
0.03
(0.03)
3.31
(7.91)
0.90
(2.31)
0.04
(0.04)
2.69
(2.73)
MONTG
3.65
(5.01)
34.91
(61.98)
1.51
(2.26)
2.29
(1.69)
0.43
(0.32)
0.25
(0.37)
51.20
(66.92)
1.26
(1.46)
2.54
(3.70)
0.30
(0.34)
1.26
(1.53)
0.30
(0.37)
1.04
(1.41)
0.26
(0.32)
0.46
(0.38)
0.25
(0.06)
MONTS3.10
(1.92)
7.74
(9.12)
0.97
(1.51)
4.10
(9.13)
0.62
(0.53)
0.25
(0.16)
15.70
(8.75)
2.19
(3.81)
2.31
(2.12)
0.51
(0.76)
1.86
(2.80)
0.34
(0.50)
1.13
(0.62)
0.21
(0.16)
0.74
(0.36)
1.02
(0.43)
PERAL6.00
(5.83)
399.93
(339.97)
0.58
(0.32)
2.87
(2.66)
0.62
(0.38)
0.83
(2.61)
158.78
(98.87)
1.20
(1.36)
2.43
(2.77)
0.25
(0.30)
1.07
(1.35)
0.20
(0.21)
2.20
(5.70)
0.20
(0.24)
0.51
(0.36)
4.54
(2.44)
PC
1.99
(1.24)
16.26
(14.33)
0.15
(0.10)
0.84
(0.66)
0.39
(0.47)
0.10
(0.07)
8.09
(5.74)
0.27
(0.24)
0.57
(0.42)
0.06
(0.04)
0.22
(0.16)
0.04
(0.03)
2.53
(6.64)
0.11
(0.08)
0.13
(0.07)
113.84
(32.64)
VSSM0.33
(0.13)
3.86
(9.65)
0.03
(0.05)
0.22
(0.16)
0.08
(0.04)
0.04
(0.03
6.98
(4.82)
0.05
(0.06)
0.11
(0.13)
0.03
(0.03)
0.06
(0.06)
0.03
(0.02)
3.11
(5.73)
0.31
(0.37)
0.03
(0.02)
11.44
(11.34)
ZURI
1.20
(1.32)
24.20
(28.59)
0.12
(0.10)
1.06
(0.83)
0.30
(0.19)
0.03
(0.14)
15.72
(8.79)
0.19
(0.17)
0.41
(0.05)
0.10
(0.09)
0.15
(0.12)
0.06
(0.05)
2.40
(3.86)
0.64
(0.49)
0.10
(0.08)
3.76
(4.31)
image/svg+xml
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Marta Sánchez de la Torre, Cynthia Belén González Olivares, Bernard Gratuze, François-Xavier Le Bourdonnec, Xavier Mangado:
Geochemical Study of Chert Artefacts from Xicotó Rockshelter (Ne Iberia) Archaeological Site. New Data on Neolithic and Mesolithic Human Occupations
111
Figure 6.
Results of Discriminant Analysis (DA) of the Be, B and values representing the evaporithic geological outcrops (circles) and the evaporithic
archaeological samples of Xicotó (triangle) with all the samples (top) and just the centroids (bottom).
image/svg+xml
IANSA 2022 ● XIII/2 ● 99–115
Marta Sánchez de la Torre, Cynthia Belén González Olivares, Bernard Gratuze, François-Xavier Le Bourdonnec, Xavier Mangado:
Geochemical Study of Chert Artefacts from Xicotó Rockshelter (Ne Iberia) Archaeological Site. New Data on Neolithic and Mesolithic Human Occupations
112
Figure 7.
Scatterplot for Ln Ti/Sr vs Ln Th/Sr representing all the marine geological outcrops (circles) and the marine archaeological samples of Xicotó
(triangle).
Garumnian facies of the Tremp Formation, outcropping
in the Pre-Pyrenean ranges. Moreover, the geochemical
analysis has established signifcant diferences between
outcrops, which has thus allowed the studied archaeological
artefacts to be connected with samples from the Vessant
Sud de Sant Mamet outcrop. This is the closest outcrop
to the site, being located less than 5 km to the north of
Xicotó. Probably because this chert type has a smooth
grain and its capability for knapping is not extraordinary,
human groups from the Middle Mesolithic also frequented
the chert outcrops from Castelló de Farfanya, in the Serra
Llarga Mountain Range, according to the geochemical study.
These outcrops are located at 25–30 km to the south-east of
Xicotó and have fne grains and high-knapping capabilities,
being the better-quality chert outcrops nearest to the site.
Moreover, the presence of two marine cherts in the Middle
Mesolithic occupation that seem to ft with the Montgaillard
chert outcrop, at more than 100 km distance in the northern
central Pyrenees, could indicate the existence of contacts
with northern groups. However, we need to be particularly
cautious with these results, as they are only two pieces of
evidence in an almost local lithic assemblage and other
possible explanations could be considered.
Taking into account that the geochemical analysis of
chert has only been developed with artefacts recovered from
the Middle Mesolithic unit, in further work we will try to
relate these results with other Middle Mesolithic sites from
the Pyrenean and Pre-Pyrenean region. The Notches and
Denticulates Mesolithic (also known as the Macrolithic
Mesolithic) has been attested in the southern Pre-Pyrenean
region, with similar procurement strategies as that observed
in Xicotó Rockshelter. Thus, in the level Ib of Forcas II
Rockshelter (Graus, Huesca), the Macrolithic Mesolithic is
represented by some lithic samples of local origin (Utrilla
and Mazo, 2014) and in the Peña 14 and Legunova (Biel,
Zaragoza) assemblages, the local cherts are heavily exploited
(García-Simón, 2018). Similarly, in the Western Pyrenean
site of Atxoste (Mendandia, Álava), the local cherts are
also predominant, the presence of more exogenous varieties
being largely anecdotal (Soto
et al.
, 2015). In the south-
eastern Pyrenees, the open air sites of Font del Ros (Berga,
Barcelona) and Sota Palou (Campdevànol, Girona) have also
revealed the main use of local materials for confectioning
the lithic assemblage (Terradas, 1995). A similar strategy
was also observed in the Mesolithic occupation of Balma del
Guilanyà (Navès, Lleida) (Martínez-Moreno
et al.
, 2016) and
the Pyrenean site of Balma Margineda (Aixovall, Andorra)
(Guilaine
et al.
, 2008). We are faced with groups that
culturally break with the previous lithic traditions, regarding
the technology, the typology and the provenance of the
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IANSA 2022 ● XIII/2 ● 99–115
Marta Sánchez de la Torre, Cynthia Belén González Olivares, Bernard Gratuze, François-Xavier Le Bourdonnec, Xavier Mangado:
Geochemical Study of Chert Artefacts from Xicotó Rockshelter (Ne Iberia) Archaeological Site. New Data on Neolithic and Mesolithic Human Occupations
113
lithic assemblage. During the Middle Mesolithic, it seems
clear that the local cherts were almost always sufcient for
confectioning lithic tools, regardless of the quality. Probably
due to new climatic and environmental conditions, the use
of wooden artefacts is strongly related to these changes.
Following this assumption, human groups would be forced
to adapt to the exploitation of this new environment, and
the changes in their lithic acquisition strategies would most
likely be a refection of these adaptations.
5. Conclusions
In this paper we have presented the archaeological sequence
revealed until now at Xicotó Rockshelter, as well as the results
of our analysis of the lithic raw materials. The archaeological
investigation has demonstrated that the site, at the very
least, was frequented by prehistoric human groups during
the Ancient Neolithic and the Notches and Denticulates
Middle Mesolithic periods. The nature of the lithological
assemblage has revealed that diferent activities took place
in each period. The study of the chert artefacts, however,
has presented similar results for both periods, with a main
source of the local cherts being from the Vessant Sud de Sant
Mamet outcrop and a regular source being from the Serra
Llarga Mountain Range (Castelló de Farfanya outcrop). The
presence of only two long-distance chert specimens in the
Mesolithic period could indicate that eventual contacts with
other groups may have existed. Forthcoming archaeological
research will help us to better understand this Mesolithic
occupation, as well as defne the existence of previous
human occupations at the site.
Acknowledgements
The research leading to these results has received funding from
the postdoctoral fellowship program Beatriu de Pinós, funded
by the Secretary of Universities and Research (AGAUR)
(Government of Catalonia) and by the Horizon 2020 program
Figure 8.
Location of the archaeological site of Xicotó and the diferent chert outcrops considered in the study. The largest circles correspond to the
frequented outcrops according to the geochemical data.
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Marta Sánchez de la Torre, Cynthia Belén González Olivares, Bernard Gratuze, François-Xavier Le Bourdonnec, Xavier Mangado:
Geochemical Study of Chert Artefacts from Xicotó Rockshelter (Ne Iberia) Archaeological Site. New Data on Neolithic and Mesolithic Human Occupations
114
of research and innovation of the European Union under the
Marie Skodowska – Curie grant agreement No. 801370, held
by M. Sánchez de la Torre. Archaeological works have been
supported by the University of Barcelona and the project
CLT009/18/00030 from the Catalan Government. This study
was also fnancially supported by the Spanish project by
the Spanish project PID2020-113960GB-I00, the French
National Research Agency (ANR) (Grant No. ANR-10-
LABX-52) and the project “The chronology of the Prehistory
in NE Iberia” from the PALARQ foundation.
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