View of the excavation of the bow area of
the Ilovik-Paržine 1 shipwreck. In the foreground, the cargo of logs and
amphoras can be seen. Archaeologists are working near the structure of the bow
complex. Credit: Adriboats L. Damelet, CNRS/CCJ
Ever since humans have embarked on
sea voyages, they needed to ensure vessels were waterproof, resistant to salty
seawater, and could withstand microorganisms or sea-dwellers like worms. Until
the mid-20th century, however, the study of non-wood materials used to build
ships was overlooked. Even today, little work has been done on materials used
for waterproofing.
Now, in a new Frontiers in
Materials study, researchers in France and Croatia have examined the
protective coating of the Roman Republic shipwreck Ilovik–Paržine 1 that sank
around 2,200 years ago off the coast of what is now Croatia.
"In archaeology, little
attention is paid to organic waterproofing materials. Yet they are essential
for navigation at sea or on rivers and are true witnesses of past naval
technologies," said first author Dr. Armelle Charrié, an archaeometrist at
the Laboratory of Mass Spectrometry of Interactions and Systems in Strasbourg.
"Studying the coatings, we
found two different kinds on this vessel: one made of pine tar, also called
pitch, and the other of a mixture of pine tar and beeswax. Analysis of pollen
in the coating made it possible to identify the plant taxa present in the
immediate environment during the construction or repairs of the ship."
Resin and wax
The wreck was discovered in 2016
and since then the ship itself and its cargo has been examined multiple times.
The current study, however, is the first to combine pollen and molecular
analyses to
characterize the ship's coating and vegetation present during its production
and application on the hull.
The work is a collaboration between
the Department for Underwater Archaeology of the Croatian Conservation
Institute and the "ADRIBOATS" program of the Center Camille Jullian
at Aix-Marseille University in France.
"Some regions throughout the
Adriatic have particular characteristics that led local populations to develop
a specific shipbuilding style," said Charrié. "Only studies like ours
offer an overview into these traditions which bear witness to genuine know-how
and diverse traditions."
To examine the coatings,
researchers carried out structural, molecular, and pollen analyses using
techniques that identify and quantify unknown components in an organic mixture,
such as mass spectrometry.
Using 10 coating samples, the team
identified the biological origin of natural substances used for the ship's
coating by molecular analysis. This molecular fingerprint analysis showed
molecules characteristic of pine trees, indicating that the main component of
all coating samples was heated coniferous resin or coniferous tar, also called
pitch.
One sample, however, showed that at
least some of the coating was made from a different composition of materials,
namely beeswax and tar. This mixture—known to Greek shipbuilders as
zopissa—improves the adhesive's flexibility and is easier to apply when hot.
Trapped in pitch
Pitch is adhesive by nature and can
trap and preserve pollen from the surrounding landscapes. Analyzing these
traces and their respective abundances allowed the researchers to narrow down
possible regions where the pitch could have been produced and reapplied during
refurbishments.
Pollen from coating samples from
the Ilovik–Paržine 1 reflected a high diversity of environments. The identified
landscapes included those characteristic of the Mediterranean and Adriatic
coasts and valleys, with forests of holly oak and pine as well as matorral—a
kind of Mediterranean shrubland—where olive and hazel trees grow.
The presence of alder and ash
points to vegetation growing close to rivers and seashores, which can be found
near the coast or in the nearby hinterland. Fir and beech were present in small
proportions, too. This vegetation is found in mountainous regions and is
typical of the north-eastern coastal regions of the Adriatic Sea, where the
mountain ranges of Istria and Dalmatia are not far.
The team's findings also indicated
that the ship likely underwent four to five distinct batches of coatings. The
ship's stern and central part were covered by the same coating, whereas three
batches at the bow were distinct from one another. This, too, could indicate
that the ship was patched up successively using materials sourced from various
locations throughout the Mediterranean.
Previous research using the ship's
ballast identified Brundisium—today Brindisi—on the south-eastern coast of
Italy as the ship's place of construction. Pollen analysis also suggests that
some of the coatings were applied close to there. Other coating layers,
however, could have been applied on the north-eastern Adriatic coast, where the
shipwreck was discovered.
"While it seems obvious that ships sailing long distances need repairs, it's simply not easy to demonstrate this," concluded Charrié. "Pollen has been very useful in identifying different coatings where the molecular profiles were identical."
Provided by Frontiers
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