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Proceedings of the 17th International Congress of Speleology 31
“Fatuk-Kuak Hosi Timor Lorosa’e”: Caves of Timor-Leste
Freire, M.1, Pinto, P.2, Soares, M.3, Medeiros, S.4, Reboleira, A.S.P.S.1,5, Reis, A.2, Gomez, M.6
Aliation: 1NEUA – Núcleo de Espeleologia da Universidade de Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro,
Portugal, neua@neua.org
2LPN-CEAE – Liga para a Protecção da Natureza - Centro de Estudos e Actividades Especiais, ceae@lpn-espeleo.org
3CIES – Centro de Investigação e Exploração Subterrânea, cies-espeleo@myspeleo.com
4GPS – Grupo Protecção Sicó, gps.sico@gmail.com
5Natural History Museum of Denmark, University of Copenhagen, Universitetsparken 15. DK-2100 København Ø,
Denmark, sreboleira@snm.ku.dk
6SUMMA – Servicio de Urgencia Médica de Madrid, genigor@movistar.es
Abstract
Timor-Leste (formerly East-Timor) is one of the youngest nations in the world. Partly because of its troubled recent history, this
small Southeast Asian country nowadays remains one of the least explored as far as speleology is concerned. With a total area of
15,000km2, a high percentage of the country’s territory is limestone and it hosts one of the largest poljes in the world.
In September, 2016, the “Fatuk-kuak hosi Timor-Lorosa’e” project (Caves of Timor-Leste), created by four Portuguese caving
clubs and joined by the only Timorese caving club, made its rst expedition to Timor-Leste, briey visiting some of its karst
areas. During the month long expedition – carried out under the auspices of the International Union of Speleology (UIS) and the
Portuguese Federation of Speleology (FPE) – more than 50 caves were registered in the districts of Ainaro, Baucau, Lautém and
Viqueque.
e major highlights are: i) Bakua cave; this 650m long, 197m deep sink near Maubisse is the country’s longest and deepest cave
to date. e Biribui spring cave, the system’s most probable resurgence point, lies roughly 800m away and 350m below; ii) e
polje of Lake Iralalaro, one of the largest in the world, continuously drains its water through the Irasiquero River, which sumps
aer 3.5km at the (yet impenetrable) Mainina sink. e resurgence of this system is unknown and probably lies at the ocean bed,
no less than 4km away; and iii) the rst biospeleological survey, providing new species for science and the discovery of a rich
biodiversity in these tropical caves.
Access remains an obstacle to visiting some areas of the country, so some of the karst with the most potential for caves is yet to be
visited. e “Fatuk-kuak hosi Timor-Lorosa’e” project will return annually, to continue exploration and support the development
of Timorese speleology.
Keywords: Timor-Leste, caves, biospeleology
1. Introduction
In 2016, four Portuguese caving clubs, Núcleo de Espeleologia
da Universidade de Aveiro (NEUA), Liga para a Protecção da
Natureza – Centro de Estudos e Actividades Especiais (LPN-
CEAE), Centro de Investigação e Exploração Subterrânea
(CIES), and Grupo Protecção Sicó (GPS), organized an
expedition to Timor-Leste. e main objectives were to visit
some of the major limestone areas and start an inventory of
caves and karst springs in the districts of Ainaro, Baucau,
Lautém and Viqueque (Fig 1). Topographic surveys of the
caves were made whenever possible. Additionally, education
sessions were given in some schools, to raise awareness for
the protection of caves, springs and other karst landforms.
Finally, we strived to nurture Timorese speleology, which is
now taking its rst steps.
2. Timor-Leste
e Democratic Republic of Timor-Leste is one of the youngest
nations in the world, having achieved its independence on
May 20th, 2002. It comprises the eastern half of the island
of Timor in the Malay Archipelago, having an area of about
15,000 km2. Also part of the country are the coastal enclave
of Oecussi-Ambeno located in West Timor and the islands of
Ataúro and Jaco.
e capital city, Dili, is located on the North shore and the
ocial language is Portuguese. However, Tetum is the most
spoken language across the country’s territory.
Timor-Leste’s climate is tropical with two seasons, rainy and
dry. Due to the island’s mountainous geography the seasons’
timings aren’t the same everywhere, being September the last
dry month common to the entire Timorese territory. is fact
weighed heavily in the choice of the timing of the expedition.
e administration and management of Timor-Leste’s under-
ground resources (including caves) falls under the scope of
the Ministry of Petroleum and Mineral Resources. In the
municipality of Lautém, the Nino Konis Santana Natural
Park, is managed by the Ministry of Agriculture and Fisheries.
3. Timor-Leste’s geology
ompson (2011) provides an excellent introduction to
the geology of Timor-Leste: “e island of Timor sits at the
eastern end of and just south of the archipelago of volcanic
islands, the Banda Arc, running eastwards from the Indo-
nesian island of Bali. is volcanic arc is the surface expres-
sion of lithospheric subduction currently taking place as the
Australian crustal plate moves north eastwards towards and
underneath the Eurasian plate.
32 Proceedings of the 17th International Congress of Speleology
However, for the last 5 million years or so that subduction has
become ‘locked’ in the Timor region thereby causing the island
of Timor to be thrust upwards as the only relief mechanism
available as the two crustal plates continue to converge. In
layman’s language, Timor is going up like a ‘Geological Cork’
at the extreme north eastern edge of continental Australia.
Structurally, the rocks on Timor belong to the Australian
plate with basement rocks (Lolotoi Complex) uplied as the
mountainous spine of the island. e results of the continental
collision, leading to immensely deformed, sheared and
thrusted lithologies are seen along the north of the island in
the syn-collisional metamorphic rocks of the Aileu Complex.
Younger, Mesozoic sediments lie in structurally controlled
basins on top of these basement lithologies and Plio-
Pleistocene to recent reefal limestones continue to be laid
down and uplied in syn/post orogenic basins on and around
the periphery of the island.” e Baucau Plateau and the
easternmost tip of the island, near Tutuala, are examples of
these reefal limestones and were visited during this expedition.
ompson (2011), continues: “e overall geological
engine behind the creation of Timor is extreme upli due
to the ‘locked’ continental collision. is is reected in the
mountainous nature of the island and the chaotic geology
with the island broken into an immense number of thrust and
uplied structural units. Soer sediments, shales, sandstones
and bedded limestones for example are sheared, crushed and
folded into complex and contorted lithologies. e more
massive reefal and marine limestones however are strong
enough to have maintained their integrity and have been
literally pushed up through the geological mélange in huge
up-thrust slices as seen at Cablac and Matebian for example
and elsewhere throughout the central spine of the island.” e
Mount Fatubessi limestones near Maubisse, visited during
this expedition, are yet another example of these up-thrust
slices.
3.1. Previous speleological exploration
Timor-Leste’s speleology is still in its infancy. Records
are scarce and most published cave references pertain to
archeology and paleontology expeditions.
e only previous specically speleological incursions in
Timor-Leste we’re aware of are:
1) Australian expedition in 2005, by S. White, N. White and
G. Middleton (White et al, 2006);
2) John Brush’s (Canberra Speleological Society) work, as
a member of the archaeological expedition led by Prof. Sue
O’Connor in June, 2009;
3) British expedition in 2014, by P. Talling, F. Loveridge, C.
Densham, A. Chapman, J. Wade and B. Wright.
More recently, a nature activities club from Dili named
Juventude Hadomi Natureza (JHN) founded a small caving
group. When we learned about them, we made contact
and they were straightaway welcomed aboard. Having only
exchanged a few emails with the JHN folks before our arrival,
we spent little time getting acquainted before heading out to
the countryside.
4. e 2016 expedition
e expedition took place between September 3rd and
October 2nd and was ocially supported by the International
Union of Speleology (UIS) and the Portuguese Federation of
Speleology (FPE). Locally, a partnership with the Universidade
Nacional Timor Lorosa’e (UNTL) was an invaluable asset.
A few days were spent in Dili for ocial contacts and logistical
preparations. en we visited the four targeted districts in this
sequence: Ainaro, Baucau, Lautém and Viqueque.
4.1. Ainaro District
In this district work was limited to the area of Mount Fatubessi,
5 km to the northeast of the town of Maubisse.
Figure 1. Map of the districts of Timor-Leste
Proceedings of the 17th International Congress of Speleology 33
Figure 2. Map of Bakua cave in Maubisse
Figure 3. Extended prole of Bakua cave.
34 Proceedings of the 17th International Congress of Speleology
e most signicant cave so far is a sink at the end of a blind
valley with a small stream (dry at the time of the expedition).
e cave was discovered and explored by the British expedition
of 2014 to a depth of -125 m. Beyond this point the passage
gets higher and wider and continues so, down to -197 m. Near
that depth, a small stream runs even in this dry season.
e survey now totals 643 m, but many passages are yet to be
explored. is sink cave, called Bakua (also known as Petrem,
in the 2014 expedition), lies less than 1 km away from the
escarpment that limits the limestone to the North.
Even though the cave develops mainly to the southwest, it is
expected to turn north towards the base of the escarpment.
Locals guided us to the probable resurgence, a spring cave
called Biribui, roughly 350 m below. We explored and surveyed
a horizontal passage for about 100 m, until we reached a high
gallery, but climbing gear was needed to progress further in.
Going back up the escarpment, the guides showed us two
horizontal caves located at dierent altitudes, which were used
as refuge by local people during the Indonesian occupation of
the country. Despite the galleries being choked aer a short
while, we were impressed by their width and height, close to
decametric dimensions. ese were probably ancient base
level resurgences, as the limestone block was being pushed up
by tectonic upli forces.
With future exploration in Bakua sink (which is to our
knowledge the longest and deepest cave in Timor-Leste) along
with Biribui spring and also in other cave shas that were
located but not explored, a good chance exists of revealing a
relatively large system with several km of development and up
to 500 m total depth, if the highest entrances can connect to
the lowest, Biribui.
In total, 20 cave entrances were registered in this area, but not
all of them were explored.
4.2. Baucau District
Aer Maubisse, the expedition moved to the reefal limestones
of the plateau of Baucau.
e team visited and mapped several caves: Lilawy Cave, a sink
in the vicinity of Kairiri; Wai-lia-bere and Wai-lia-mata, two
caves near Darasula that provide access to the plateau’s aquifer;
Lilawehú, an ancient resurgence cave near Karavela. We also
spotted several caves and shelters in the escarpments near
Ossowa, and visited the Baninau doline, which has a diameter
close to one km. In total, 9 caves and springs were registered.
4.3. Lautém District
In this district, the team divided their time by two areas: the
Paitchau range and the coastal karst near Tutuala.
e Paitchau range marks the southern limit of Lake Iralalaro.
is lake, with an area that uctuates seasonally between 10 –
55 km2, is contained inside a very large polje, which as an area
of about 100 km2, with 406km2 entirely contained as internal
drainage (White et al, 2009). e water from Lake Iralalaro
drains south via the Irasiquero River and sinks aer roughly
3.5 km, at the Mainina sinkhole.
No resurgence is yet known and the shortest distance to the sea
(in a straight line) is no less than 4 km to the southeast, over
the Paitchau range. At the sinkhole, a huge pile of boulders
blocks the way into a possible cave gallery. We managed to
progress between the boulders for more than 20 m, but it got
too narrow to continue further in.
As far as we know, the Irasiquero never dries, which is not
surprising with such a wide area draining to the lake at the
center. However, there are no open streams at the surface in
the dry season, so all the water that streams into the polje
ows underground.
Near the southwestern edge of the polje, two caves were
visited: Kuronohonoho sinkhole, which has very high levels
of CO2 blocking any exploration attempt, and the Puropoko
cave that carries an active stream in it. is cave was explored
upstream until a boulder choke was reached. Downstream,
153 m were mapped, but once again the presence of CO2
limited the exploration. e stream inside Puropoko ows
towards the Iralalaro Lake, even though the cave lies 6.5 km
away from the lake’s boundary.
Tutuala is probably the Timorese area with the most published
cave references, due to the several archeological studies made
there. e archeological sites are in general small caves and
shelters, but we visited some interesting caves like the ponor
Lenetulu, with 170 m of extension, 51 m depth. Its main
gallery is impressive, as it is more than 10 m wide.
In both the Paitchau range and the Tutuala coast, 18 caves
were registered.
Figure 4. Map of Biribui cave, in Maubisse.
Proceedings of the 17th International Congress of Speleology 35
4.4. Viqueque District
Only two days were spent here, in the vicinity of Ossu, which
allowed us to register 5 caves. On the rst of those days, for
lack of a guide, the team made a reconnaissance hike up
Mount Mundo Perdido.
On the second day, now accompanied by a local guide, the
team went south of Ossu, and were led to an impenetrable
sink, a ri cave and an open sink. e ri cave, called Kaisahe,
is home to a colony of fruit bats and was explored down to
-30 m, at which level the ri widens into a small horizontal
passage, about 25 m long, without further continuation. e
ri should be explored horizontally at entrance level (traverse
line needed), but we couldn’t for lack of equipment. e
open sink, called Lunaha Mana, starts as an 8 m wide, 18 m
deep sha, and continues down through a series of narrow
steps until reaching a larger down-sloping passage at -40 m.
Although the way ahead was open, the exploration and survey
were cut short due to rainfall: the probability of a ash ood
was low but we just wouldn’t risk it. Aer all, it was our rst
visit to the country and we were warned about how fast dry
river beds change into high ow rivers in Timor-Leste.
4.5. Cave biology
During our expedition an ad-hoc sampling using direct
prospection of cave invertebrates was performed. Only
the cave-adapted fauna of East-Timor was studied and it is
hitherto composed of arachnids, crustaceans and insects.
Whip spiders (Amblypigydi), shorttailed whipscorpion
(Schizomida), amphipods (Amphipoda), centipedes
(Chilopoda), decapods (Decapoda), cockroaches (Blattodea)
and water beetles (Dytiscidae), contribute to the troglobiont
and stygobiont fauna of the country. Ongoing taxonomics
study reveals the existence of new species for science. We
also registered the presence of the wide dispersed species
of millipedes: Chondromorpha xanthotricha (Attems, 1898)
andCylindroiulus hirsutus (Pocock, 1889) in caves of the
province of Baucau and the presence of the coconut crab,
Birgus latro (Leach, 1816), in caves of the Tutuala region
(Figure 6).
5. Conclusions
In total, 50 caves, sinkholes and springs were registered in
the four districts that were visited. e surface has only been
scratched, in terms of speleological exploration in Timor-
Leste. e data collected in areas like Maubisse, the Paitchau
range and Ossu, for example, points to cave systems much
larger than seen so far. Other, less accessible, major limestone
areas in the country are yet to be visited.
e young speleologists of Timor-Leste will continue to
gain experience by taking part in future expeditions, as the
“Fatuk-kuak hosi Timor-Lorosa’e” project returns annually.
In areas like the Baucau plateau, where the aquifer lies at
a very low depth, pollution is a real problem, especially
considering that this aquifer is the sole provider of freshwater
to the second largest city in Timor-Leste.
Figure 5. Mainina sinkhole (Photo: A. Reis)
Figure 6. Specimens of the coconut crab in caves of Timor-Leste
(Photo: M. Soares)
36 Proceedings of the 17th International Congress of Speleology
In a country that struggles to provide quality freshwater
to its population all year round, the knowledge of caves,
their underground waters and springs is indeed valuable
information.
Acknowledgements
e team would like to thank the following persons and
institutions, without whose help this expedition would not be
possible: Portuguese embassy in Timor-Leste, Universidade
Nacional Timor Lorosa’e, Universidade de Aveiro, Fundação
Oriente, Vodacabo, SA, Câmara Municipal de Pombal, the
UIS, the FPE, Geiza Marques d’Oliveira, Graça Viegas, Miguel
Ferreira, Henrique Peixoto, Pete Talling, Fleur Loveridge,
Greg Lauer, Joe Sydney, Greg Middleton, Tim Anderson, Dr.
Nuno Oliveira, Raul Pedro, the people of Timor-Leste and
everyone at JHN.
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