Golubinsky Proval, often translated as the "Funnel of Golubino" or "Golubino Sinkhole," is a prominent karst cave located in the Pinezhsky Nature Reserve in Arkhangelsk Oblast, northern Russia. Situated near the village of Golubino on the right bank of the Pinega River, it lies approximately 188 km northeast of Arkhangelsk along the road to Mezen and about 17 km downstream from the town of Pinega. This cave is part of the expansive Golubino karst area, which hosts around 385 caves with a combined passage length of roughly 120 km, making it one of the largest karst systems in Europe. The region is characterized by its remote taiga forests, river valleys, and unique subterranean features, drawing adventure seekers, geologists, and nature enthusiasts.
Golubinsky Proval is a classic example of gypsum karst, formed
through the dissolution of Permian gypsum and anhydrite bedrock by
groundwater over millions of years. The Pinega karst landscape,
including this cave, developed in a thick layer of evaporite rocks,
similar to other gypsum cave systems in Russia and Ukraine. The cave's
structure reflects multiple stages of erosion and hydrological activity,
with three distinct tiers of passages indicating phased development. The
roof lies 17 to 37 meters below the surface, and the cave is
predominantly dry, though it features two short watercourses: a northern
one about 30 meters long and a southern one about 20 meters.
Water-mechanical sediments, such as clays and sands deposited by ancient
streams, are common, contributing to the cave's textured floors and
walls.
The cave's cold climate plays a key role in its geology,
acting as a "cold trap" where frigid air accumulates, leading to
perennial ice formations. These include frost-covered walls in the outer
passages (where temperatures hover near zero degrees Celsius), ice
crystals that sparkle like rays piercing the air, and frozen "streams"
that appear to spill from cracks in the grottos onto the ceilings.
Gypsum speleothems of freezing origin, such as needle-like "yozh"
(hedgehog) formations, are also present, formed by sublimation and
recrystallization processes in sub-zero conditions. Detached stone
layers in some sections give the illusion of movement, resembling
enormous snake tongues frozen in place, while the overall environment
creates an "inverted" perception of space and time due to the echoing
sounds of hidden brooks in otherwise silent rock.
The cave was formed as a result of karst processes in a layer of
Permian gypsum with interlayers of anhydrite. These rocks were dissolved
by groundwater over millions of years, leading to the creation of
underground cavities. The cave's structure reflects several stages of
erosion and hydrological activity: it has three levels of passages,
indicating its gradual development. The cave roof is located at a depth
of 17–37 m from the surface. Most of the cave is dry, but it contains
two short watercourses (northern – about 30 m, southern – about 20 m).
The cold climate of the region makes the cave a "cold trap" for frosty
air, leading to the formation of permanent ice formations: ice-covered
walls, ice crystals, frozen "streams," and gypsum speleothems, such as
needle-like "hedgehog" formations, arising from sublimation and
recrystallization at negative temperatures. Sediments, such as clays and
sands from ancient streams, create textured floors and walls. Unlike
humid caves with stalactites, cryogenic speleothems and deposits prevail
here.
Cave Description
The entrance to the cave is an
impressive collapse valley – a large funnel-shaped depression, from
which the name "Proval" (Collapse) originates. Visitors descend via
wooden ladders and ramps into the first hall, known as Santa Claus
Cavern, approximately 9 m high and 15x20 m wide, covered with thick
layers of ice on the floor and walls, creating a winter atmosphere. From
here, horizontal passages branch out, some of which require crawling or
bending. They lead to wider halls and multi-tiered galleries, ending in
a siphon. Among its features are erosional formations such as scalloped
ceilings created by water flows, ice-covered surfaces, and acoustic
effects from dripping water and underground streams. The cave is
relatively accessible compared to vertical shafts, but requires special
equipment: camouflage clothing, rubber boots, and helmets with
headlamps.
Regional Geological Context
The Golubinsky sinkhole is located on
the right bank of the Pinega River, approximately 16.5 km downstream
from the village of Pinega, near the escarpment of the White Sea-Kuloy
Plateau. It is part of the Pinega karst massif, which is one of the
largest areas of sulfate karst in European Russia. The Pinega region
occupies about a quarter of the area of the Arkhangelsk region and is
characterized by a unique combination of geological factors:
Geological structure of the plateau: The White Sea-Kuloy Plateau is
composed of sedimentary rocks of Permian age (Permian system,
approximately 299–252 million years ago). The main karst-forming rocks
are sulfates: gypsum (CaSO₄·2H₂O) and anhydrite (CaSO₄), with
interlayers of dolomites (CaMg(CO₃)₂) and limestones. The thickness of
these deposits reaches hundreds of meters, formed in ancient marine
basins. Above them lie Quaternary deposits (sandstones, clays,
moraines), formed during the glacial period (Pleistocene, about 2.5
million - 11 thousand years ago), which partially mask the karst forms.
Influence of tectonics and hydrology: The area is subject to weak
tectonic activity, with cracks and faults that facilitate water
penetration. Groundwater, enriched with carbon dioxide (CO₂) from the
atmosphere and soils, actively dissolves sulfate rocks. This leads to
the formation of underground cavities. The region's climate (subarctic,
with long winters and abundant precipitation - up to 600 mm per year)
contributes to intensive karst formation, especially during the spring
and autumn periods, when snow melts and water infiltration increases.
Stages of karst denudation: In the Pinega region, karst is developed at
different stages – from covered (where the rocks are covered with
insoluble deposits) to open (where the gypsum is exposed). This is
manifested in the variety of relief forms: sinkholes, collapses, ravines
(deep gorges with waterfalls), hollows (closed depressions), and
underground rivers. The reserve has about 140 caves, as well as hundreds
of lakes of karst origin.
The Pinega karst is unique in that it
combines sulfate (dominant) and carbonate types. Sulfate rocks are less
stable than carbonate rocks (limestones), so the caves here are more
susceptible to collapse and deformation.
Processes of formation
of the Golubinsky sinkhole
The cave was formed as a result of classic
karst processes typical of sulfate rocks:
Dissolution
(corrosion): The main mechanism is the chemical dissolution of gypsum
and anhydrite by water containing CO2. Reaction: CaSO₄·2H₂O + H₂O →
dissolved ions. This occurs in the phreatic zone (below the groundwater
level) and the vadose zone (above, where water seeps). The processes
began millions of years ago, in the post-Permian period, but intensified
after the retreat of glaciers (Holocene, the last 11 thousand years),
when surface water runoff increased.
Mechanical processes: After
dissolution, the voids expand due to erosion, roof collapses, and
gravitational movement of rocks. The entrance to the cave is a
sinkhole-funnel measuring 7.5 × 12.5 m, formed by the collapse of the
vault. Such sinkholes are typical of the Pinega region and are often
associated with underground rivers.
Hydrological role: The cave has
two short watercourses, but most of it is dry. The water comes from the
Tarakan'ya Shchel (Tarakan'y Log) ravine, where the entrance is located
20 meters above the bottom. The groundwater is connected to the Pinega
River, forming a drainage system.
Overall, the formation of the
cave is the result of a long-term interaction of hydrology, chemistry,
and mechanics, with peak activity in the post-glacial period.
Cave Structure and Morphology
Dimensions and parameters: Length –
1622 m, area – 5267 m², amplitude (height difference) – 17 m. This makes
it one of the largest in the region.
Internal structure: The cave is
three-tiered, with height differences between the tiers ranging from 2.5
to 4.5 m. The roof (upper part) is located at a depth of 17–37 m from
the surface. The passages are labyrinthine, with meanders (winding
passages), vertical shafts, and scree slopes. The walls are decorated
with speleothems: gypsum "flowers," stalactites, stalagmites, and
draperies formed from secondary deposits.
Microclimate: The
temperature is stable (+4…+6°C), humidity is about 100%. This creates
conditions for the preservation of formations, but also contributes to
further dissolution.
Seismogeodynamics: Recent studies (2025) show
that the cave is subject to micro-pulses from stresses in the rocks,
which can lead to collapse. Sensors record the accumulation of stresses
in the gypsum massifs.
History of Study and Protection
The
study of the Pinega karst, including the Golubinsky sinkhole, began in
the 19th century:
1837–1911: First descriptions by geologists such as
I. E. Repinsky and E. Toll, focusing on surface formations. 1918–1969:
Soviet expeditions, mapping at a scale of 1:1,000,000, documentation of
caves.
1970–present: Detailed maps (1:200,000), monographs on
hydrogeology. The sinkhole became a "milestone" in research after the
discovery of the crater in the 1840s.
The cave has been closed to
general public access since 2022 due to instability, but is used for
scientific and guided tour purposes within the nature reserve. This
highlights the fragility of the sulfate karst.
The cave is open year-round with no entry fees or restrictions, but
guided tours are recommended for safety and are organized through the
Golubino Tourist Complex or local operators. Visitors are provided with
protective gear, including camouflage suits (often repurposed military
attire), rubber boots, gloves, helmets, and headlamps—essential for the
muddy, cold, and uneven terrain. Tours typically last 1-2 hours and
involve moderate physical activity, such as descending ladders and
navigating tight spaces. An extra fee (around 400 rubles as of recent
reports) may apply for the outfit.
The best time to visit is winter,
when ice formations are at their peak and the frozen ground makes access
easier. To reach it, take a bus from Arkhangelsk to Pinega (about 4-5
hours), then arrange local transport or join a tour to Golubino.
Alternatively, trains go to Karpogory on the Pinega River, followed by
bus or taxi. Be prepared for sub-zero temperatures inside, even in
summer, and note that the cave is undeveloped beyond basic stairs—no
lighting or paths.
Golubinsky Proval is embedded in a broader natural and cultural
landscape. The Pinezhsky Reserve offers hiking, white-water rafting on
the Pinega River, fishing, camping, and mountaineering. Nearby, the Holy
Spring waterfall and other caves like Malaya Golubinskaya and
Pekhorovsky Proval provide additional exploration opportunities.
Krasnaya Gorka (Red Hill), the highest point in Arkhangelsk Oblast,
features alpine skiing, the ruins of Krasnogorskiy Bogoroditskiy
Monastery, and panoramic views. Accommodation is available at the
Golubino Forest Hotel, making it a base for multi-day adventures.
Scientifically, the cave contributes to studies of gypsum karst and
cryogenic speleogenesis, highlighting how climate influences
subterranean features in northern latitudes. For visitors, it offers an
immersive experience of Russia's wild north, blending geological wonder
with the thrill of underground exploration.