2. INTRODUCTION
The name “Yehliu” was derived from:
1. A term translated from the Pinpu language
2. An abbreviation of the Spanish words “Punto Diablos (“devil’s cape”)
3. In early days, local residents earned their living at sea and they relied on rice
suppliers from inner land to offer rice to them. During transportation, some local
people would use the sharp bamboo tube to stick the rick sack and leave a hole on it,
so that the rice may slip out and could be picked up by them. As a result, rice traders
often mentioned “the rice was stolen by the savages” (whereas “steal” and “savage”
are pronounced similar to Yeh (savage) and liu (steal) in Taiwanese).
Yehliu is located at Wanli of
Taipei County with a long cape.
Because the rock layer of nearby seashore contains
limestone subject to sea erosion, weathering and earth
movements, Yehliu is full of seawater-eroded holes as
well as numerous rocks in the shape of mushroom,
candle, ginger, and chessboard.
3. INTRODUCTION
The rock landscape of Yehliu Geopark is one of most famous wonders in
the world.
The costal line is stretching in a direction vertical to the layer and the
structure line - besides, the influences caused by wave attack, rock
weathering, earth movement and crustal movement all contribute to the
formation of such a rare and stunning geological landscape.
Yehliu Geopark is divided into three areas, each containing different
types of landform features.
Yehliu Geopark is famous for its sea-erosion landscape, while most of the
spots are very close to the sea
4. SIX DIFFERENT TYPES OF
LANDFORM FEATURES
1) Hoodoos
2) Pedestal Rocks
3) Ginger rocks
4) Honeycomb Rocks
5) Tafoni
6) Mushroom Rocks
6. GEOLOGICAL PROCESSES
1) Hoodoos
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Hoodoos typically form in areas where a thick layer of a relatively soft rock, such as mudstone, poorly cemented
sandstone or tuff (consolidated volcanic ash), is covered by a thin layer of hard rock, such as well-cemented
sandstone, limestone or basalt.
In glaciated mountainous valleys, the soft eroded material may be glacial till with the protective capstones being
large boulders in the till.
Over time, cracks in the resistant layer allow the much softer rock beneath to be eroded and washed away.
Hoodoos are formed where a small cap of the resistant layer remains, and protects a cone of the underlying
softer layer from erosion.
Further erosion of the soft layer causes the cap to be undercut, eventually falling off, and the remaining cone is
then quickly eroded.
Typically, two weathering processes that continuously work together in eroding the edges of a rock formation
form most hoodoos. The primary weathering force is frost wedging.
In the winter, melting snow, in the form of water, seeps into the cracks and then freezes at night. When water
freezes it expands by almost 10%, pries open the cracks bit by bit, making them even wider, much like the way in
which a pothole forms in a paved road.
In addition to frost wedging, rain also sculpts these hoodoos.
In most places today, the rainwater is slightly acidic which allows the weak carbonic acid to slowly dissolve
limestone grain by grain. It is this process that rounds the edges of hoodoos and gives them their lumpy and
bulging profiles.
Where internal mudstone and siltstone layers interrupt the limestone, you can expect the rock to be more
resistant to the chemical weathering because of the comparative lack of limestone.
Many of the more durable hoodoos are capped with a special kind of magnesium -rich limestone called dolomite.
Dolomite, being fortified by the mineral magnesium, dissolves at a much slower rate, and consequently protects
the weaker limestone underneath it.
7. GEOLOGICAL PROCESSES
2) Pedestal rock:
Two broken concretions within rock layers
are formed vertical to the sea level; as a
result, the erosion caused by seawater may
progress along the concretions, leading to
the formation of stone pillar lining up in
row.
3) Ginger rock:
Since the rock layer contains irregular
concretions within, the harder concretions
may raise above the ground while the
softer ones may descend downward as
erosion imposes upon the rock.
The formation of mushroom rock is caused The surface of the hard concretion may
by differential erosion as the top rock layer
become rough and uneven as it is exposed
containing calcium and being more durable
to the atmosphere and having direct
for erosion than the lower rock layer.
contact with the wind and the sea.
The mushroom rock as formed is under The interlacing patterns as shown on the
continuous plate extrusion and thus is
surface of ginger rock are the result of
raised above sea level. Once it’s exposed to
crust extrusion occurred underground.
the planet’s atmosphere, it will suffer from These patterns as shown are called “joints”
weathering as well as rain erosion and turn
in Geology.
into the shape as we see it now
8. GEOLOGICAL PROCESSES
4) Honeycomb rocks:
5) Tafoni:
Honeycomb rock forms in three stages,
and is caused by nodules composed of
organic detritus:
The rock is full of nodules composed of
organic detritus, including debris from
mollusks and sea urchins. As the rock
dissolves away, or crumbles due to the
effect of weathering, the nodules
exposed on the surface are transformed
into many small pits.
Salt from seawater continue to eat away
at the rock, gradually expanding the
small pits and forming the current
honeycomb shape.
Tafoni are small cave-like features found in
granular rock such as sandstone, with
rounded entrances and smooth concave
walls. They often occur in groups that can
riddle a hillside, cliff, or other rock
formation.
If the water is carrying salts - minerals
dissolved in the water than can include
sodium chloride but also a host of other
chlorides, sulphates, and carbonates then they will crystallize out as the water
dries.
Crystallizing salts increase their volume as
they form, which produces significant
pressures between the grains, forcing the
solid rock to crumble. The chemical and
physical solidity of any rock is not uniform
and some parts will be more vulnerable
than others; the process continues
through cycles of wetting and drying,
chiseling, excavating, and smoothing .
9. GEOLOGICAL PROCESSES
6) Mushroom Rocks
Two broken concretions within rock layers are formed vertical to the sea level, as a
result, the erosion caused by seawater may progress along the concretions, leading
to the formation of stone pillar lining up in row.
The formation of mushroom rock is caused by differential erosion as the top rock
layer containing calcium and being more durable for erosion than the lower rock
layer.
The mushroom rock as formed is under continuous plate extrusion and thus is
raised above sea level.
Once it’s exposed to the planet’s atmosphere, it will suffer from weathering as well
as rain erosion and turn into the shape as we see it now.
The mushroom rocks can be divided into three types :
“Thin-neck rock”,” thick-neck rock” and “neckless rock”.
As many of the thin-neck mushroom rocks undertake heavier load on the top
and they may be toppled down easily if striking by earthquake or violent winds
and waves.
They may involve into neckless rock, thick rock, thin rock and even the brokenend rock eventually.
The top of the thin rock may fall apart if the neck of the rock contains
incomplete sands and thud accelerating the formation of broken-end rock.
10. ROLE OF NATURE IN SHAPING THESE
LANDFORMS
• Yehliu Geopark is a coastal area, and rocks are often subjected to erosion
by seawater.
• It forms many different types of rocks such as elephant rocks, fairy shoe,
earth rock and peanut rock.
• The rocks consist mainly of Sedimentary rocks, which results in the
formation of sea bays due to sea erosion on softer rock layer
• Hard and solid rocks may turn into sea capes
11. ROLE OF NATURE IN SHAPING THESE
LANDFORMS
• Weathering results and decomposition of earth rocks, rocks may turn
into sand, mud and soils due to chemical changes of inner substances
or physical functions such as heat expansion and cold contraction.
• Because of the influences of Northern monsoon which allows
weathering to be detected.
• Formation of strange rocks due to the decomposition of special rock
layer which exist underground
• Because of the erosion and weathering that many different and
interesting types of rocks can be formed in that area. beautiful rock
landscape
