The Dent Peninsula () is a
peninsula
A peninsula is a landform that extends from a mainland and is only connected to land on one side. Peninsulas exist on each continent. The largest peninsula in the world is the Arabian Peninsula.
Etymology
The word ''peninsula'' derives , . T ...
in eastern
Sabah, Malaysia. It consists of hills and broad coastal areas. The Peninsula is also previously considered as a
volcanic arc
A volcanic arc (also known as a magmatic arc) is a belt of volcanoes formed above a subducting oceanic tectonic plate, with the belt arranged in an arc shape as seen from above. Volcanic arcs typically parallel an oceanic trench, with the arc ...
of the region which have since migrated southward to
Semporna Peninsula.
Geology
Volcanic activity in the
tertiary
Tertiary (from Latin, meaning 'third' or 'of the third degree/order..') may refer to:
* Tertiary period, an obsolete geologic period spanning from 66 to 2.6 million years ago
* Tertiary (chemistry), a term describing bonding patterns in organic ch ...
causing rise to
andesite
Andesite () is a volcanic rock of intermediate composition. In a general sense, it is the intermediate type between silica-poor basalt and silica-rich rhyolite. It is fine-grained (aphanitic) to porphyritic in texture, and is composed predomina ...
and
dacite
Dacite () is a volcanic rock formed by rapid solidification of lava that is high in silica and low in alkali metal oxides. It has a fine-grained (aphanitic) to porphyritic texture and is intermediate in composition between andesite and rhyolite. ...
in the area around Bakapit in the southern area of the peninsula.
The rocks in east of
Lahad Datu
Lahad Datu () is the capital of the Lahad Datu District in the Dent Peninsula on Tawau Division of Sabah, Malaysia. Its population was estimated to be around 27,887 in 2010. The town is surrounded by stretches of cocoa and palm oil plantatio ...
are mixed
volcanic
A volcano is commonly defined as a vent or fissure in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface.
On Earth, volcanoes are most often fo ...
and
sedimentary
Sedimentary rocks are types of rock formed by the cementation of sediments—i.e. particles made of minerals (geological detritus) or organic matter (biological detritus)—that have been accumulated or deposited at Earth's surface. Sedime ...
: tuffaceous
sandstone
Sandstone is a Clastic rock#Sedimentary clastic rocks, clastic sedimentary rock composed mainly of grain size, sand-sized (0.0625 to 2 mm) silicate mineral, silicate grains, Cementation (geology), cemented together by another mineral. Sand ...
s and
conglomerate mixed with Ayer, Tabanak and Tungku formations materials of
shale
Shale is a fine-grained, clastic sedimentary rock formed from mud that is a mix of flakes of Clay mineral, clay minerals (hydrous aluminium phyllosilicates, e.g., Kaolinite, kaolin, aluminium, Al2Silicon, Si2Oxygen, O5(hydroxide, OH)4) and tiny f ...
s,
mudstone
Mudstone, a type of mudrock, is a fine-grained sedimentary rock whose original constituents were clays or muds. Mudstone is distinguished from ''shale'' by its lack of fissility.Blatt, H., and R.J. Tracy, 1996, ''Petrology.'' New York, New York, ...
s and sandstones.
Inner neritic to littoral deposits at the east of the peninsula consist of mudstone, clay and coral limestone with Sabahat (
Middle Miocene
The Middle Miocene is a sub-epoch of the Miocene epoch (geology), epoch made up of two Stage (stratigraphy), stages: the Langhian and Serravallian stages. The Middle Miocene is preceded by the Early Miocene.
The sub-epoch lasted from 15.97 ± 0. ...
and
Early Pliocene
Early may refer to:
Places in the United States
* Early, Iowa, a city
* Early, Texas, a city
* Early Branch, a stream in Missouri
* Early County, Georgia
* Fort Early, Georgia, an early 19th century fort
Music
* Early B, stage name of Jamaican d ...
) and Ganduman (Early Pliocene to
Late Pliocene
Late or LATE may refer to:
Everyday usage
* Tardy, or late, not being on time
* Late (or the late) may refer to a person who is dead
Music
* Late (The 77s album), ''Late'' (The 77s album), 2000
* Late (Alvin Batiste album), 1993
* Late!, a pseudo ...
) formations materials of
lignite
Lignite (derived from Latin ''lignum'' meaning 'wood'), often referred to as brown coal, is a soft, brown, combustible sedimentary rock formed from naturally compressed peat. It has a carbon content around 25–35% and is considered the lowest ...
,
marl
Marl is an earthy material rich in carbonate minerals, Clay minerals, clays, and silt. When Lithification, hardened into rock, this becomes marlstone. It is formed in marine or freshwater environments, often through the activities of algae.
M ...
and conglomerate.
The Ganduman formation displays well preserved outcrops of delta plain deposits grading to shallow marine
deltaic and holomarine eastward while the Sabahat is represented by the clinoform and downlap seismic packages.
The Togopi formation on the onshore of the peninsula is mainly made of marls and preserves
Plio-Pleistocene
The Plio-Pleistocene is an informally described geological pseudo-period, which begins about 5 million years ago (Mya) and, drawing forward, combines the time ranges of the formally defined Pliocene and Pleistocene epochs—marking from about 5&n ...
sedimentary sequences which have a relatively high
coral
Corals are colonial marine invertebrates within the subphylum Anthozoa of the phylum Cnidaria. They typically form compact Colony (biology), colonies of many identical individual polyp (zoology), polyps. Coral species include the important Coral ...
diversity.
Based on organic
geochemical
Geochemistry is the science that uses the tools and principles of chemistry to explain the mechanisms behind major geological systems such as the Earth's crust and its oceans. The realm of geochemistry extends beyond the Earth, encompassing the ...
and
petrological
Petrology () is the branch of geology that studies rocks, their mineralogy, composition, texture, structure and the conditions under which they form. Petrology has three subdivisions: igneous, metamorphic, and sedimentary petrology. Igneous an ...
analyses, both formations of Sabahat and Ganduman found to be
gas-prone source rocks. The narrow continental shelf fronting the coastal areas of both Dent and
Semporna
Semporna () is the capital of the Semporna District in the Tawau Division of Sabah, Malaysia. Its population was estimated to be around 35,301 in 2010.
The federal constituency represented in the Dewan Rakyat is Semporna.
History
Sempor ...
Peninsulas also could be exposed to future
tsunami
A tsunami ( ; from , ) is a series of waves in a water body caused by the displacement of a large volume of water, generally in an ocean or a large lake. Earthquakes, volcanic eruptions and underwater explosions (including detonations, ...
s with the active fault in the eastern coast.
Climate and biodiversity
The peninsula especially in the northern generally received mean annual rainfall ranging from 2,000 millimetres to 2,500 millimetres. In the southern coast, the area received annual rainfall ranging from 1,500 millimetres to 2,000 millimetres while the Tungku area received less than 1,500 millimetres.
Located in the centre of the peninsula is the
Tabin Wildlife Reserve which is a forest reserve area with variety of protected species.
References
{{Geography of Sabah
Peninsulas of Asia
Landforms of Sabah