The Qinling orogenic belt is a tectonic feature that evolved throughout the Proterozoic and Phanerozoic eons due to a variety of tectonic activities. It is a part of the Central China Orogenic Belt, aligned in an east–west orientation across Central China, and spans portions of
Shaanxi
Shaanxi (alternatively Shensi, see § Name) is a landlocked province of China. Officially part of Northwest China, it borders the province-level divisions of Shanxi (NE, E), Henan (E), Hubei (SE), Chongqing (S), Sichuan (SW), Gansu (W), N ...
,
Henan
Henan (; or ; ; alternatively Honan) is a landlocked province of China, in the central part of the country. Henan is often referred to as Zhongyuan or Zhongzhou (), which literally means "central plain" or "midland", although the name is al ...
Qinling
The Qinling () or Qin Mountains, formerly known as the Nanshan ("Southern Mountains"), are a major east–west mountain range in southern Shaanxi Province, China. The mountains mark the divide between the drainage basins of the Yangtze and Yellow ...
Mountains which are one of the greatest mountain ranges in China. The first materials involved in the Qinling orogenic belt formed around 2.5 billion years ago, whereas the main
morphology
Morphology, from the Greek and meaning "study of shape", may refer to:
Disciplines
* Morphology (archaeology), study of the shapes or forms of artifacts
* Morphology (astronomy), study of the shape of astronomical objects such as nebulae, galaxies ...
of the belt now largely reflects the
Triassic
The Triassic ( ) is a geologic period and system (stratigraphy), system which spans 50.6 million years from the end of the Permian Period 251.902 million years ago (Year#Abbreviations yr and ya, Mya), to the beginning of the Jurassic Period 201.36 ...
collision between the
North China Plate
The North China Craton is a continental crustal block with one of Earth's most complete and complex records of igneous, sedimentary and metamorphic processes. It is located in northeast China, Inner Mongolia, the Yellow Sea, and North Korea. The ...
and the South China Plate and Cenozoic extension across China. During these 2.5 billion years, various types of rocks have been formed here due to different tectonic processes and
chemical reactions
A chemical reaction is a process that leads to the chemical transformation of one set of chemical substances to another. Classically, chemical reactions encompass changes that only involve the positions of electrons in the forming and breaking ...
between rocks. Therefore,
geologists
A geologist is a scientist who studies the solid, liquid, and gaseous matter that constitutes Earth and other terrestrial planets, as well as the processes that shape them. Geologists usually study geology, earth science, or geophysics, althou ...
are able to reconstruct the evolution of mountain belt based on evidence preserved in these rocks.
Tectonic evolution
Throughout the long history of the evolution of Qinling
orogenic belt
An orogenic belt, or orogen, is a zone of Earth's crust affected by orogeny. An orogenic belt develops when a continental plate crumples and is uplifted to form one or more mountain ranges; this involves a series of geological processes collec ...
, there were several cycles of plate collisions and plate separations together with ocean openings and closures occurred. The process is known as a
Wilson Cycle
The Wilson Cycle is a model that describes the opening and closing of ocean basins and the subduction and divergence of tectonic plates during the assembly and disassembly of supercontinents. A classic example of the Wilson Cycle is the opening a ...
. The Qinling
orogenic belt
An orogenic belt, or orogen, is a zone of Earth's crust affected by orogeny. An orogenic belt develops when a continental plate crumples and is uplifted to form one or more mountain ranges; this involves a series of geological processes collec ...
was formed largely because of the movements of North China Block and Yangtze Block of the South China Plate.
The Qingling orogenic belt can be divided into two major regions, the North Qinling Belt and the South Qingling belt, which are located at the boundary of the southern
North China Craton
The North China Craton is a continental crustal block with one of Earth's most complete and complex records of igneous, sedimentary and metamorphic processes. It is located in northeast China, Inner Mongolia, the Yellow Sea, and North Korea. Th ...
and the northern South China Craton respectively. The most interesting thing about the evolution of Qinling orogenic belt is the multiple individual micro-block interactions. The tectonic evolution of the whole Qinling belt was not a single event but a combination of several collisional and extensional events, which mainly includes 4 phases:
# Development of basement of the belt (2.5 billion years to 800 million years ago)
# Evolution of plates and associated ocean basin (800 to 250 million years ago)
# Major belt formation (orogeny) (250 to 140 million years ago)
# Extension and stretching of the belt (140 million years before to the present)
Development of basement of belt (2.5 billion years to 800 million years ago)
At the beginning of the Qinling rock record (around 2.5 billion years ago), the North Qinling belt and South Qinling belt were not initially formed together at the same location at the same time. The South Qinling belt was formed by continental magmatic activities 2.5 billion years ago. Then,
magma
Magma () is the molten or semi-molten natural material from which all igneous rocks are formed. Magma is found beneath the surface of the Earth, and evidence of magmatism has also been discovered on other terrestrial planets and some natural sa ...
cooled down and became rocks which contribute to the major basement of the South Qinling belt. On the other hand, the North Qinling belt was formed later. It was first formed 1000 million years ago by magmatic activities which occurred in an oceanic-arc environment.
During the early Neoproterozoic (1000 million years ago), the North Qinling belt and the South Qinling were aligned along the same subducting plate boundary at the Northeastern part of super-continentRodinia (an extremely large tectonic plate composed of different smaller plates). During subduction, the South China block overrode an oceanic plate was compressed and South Qinling belt first formed on a small scale.
On the other hand, the formation of North Qinling belt was more complicated. It did not initially exist with North China Block, but a part of
supercontinent
In geology, a supercontinent is the assembly of most or all of Earth's continental blocks or cratons to form a single large landmass. However, some geologists use a different definition, "a grouping of formerly dispersed continents", which leav ...
Rodinia. At the subducting plate boundary, it collided with Rodinia and was folded up forming North Qinling Belt.
In addition, at some distances further away from the North Qinling Belt, a
continental arc
A continental arc is a type of volcanic arc occurring as an "arc-shape" topographic high region along a continental margin. The continental arc is formed at an active continental margin where two tectonic plates meet, and where one plate has cont ...
with
volcano
A volcano is a rupture in the Crust (geology), crust of a Planet#Planetary-mass objects, planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and volcanic gas, gases to escape from a magma chamber below the surface.
On Ear ...
es was formed at another subducting plate boundary as well, which is named the Proto-Erlangping arc. An arc can be formed because the subducted lower plate melted in the mantle and rose up to the opposite upper plate while cutting through lines of weakness of plate. As a result, magma eventually reached the top of the
plate
Plate may refer to:
Cooking
* Plate (dishware), a broad, mainly flat vessel commonly used to serve food
* Plates, tableware, dishes or dishware used for setting a table, serving food and dining
* Plate, the content of such a plate (for example: ...
, then cooled down and solidified into rocks, forming an arc. In the meantime, Proto-Erlangping ocean was created at
divergent plate boundary
In plate tectonics, a divergent boundary or divergent plate boundary (also known as a constructive boundary or an extensional boundary) is a linear feature that exists between two tectonic plates that are moving away from each other. Divergent b ...
where plates separate, so that the Proto-Erlangping arc was moving away from North Qinling belt.
Evolution of belt and associated ocean (800 to 250 million years ago)
Later on in the middle
Neoproterozoic
The Neoproterozoic Era is the unit of geologic time from 1 billion to 538.8 million years ago.
It is the last era of the Precambrian Supereon and the Proterozoic Eon; it is subdivided into the Tonian, Cryogenian, and Ediacaran periods. It is prec ...
(around 750 million years ago), the
supercontinent
In geology, a supercontinent is the assembly of most or all of Earth's continental blocks or cratons to form a single large landmass. However, some geologists use a different definition, "a grouping of formerly dispersed continents", which leav ...
containing Proto-Erlangping arc, North Qinling Belt and South Qinling Belt was broken up. The two belts were transported to another place together. The oceanic part of South China block was broken and separated into two parts creating the Shangdan ocean. This is because divergent convection magma dominated at that period, when two parts separate, magma rise up from the gap of them creating a larger
oceanic plate
Oceanic crust is the uppermost layer of the oceanic portion of the tectonic plates. It is composed of the upper oceanic crust, with pillow lavas and a dike complex, and the lower oceanic crust, composed of troctolite, gabbro and ultramafic c ...
(as well as an ocean). On the other end of the
oceanic plate
Oceanic crust is the uppermost layer of the oceanic portion of the tectonic plates. It is composed of the upper oceanic crust, with pillow lavas and a dike complex, and the lower oceanic crust, composed of troctolite, gabbro and ultramafic c ...
, it collided with another oceanic plate coincidently. An island arc called 'DanFeng island arc' was formed.
A similar process occurred at the North Qinling belt, North Qinling belt and Rodinia were separated. As a result, a new ocean formed as well. At this time North and South Qinling belt were still aligning next to each other, therefore they shared the same Shangdan ocean. By the time the North Qinling Belt moved away from Rodinia, it was colliding with the Proto-Erlangping arc as well. Therefore, two subduction processes occurred at the same time at the Proto-Erlangping arc.
At the early Cambrian (around 540 million years ago), Gondwana (considered as super-continent by some geologists) started to develop. The North and South Qinling Belt were located at the Northeastern part of it. This was the time when North China Block first met the North Qinling belt, locating at the other end of Proto-Erlangping arc. During that period, the North Qinling belt was no longer located next to South Qinling belt, but facing it. As same as the situation before Cambrian, the North Qingling belt and South Qinling Belt still share the Shangdan ocean. What different was the subducting plate changed from one to another, at the Danfeng island.
At late Cambrian (around 500 million years ago), the North China block migrated closer to North Qinling block. Consequently, the Proto-Erlangping ocean was closed as the whole oceanic plate had subducted to the mantle. This also implies the North Qinling belt collided with Proto-Erlangping belt after the closure of the ocean.
From the late
Ordovician
The Ordovician ( ) is a geologic period and system, the second of six periods of the Paleozoic Era. The Ordovician spans 41.6 million years from the end of the Cambrian Period million years ago (Mya) to the start of the Silurian Period Mya.
T ...
to late Silurian (460 to 420 million years), the collided North Qinling belt and Proto-Erlangping belt were moved to a magma spreading centre, which split plates apart by divergent convection magma. This turn out the Erlangping ocean was opened again.
At the early Devonian (around 400 million years ago), South Qinling belt and North China block moved towards each other, while extensive convergent convection magma occurred, although some geologists claimed it happened between 320 and 300 million years before. As a result, Erlangping arc, North Qinling belt, South Qinling belt and North China block all collided together. With all oceans closed up and blocks moving towards each other, rocks were then piled up within blocks. Meanwhile, Mianlue ocean was opened, since South China block and the rest of the block complex were separated by divergent convection magma current. The ocean created is also regarded as back-arc basin.
During the middle Mississippian (around 300 million years ago), the Mianlue ocean stopped spreading. The South China Plate moved towards the Qinling complex and North China Block. The oceanic part of South China Block subducted to the mantle and the ocean started closing.
Major belt formation (250 to 140 million years ago)
At the early
Triassic
The Triassic ( ) is a geologic period and system (stratigraphy), system which spans 50.6 million years from the end of the Permian Period 251.902 million years ago (Year#Abbreviations yr and ya, Mya), to the beginning of the Jurassic Period 201.36 ...
(around 250 million years ago), the South China block finally collided with Qinling complex, and the continent-continent collision occurred. Accordingly, the Mianlue ocean eventually closed completely. Resulting from extremely strong compressional force, all individual blocks were shortened horizontally but thickened vertically. At middle Jurassic (174-163 million years ago), the
South China block
The Yangtze Plate, also called the South China Block or the South China Subplate, comprises the bulk of southern China. It is separated on the east from the Okinawa Plate by a rift that forms the Okinawa Trough which is a back-arc basin, on the so ...
subducted beneath the South Qinling block and part of the plate broke off to the subduction zone.
However, the collisional event was different from normal one. It is because the South China Plate collided to the North China plate with a relatively rotational motion. Such that the eastern part of Qinling belt was compressed earlier than the western part.
Extension and stretching of belt (140 million years ago to the present)
Starting from 140 million years (
Cretaceous
The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of ...
) before to the present, the tectonic activities changed from collisional to extensional, which is a process of crustal stretching resulting in crustal thinning. Until the late Cretaceous (83 million years ago), the Qinling complex was affected by a WNW-ESE extension event in west of Qinling. As a result, right-lateral strike slip fault became dominated. At Mid-
Eocene
The Eocene ( ) Epoch is a geological epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period in the modern Cenozoic Era. The name ''Eocene'' comes from the Ancient Greek (''ēṓs'', " ...
normal fault
In geology, a fault is a planar fracture or discontinuity in a volume of rock across which there has been significant displacement as a result of rock-mass movements. Large faults within Earth's crust result from the action of plate tecton ...
dominated the complex back due to extensional event at the northern part. Until the late Oligocene to early
Miocene
The Miocene ( ) is the first epoch (geology), geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and mea ...
(24 to 14 million years ago), left-lateral strike-slip fault became the major deformation feature in Qinling. However, at the late Miocene (9 million years ago),
normal fault
In geology, a fault is a planar fracture or discontinuity in a volume of rock across which there has been significant displacement as a result of rock-mass movements. Large faults within Earth's crust result from the action of plate tecton ...
Pliocene
The Pliocene ( ; also Pleiocene) is the epoch in the geologic time scale that extends from 5.333 million to 2.58 At the late Pliocene (3.5 million years ago), left-lateral strike-slip fault dominated the Qinling, which was caused by a NNW-SSE extension event until the Present.
Geology of Qinling
The geology of Qinling is complex which is formed due to many
tectonic
Tectonics (; ) are the processes that control the structure and properties of the Earth's crust and its evolution through time. These include the processes of mountain building, the growth and behavior of the strong, old cores of continents ...
activities and multiple
crustal block
Fault blocks are very large blocks of rock, sometimes hundreds of kilometres in extent, created by tectonic and localized stresses in Earth's crust. Large areas of bedrock are broken up into blocks by faults. Blocks are characterized by relat ...
interactions. It can be divided into 9 main groups: South-North China Block, Kuanping Group, Erlangping Group, North Qingling Block, Shangdan suture zone, North-South Qinling Block, South-South Qinling Block, Mianlue Suture zone and Dabie terrane.
South-North China Block
At the northern edge of Qinling
orogenic belt
An orogenic belt, or orogen, is a zone of Earth's crust affected by orogeny. An orogenic belt develops when a continental plate crumples and is uplifted to form one or more mountain ranges; this involves a series of geological processes collec ...
tillite
image:Geschiebemergel.JPG, Closeup of glacial till. Note that the larger grains (pebbles and gravel) in the till are completely surrounded by the matrix of finer material (silt and sand), and this characteristic, known as ''matrix support'', is d ...
Ordovician
The Ordovician ( ) is a geologic period and system, the second of six periods of the Paleozoic Era. The Ordovician spans 41.6 million years from the end of the Cambrian Period million years ago (Mya) to the start of the Silurian Period Mya.
T ...
(545-492 million years ago). During
Cretaceous
The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of ...
granitoid
A granitoid is a generic term for a diverse category of coarse-grained igneous rocks that consist predominantly of quartz, plagioclase, and alkali feldspar. Granitoids range from plagioclase-rich tonalites to alkali-rich syenites and from quartz- ...
) were emplaced resulting from crustal blocks collision.
greenschist
Greenschists are metamorphic rocks that formed under the lowest temperatures and pressures usually produced by regional metamorphism, typically and 2–10 kilobars (). Greenschists commonly have an abundance of green minerals such as chlorite ...
mica-schist
Schist ( ) is a medium-grained metamorphic rock showing pronounced schistosity. This means that the rock is composed of mineral grains easily seen with a low-power hand lens, oriented in such a way that the rock is easily split into thin flakes ...
, which were metamorphosed due to a collision between North China Block and Erlangping island arc. In addition, ophiolites were exposed to the earth surface by
obduction
Obduction is a geological process whereby denser oceanic crust (and even upper mantle) is scraped off a descending ocean plate at a convergent plate boundary and thrust on top of an adjacent plate. When oceanic and continental plates converge ...
. The Kuanping group was formed in the early to middle Proterozoic (2.5-1 billion years ago).
Erlangping Group
At the early
Paleozoic
The Paleozoic (or Palaeozoic) Era is the earliest of three geologic eras of the Phanerozoic Eon.
The name ''Paleozoic'' ( ;) was coined by the British geologist Adam Sedgwick in 1838
by combining the Greek words ''palaiós'' (, "old") and ' ...
(around 545–440 million years ago), the Erlangping
island arc
Island arcs are long chains of active volcanoes with intense seismic activity found along convergent tectonic plate boundaries. Most island arcs originate on oceanic crust and have resulted from the descent of the lithosphere into the mantle alon ...
subducted beneath the North China Block (
obduction
Obduction is a geological process whereby denser oceanic crust (and even upper mantle) is scraped off a descending ocean plate at a convergent plate boundary and thrust on top of an adjacent plate. When oceanic and continental plates converge ...
), so that those arc-related
ophiolite
An ophiolite is a section of Earth's oceanic crust and the underlying upper mantle that has been uplifted and exposed above sea level and often emplaced onto continental crustal rocks.
The Greek word ὄφις, ''ophis'' (''snake'') is found ...
with
mélange
In geology, a mélange is a large-scale breccia, a mappable body of rock characterized by a lack of continuous bedding and the inclusion of fragments of rock of all sizes, contained in a fine-grained deformed matrix. The mélange typically cons ...
was moved to the surface of the earth. Within an ophiolite sequence, ultramafic rock, pillow basalt. sill basalt and a small amount of chert can be found.
North Qinling Group
The North Qinling Group, one of the major block that built up the Qinling orogen, is characterized by
gneiss
Gneiss ( ) is a common and widely distributed type of metamorphic rock. It is formed by high-temperature and high-pressure metamorphic processes acting on formations composed of igneous or sedimentary rocks. Gneiss forms at higher temperatures a ...
marble
Marble is a metamorphic rock composed of recrystallized carbonate minerals, most commonly calcite or dolomite. Marble is typically not foliated (layered), although there are exceptions. In geology, the term ''marble'' refers to metamorphose ...
which were metamorphosed from
clastic sedimentary rock
Clastic rocks are composed of fragments, or clasts, of pre-existing minerals and rock. A clast is a fragment of geological detritus,Essentials of Geology, 3rd Ed, Stephen Marshak, p. G-3 chunks, and smaller grains of rock broken off other rocks ...
and
carbonate
A carbonate is a salt of carbonic acid (H2CO3), characterized by the presence of the carbonate ion, a polyatomic ion with the formula . The word ''carbonate'' may also refer to a carbonate ester, an organic compound containing the carbonate ...
Paleozoic
The Paleozoic (or Palaeozoic) Era is the earliest of three geologic eras of the Phanerozoic Eon.
The name ''Paleozoic'' ( ;) was coined by the British geologist Adam Sedgwick in 1838
by combining the Greek words ''palaiós'' (, "old") and ' ...
Permian
The Permian ( ) is a geologic period and System (stratigraphy), stratigraphic system which spans 47 million years from the end of the Carboniferous Period million years ago (Mya), to the beginning of the Triassic Period 251.9 Mya. It is the last ...
(354 to 250 million years ago).
Shangdan suture zone
The Shangdan suture zone is considered as the dividing boundary of the North and South Qinling Belt. It is composed of extensive
ophiolite
An ophiolite is a section of Earth's oceanic crust and the underlying upper mantle that has been uplifted and exposed above sea level and often emplaced onto continental crustal rocks.
The Greek word ὄφις, ''ophis'' (''snake'') is found ...
,
clastic sedimentary rock
Clastic rocks are composed of fragments, or clasts, of pre-existing minerals and rock. A clast is a fragment of geological detritus,Essentials of Geology, 3rd Ed, Stephen Marshak, p. G-3 chunks, and smaller grains of rock broken off other rocks ...
and
carbonate
A carbonate is a salt of carbonic acid (H2CO3), characterized by the presence of the carbonate ion, a polyatomic ion with the formula . The word ''carbonate'' may also refer to a carbonate ester, an organic compound containing the carbonate ...
. Ophiolites were formed during early Cambrian to Early Silurian (545 to 423 million years ago). Series of
volcanic rock
Volcanic rock (often shortened to volcanics in scientific contexts) is a rock formed from lava erupted from a volcano. In other words, it differs from other igneous rock by being of volcanic origin. Like all rock types, the concept of volcanic ...
sedimentary rock
Sedimentary rocks are types of rock that are formed by the accumulation or deposition of mineral or organic particles at Earth's surface, followed by cementation. Sedimentation is the collective name for processes that cause these particles ...
which indicates an
island arc
Island arcs are long chains of active volcanoes with intense seismic activity found along convergent tectonic plate boundaries. Most island arcs originate on oceanic crust and have resulted from the descent of the lithosphere into the mantle alon ...
environment in the Early
Paleozoic
The Paleozoic (or Palaeozoic) Era is the earliest of three geologic eras of the Phanerozoic Eon.
The name ''Paleozoic'' ( ;) was coined by the British geologist Adam Sedgwick in 1838
by combining the Greek words ''palaiós'' (, "old") and ' ...
. This is explained by
gabbro
Gabbro () is a phaneritic (coarse-grained), mafic intrusive igneous rock formed from the slow cooling of magnesium-rich and iron-rich magma into a holocrystalline mass deep beneath the Earth's surface. Slow-cooling, coarse-grained gabbro is ch ...
ic and
granitic
A granitoid is a generic term for a diverse category of coarse-grained igneous rocks that consist predominantly of quartz, plagioclase, and alkali feldspar. Granitoids range from plagioclase-rich tonalites to alkali-rich syenites and from quartz- ...
intrusion within the
suture zone
In structural geology, a suture is a joining together along a major fault zone, of separate terranes, tectonic units that have different plate tectonic, metamorphic and paleogeographic histories. The suture is often represented on the surface by ...
, with the low amount of
ultramafic rock
Ultramafic rocks (also referred to as ultrabasic rocks, although the terms are not wholly equivalent) are igneous and meta-igneous rocks with a very low silica content (less than 45%), generally >18% MgO, high FeO, low potassium, and are composed ...
s involved.
South Qinling Block
The South Qinling Block is comparatively larger than the North Qinling Block, which is further divided into two parts: North and South Qinling Belt. The North-South Qinling Belt involves
Archean
The Archean Eon ( , also spelled Archaean or Archæan) is the second of four geologic eons of Earth's history, representing the time from . The Archean was preceded by the Hadean Eon and followed by the Proterozoic.
The Earth during the Arc ...
to Late Proterozoic basement rock, which can be dated back to 3.8 to 0.545 billion years ago.
Limestone
Limestone ( calcium carbonate ) is a type of carbonate sedimentary rock which is the main source of the material lime. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of . Limestone forms whe ...
sandstone
Sandstone is a clastic sedimentary rock composed mainly of sand-sized (0.0625 to 2 mm) silicate grains. Sandstones comprise about 20–25% of all sedimentary rocks.
Most sandstone is composed of quartz or feldspar (both silicates ...
and other
sedimentary rock
Sedimentary rocks are types of rock that are formed by the accumulation or deposition of mineral or organic particles at Earth's surface, followed by cementation. Sedimentation is the collective name for processes that cause these particles ...
s were deposited on top of basement rocks at the
Paleozoic
The Paleozoic (or Palaeozoic) Era is the earliest of three geologic eras of the Phanerozoic Eon.
The name ''Paleozoic'' ( ;) was coined by the British geologist Adam Sedgwick in 1838
by combining the Greek words ''palaiós'' (, "old") and ' ...
(545–250 million years ago), with a minor amount of
sandstone
Sandstone is a clastic sedimentary rock composed mainly of sand-sized (0.0625 to 2 mm) silicate grains. Sandstones comprise about 20–25% of all sedimentary rocks.
Most sandstone is composed of quartz or feldspar (both silicates ...
deposited until the
Triassic
The Triassic ( ) is a geologic period and system (stratigraphy), system which spans 50.6 million years from the end of the Permian Period 251.902 million years ago (Year#Abbreviations yr and ya, Mya), to the beginning of the Jurassic Period 201.36 ...
period (205 million years ago). On the other hand, the geology of South-South Qinling Belt is mainly presented by precambrian (545 billion years ago) basement rock. Besides, the basement rocks were intruded by alkaline dyke in the Silurian. After that, since the North part of South Qinling belt was in a shallow
marine environment
Marine habitats are habitats that support marine life. Marine life depends in some way on the saltwater that is in the sea (the term ''marine'' comes from the Latin ''mare'', meaning sea or ocean). A habitat is an ecological or environmental ...
, sedimentary facies reflecting the paleo-environment was formed. This included shale,
turbidite
A turbidite is the geologic deposit of a turbidity current, which is a type of amalgamation of fluidal and sediment gravity flow responsible for distributing vast amounts of clastic sediment into the deep ocean.
Sequencing
Turbidites wer ...
and
limestone
Limestone ( calcium carbonate ) is a type of carbonate sedimentary rock which is the main source of the material lime. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of . Limestone forms whe ...
. Starting from the late
Triassic
The Triassic ( ) is a geologic period and system (stratigraphy), system which spans 50.6 million years from the end of the Permian Period 251.902 million years ago (Year#Abbreviations yr and ya, Mya), to the beginning of the Jurassic Period 201.36 ...
to
Cretaceous
The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of ...
, the sedimentary environment turned to a terrestrial setting. The terrestrial facies can be indicated by conglomerate and
sandstone
Sandstone is a clastic sedimentary rock composed mainly of sand-sized (0.0625 to 2 mm) silicate grains. Sandstones comprise about 20–25% of all sedimentary rocks.
Most sandstone is composed of quartz or feldspar (both silicates ...
.
Mianlue suture zone
The Mianlue
suture zone
In structural geology, a suture is a joining together along a major fault zone, of separate terranes, tectonic units that have different plate tectonic, metamorphic and paleogeographic histories. The suture is often represented on the surface by ...
was evolved from Mianlue
oceanic basin
In hydrology, an oceanic basin (or ocean basin) is anywhere on Earth that is covered by seawater. Geologically, ocean basins are large geologic basins that are below sea level.
Most commonly the ocean is divided into basins fol ...
, which was closed at the Mid-
Triassic
The Triassic ( ) is a geologic period and system (stratigraphy), system which spans 50.6 million years from the end of the Permian Period 251.902 million years ago (Year#Abbreviations yr and ya, Mya), to the beginning of the Jurassic Period 201.36 ...
and developed into suture zone. Therefore,
ophiolite
An ophiolite is a section of Earth's oceanic crust and the underlying upper mantle that has been uplifted and exposed above sea level and often emplaced onto continental crustal rocks.
The Greek word ὄφις, ''ophis'' (''snake'') is found ...
representing oceanic setting and
volcanic rock
Volcanic rock (often shortened to volcanics in scientific contexts) is a rock formed from lava erupted from a volcano. In other words, it differs from other igneous rock by being of volcanic origin. Like all rock types, the concept of volcanic ...
indicating subduction zone was discovered there. As the ocean closed and blocks collided towards each other,
basalt
Basalt (; ) is an aphanitic (fine-grained) extrusive igneous rock formed from the rapid cooling of low-viscosity lava rich in magnesium and iron (mafic lava) exposed at or very near the surface of a rocky planet or moon. More than 90 ...
s were metamorphosed into meta-basaltic rock. From data provided, rocks mentioned above can be dated back to 345 to 200 million years ago.
North-South China Block
The Northern part of South China Block contains one of the oldest rock complexes in China, which i Kongling complex from the Archean Eon. It is mainly composed highly metamorphosed rock, including amphibolite,
migmatite
Migmatite is a composite rock found in medium and high-grade metamorphic environments, commonly within Precambrian cratonic blocks. It consists of two or more constituents often layered repetitively: one layer is an older metamorphic rock th ...
sedimentary rock
Sedimentary rocks are types of rock that are formed by the accumulation or deposition of mineral or organic particles at Earth's surface, followed by cementation. Sedimentation is the collective name for processes that cause these particles ...
s deposited before the collision.
Limestone
Limestone ( calcium carbonate ) is a type of carbonate sedimentary rock which is the main source of the material lime. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of . Limestone forms whe ...
turbidite
A turbidite is the geologic deposit of a turbidity current, which is a type of amalgamation of fluidal and sediment gravity flow responsible for distributing vast amounts of clastic sediment into the deep ocean.
Sequencing
Turbidites wer ...
sandstone
Sandstone is a clastic sedimentary rock composed mainly of sand-sized (0.0625 to 2 mm) silicate grains. Sandstones comprise about 20–25% of all sedimentary rocks.
Most sandstone is composed of quartz or feldspar (both silicates ...
Wilson Cycle
The Wilson Cycle is a model that describes the opening and closing of ocean basins and the subduction and divergence of tectonic plates during the assembly and disassembly of supercontinents. A classic example of the Wilson Cycle is the opening a ...
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Orogenic belt
An orogenic belt, or orogen, is a zone of Earth's crust affected by orogeny. An orogenic belt develops when a continental plate crumples and is uplifted to form one or more mountain ranges; this involves a series of geological processes collec ...
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Plate tectonics
Plate tectonics (from the la, label=Late Latin, tectonicus, from the grc, τεκτονικός, lit=pertaining to building) is the generally accepted scientific theory that considers the Earth's lithosphere to comprise a number of large ...
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Qinling
The Qinling () or Qin Mountains, formerly known as the Nanshan ("Southern Mountains"), are a major east–west mountain range in southern Shaanxi Province, China. The mountains mark the divide between the drainage basins of the Yangtze and Yellow ...