West of this is the Eastern Central Range terrane, part of the continental base that has been upturned.

The Lishan Fault separates the Hsuehshan Range terrane Eocene to Oligocene sandstone and shale.

The Chukou Fault (觸口斷層) provides the boundary for the Western Foothills terrane, which is shallow marine detritus from Miocene to Pleistocene.

A deformation front forms the boundary with the undeformed coastal plains alluvium, which is still depositing.

They form a band of rock from Nan'ao in the north to inland of Jinfeng on the eastern flank of the Central Mountain Range.

It is the easternmost part and extends from Chian southwards to the west of the Chihpen hot springs in a belt about 150 km long.

The Chiuchu Formation or Tailuge Marble forms a band from Tailuko in the north to a point between Wulu and Kuanshan in the south.

Although the colour is usually a shade of grey, there are also black or white limestone, which is chopped into blocks for building purposes.

The gneiss derived from sedimentary rocks contains coarse grained quartz, biotite, and albitic plagioclase.

[10] The area was subjected to the Nanao Orogeny around 85 Ma which involved the granite intrusion and regional metamorphism.

Rifting that opened the South China Sea around 40 Ma may be connected with some dolerite intrusions.

The Paleocene Wangong Formation consisting of volcaniclastics, sandstone, shale and limestone is over 1046 meters thick.

The Yeliu Group from the Miocene is fine grained sandstone, with some beds of shale, basaltic tuff and three seams of coal.

The Sangxia Group starts with medium grained sandstone, but in the upper layers increases shale.

[15] The ophiolite melange contains pebbles and blocks of Miocene age consisting of basic and ultrabasic rock from the ocean floor.

The interpretation is that a wedge of seafloor was pushed above sea level, eroded and dropped fragments into the mud.

The Szekou Formation is a light bluish gray siltstone, with shale and fine grained sandstone.

Holocene mud sand and coral form a wide belt on the west side of the island.

The rocks are poor in sodium and magnesium, but rich in iron, potassium, rubidium and strontium and strong in rare earth elements.

The magma was derived by melting of the underthrust sea plate behind the Ryukyu Volcanic Arc during the Pleistocene.

This is rich in K, Rb, Mg, Sr, Cr, and Ni, but poor in Na, Al, and Fe.

The magma was derived by deep mantle melting of the underthrust sea plate behind the Ryukyu Volcanic Arc during the Pleistocene.

Geochemistry of the rock shows that iron, aluminium, titanium, potassium, rubidium and strontium are enriched, but sodium, magnesium and nickel are impoverished.

[8] Alkaline volcanic rocks from north west Taiwan are found at the Shihmen Reservoir, Chiaopanshan, Taoyuan and Fuxing.

[8] Volcanoes on the Coastal Range and Green Island erupted tholeiite andesite, and volcanic explosive fragments.

The geochemistry of the rock shows it is enriched in potassium, strontium and rubidium and light rare earth elements.

[21] The offshore features include the Kaoping Slope extending off the southwest coast of Taiwan into the South China Sea.

[23] A 5.5 magnitude earthquake struck at 08:00 GMT on 20 March 2011, near the canyon[24] breaking segments C and D of the East Asia Crossing undersea cable.

The Chingshui geothermal region is named after the Cingshuei River 13 km south west of Yilan.

The south end of the Longitudonal Valley discharges the Peinan River with 88,000,000 tons of sediment per year.