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The geology of North Korea has been studied by the Central Geological Survey of Mineral Resources, [1] [2] rare international research, and by inference from South Korea's geology. [3] [4]
Some international dating work around 1973 indicated that most basement rock in North Korea dates to the Proterozoic or the earlier Archean. The North Kyangsong Province gneiss samples indicated ages to 2.12 billion years ago and in 1985, the Sangni Metamorphic Supergroup and the Sangni Revolution were proposed as names for the gneiss-schist and gneiss formation. These groupings have been used to make sense of the 2.1 billion year old Punchon Granitic Gneiss, the Wonnan Group and the P'yonghae Group.
The Machyollong Metamorphic Supergroup is particularly widespread in the northeast, overlying older basement rock near the Yalu River. The supergroup is up to 10 kilometers thick with magnesite-bearing marble, mica schist and quartzite (quartzite units increase in thickness to the west). The western edge of the Machyollong Zone is known as the Iwon Mobile Belt and contains extrusive and intrusive igneous rocks.
The late Proterozoic Sangwon Synthem is widespread in the Pyongnam Basin and other, smaller basins in North Korea and experienced deformation during orogenies in the Mesozoic. [5]
The Late Ordovician Miru Series was identified beginning in 1971 as the Koksan Series and subsequently renamed after 1975. The 170 meter thick limestone and siltstone centered around the P'yongnam Basin has extensive crinoid, coral and gastropod fossils. Paleogeography researchers have suggested that corals formed in the Miru Sea—a branch of the South Yangtze Sea. The discovery of Ordovician fossils meant that the previous Koksan Series was revised to be younger, encompassing Silurian slate, limestone and siltstone in the Singye-Koksan area up to 280 meters thick. It includes trilobite and Rugosa fossils.
For years, geologists in the Korean Peninsula were puzzled about the early Paleozoic fossils found in the early Mesozoic Taedong Synthem (limestone pebbles in the Kyomipo Conglomerate). However, in 1991, Kang and Pak inferred an origin from the Koksan Series. Marine fossils are also widespread in the Imjin Group, first recognized in 1962 in the Kaesong-Kumchon-Cholwon area. The three kilometer thick unit is subdivided into the Anhyop, Puapsan and Saknyong Series and is widespread throughout the Imjinang Fold Belt in central North Korea. The Anhyop Series represents one kilometer of schist, limestone, phyllite and sandstone. The 1.1 kilometer Puapsan Series and one kilometer Saknyong Series are both very similar, although the Saknyong also has siltstone and volcanic rocks. North Korean geologists have identified the Imjin Group as a continental rift basin, correlated with similar rocks on the Shandong Peninsula across the Yellow Sea in China. Many of the rocks have experienced low-grade metamorphism and volcanic sequences are comparatively thick. [6]
At the base of the Taedong Synthem is the P'yong'an Supergroup, which lies disconformably atop older Paleozoic rocks. In the Pyongyang Coalfield it is divided into the 650 meter sandstone, shale and conglomerate of the Nogam Formation, the 500 meter Kobangsan Formation, 350 meter coal-bearing Sadong Formation and 250 meter chert-bearing Hongjom Formation, all typically assigned to an Upper Permian shallow marine environment.
During the Mesozoic, the region experienced the Songnim Orogeny, named for overturned, overthrusted Choson and P'yong'an synthem rocks near Songnim, north of Pyongyang. This event is associated with the 240 to 190 million year old Triassic and Jurassic Hyesan Complex pluton.
Taebo, a place north of Pyongyang is the namesake of the Taebo orogeny, a period of tectonic activity that emplaced the Taebo Granite around 180 million years ago. The orogeny, which is evidenced in the Okchon Supergroup, is likely related to the separation of Japan from Asia.
North of Pyongyang, Precambrian basement rocks are unconformably overlain by a Jurassic limestone conglomerate ascending to layers of siltstone and mudstone. The Upper Jurassic Shinuiju Formation northwest of Shinuiju has sandstone, conglomerate and mudstone up to two kilometers thick. Offshore drilling in the West Korea Bay Basin indicates these rocks are the onshore extension of offshore units. It is subdivided into fluvial rocks and Upper Jurassic black shale, limestone, conglomerate and sandstone formed in a lake environment. [7]
Longstanding terrestrial conditions prevailed through much of the Cenozoic, until the recent geological past, when the a marine regression flooded the area around the peninsula. Very few Cenozoic sediments are known from either Korea, likely as a result of erosion due to uplift of the peninsula. Submarine normal faults along the eastern coastline may have driven crustal tilting. The 350 meter thick Bongsan Coalfield in Hwanghae Province on the west coast preserves and coal-bearing layers dating to the Eocene. Further to the north, in the West Korea Bay Basin Eocene and Oligocene sedimentary rocks up to three kilometers thick unconformably overlie Mesozoic rocks, formed in lakes and coal swamps during the Paleogene.
The geology of Mozambique is primarily extremely old Precambrian metamorphic and igneous crystalline basement rock, formed in the Archean and Proterozoic, in some cases more than two billion years ago. Mozambique contains greenstone belts and spans the Zimbabwe Craton, a section of ancient stable crust. The region was impacted by major tectonic events, such as the mountain building Irumide orogeny, Pan-African orogeny and the Snowball Earth glaciation. Large basins that formed in the last half-billion years have filled with extensive continental and marine sedimentary rocks, including rocks of the extensive Karoo Supergroup which exist across Southern Africa. In some cases these units are capped by volcanic rocks. As a result of its complex and ancient geology, Mozambique has deposits of iron, coal, gold, mineral sands, bauxite, copper and other natural resources.
The geology of Tanzania began to form in the Precambrian, in the Archean and Proterozoic eons, in some cases more than 2.5 billion years ago. Igneous and metamorphic crystalline basement rock forms the Archean Tanzania Craton, which is surrounded by the Proterozoic Ubendian belt, Mozambique Belt and Karagwe-Ankole Belt. The region experienced downwarping of the crust during the Paleozoic and Mesozoic, as the massive Karoo Supergroup deposited. Within the past 100 million years, Tanzania has experienced marine sedimentary rock deposition along the coast and rift formation inland, which has produced large rift lakes. Tanzania has extensive, but poorly explored and exploited natural resources, including coal, gold, diamonds, graphite and clays.
The geology of Morocco formed beginning up to two billion years ago, in the Paleoproterozoic and potentially even earlier. It was affected by the Pan-African orogeny, although the later Hercynian orogeny produced fewer changes and left the Maseta Domain, a large area of remnant Paleozoic massifs. During the Paleozoic, extensive sedimentary deposits preserved marine fossils. Throughout the Mesozoic, the rifting apart of Pangaea to form the Atlantic Ocean created basins and fault blocks, which were blanketed in terrestrial and marine sediments—particularly as a major marine transgression flooded much of the region. In the Cenozoic, a microcontinent covered in sedimentary rocks from the Triassic and Cretaceous collided with northern Morocco, forming the Rif region. Morocco has extensive phosphate and salt reserves, as well as resources such as lead, zinc, copper and silver.
The geology of Belarus began to form more than 2.5 billion years ago in the Precambrian, although many overlying sedimentary units deposited during the Paleozoic and the current Quaternary. Belarus is located in the eastern European plain. From east to west it covers about 650 kilometers while from north to south it covers about 560 kilometers, and the total area is about 207,600 square kilometers. It borders Poland in the north, Lithuania in the northwest, Latvia and Russia in the north, and Ukraine in the south. Belarus has a planar topography with a height of about 160 m above sea level. The highest elevation at 346 meters above sea level is Mt. Dzerzhinskaya, and the lowest point at the height of 80 m is in the Neman River valley.
The geology of Georgia is the study of rocks, minerals, water, landforms and geologic history in Georgia. The country is dominated by the Caucasus Mountains at the junction of the Eurasian Plate and the Afro-Arabian Plate, and rock units from the Mesozoic and Cenozoic are particularly prevalent. For much of its geologic history, until the uplift of the Caucasus, Georgia was submerged by marine transgression events. Geologic research for 150 years by Georgian and Russian geologists has shed significant light on the region and since the 1970s has been augmented with the understanding of plate tectonics.
The geology of Bosnia & Herzegovina is the study of rocks, minerals, water, landforms and geologic history in the country. The oldest rocks exposed at or near the surface date to the Paleozoic and the Precambrian geologic history of the region remains poorly understood. Complex assemblages of flysch, ophiolite, mélange and igneous plutons together with thick sedimentary units are a defining characteristic of the Dinaric Alps, also known as the Dinaride Mountains, which dominate much of the country's landscape.
The geology of Sweden is the regional study of rocks, minerals, tectonics, natural resources and groundwater in the country. The oldest rocks in Sweden date to more than 2.5 billion years ago in the Precambrian. Complex orogeny mountain building events and other tectonic occurrences built up extensive metamorphic crystalline basement rock that often contains valuable metal deposits throughout much of the country. Metamorphism continued into the Paleozoic after the Snowball Earth glaciation as the continent Baltica collided with an island arc and then the continent Laurentia. Sedimentary rocks are most common in southern Sweden with thick sequences from the last 250 million years underlying Malmö and older marine sedimentary rocks forming the surface of Gotland.
The geology of Moldova encompasses basement rocks from the Archean and Paleoproterozoic dating back more than 2.5 billion years, overlain by thick sequences of Neoproterozoic, Paleozoic, Mesozoic and Cenozoic sedimentary rocks.
The geology of Bhutan is less well studied than many countries in Asia, together with the broader Eastern Himalayas region. Older Paleozoic and Precambrian rocks often appear mixed together with younger sediments due to the Himalayan orogeny.
The geology of North Macedonia includes the study of rocks dating to the Precambrian and a wide array of volcanic, sedimentary and metamorphic rocks formed in the last 539 million years.
The geology of Kazakhstan includes extensive basement rocks from the Precambrian and widespread Paleozoic rocks, as well as sediments formed in rift basins during the Mesozoic.
The geology of South Korea includes rocks dating to the Archean and two large massifs of metamorphic rock as the crystalline basement, overlain by thick sedimentary sequences, younger metamorphic rocks and volcanic deposits. Despite the country's small size, its geology is diverse, containing rocks formed during the Precambrian to Cenozoic eras.
The geology of Afghanistan includes nearly one billion year old rocks from the Precambrian. The region experienced widespread marine transgressions and deposition during the Paleozoic and Mesozoic, that continued into the Cenozoic with the uplift of the Hindu Kush mountains.
The geology of Thailand includes deep crystalline metamorphic basement rocks, overlain by extensive sandstone, limestone, turbidites and some volcanic rocks. The region experienced complicated tectonics during the Paleozoic, long-running shallow water conditions and then renewed uplift and erosion in the past several million years ago.
The geology of Turkmenistan includes two different geological provinces: the Karakum, or South Turan Platform, and the Alpine Orogen.
The geology of Bulgaria consists of two major structural features. The Rhodope Massif in southern Bulgaria is made up of Archean, Proterozoic and Cambrian rocks and is a sub-province of the Thracian-Anatolian polymetallic province. It has dropped down, faulted basins filled with Cenozoic sediments and volcanic rocks. The Moesian Platform to the north extends into Romania and has Paleozoic rocks covered by rocks from the Mesozoic, typically buried by thick Danube River valley Quaternary sediments. In places, the Moesian Platform has small oil and gas fields. Bulgaria is a country in southeastern Europe. It is bordered by Romania to the north, Serbia and North Macedonia to the west, Greece and Turkey to the south, and the Black Sea to the east.
The geology of Lithuania consists of ancient Proterozoic basement rock overlain by thick sequences of Paleozoic, Mesozoic and Cenozoic marine sedimentary rocks, with some oil reserves, abundant limestone, dolomite, phosphorite and glauconite. Lithuania is a country in the Baltic region of northern-eastern Europe.
Geology of Latvia includes an ancient Archean and Proterozoic crystalline basement overlain with Neoproterozoic volcanic rocks and numerous sedimentary rock sequences from the Paleozoic, some from the Mesozoic and many from the recent Quaternary past. Latvia is a country in the Baltic region of Northern Europe.
The geology of Greece is highly structurally complex due to its position at the junction between the European and African tectonic plates.
The geology of Yukon includes sections of ancient Precambrian Proterozoic rock from the western edge of the proto-North American continent Laurentia, with several different island arc terranes added through the Paleozoic, Mesozoic and Cenozoic, driving volcanism, pluton formation and sedimentation.
