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85-480: Chronological history The Scandinavian Peninsula is located in Northern Europe , and roughly comprises the mainlands of Sweden , Norway and the northwestern area of Finland . The name of the peninsula is derived from the term Scandinavia , the cultural region of Denmark , Norway and Sweden . That cultural name is in turn derived from the name of Scania , the region at the southern extremity of

170-535: A characteristic fabric . All three types may melt again, and when this happens, new magma is formed, from which an igneous rock may once again solidify. Organic matter, such as coal, bitumen, oil, and natural gas, is linked mainly to organic-rich sedimentary rocks. To study all three types of rock, geologists evaluate the minerals of which they are composed and their other physical properties, such as texture and fabric . Geologists also study unlithified materials (referred to as superficial deposits ) that lie above

255-485: A petrographic microscope , where the minerals can be identified through their different properties in plane-polarized and cross-polarized light, including their birefringence , pleochroism , twinning , and interference properties with a conoscopic lens . In the electron microprobe, individual locations are analyzed for their exact chemical compositions and variation in composition within individual crystals. Stable and radioactive isotope studies provide insight into

340-506: A given location; geochemistry (a branch of geology) determines their absolute ages . By combining various petrological, crystallographic, and paleontological tools, geologists are able to chronicle the geological history of the Earth as a whole. One aspect is to demonstrate the age of the Earth . Geology provides evidence for plate tectonics , the evolutionary history of life , and the Earth's past climates . Geologists broadly study

425-635: A large portion of the present day eastern seacoast of Sweden and the Geats in Västergötland and Östergötland . These peoples spoke closely related dialects of an Indo-European language, Old Norse . Although political boundaries have shifted, descendants of these peoples still are the dominant populations in the peninsula in the early 21st century. Although the Nordic countries look back on more than 1,000 years of history as distinct political entities,

510-627: A length of less than a meter. Rocks at the depth to be ductilely stretched are often also metamorphosed. These stretched rocks can also pinch into lenses, known as boudins , after the French word for "sausage" because of their visual similarity. Where rock units slide past one another, strike-slip faults develop in shallow regions, and become shear zones at deeper depths where the rocks deform ductilely. The addition of new rock units, both depositionally and intrusively, often occurs during deformation. Faulting and other deformational processes result in

595-400: A means to provide information about geological history and the timing of geological events. The principle of uniformitarianism states that the geological processes observed in operation that modify the Earth's crust at present have worked in much the same way over geological time. A fundamental principle of geology advanced by the 18th-century Scottish physician and geologist James Hutton

680-608: A number of fields, laboratory, and numerical modeling methods to decipher Earth history and to understand the processes that occur on and inside the Earth. In typical geological investigations, geologists use primary information related to petrology (the study of rocks), stratigraphy (the study of sedimentary layers), and structural geology (the study of positions of rock units and their deformation). In many cases, geologists also study modern soils, rivers , landscapes , and glaciers ; investigate past and current life and biogeochemical pathways, and use geophysical methods to investigate

765-466: A relatively small percentage of its land is arable . The glaciation during the Ice Ages also deepened many of the river valleys, which were invaded by the sea when the ice melted, creating the noteworthy fjords of Norway. In the southern part of the peninsula, the glaciers deposited vast numbers of terminal moraines , configuring a very chaotic landscape. These terminal moraines covered all of what

850-499: A single environment and do not necessarily occur in a single order. The Hawaiian Islands , for example, consist almost entirely of layered basaltic lava flows. The sedimentary sequences of the mid-continental United States and the Grand Canyon in the southwestern United States contain almost-undeformed stacks of sedimentary rocks that have remained in place since Cambrian time. Other areas are much more geologically complex. In

935-400: A variety of applications. Dating of lava and volcanic ash layers found within a stratigraphic sequence can provide absolute age data for sedimentary rock units that do not contain radioactive isotopes and calibrate relative dating techniques. These methods can also be used to determine ages of pluton emplacement. Thermochemical techniques can be used to determine temperature profiles within

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1020-655: Is a major academic discipline , and it is central to geological engineering and plays an important role in geotechnical engineering . The majority of geological data comes from research on solid Earth materials. Meteorites and other extraterrestrial natural materials are also studied by geological methods. Minerals are naturally occurring elements and compounds with a definite homogeneous chemical composition and an ordered atomic arrangement. Each mineral has distinct physical properties, and there are many tests to determine each of them. Minerals are often identified through these tests. The specimens can be tested for: A rock

1105-422: Is accomplished in two primary ways: through faulting and folding . In the shallow crust, where brittle deformation can occur, thrust faults form, which causes the deeper rock to move on top of the shallower rock. Because deeper rock is often older, as noted by the principle of superposition , this can result in older rocks moving on top of younger ones. Movement along faults can result in folding, either because

1190-556: Is an igneous rock . This rock can be weathered and eroded , then redeposited and lithified into a sedimentary rock. Sedimentary rocks are mainly divided into four categories: sandstone, shale, carbonate, and evaporite. This group of classifications focuses partly on the size of sedimentary particles (sandstone and shale), and partly on mineralogy and formation processes (carbonation and evaporation). Igneous and sedimentary rocks can then be turned into metamorphic rocks by heat and pressure that change its mineral content, resulting in

1275-460: Is an intimate coupling between the movement of the plates on the surface and the convection of the mantle (that is, the heat transfer caused by the slow movement of ductile mantle rock). Thus, oceanic parts of plates and the adjoining mantle convection currents always move in the same direction – because the oceanic lithosphere is actually the rigid upper thermal boundary layer of the convecting mantle. This coupling between rigid plates moving on

1360-469: Is any naturally occurring solid mass or aggregate of minerals or mineraloids . Most research in geology is associated with the study of rocks, as they provide the primary record of the majority of the geological history of the Earth. There are three major types of rock: igneous , sedimentary , and metamorphic . The rock cycle illustrates the relationships among them (see diagram). When a rock solidifies or crystallizes from melt ( magma or lava ), it

1445-433: Is horizontal). The principle of superposition states that a sedimentary rock layer in a tectonically undisturbed sequence is younger than the one beneath it and older than the one above it. Logically a younger layer cannot slip beneath a layer previously deposited. This principle allows sedimentary layers to be viewed as a form of the vertical timeline, a partial or complete record of the time elapsed from deposition of

1530-540: Is now Denmark. Although the Baltic Shield is mostly geologically stable and hence resistant to the influences of other neighbouring tectonic formations, the weight of nearly four kilometres of ice during the Ice Ages caused all of the Scandinavian terrain to sink. When the ice sheet disappeared, the shield rose again, a tendency that continues to this day at a rate of about one metre per century. Conversely,

1615-484: Is primarily accomplished through normal faulting and through the ductile stretching and thinning. Normal faults drop rock units that are higher below those that are lower. This typically results in younger units ending up below older units. Stretching of units can result in their thinning. In fact, at one location within the Maria Fold and Thrust Belt , the entire sedimentary sequence of the Grand Canyon appears over

1700-568: Is that "the present is the key to the past." In Hutton's words: "the past history of our globe must be explained by what can be seen to be happening now." The principle of intrusive relationships concerns crosscutting intrusions. In geology, when an igneous intrusion cuts across a formation of sedimentary rock , it can be determined that the igneous intrusion is younger than the sedimentary rock. Different types of intrusions include stocks, laccoliths , batholiths , sills and dikes . The principle of cross-cutting relationships pertains to

1785-523: Is used for geologically young materials containing organic carbon . The geology of an area changes through time as rock units are deposited and inserted, and deformational processes alter their shapes and locations. Rock units are first emplaced either by deposition onto the surface or intrusion into the overlying rock . Deposition can occur when sediments settle onto the surface of the Earth and later lithify into sedimentary rock, or when as volcanic material such as volcanic ash or lava flows blanket

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1870-523: The Baltic Shield , a stable and large crust segment formed of very old, crystalline metamorphic rocks . Most of the soil covering this substrate was scraped by glaciers during the Ice Ages of antiquity, especially in northern Scandinavia, where the Baltic Shield is closest to the surface of the land. As a consequence of this scouring, the elevation of the land, and the cool-to-cold climate ,

1955-606: The Gulf of Finland disappeared, and the countries now surrounding them, including Germany, Poland, the other Baltic countries and Scandinavia, were directly joined by land. The largest peninsula in Europe, the Scandinavian Peninsula is approximately 1,850 kilometres (1,150 mi) long with a width varying approximately from 370 to 805 km (230 to 500 mi). The Scandinavian mountain range generally defines

2040-907: The Isle of Man , the United Kingdom and Ireland are included in Western Europe , while Estonia , Latvia and Lithuania are included in Eastern Europe . The World Geographical Scheme for Recording Plant Distributions is a biogeographical system developed by the international Biodiversity Information Standards (TDWG) organization, formerly the International Working Group on Taxonomic Databases. The WGSRPD standards, like other standards for data fields in botanical databases, were developed to promote "the wider and more effective dissemination of information about

2125-497: The Isle of Man , the United Kingdom and Ireland are included in Western Europe . In the CIA World Factbook , the description of each country includes information about "Location" under the heading "Geography", where the country is classified into a region. The following countries are included in their classification "northern Europe": as well as the dependent areas: In this classification Jersey , Guernsey ,

2210-572: The Mesolithic (8200 BC), up to the advent of agriculture in the Neolithic (3200 BC). The northern and central part of the peninsula is partially inhabited by the Sami , who began to arrive several thousand years after the Scandinavian Peninsula had already been inhabited in the south. In the earliest recorded periods they occupied the arctic and subarctic regions as well as the central part of

2295-738: The Napoleonic Wars and only attained full independence in 1905. Having been an autonomous grand duchy within the Russian Empire since 1809, Finland declared independence during the Soviet revolution of Russia in 1917. Iceland declared its independence from Denmark in 1944, while Denmark was under the occupation of Nazi Germany . Iceland was encouraged to do this by the British and American armed forces that were defending Iceland from Nazi invasion. The Wehrmacht invaded Norway in 1940 and

2380-679: The Nordic countries , often the British Isles and Baltic states , and sometimes Greenland . The United Nations geoscheme is a system devised by the United Nations Statistics Division (UNSD) which divides the countries of the world into regional and subregional groups, based on the M49 coding classification . The partition is for statistical convenience and does not imply any assumption regarding political or other affiliation of countries or territories. In

2465-780: The Red Army had invaded southeastern Finland in the Winter War (1939–40) and had taken a large area of territory away from Finland. Sweden remained a neutral country during the First World War , the Korean War and the Cold War . In 1945, Norway, Denmark and Iceland were founding members of the United Nations . Sweden joined the U.N. soon after. Finland joined during the 1950s. The first Secretary General of

2550-506: The bedrock . This study is often known as Quaternary geology , after the Quaternary period of geologic history, which is the most recent period of geologic time. Magma is the original unlithified source of all igneous rocks . The active flow of molten rock is closely studied in volcanology , and igneous petrology aims to determine the history of igneous rocks from their original molten source to their final crystallization. In

2635-512: The geochemical evolution of rock units. Petrologists can also use fluid inclusion data and perform high temperature and pressure physical experiments to understand the temperatures and pressures at which different mineral phases appear, and how they change through igneous and metamorphic processes. This research can be extrapolated to the field to understand metamorphic processes and the conditions of crystallization of igneous rocks. This work can also help to explain processes that occur within

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2720-402: The mantle below (separated within itself by seismic discontinuities at 410 and 660 kilometers), and the outer core and inner core below that. More recently, seismologists have been able to create detailed images of wave speeds inside the earth in the same way a doctor images a body in a CT scan . These images have led to a much more detailed view of the interior of the Earth, and have replaced

2805-440: The 1960s, it was discovered that the Earth's lithosphere , which includes the crust and rigid uppermost portion of the upper mantle , is separated into tectonic plates that move across the plastically deforming, solid, upper mantle, which is called the asthenosphere . This theory is supported by several types of observations, including seafloor spreading and the global distribution of mountain terrain and seismicity. There

2890-766: The British Isles including the Brythonic Welsh and the Goidelic Scots Gaelic and Irish . The Celtic languages Cornish and Manx have been revived since becoming classed as extinct, being now spoken to a limited extent in Cornwall and the Isle of Man respectively. The Norman languages of Jèrriais and Guernésiais are spoken in Jersey and Guernsey, though are listed as endangered due to

2975-424: The Earth, such as subduction and magma chamber evolution. Structural geologists use microscopic analysis of oriented thin sections of geological samples to observe the fabric within the rocks, which gives information about strain within the crystalline structure of the rocks. They also plot and combine measurements of geological structures to better understand the orientations of faults and folds to reconstruct

3060-528: The European Union comprises most of the northern European states, plus the Netherlands. Geology Geology describes the structure of the Earth on and beneath its surface and the processes that have shaped that structure. Geologists study the mineralogical composition of rocks in order to get insight into their history of formation. Geology determines the relative ages of rocks found at

3145-637: The German Army occupied all of Norway until May 1945. With the acquiescence of the Kingdom of Sweden , German troops moved from northern Norway, across northern Sweden, into Finland, which had become an ally of Nazi Germany. Then, in the spring of 1941, the German Army and the Finnish Army invaded the Soviet Union together. The Republic of Finland had a grievance against the Soviet Union because

3230-484: The Grand Canyon in the southwestern United States being a very visible example, the lower rock units were metamorphosed and deformed, and then deformation ended and the upper, undeformed units were deposited. Although any amount of rock emplacement and rock deformation can occur, and they can occur any number of times, these concepts provide a guide to understanding the geological history of an area. Geologists use

3315-469: The Scandinavian Peninsula lies north of the Arctic Circle , its northernmost point being at Cape Nordkyn , Norway . The climate across Scandinavia varies from tundra ( Köppen : ET) and subarctic (Dfc) in the north, with cool marine west coast climate (Cfc) in northwestern coastal areas reaching just north of Lofoten , to humid continental (Dfb) in the central portion and marine west coast (Cfb) in

3400-544: The Soviet Union and all other potential invaders. Finland later joined NATO in 2023, and Sweden in 2024, in response to the 2022 Russian invasion of Ukraine . Sweden and Finland joined the European Union in 1995. Norway, however, remains outside the Union. Northern Europe The northern region of Europe has several definitions. A restrictive definition may describe northern Europe as being roughly north of

3485-546: The UN geoscheme, the following countries are classified as being in northern Europe: as well as the dependent areas: EuroVoc is a multilingual thesaurus maintained by the Publications Office of the European Union , giving definitions of terms for official use. In the definition of "northern Europe", the following countries are included: as well as the dependent area: In this classification Jersey , Guernsey ,

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3570-715: The United Kingdom and the Republic of Ireland, however, the West Germanic language Scots is also spoken as a minority language in parts of Scotland and Ireland. Beyond this, the Finnic languages of Finnish and Estonian are the most common first languages of Finland and Estonia respectively. The Baltic languages of Lithuanian and Latvian are the most common first languages of Lithuania and Latvia respectively. A number of Celtic languages are spoken in

3655-574: The United Nations , Trygve Lie , was a Norwegian citizen. The second Secretary General of the United Nations, Dag Hammarskjöld , was a Swedish citizen. Thus the people of the Scandinavian Peninsula had a strong influence in international affairs during the 20th century. In 1949, Norway, Denmark and Iceland became founding members of the North Atlantic Treaty Organisation for their defence against East Germany,

3740-537: The beginning of the 20th century, advancement in geological science was facilitated by the ability to obtain accurate absolute dates to geological events using radioactive isotopes and other methods. This changed the understanding of geological time. Previously, geologists could only use fossils and stratigraphic correlation to date sections of rock relative to one another. With isotopic dates, it became possible to assign absolute ages to rock units, and these absolute dates could be applied to fossil sequences in which there

3825-455: The border between Norway and Sweden. Its highest elevation was Glittertinden in Norway at 2,470 m (8,104 ft) above sea level, but since the glacier at its summit partially melted, the highest elevation is at 2,469 m (8,100 ft) at Galdhøpiggen , also in Norway. These mountains also have the largest glacier on the mainland of Europe, Jostedalsbreen . About one quarter of

3910-677: The borders were still fluid, with Finland gaining access to the Barents Sea in 1920, but ceding this territory to the Soviet Union in 1944. Denmark, Sweden and the Russian Empire dominated the political relationships on the Scandinavian Peninsula for centuries, with Iceland , Finland and Norway only gaining their full independence during the 20th century. The Kingdom of Norway  – long held in personal union by Denmark  – fell to Sweden after

3995-514: The building of a railway from northwestern Sweden to the Norwegian seaport of Narvik so that the iron ore could be exported by ship to places like southern Sweden, Germany, Great Britain and Belgium for smelting into iron and steel. This railway is in a region of Norway and Sweden that otherwise does not have any railways because of the very rugged terrain, mountains and fjords of that part of Scandinavia. The first recorded human presence in

4080-515: The creation of topographic gradients, causing material on the rock unit that is increasing in elevation to be eroded by hillslopes and channels. These sediments are deposited on the rock unit that is going down. Continual motion along the fault maintains the topographic gradient in spite of the movement of sediment and continues to create accommodation space for the material to deposit. Deformational events are often also associated with volcanism and igneous activity. Volcanic ashes and lavas accumulate on

4165-437: The crust, the uplift of mountain ranges, and paleo-topography. Fractionation of the lanthanide series elements is used to compute ages since rocks were removed from the mantle. Other methods are used for more recent events. Optically stimulated luminescence and cosmogenic radionuclide dating are used to date surfaces and/or erosion rates. Dendrochronology can also be used for the dating of landscapes. Radiocarbon dating

4250-570: The fault is a normal fault or a thrust fault . The principle of inclusions and components states that, with sedimentary rocks, if inclusions (or clasts ) are found in a formation, then the inclusions must be older than the formation that contains them. For example, in sedimentary rocks, it is common for gravel from an older formation to be ripped up and included in a newer layer. A similar situation with igneous rocks occurs when xenoliths are found. These foreign bodies are picked up as magma or lava flows, and are incorporated, later to cool in

4335-403: The faults are not planar or because rock layers are dragged along, forming drag folds as slip occurs along the fault. Deeper in the Earth, rocks behave plastically and fold instead of faulting. These folds can either be those where the material in the center of the fold buckles upwards, creating " antiforms ", or where it buckles downwards, creating " synforms ". If the tops of the rock units within

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4420-483: The folds remain pointing upwards, they are called anticlines and synclines , respectively. If some of the units in the fold are facing downward, the structure is called an overturned anticline or syncline, and if all of the rock units are overturned or the correct up-direction is unknown, they are simply called by the most general terms, antiforms, and synforms. Even higher pressures and temperatures during horizontal shortening can cause both folding and metamorphism of

4505-404: The formation of faults and the age of the sequences through which they cut. Faults are younger than the rocks they cut; accordingly, if a fault is found that penetrates some formations but not those on top of it, then the formations that were cut are older than the fault, and the ones that are not cut must be younger than the fault. Finding the key bed in these situations may help determine whether

4590-476: The highest standards of living in the world. They often score highly on surveys measuring quality of life, such as the Human Development Index . Aside from the United Kingdom, they generally have a small population relative to their size, most of whom live in cities. The quality of education in much of Northern Europe is rated highly in international rankings, with Estonia and Finland topping

4675-627: The increasing prominence of English in the islands. While not the most common first languages in any country, Sámi languages such as North Sámi , Lule Sámi and South Sámi are spoken in the transnational region of Sápmi and are listed as endangered. During the Early Middle Ages , the Roman Catholic Church expanded into northern Europe and spread Christianity among the Germanic peoples . Christianity reached

4760-423: The internal composition and structure of the Earth. Seismologists can use the arrival times of seismic waves to image the interior of the Earth. Early advances in this field showed the existence of a liquid outer core (where shear waves were not able to propagate) and a dense solid inner core . These advances led to the development of a layered model of the Earth, with a lithosphere (including crust) on top,

4845-519: The international boundaries came late and emerged gradually. It was not until the middle of the 17th century that Sweden had a secure outlet on the Kattegat and control of the south Baltic coast. The Swedish and Norwegian boundaries were finally agreed and marked out in 1751. The Finnish-Norwegian border on the peninsula was established after extensive negotiation in 1809, and the common Norwegian-Russian districts were not partitioned until 1826. Even then

4930-464: The later end of the scale, it is marked by the present day (in the Holocene epoch ). The following five timelines show the geologic time scale to scale. The first shows the entire time from the formation of the Earth to the present, but this gives little space for the most recent eon. The second timeline shows an expanded view of the most recent eon. In a similar way, the most recent era is expanded in

5015-527: The list among the OECD countries in Europe. Germanic languages are widely spoken in northern Europe with North Germanic languages being the most common first language in the Faroe Islands ( Faroese ), Iceland ( Icelandic ), Denmark ( Danish ), Norway ( Norwegian ) and Sweden ( Swedish ). The West Germanic language English is the most common first language in Jersey, Guernsey, the Isle of Man,

5100-454: The lowest layer to deposition of the highest bed. The principle of faunal succession is based on the appearance of fossils in sedimentary rocks. As organisms exist during the same period throughout the world, their presence or (sometimes) absence provides a relative age of the formations where they appear. Based on principles that William Smith laid out almost a hundred years before the publication of Charles Darwin 's theory of evolution ,

5185-497: The mantle and show the crystallographic structures expected in the inner core of the Earth. The geological time scale encompasses the history of the Earth. It is bracketed at the earliest by the dates of the first Solar System material at 4.567 Ga (or 4.567 billion years ago) and the formation of the Earth at 4.54 Ga (4.54 billion years), which is the beginning of the Hadean eon  – a division of geological time. At

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5270-405: The matrix. As a result, xenoliths are older than the rock that contains them. The principle of original horizontality states that the deposition of sediments occurs as essentially horizontal beds. Observation of modern marine and non-marine sediments in a wide variety of environments supports this generalization (although cross-bedding is inclined, the overall orientation of cross-bedded units

5355-616: The mountainous western seaboard, Scotland and Scandinavia , and also often includes part of the large plain east of the Baltic Sea . The entire region's climate is at least mildly affected by the Gulf Stream . From the west climates vary from maritime and maritime subarctic climates. In the north and central climates are generally subarctic or Arctic and to the east climates are mostly subarctic and temperate / continental . Just as both climate and relief are variable across

5440-614: The peninsula as far south as Dalarna , Sweden. They speak the Sami language , a non- Indo-European language of the Uralic family which is related to Finnish and Estonian . The first inhabitants of the peninsula were the Norwegians on the west coast of Norway, the Danes in what is now southern and western Sweden and southeastern Norway, the Svear in the region around Mälaren as well as

5525-570: The peninsula of Jutland , the Baltic plain that lies to the east, and the many islands that lie offshore from mainland northern Europe and the main European continent. In some cases, Greenland is also included, although it is only politically European, comprising part of the Kingdom of Denmark , and not considered to be geographically in Europe. The area is partly mountainous, including the northern volcanic islands of Iceland and Jan Mayen , and

5610-569: The peninsula which was for centuries a part of Denmark, which is the ancestral home of the Danes , and is now part of Sweden. The Scandinavian Peninsula is the largest of the peninsulas of Europe , with a greater area than the Balkan , Iberian and Italian peninsulas. During the Ice Ages , the sea level of the Atlantic Ocean dropped so much that the Baltic Sea , the Gulf of Bothnia and

5695-433: The peoples of Scandinavia and the Baltic region in later centuries. The Latin alphabet along with the influence of Western Christianity spread northward from Rome , leading to written English , German , Dutch , Danish , Norwegian , Swedish , Icelandic , Latvian , Lithuanian , Estonian , Finnish and Sámi languages . The Sámi were the last peoples to be converted in the 18th century. The Hansa group in

5780-569: The principles of succession developed independently of evolutionary thought. The principle becomes quite complex, however, given the uncertainties of fossilization, localization of fossil types due to lateral changes in habitat ( facies change in sedimentary strata), and that not all fossils formed globally at the same time. Geologists also use methods to determine the absolute age of rock samples and geological events. These dates are useful on their own and may also be used in conjunction with relative dating methods or to calibrate relative methods. At

5865-564: The properties and processes of Earth and other terrestrial planets. Geologists use a wide variety of methods to understand the Earth's structure and evolution, including fieldwork , rock description , geophysical techniques , chemical analysis , physical experiments , and numerical modelling . In practical terms, geology is important for mineral and hydrocarbon exploration and exploitation, evaluating water resources , understanding natural hazards , remediating environmental problems, and providing insights into past climate change . Geology

5950-483: The region, so too is vegetation, with sparse tundra in the north and high mountains, boreal forest on the north-eastern and central regions temperate coniferous forests (formerly of which a majority was in the Scottish Highlands and south west Norway ) and temperate broadleaf forests growing in the south, west and temperate east. There are various definitions of northern Europe which always include

6035-428: The rocks. This metamorphism causes changes in the mineral composition of the rocks; creates a foliation , or planar surface, that is related to mineral growth under stress. This can remove signs of the original textures of the rocks, such as bedding in sedimentary rocks, flow features of lavas , and crystal patterns in crystalline rocks . Extension causes the rock units as a whole to become longer and thinner. This

6120-433: The simplified layered model with a much more dynamic model. Mineralogists have been able to use the pressure and temperature data from the seismic and modeling studies alongside knowledge of the elemental composition of the Earth to reproduce these conditions in experimental settings and measure changes within the crystal structure. These studies explain the chemical changes associated with the major seismic discontinuities in

6205-694: The south and southwest. The region is rich in timber, iron and copper with the best farmland in southern Sweden. Large petroleum and natural-gas deposits have been found off Norway's coast in the North Sea and the Atlantic Ocean. Much of the population of the Scandinavian Peninsula is naturally concentrated in its southern part, which is also its agricultural region. The largest cities of the peninsula are Stockholm , Sweden; Oslo , Norway; Gothenburg , Sweden; Malmö , Sweden and Bergen , Norway, in that order. The Scandinavian Peninsula occupies part of

6290-412: The southern area of the peninsula and Denmark dates from 12,000 years ago. As the ice sheets from the glaciation retreated, the climate allowed a tundra biome that attracted reindeer hunters. The climate warmed up gradually, favouring the growth of evergreen trees first and then deciduous forest which brought animals like aurochs . Groups of hunter-fisher-gatherers started to inhabit the area from

6375-401: The southern coast of the Baltic Sea , which is about 54°N , or may be based on other geographical factors such as climate and ecology . The climate is mainly Oceanic climate (Cfb), Humid continental climate (Dfb), Subarctic climate (Dfc and Dsc) and Tundra (ET). Northern Europe might be defined roughly to include some or all of the following areas: British Isles , Fennoscandia ,

6460-499: The southern part has tended to sink to compensate, causing flooding of the Low Countries and Denmark. The crystalline substrate of the land and absence of soil in many places have exposed mineral deposits of metal ores , such as those of iron , copper , nickel , zinc , silver and gold . The very most valuable of these have been the deposits of iron ore in northwestern Sweden. In the 19th century these deposits prompted

6545-532: The southwestern United States, sedimentary, volcanic, and intrusive rocks have been metamorphosed, faulted, foliated, and folded. Even older rocks, such as the Acasta gneiss of the Slave craton in northwestern Canada , the oldest known rock in the world have been metamorphosed to the point where their origin is indiscernible without laboratory analysis. In addition, these processes can occur in stages. In many places,

6630-550: The subsurface. Sub-specialities of geology may distinguish endogenous and exogenous geology. Geological field work varies depending on the task at hand. Typical fieldwork could consist of: In addition to identifying rocks in the field ( lithology ), petrologists identify rock samples in the laboratory. Two of the primary methods for identifying rocks in the laboratory are through optical microscopy and by using an electron microprobe . In an optical mineralogy analysis, petrologists analyze thin sections of rock samples using

6715-407: The surface of the Earth and the convecting mantle is called plate tectonics . The development of plate tectonics has provided a physical basis for many observations of the solid Earth . Long linear regions of geological features are explained as plate boundaries: Plate tectonics has provided a mechanism for Alfred Wegener 's theory of continental drift , in which the continents move across

6800-488: The surface of the Earth over geological time. They also provided a driving force for crustal deformation, and a new setting for the observations of structural geology. The power of the theory of plate tectonics lies in its ability to combine all of these observations into a single theory of how the lithosphere moves over the convecting mantle. Advances in seismology , computer modeling , and mineralogy and crystallography at high temperatures and pressures give insights into

6885-479: The surface, and igneous intrusions enter from below. Dikes , long, planar igneous intrusions, enter along cracks, and therefore often form in large numbers in areas that are being actively deformed. This can result in the emplacement of dike swarms , such as those that are observable across the Canadian shield, or rings of dikes around the lava tube of a volcano. All of these processes do not necessarily occur in

6970-742: The surface. Igneous intrusions such as batholiths , laccoliths , dikes , and sills , push upwards into the overlying rock, and crystallize as they intrude. After the initial sequence of rocks has been deposited, the rock units can be deformed and/or metamorphosed . Deformation typically occurs as a result of horizontal shortening, horizontal extension , or side-to-side ( strike-slip ) motion. These structural regimes broadly relate to convergent boundaries , divergent boundaries , and transform boundaries, respectively, between tectonic plates. When rock units are placed under horizontal compression , they shorten and become thicker. Because rock units, other than muds, do not significantly change in volume , this

7055-407: The third timeline, the most recent period is expanded in the fourth timeline, and the most recent epoch is expanded in the fifth timeline. Horizontal scale is Millions of years (above timelines) / Thousands of years (below timeline) Epochs: Methods for relative dating were developed when geology first emerged as a natural science . Geologists still use the following principles today as

7140-452: The world's heritage of biological organisms for the benefit of the world at large". The system provides clear definitions and codes for recording plant distributions at four scales or levels, from "botanical continents" down to parts of large countries. The following countries are included in their classification of "northern Europe": as well as the dependent areas: Countries in northern Europe generally have developed economies and some of

7225-615: Was datable material, converting the old relative ages into new absolute ages. For many geological applications, isotope ratios of radioactive elements are measured in minerals that give the amount of time that has passed since a rock passed through its particular closure temperature , the point at which different radiometric isotopes stop diffusing into and out of the crystal lattice . These are used in geochronologic and thermochronologic studies. Common methods include uranium–lead dating , potassium–argon dating , argon–argon dating and uranium–thorium dating . These methods are used for

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