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137-799: Unconformities tend to reflect long-term changes in the pattern of the accumulation of sedimentary or igneous strata in low-lying areas (often ocean basins, such as the Gulf of Mexico or the North Sea , but also Bangladesh and much of Brazil ), then being uplifted and eroded (such as the ongoing Himalayan orogeny , the older Laramide orogeny of the Rocky Mountains , or much older Appalachian (Alleghanian) and Ouachita orogenies), then subsequently subsiding, eventually to be buried under younger sediments. The intervening periods of tectonic uplift are generally periods of mountain building, often due to

274-522: A Baltimore newspaper editor, Frank Key Howard , after he criticized Lincoln in an editorial for ignoring Taney's ruling. In Missouri, an elected convention on secession voted to remain in the Union. When pro-Confederate Governor Claiborne Fox Jackson called out the state militia, it was attacked by federal forces under General Nathaniel Lyon , who chased the governor and rest of the State Guard to

411-525: A blockade of the Confederacy to suffocate the South into surrender. Lincoln adopted parts of the plan but opted for a more active war strategy. In April 1861, Lincoln announced a blockade of all Southern ports; commercial ships could not get insurance, ending regular traffic. The South blundered by embargoing cotton exports before the blockade was fully effective; by the time they reversed this decision, it

548-459: A combination of these processes. Other mechanisms, such as melting from a meteorite impact , are less important today, but impacts during the accretion of the Earth led to extensive melting, and the outer several hundred kilometres of our early Earth was probably an ocean of magma. Impacts of large meteorites in the last few hundred million years have been proposed as one mechanism responsible for

685-405: A crystalline basement formed of a great variety of metamorphic and igneous rocks, including granulite and granite. Oceanic crust is composed primarily of basalt and gabbro . Both continental and oceanic crust rest on peridotite of the mantle. Rocks may melt in response to a decrease in pressure, to a change in composition (such as an addition of water), to an increase in temperature, or to

822-400: A deep sea environment about 425 million years ago. The overlying Devonian strata were deposited by rivers and streams about 345 million years ago. Thus, this unconformity reflects a gap of about 80 million years during which deep sea sediments were lithified , folded , and uplifted ; later deeply eroded and weathered subaerially; and finally buried by river and stream sediments. Exposures of

959-705: A draft law in April 1862 for men aged 18–35, with exemptions for overseers, government officials, and clergymen. The U.S. Congress followed in July, authorizing a militia draft within states that could not meet their quota with volunteers. European immigrants joined the Union Army in large numbers, including 177,000 born in Germany and 144,000 in Ireland. About 50,000 Canadians served, around 2,500 of whom were black. When

1096-483: A firm hand by Lincoln tamed Seward, who was a staunch Lincoln ally. Lincoln decided holding the fort, which would require reinforcing it, was the only workable option. On April 6, Lincoln informed the Governor of South Carolina that a ship with food but no ammunition would attempt to supply the fort. Historian McPherson describes this win-win approach as "the first sign of the mastery that would mark Lincoln's presidency";

1233-527: A huge mass of analytical data—over 230,000 rock analyses can be accessed on the web through a site sponsored by the U. S. National Science Foundation (see the External Link to EarthChem). The single most important component is silica, SiO 2 , whether occurring as quartz or combined with other oxides as feldspars or other minerals. Both intrusive and volcanic rocks are grouped chemically by total silica content into broad categories. This classification

1370-479: A man until she died in 1915 at the age of 71. The small U.S. Navy of 1861 rapidly expanded to 6,000 officers and 45,000 sailors by 1865, with 671 vessels totaling 510,396 tons. Its mission was to blockade Confederate ports, control the river system, defend against Confederate raiders on the high seas, and be ready for a possible war with the British Royal Navy . The main riverine war was fought in

1507-653: A microscope for fine-grained volcanic rock, and may be impossible for glassy volcanic rock. The rock must then be classified chemically. Mineralogical classification of an intrusive rock begins by determining if the rock is ultramafic, a carbonatite, or a lamprophyre . An ultramafic rock contains more than 90% of iron- and magnesium-rich minerals such as hornblende, pyroxene, or olivine, and such rocks have their own classification scheme. Likewise, rocks containing more than 50% carbonate minerals are classified as carbonatites, while lamprophyres are rare ultrapotassic rocks. Both are further classified based on detailed mineralogy. In

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1644-451: A patriotic fire under the North. On April 15, Lincoln called on the states to field 75,000 volunteer troops for 90 days; impassioned Union states met the quotas quickly. On May 3, 1861, Lincoln called for an additional 42,000 volunteers for three years. Shortly after this, Virginia , Tennessee , Arkansas , and North Carolina seceded and joined the Confederacy. To reward Virginia,

1781-421: A republic, but a third challenge faced the nation: maintaining a republic based on the people's vote, in the face of an attempt to destroy it. Lincoln's election provoked South Carolina 's legislature to call a state convention to consider secession. South Carolina had done more than any other state to advance the notion that a state had the right to nullify federal laws and even secede. On December 20, 1860,

1918-757: A sequence of Phanerozoic strata equivalent to those found in the Grand Canyon. At the base of this sequence, the Great Unconformity, with the Tapeats Sandstone of the Tonto Group overlying the Vishnu Basement Rocks, is well exposed in a manner that is atypical and scientifically significant in its combination of extent and accessibility. This exposure is frequently illustrated in popular and educational publications, and

2055-553: A simplified compositional classification, igneous rock types are categorized into felsic or mafic based on the abundance of silicate minerals in the Bowen's Series. Rocks dominated by quartz, plagioclase, alkali feldspar and muscovite are felsic. Mafic rocks are primarily composed of biotite, hornblende, pyroxene and olivine. Generally, felsic rocks are light colored and mafic rocks are darker colored. For textural classification, igneous rocks that have crystals large enough to be seen by

2192-462: A viscosity similar to thick, cold molasses or even rubber when erupted. Felsic magma, such as rhyolite , is usually erupted at low temperature and is up to 10,000 times as viscous as basalt. Volcanoes with rhyolitic magma commonly erupt explosively, and rhyolitic lava flows are typically of limited extent and have steep margins because the magma is so viscous. Felsic and intermediate magmas that erupt often do so violently, with explosions driven by

2329-569: A wide range of geological settings: shields, platforms, orogens, basins, large igneous provinces, extended crust and oceanic crust. Igneous and metamorphic rocks make up 90–95% of the top 16 kilometres (9.9 mi) of the Earth's crust by volume. Igneous rocks form about 15% of the Earth's current land surface. Most of the Earth's oceanic crust is made of igneous rock. Igneous rocks are also geologically important because: Igneous rocks can be either intrusive ( plutonic and hypabyssal) or extrusive ( volcanic ). Intrusive igneous rocks make up

2466-589: Is a nonconformity . The break between the Tonto Group and the Grand Canyon Supergroup is an angular unconformity. Powell's Great Unconformity is part of a continent-wide unconformity that extends across Laurentia , the ancient core of North America. It was first recognized twelve years before Powell's expedition by John Newberry in New Mexico , during the Ives expedition of 1857–1858. However,

2603-531: Is an angular unconformity that consists of gently dipping, reddish, Upper Devonian and Lower Carboniferous breccias , sandstones , and conglomerates of the Old Red Sandstone overlying deeply eroded, near-vertical, greyish, Silurian ( Llandovery ) greywackes and shales . The Llandovery greywackes and graptolite -bearing shales of the Gala Group were deposited by turbidity currents in

2740-584: Is an example. The molten rock, which typically contains suspended crystals and dissolved gases, is called magma . It rises because it is less dense than the rock from which it was extracted. When magma reaches the surface, it is called lava . Eruptions of volcanoes into air are termed subaerial , whereas those occurring underneath the ocean are termed submarine . Black smokers and mid-ocean ridge basalt are examples of submarine volcanic activity. The volume of extrusive rock erupted annually by volcanoes varies with plate tectonic setting. Extrusive rock

2877-728: Is distinguishable from the other two on the TAS diagram, being higher in total alkali oxides for a given silica content, but the tholeiitic and calc-alkaline series occupy approximately the same part of the TAS diagram. They are distinguished by comparing total alkali with iron and magnesium content. These three magma series occur in a range of plate tectonic settings. Tholeiitic magma series rocks are found, for example, at mid-ocean ridges, back-arc basins , oceanic islands formed by hotspots, island arcs and continental large igneous provinces . All three series are found in relatively close proximity to each other at subduction zones where their distribution

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3014-595: Is expressed differently for major and minor elements and for trace elements. Contents of major and minor elements are conventionally expressed as weight percent oxides (e.g., 51% SiO 2 , and 1.50% TiO 2 ). Abundances of trace elements are conventionally expressed as parts per million by weight (e.g., 420 ppm Ni, and 5.1 ppm Sm). The term "trace element" is typically used for elements present in most rocks at abundances less than 100 ppm or so, but some trace elements may be present in some rocks at abundances exceeding 1,000 ppm. The diversity of rock compositions has been defined by

3151-506: Is formed by the cooling of molten magma on the earth's surface. The magma, which is brought to the surface through fissures or volcanic eruptions , rapidly solidifies. Hence such rocks are fine-grained ( aphanitic ) or even glassy. Basalt is the most common extrusive igneous rock and forms lava flows, lava sheets and lava plateaus. Some kinds of basalt solidify to form long polygonal columns . The Giant's Causeway in Antrim, Northern Ireland

3288-436: Is most often used to classify plutonic rocks. Chemical classifications are preferred to classify volcanic rocks, with phenocryst species used as a prefix, e.g. "olivine-bearing picrite" or "orthoclase-phyric rhyolite". The IUGS recommends classifying igneous rocks by their mineral composition whenever possible. This is straightforward for coarse-grained intrusive igneous rock, but may require examination of thin sections under

3425-529: Is often part of geological fieldtrips. There is a gap of about 1.2 billion years where 550 million year old strata of the Tapeats Sandstone rests on 1.7 billion (1700 million) year old Vishnu Basement Rocks. The term "Great Unconformity" has also been used to refer to the anomalous concentration of unconformities, including basement nonconformities, below the base of the Cambrian. Charles Walcott

3562-496: Is produced in the following proportions: The behaviour of lava depends upon its viscosity , which is determined by temperature, composition, and crystal content. High-temperature magma, most of which is basaltic in composition, behaves in a manner similar to thick oil and, as it cools, treacle . Long, thin basalt flows with pahoehoe surfaces are common. Intermediate composition magma, such as andesite , tends to form cinder cones of intermingled ash , tuff and lava, and may have

3699-402: Is related to depth and the age of the subduction zone. The tholeiitic magma series is well represented above young subduction zones formed by magma from relatively shallow depth. The calc-alkaline and alkaline series are seen in mature subduction zones, and are related to magma of greater depths. Andesite and basaltic andesite are the most abundant volcanic rock in island arc which is indicative of

3836-487: Is summarized in the following table: The percentage of alkali metal oxides ( Na 2 O plus K 2 O ) is second only to silica in its importance for chemically classifying volcanic rock. The silica and alkali metal oxide percentages are used to place volcanic rock on the TAS diagram , which is sufficient to immediately classify most volcanic rocks. Rocks in some fields, such as the trachyandesite field, are further classified by

3973-528: Is widely accepted that there was a combination of more than one event which may have caused such an extensive phenomenon. One example is a large glaciation event which took place during the Neoproterozoic , starting around 720 million years ago. This is also when a significant glaciation event known as Snowball Earth occurred. Snowball Earth periods covered almost the entire planet with ice. The areas that underwent glaciation were approximately those where

4110-490: The 1860 presidential election . Southern leaders feared Lincoln would stop slavery's expansion and put it on a course toward extinction. His victory triggered declarations of secession by seven slave states of the Deep South , all of whose riverfront or coastal economies were based on cotton that was cultivated by slave labor. Lincoln was not inaugurated until March 4, 1861, giving the South time to prepare for war during

4247-541: The Battle of Appomattox Court House , setting in motion the end of the war . Lincoln led the nation through that victory but was shot by an assassin on April 14. By the end of the war, much of the South's infrastructure was destroyed. The Confederacy collapsed, slavery was abolished, and four million enslaved black people were freed. The war-torn nation then entered the Reconstruction era in an attempt to rebuild

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4384-689: The Dred Scott decision was proof the Southern states had no reason to secede and that the Union "was intended to be perpetual". He added, however, that "The power by force of arms to compel a State to remain in the Union" was not among the "enumerated powers granted to Congress". A quarter of the US army—the Texas garrison—was surrendered in February to state forces by its general, David E. Twiggs , who joined

4521-618: The Emancipation Proclamation went into effect in January 1863, ex-slaves were energetically recruited to meet state quotas. States and local communities offered higher cash bonuses for white volunteers. Congress tightened the draft law in March 1863. Men selected in the draft could provide substitutes or, until mid-1864, pay commutation money. Many eligibles pooled their money to cover the cost of anyone drafted. Families used

4658-479: The IUGS , this is often impractical, and chemical classification is done instead using the TAS classification . Igneous rocks are classified according to mode of occurrence, texture, mineralogy, chemical composition, and the geometry of the igneous body. The classification of the many types of igneous rocks can provide important information about the conditions under which they formed. Two important variables used for

4795-734: The Neoproterozoic Snowball Earth glaciations . Alternatively, it has been proposed that multiple smaller events, such as the formation and breakup of Rodinia , created many unconformities worldwide. Evidence indicates that the Pikes Peak unconformity was formed before the Snowball Earth glaciations. There is currently no widely accepted explanation for the Great Unconformity among geoscientists . There are hypotheses that have been proposed; it

4932-592: The Virginia to prevent its capture, while the Union built many copies of the Monitor . The Confederacy's efforts to obtain warships from Great Britain failed, as Britain had no interest in selling warships to a nation at war with a stronger enemy and feared souring relations with the U.S. By early 1861, General Winfield Scott had devised the Anaconda Plan to win the war with minimal bloodshed, calling for

5069-453: The convection of solid mantle, it will cool slightly as it expands in an adiabatic process , but the cooling is only about 0.3 °C per kilometre. Experimental studies of appropriate peridotite samples document that the solidus temperatures increase by 3 °C to 4 °C per kilometre. If the rock rises far enough, it will begin to melt. Melt droplets can coalesce into larger volumes and be intruded upwards. This process of melting from

5206-526: The electrical telegraph , steamships, the ironclad warship , and mass-produced weapons were widely used. The war left an estimated 698,000 soldiers dead, along with an undetermined number of civilian casualties, making the Civil War the deadliest military conflict in American history. The technology and brutality of the Civil War foreshadowed the coming World Wars . The origins of the war were rooted in

5343-473: The 1640s and is derived either from French granit or Italian granito , meaning simply "granulate rock". The term rhyolite was introduced in 1860 by the German traveler and geologist Ferdinand von Richthofen The naming of new rock types accelerated in the 19th century and peaked in the early 20th century. Much of the early classification of igneous rocks was based on the geological age and occurrence of

5480-406: The 168,649 men procured for the Union through the draft, 117,986 were substitutes, leaving only 50,663 who were conscripted. In the North and South, draft laws were highly unpopular. In the North, some 120,000 men evaded conscription, many fleeing to Canada, and another 280,000 soldiers deserted during the war. At least 100,000 Southerners deserted, about 10 percent of the total. Southern desertion

5617-434: The 1960s. However, the concept of normative mineralogy has endured, and the work of Cross and his coinvestigators inspired a flurry of new classification schemes. Among these was the classification scheme of M.A. Peacock, which divided igneous rocks into four series: the alkalic, the alkali-calcic, the calc-alkali, and the calcic series. His definition of the alkali series, and the term calc-alkali, continue in use as part of

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5754-624: The 4 million enslaved people in the country. To the west, the Union first destroyed the Confederacy's river navy by the summer of 1862, then much of its western armies, and seized New Orleans . The successful 1863 Union siege of Vicksburg split the Confederacy in two at the Mississippi River , while Confederate General Robert E. Lee 's incursion north failed at the Battle of Gettysburg . Western successes led to General Ulysses S. Grant 's command of all Union armies in 1864. Inflicting an ever-tightening naval blockade of Confederate ports,

5891-601: The Atlantic and Pacific oceans. Insurance rates soared, and the American flag virtually disappeared from international waters, though reflagging ships with European flags allowed them to continue operating unmolested. After the war, the U.S. government demanded Britain compensate it for the damage caused by blockade runners and raiders outfitted in British ports. Britain paid the U.S. $ 15 million in 1871, but only for commerce raiding. Dinçaslan argues that another outcome of

6028-566: The Bahamas in exchange for high-priced cotton. Many were lightweight and designed for speed, only carrying small amounts of cotton back to England. When the Union Navy seized a blockade runner, the ship and cargo were condemned as a prize of war and sold, with proceeds given to the Navy sailors; the captured crewmen, mostly British, were released. The Southern economy nearly collapsed during

6165-400: The British response to the U.S. was toned down, helping avert war. In 1862, the British government considered mediating between the Union and Confederacy, though such an offer would have risked war with the U.S. British Prime Minister Lord Palmerston reportedly read Uncle Tom's Cabin three times when deciding what his decision would be. The Union victory at the Battle of Antietam caused

6302-621: The British to delay this decision. The Emancipation Proclamation increased the political liability of supporting the Confederacy. Realizing that Washington could not intervene in Mexico as long as the Confederacy controlled Texas, France invaded Mexico in 1861 and installed the Habsburg Austrian archduke Maximilian I as emperor. Washington repeatedly protested France's violation of the Monroe Doctrine . Despite sympathy for

6439-575: The Commonwealth, which at its greatest extent was over half the state, and it went into exile after October 1862. After Virginia's secession, a Unionist government in Wheeling asked 48 counties to vote on an ordinance to create a new state in October 1861. A voter turnout of 34% approved the statehood bill (96% approving). Twenty-four secessionist counties were included in the new state, and

6576-605: The Confederacy asserted control over a third of the U.S. population in eleven states. Four years of intense combat, mostly in the South, ensued. During 1861–1862 in the Western theater , the Union made permanent gains—though in the Eastern theater the conflict was inconclusive. The abolition of slavery became a Union war goal on January 1, 1863, when Lincoln issued the Emancipation Proclamation , which declared all slaves in rebel states to be free, applying to more than 3.5 million of

6713-400: The Confederacy refused to exchange black prisoners. After that, about 56,000 of the 409,000 POWs died in prisons, accounting for 10 percent of the conflict's fatalities. Historian Elizabeth D. Leonard writes that between 500 and 1,000 women enlisted as soldiers on both sides, disguised as men. Women also served as spies, resistance activists, nurses, and hospital personnel. Women served on

6850-518: The Confederacy, France's seizure of Mexico ultimately deterred it from war with the Union. Confederate offers late in the war to end slavery in return for diplomatic recognition were not seriously considered by London or Paris. After 1863, the Polish revolt against Russia further distracted the European powers and ensured they remained neutral. Russia supported the Union, largely because it believed

6987-706: The Confederacy. As Southerners resigned their Senate and House seats, Republicans could pass projects that had been blocked. These included the Morrill Tariff , land grant colleges, a Homestead Act , a transcontinental railroad, the National Bank Act , authorization of United States Notes by the Legal Tender Act of 1862 , and the end of slavery in the District of Columbia . The Revenue Act of 1861 introduced income tax to help finance

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7124-755: The Confederate capital was moved to Richmond . Maryland , Delaware , Missouri , West Virginia and Kentucky were slave states whose people had divided loyalties to Northern and Southern businesses and family members. Some men enlisted in the Union Army and others in the Confederate Army. West Virginia separated from Virginia and was admitted to the Union on June 20, 1863, though half its counties were secessionist. Maryland's territory surrounded Washington, D.C. , and could cut it off from

7261-542: The District of Columbia by seizing prominent figures, including arresting one-third of the members of the Maryland General Assembly on the day it reconvened. All were held without trial, with Lincoln ignoring a ruling on June 1, 1861, by Supreme Court Chief Justice Roger Taney , not speaking for the Court, that only Congress could suspend habeas corpus ( Ex parte Merryman ). Federal troops imprisoned

7398-687: The Earth and the vastness of the geological time-scale. The Great Unconformity of Powell in the Grand Canyon is a regional unconformity that separates the Tonto Group from the underlying, faulted and tilted sedimentary rocks of the Grand Canyon Supergroup and vertically foliated metamorphic and igneous rocks of the Vishnu Basement Rocks . The unconformity between the Tonto Group and the Vishnu Basement Rocks

7535-520: The Earth's surface. Intrusive igneous rocks that form at depth within the crust are termed plutonic (or abyssal ) rocks and are usually coarse-grained. Intrusive igneous rocks that form near the surface are termed subvolcanic or hypabyssal rocks and they are usually much finer-grained, often resembling volcanic rock. Hypabyssal rocks are less common than plutonic or volcanic rocks and often form dikes, sills, laccoliths, lopoliths , or phacoliths . Extrusive igneous rock, also known as volcanic rock,

7672-471: The Earth's surface. As a result, Powell's Great Unconformity is unusual in its geographic extent and its stratigraphic significance. The length of time represented by Powell's Great Unconformity varies along its length. Within the Grand Canyon, the Great Unconformity represents a period of about 175 million years between the Tonto Group and the youngest subdivision, the Sixtymile Formation , of

7809-692: The Grand Canyon Supergroup. At the base of the Grand Canyon Supergroup, where it truncates the Bass Formation , the period of time represented by this angular unconformity increases to about 725 million years. Where the Tonto Group overlies the Vishnu Basement Rocks, the Great Unconformity represents a period as much as 1.2 to 1.6 billion years. (See also geological timescale .) A prominent exposure of Powell's Great Unconformity occurs in Frenchman Mountain in Nevada . Frenchman Mountain exposes

7946-478: The Great Unconformity is located today. When glaciers move, they drag and erode sediment away from the underlying rock. This would explain how a large section of rock was taken away from widespread areas around the same time. Igneous Igneous rock ( igneous from Latin igneus  'fiery'), or magmatic rock , is one of the three main rock types , the others being sedimentary and metamorphic . Igneous rocks are formed through

8083-479: The North, where anti-slavery sentiment had grown, and for the South, where the fear of slavery's abolition had grown. Another factor leading to secession and the formation of the Confederacy was the development of white Southern nationalism in the preceding decades. The primary reason for the North to reject secession was to preserve the Union, a cause based on American nationalism . Background factors in

8220-658: The North. It had anti-Lincoln officials who tolerated anti-army rioting in Baltimore and the burning of bridges, both aimed at hindering the passage of troops to the South. Maryland's legislature voted overwhelmingly to stay in the Union, but rejected hostilities with its southern neighbors, voting to close Maryland's rail lines to prevent their use for war. Lincoln responded by establishing martial law and unilaterally suspending habeas corpus in Maryland, along with sending in militia units. Lincoln took control of Maryland and

8357-461: The South's post-war recovery. Cotton diplomacy proved a failure as Europe had a surplus of cotton, while the 1860–62 crop failures in Europe made the North's grain exports critically important. It also helped turn European opinion against the Confederacy. It was said that "King Corn was more powerful than King Cotton," as U.S. grain went from a quarter to almost half of British imports. Meanwhile,

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8494-545: The South. The Confederacy turned to foreign sources, connecting with financiers and companies like S. Isaac, Campbell & Company and the London Armoury Company in Britain, becoming the Confederacy's main source of arms. To transport arms safely to the Confederacy, British investors built small, fast, steam-driven blockade runners that traded arms and supplies from Britain, through Bermuda, Cuba, and

8631-500: The U.S. and Britain over the Trent affair , which began when U.S. Navy personnel boarded the British ship Trent and seized two Confederate diplomats. However, London and Washington smoothed this over after Lincoln released the two men. Prince Albert left his deathbed to issue diplomatic instructions to Lord Lyons during the Trent affair. His request was honored, and, as a result,

8768-471: The Union Army or pro-Union guerrilla groups. Although they came from all classes, most Southern Unionists differed socially, culturally, and economically from their region’s dominant prewar, slave-owning planter class. At the war's start, a parole system operated, under which captives agreed not to fight until exchanged. They were held in camps run by their army, paid, but not allowed to perform any military duties. The system of exchanges collapsed in 1863 when

8905-456: The Union blockade. The Confederacy purchased warships from commercial shipbuilders in Britain, with the most famous being the CSS ; Alabama , which caused considerable damage and led to serious postwar disputes . However, public opinion against slavery in Britain created a political liability for politicians, where the anti-slavery movement was powerful. War loomed in late 1861 between

9042-464: The Union hospital ship Red Rover and nursed Union and Confederate troops at field hospitals. Mary Edwards Walker , the only woman ever to receive the Medal of Honor , served in the Union Army and was given the medal for treating the wounded during the war. One woman, Jennie Hodgers, fought for the Union under the name Albert D. J. Cashier. After she returned to civilian life, she continued to live as

9179-435: The Union marshaled resources and manpower to attack the Confederacy from all directions. This led to the fall of Atlanta in 1864 to Union General William Tecumseh Sherman , followed by his March to the Sea . The last significant battles raged around the ten-month Siege of Petersburg , gateway to the Confederate capital of Richmond . The Confederates abandoned Richmond, and on April 9, 1865, Lee surrendered to Grant following

9316-440: The Union would win if it could resupply and hold the fort, and the South would be the aggressor if it opened fire on an unarmed ship supplying starving men. An April 9 Confederate cabinet meeting resulted in Davis ordering General P. G. T. Beauregard to take the fort before supplies reached it. At 4:30 am on April 12, Confederate forces fired the first of 4,000 shells at the fort; it fell the next day. The loss of Fort Sumter lit

9453-433: The Union, this was never likely, so they sought to bring them in as mediators. The Union worked to block this and threatened war if any country recognized the Confederacy. In 1861, Southerners voluntarily embargoed cotton shipments, hoping to start an economic depression in Europe that would force Britain to enter the war, but this failed. Worse, Europe turned to Egypt and India for cotton, which they found superior, hindering

9590-408: The Union-held Fort Sumter. Fort Sumter is located in the harbor of Charleston , South Carolina. Its status had been contentious for months. Outgoing President Buchanan had dithered in reinforcing its garrison, commanded by Major Robert Anderson . Anderson took matters into his own hands and on December 26, 1860, under the cover of darkness, sailed the garrison from the poorly placed Fort Moultrie to

9727-462: The Union. A February peace conference met in Washington, proposing a solution similar the Compromise; it was rejected by Congress. The Republicans proposed the Corwin Amendment , an alternative, not to interfere with slavery where it existed, but the South regarded it as insufficient. The remaining eight slave states rejected pleas to join the Confederacy, following a no-vote in Virginia's First Secessionist Convention on April 4. On March 4, Lincoln

9864-547: The United States and forming the Confederacy. The Confederacy seized U.S. forts and other federal assets within their borders. The war began on April 12, 1861, when the Confederacy bombarded Fort Sumter in South Carolina . A wave of enthusiasm for war swept over the North and South, as military recruitment soared. Four more Southern states seceded after the war began and, led by its president, Jefferson Davis ,

10001-577: The West, where major rivers gave access to the Confederate heartland. The U.S. Navy eventually controlled the Red, Tennessee, Cumberland, Mississippi, and Ohio rivers. In the East, the Navy shelled Confederate forts and supported coastal army operations. The Civil War occurred during the early stages of the industrial revolution, leading to naval innovations, notably the ironclad warship . The Confederacy, recognizing

10138-579: The Western territories destined to become states. Initially Congress had admitted new states into the Union in pairs, one slave and one free . This had kept a sectional balance in the Senate but not in the House of Representatives , as free states outstripped slave states in numbers of eligible voters. Thus, at mid-19th century, the free-versus-slave status of the new territories was a critical issue, both for

10275-450: The basic TAS classification include: In older terminology, silica oversaturated rocks were called silicic or acidic where the SiO 2 was greater than 66% and the family term quartzolite was applied to the most silicic. A normative feldspathoid classifies a rock as silica-undersaturated; an example is nephelinite . Magmas are further divided into three series: The alkaline series

10412-521: The blockade was the rise of oil as a prominent commodity. The declining whale oil industry took a blow as many old whaling ships were used in blockade efforts, such as the Stone Fleet , and Confederate raiders harassed Union whalers. Oil products, especially kerosene, began replacing whale oil in lamps, increasing oil's importance long before it became fuel for combustion engines. Although the Confederacy hoped Britain and France would join them against

10549-568: The calc-alkaline magmas. Some island arcs have distributed volcanic series as can be seen in the Japanese island arc system where the volcanic rocks change from tholeiite—calc-alkaline—alkaline with increasing distance from the trench. Some igneous rock names date to before the modern era of geology. For example, basalt as a description of a particular composition of lava-derived rock dates to Georgius Agricola in 1546 in his work De Natura Fossilium . The word granite goes back at least to

10686-429: The chemical composition of an igneous rock was its most fundamental characteristic, it should be elevated to prime position. Geological occurrence, structure, mineralogical constitution—the hitherto accepted criteria for the discrimination of rock species—were relegated to the background. The completed rock analysis is first to be interpreted in terms of the rock-forming minerals which might be expected to be formed when

10823-625: The classification of igneous rocks are particle size, which largely depends on the cooling history, and the mineral composition of the rock. Feldspars , quartz or feldspathoids , olivines , pyroxenes , amphiboles , and micas are all important minerals in the formation of almost all igneous rocks, and they are basic to the classification of these rocks. All other minerals present are regarded as nonessential in almost all igneous rocks and are called accessory minerals . Types of igneous rocks with other essential minerals are very rare, but include carbonatites , which contain essential carbonates . In

10960-421: The collision of tectonic plates. The "great" unconformities of regional or continental scale (in both geography and chronology) are associated with either global changes in eustatic sea level or the supercontinent cycle , the periodic merger of all the continents into one approximately every 500 million years. Hutton's Unconformity at Siccar Point , in county of Berwickshire on the east coast of Scotland ,

11097-508: The convention unanimously voted to secede and adopted a secession declaration . It argued for states' rights for slave owners but complained about states' rights in the North in the form of resistance to the federal Fugitive Slave Act, claiming that Northern states were not fulfilling their obligations to assist in the return of fugitive slaves. The "cotton states" of Mississippi , Florida , Alabama , Georgia , Louisiana , and Texas followed suit, seceding in January and February 1861. Among

11234-591: The cooling and solidification of magma or lava . The magma can be derived from partial melts of existing rocks in either a planet 's mantle or crust . Typically, the melting is caused by one or more of three processes: an increase in temperature, a decrease in pressure , or a change in composition. Solidification into rock occurs either below the surface as intrusive rocks or on the surface as extrusive rocks. Igneous rock may form with crystallization to form granular, crystalline rocks, or without crystallization to form natural glasses . Igneous rocks occur in

11371-489: The country, bring the former Confederate states back into the United States, and grant civil rights to freed slaves. The war is one of the most extensively studied and written about episodes in U.S. history . It remains the subject of cultural and historiographical debate . Of continuing interest is the fading myth of the Lost Cause of the Confederacy . The war was among the first to use industrial warfare . Railroads,

11508-477: The crisis was Secretary of State William H. Seward , who had been Lincoln's rival for the Republican nomination . Embittered by his defeat, Seward agreed to support Lincoln's candidacy only after he was guaranteed the executive office then considered the second most powerful. In the early stages of Lincoln's presidency Seward held little regard for him, due to his perceived inexperience. Seward viewed himself as

11645-713: The de facto head of government, the " prime minister " behind the throne. Seward attempted to engage in unauthorized and indirect negotiations that failed. Lincoln was determined to hold all remaining Union-occupied forts in the Confederacy: Fort Monroe in Virginia, Fort Pickens , Fort Jefferson , and Fort Taylor in Florida, and Fort Sumter in South Carolina. The American Civil War began on April 12, 1861, when Confederate forces opened fire on

11782-529: The desire of the Southern states to preserve the institution of slavery . Historians in the 21st century overwhelmingly agree on the centrality of slavery in the conflict. They disagree on which aspects (ideological, economic, political, or social) were most important, and on the North 's reasons for refusing to allow the Southern states to secede. The pseudo-historical Lost Cause ideology denies that slavery

11919-402: The different types of extrusive igneous rocks than between different types of intrusive igneous rocks. Generally, the mineral constituents of fine-grained extrusive igneous rocks can only be determined by examination of thin sections of the rock under a microscope , so only an approximate classification can usually be made in the field . Although classification by mineral makeup is preferred by

12056-616: The disruption of the American Civil War kept Newberry's work from becoming widely known. This Great Unconformity marks the progressive submergence of this landmass by a shallow cratonic sea and its burial by shallow marine sediments of the Cambrian -Early Ordovician Sauk sequence . The submergence of Laurentia ended a lengthy period of widespread continental denudation that exhumed and deeply eroded Precambrian rocks and exposed them to extensive physical and chemical weathering at

12193-493: The ensuing guerrilla war engaged about 40,000 federal troops for much of the war. Congress admitted West Virginia to the Union on June 20, 1863. West Virginians provided about 20,000 soldiers to each side in the war. A Unionist secession attempt occurred in East Tennessee , but was suppressed by the Confederacy, which arrested over 3,000 men suspected of loyalty to the Union; they were held without trial. The Civil War

12330-430: The essential role of cotton in the European economy. The European aristocracy was "absolutely gleeful in pronouncing the American debacle as proof that the entire experiment in popular government had failed. European government leaders welcomed the fragmentation of the ascendant American Republic." However, a European public with liberal sensibilities remained, which the U.S. sought to appeal to by building connections with

12467-402: The existence of significant breaks in the geological record, in this case a break separating strata that were then called alpine schistus and secondary strata. This and other unconformities provided evidence for Hutton's ideas about the recycling of geological materials and for unconformities representing very large time periods. He argued that these concepts pointed to the great antiquity of

12604-484: The extensive basalt magmatism of several large igneous provinces. Decompression melting occurs because of a decrease in pressure. The solidus temperatures of most rocks (the temperatures below which they are completely solid) increase with increasing pressure in the absence of water. Peridotite at depth in the Earth's mantle may be hotter than its solidus temperature at some shallower level. If such rock rises during

12741-486: The great majority of cases, the rock has a more typical mineral composition, with significant quartz, feldspars, or feldspathoids. Classification is based on the percentages of quartz, alkali feldspar, plagioclase, and feldspathoid out of the total fraction of the rock composed of these minerals, ignoring all other minerals present. These percentages place the rock somewhere on the QAPF diagram , which often immediately determines

12878-439: The homefront economy could no longer supply. Surdam contends that the blockade was a powerful weapon that eventually ruined the Southern economy, costing few lives in combat. The Confederate cotton crop became nearly useless, cutting off the Confederacy's primary income source. Critical imports were scarce, and coastal trade largely ended as well. The blockade's success was not measured by the few ships that slipped through but by

13015-554: The international press. By 1861, Union diplomats like Carl Schurz realized emphasizing the war against slavery was the Union's most effective moral asset in swaying European public opinion. Seward was concerned an overly radical case for reunification would distress European merchants with cotton interests; even so, he supported a widespread campaign of public diplomacy. U.S. minister to Britain Charles Francis Adams proved adept and convinced Britain not to challenge

13152-433: The larger crystals, called phenocrysts, grow to considerable size before the main mass of the magma crystallizes as finer-grained, uniform material called groundmass. Grain size in igneous rocks results from cooling time so porphyritic rocks are created when the magma has two distinct phases of cooling. Igneous rocks are classified on the basis of texture and composition. Texture refers to the size, shape, and arrangement of

13289-399: The magma crystallizes, e.g., quartz feldspars, olivine , akermannite, Feldspathoids , magnetite , corundum , and so on, and the rocks are divided into groups strictly according to the relative proportion of these minerals to one another. This new classification scheme created a sensation, but was criticized for its lack of utility in fieldwork, and the classification scheme was abandoned by

13426-437: The majority of igneous rocks and are formed from magma that cools and solidifies within the crust of a planet. Bodies of intrusive rock are known as intrusions and are surrounded by pre-existing rock (called country rock ). The country rock is an excellent thermal insulator , so the magma cools slowly, and intrusive rocks are coarse-grained ( phaneritic ). The mineral grains in such rocks can generally be identified with

13563-457: The majority of minerals will be visible to the naked eye or at least using a hand lens, magnifying glass or microscope. Plutonic rocks also tend to be less texturally varied and less prone to showing distinctive structural fabrics. Textural terms can be used to differentiate different intrusive phases of large plutons, for instance porphyritic margins to large intrusive bodies, porphyry stocks and subvolcanic dikes . Mineralogical classification

13700-697: The mineral grains or crystals of which the rock is composed. Texture is an important criterion for the naming of volcanic rocks. The texture of volcanic rocks, including the size, shape, orientation, and distribution of mineral grains and the intergrain relationships, will determine whether the rock is termed a tuff , a pyroclastic lava or a simple lava . However, the texture is only a subordinate part of classifying volcanic rocks, as most often there needs to be chemical information gleaned from rocks with extremely fine-grained groundmass or from airfall tuffs, which may be formed from volcanic ash. Textural criteria are less critical in classifying intrusive rocks where

13837-607: The movement to abolish slavery and its influence over the North. Southern states believed that the Fugitive Slave Clause made slaveholding a constitutional right. These states agreed to form a new federal government, the Confederate States of America , on February 4, 1861. They took control of federal forts and other properties within their boundaries, with little resistance from outgoing President James Buchanan , whose term ended on March 4. Buchanan said

13974-415: The naked eye are called phaneritic ; those with crystals too small to be seen are called aphanitic . Generally speaking, phaneritic implies an intrusive origin or plutonic, indicating slow cooling; aphanitic are extrusive or volcanic, indicating rapid cooling. An igneous rock with larger, clearly discernible crystals embedded in a finer-grained matrix is termed porphyry . Porphyritic texture develops when

14111-492: The naked eye. Intrusions can be classified according to the shape and size of the intrusive body and its relation to the bedding of the country rock into which it intrudes. Typical intrusive bodies are batholiths , stocks , laccoliths , sills and dikes . Common intrusive rocks are granite , gabbro , or diorite . The central cores of major mountain ranges consist of intrusive igneous rocks. When exposed by erosion, these cores (called batholiths ) may occupy huge areas of

14248-476: The need to counter the Union's naval superiority, built or converted over 130 vessels, including 26 ironclads. Despite these efforts, Confederate ships were largely unsuccessful against Union ironclads. The Union Navy used timberclads, tinclads, and armored gunboats. Shipyards in Cairo, Illinois, and St. Louis built or modified steamboats . The Confederacy experimented with the submarine CSS  Hunley , which

14385-418: The new Confederacy sent delegates to Washington to negotiate a peace treaty. Lincoln rejected negotiations, because he claimed that the Confederacy was not a legitimate government and to make a treaty with it would recognize it as such. Lincoln instead attempted to negotiate directly with the governors of seceded states, whose administrations he continued to recognize. Complicating Lincoln's attempts to defuse

14522-417: The ordinances of secession, those of Texas, Alabama, and Virginia mentioned the plight of the "slaveholding states" at the hands of Northern abolitionists. The rest made no mention of slavery but were brief announcements by the legislatures of the dissolution of ties to the Union. However, at least four—South Carolina, Mississippi, Georgia, and Texas —provided detailed reasons for their secession, all blaming

14659-505: The pre-Cambrian land surface was formed of sedimentary, eruptive, and crystalline rocks that did not in any known instance immediately precede in deposition or origin the Cambrian sediments. Everywhere there is a stratigraphic and time break between the known pre-Cambrian rocks and Cambrian sediments of the North American continent. A potential link has been proposed between such sub-Cambrian unconformities and glacial erosion during

14796-441: The ratio of potassium to sodium (so that potassic trachyandesites are latites and sodic trachyandesites are benmoreites). Some of the more mafic fields are further subdivided or defined by normative mineralogy , in which an idealized mineral composition is calculated for the rock based on its chemical composition. For example, basanite is distinguished from tephrite by having a high normative olivine content. Other refinements to

14933-403: The release of dissolved gases—typically water vapour, but also carbon dioxide . Explosively erupted pyroclastic material is called tephra and includes tuff , agglomerate and ignimbrite . Fine volcanic ash is also erupted and forms ash tuff deposits, which can often cover vast areas. Because volcanic rocks are mostly fine-grained or glassy, it is much more difficult to distinguish between

15070-473: The rock must be classified chemically. There are relatively few minerals that are important in the formation of common igneous rocks, because the magma from which the minerals crystallize is rich in only certain elements: silicon , oxygen , aluminium, sodium , potassium , calcium , iron, and magnesium . These are the elements that combine to form the silicate minerals , which account for over ninety percent of all igneous rocks. The chemistry of igneous rocks

15207-424: The rock type. In a few cases, such as the diorite-gabbro-anorthite field, additional mineralogical criteria must be applied to determine the final classification. Where the mineralogy of an volcanic rock can be determined, it is classified using the same procedure, but with a modified QAPF diagram whose fields correspond to volcanic rock types. When it is impractical to classify a volcanic rock by mineralogy,

15344-411: The rocks. However, in 1902, the American petrologists Charles Whitman Cross , Joseph P. Iddings , Louis V. Pirsson , and Henry Stephens Washington proposed that all existing classifications of igneous rocks should be discarded and replaced by a "quantitative" classification based on chemical analysis. They showed how vague, and often unscientific, much of the existing terminology was and argued that as

15481-427: The run up to the Civil War were partisan politics , abolitionism , nullification versus secession , Southern and Northern nationalism, expansionism , economics , and modernization in the antebellum period . As a panel of historians emphasized in 2011, "while slavery and its various and multifaceted discontents were the primary cause of disunion, it was disunion itself that sparked the war." Abraham Lincoln won

15618-636: The southwestern corner of Missouri (see Missouri secession ). Early in the war the Confederacy controlled southern Missouri through the Confederate government of Missouri but was driven out after 1862. In the resulting vacuum, the convention on secession reconvened and took power as the Unionist provisional government of Missouri. Kentucky did not secede, it declared itself neutral. When Confederate forces entered in September 1861, neutrality ended and

15755-532: The stalwart island Fort Sumter. Anderson's actions catapulted him to hero status in the North. An attempt to resupply the fort on January 9, 1861, failed and nearly started the war then, but an informal truce held. On March 5, Lincoln was informed the fort was low on supplies. Fort Sumter proved a key challenge to Lincoln's administration. Back-channel dealing by Seward with the Confederates undermined Lincoln's decision-making; Seward wanted to pull out. But

15892-446: The state reaffirmed its Union status while maintaining slavery. During an invasion by Confederate forces in 1861, Confederate sympathizers and delegates from 68 Kentucky counties organized the secession Russellville Convention, formed the shadow Confederate Government of Kentucky , inaugurated a governor, and Kentucky was admitted into the Confederacy on December 10, 1861. Its jurisdiction extended only as far as Confederate battle lines in

16029-457: The substitute provision to select which man should go into the army and which should stay home. There was much evasion and resistance to the draft, especially in Catholic areas. The New York City draft riots in July 1863 involved Irish immigrants who had been signed up as citizens to swell the vote of the city's Democratic political machine , not realizing it made them liable for the draft. Of

16166-451: The thousands that never tried. European merchant ships could not get insurance and were too slow to evade the blockade, so they stopped calling at Confederate ports. To fight an offensive war, the Confederacy purchased arms in Britain and converted British-built ships into commerce raiders . The smuggling of 600,000 arms enabled the Confederacy to fight on for two more years, and the commerce raiders targeted U.S. Merchant Marine ships in

16303-503: The unconformity at Siccar Point, provided James Hutton, accompanied by John Playfair and Sir James Hall , the clearest example of an unconformable relationship between two sets of sedimentary strata that involved a complex geological history. The clear truncation of near-vertical Silurian sedimentary strata by well-bedded conglomerates and sandstones belonging to the Upper Old Red Sandstone allowed Hutton to demonstrate

16440-497: The upward movement of solid mantle is critical in the evolution of the Earth. American Civil War The American Civil War (April 12, 1861 – May 26, 1865; also known by other names ) was a civil war in the United States between the Union ("the North") and the Confederacy ("the South"), which was formed in 1861 by states that had seceded from the Union. The central conflict leading to war

16577-430: The war created jobs for arms makers, ironworkers, and ships to transport weapons. Lincoln's administration initially struggled to appeal to European public opinion. At first, diplomats explained that the U.S. was not committed to ending slavery and emphasized legal arguments about the unconstitutionality of secession. Confederate representatives, however, focused on their struggle for liberty, commitment to free trade, and

16714-478: The war due to multiple factors: severe food shortages, failing railroads, loss of control over key rivers, foraging by Northern armies, and the seizure of animals and crops by Confederate forces. Historians agree the blockade was a major factor in ruining the Confederate economy; however, Wise argues blockade runners provided enough of a lifeline to allow Lee to continue fighting for additional months, thanks to supplies like 400,000 rifles, lead, blankets, and boots that

16851-603: The war. In December 1860, the Crittenden Compromise was proposed to re-establish the Missouri Compromise line, by constitutionally banning slavery in territories to the north of it, while permitting it to the south. The Compromise would likely have prevented secession, but Lincoln and the Republicans rejected it. Lincoln stated that any compromise that would extend slavery would bring down

16988-586: The widely used Irvine-Barager classification, along with W.Q. Kennedy's tholeiitic series. By 1958, there were some 12 separate classification schemes and at least 1637 rock type names in use. In that year, Albert Streckeisen wrote a review article on igneous rock classification that ultimately led to the formation of the IUGG Subcommission of the Systematics of Igneous Rocks. By 1989 a single system of classification had been agreed upon, which

17125-436: The winter of 1860–1861. Nationalists in the North and "Unionists" in the South refused to accept the declarations of secession. No foreign government ever recognized the Confederacy. The U.S. government, under President James Buchanan , refused to relinquish its forts that were in territory claimed by the Confederacy. According to Lincoln, the American people had shown they had been successful in establishing and administering

17262-478: The world" within a few years. Some European observers at the time dismissed them as amateur and unprofessional, but historian John Keegan concluded that each outmatched the French, Prussian, and Russian armies, and without the Atlantic, could have threatened any of them with defeat. Unionism was strong in certain areas within the Confederacy. As many as 100,000 men living in states under Confederate control served in

17399-472: Was a dispute over whether slavery should be permitted to expand into the western territories, leading to more slave states , or be prohibited from doing so, which many believed would place slavery on a course of ultimate extinction. Decades of controversy over slavery were brought to a head when Abraham Lincoln , who opposed slavery's expansion, won the 1860 presidential election . Seven Southern slave states responded to Lincoln's victory by seceding from

17536-436: Was among the first to note this phenomenon, remarking in 1910: I do not know of a case of proven conformity between Cambrian and pre-Cambrian Algonkian rocks on the North American continent. In all localities where the contact is sufficiently extensive, or where fossils have been found in the basal Cambrian beds or above the basal conglomerate and coarser sandstones, an unconformity has been found to exist. Stated in another way,

17673-467: Was further revised in 2005. The number of recommended rock names was reduced to 316. These included a number of new names promulgated by the Subcommission. The Earth's crust averages about 35 kilometres (22 mi) thick under the continents , but averages only some 7–10 kilometres (4.3–6.2 mi) beneath the oceans . The continental crust is composed primarily of sedimentary rocks resting on

17810-408: Was high because many soldiers were more concerned about the fate of their local area than the Southern cause. In the North, " bounty jumpers " enlisted to collect the generous bonus, deserted, then re-enlisted under a different name for a second bonus; 141 were caught and executed. From a tiny frontier force in 1860, the Union and Confederate armies grew into the "largest and most efficient armies in

17947-405: Was made of bullion lost from mints. He stated that it would be US policy "to collect the duties and imposts"; "there will be no invasion, no using of force against or among the people anywhere" that would justify an armed revolution. His speech closed with a plea for restoration of the bonds of union, famously calling on "the mystic chords of memory" binding the two regions. The Davis government of

18084-566: Was marked by intense and frequent battles. Over four years, 237 named battles were fought, along with many smaller actions, often characterized by their bitter intensity and high casualties. Historian John Keegan described it as "one of the most ferocious wars ever fought," where, in many cases, the only target was the enemy's soldiers. As the Confederate states organized, the U.S. Army numbered 16,000, while Northern governors began mobilizing their militias. The Confederate Congress authorized up to 100,000 troops in February. By May, Jefferson Davis

18221-512: Was not successful, and with the ironclad CSS  Virginia , rebuilt from the sunken Union ship Merrimack . On March 8, 1862, Virginia inflicted significant damage on the Union's wooden fleet, but the next day, the first Union ironclad, USS  Monitor , arrived to challenge it in the Chesapeake Bay . The resulting three-hour Battle of Hampton Roads was a draw, proving ironclads were effective warships. The Confederacy scuttled

18358-460: Was pushing for another 100,000 soldiers for one year or the duration, and the U.S. Congress responded in kind. In the first year of the war, both sides had more volunteers than they could effectively train and equip. After the initial enthusiasm faded, relying on young men who came of age each year was not enough. Both sides enacted draft laws (conscription) to encourage or force volunteering, though relatively few were drafted. The Confederacy passed

18495-769: Was sworn in as president. In his inaugural address , he argued that the Constitution was a more perfect union than the earlier Articles of Confederation and Perpetual Union , was a binding contract, and called secession "legally void". He did not intend to invade Southern states, nor to end slavery where it existed, but he said he would use force to maintain possession of federal property, including forts, arsenals, mints, and customhouses that had been seized. The government would not try to recover post offices, and if resisted, mail delivery would end at state lines. Where conditions did not allow peaceful enforcement of federal law, US marshals and judges would be withdrawn. No mention

18632-439: Was the principal cause of the secession, a view disproven by historical evidence, notably some of the seceding states' own secession documents . After leaving the Union, Mississippi issued a declaration stating, "Our position is thoroughly identified with the institution of slavery—the greatest material interest of the world." The principal political battle leading to Southern secession was over whether slavery would expand into

18769-525: Was too late. " King Cotton " was dead, as the South could export less than 10% of its cotton. The blockade shut down the ten Confederate seaports with railheads that moved almost all the cotton. By June 1861, warships were stationed off the principal Southern ports, and a year later nearly 300 ships were in service. The Confederates began the war short on military supplies, which the agrarian South could not produce. Northern arms manufacturers were restricted by an embargo, ending existing and future contracts with

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