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39-674: Origin: Puntukas is a glacial erratic —it was brought by glaciers during the last glacial period (18th–12th millennium BC) probably from Finland . It measures 6.9 metres (23 ft) in length, 6.7 m (22 ft) in width, and 5.7 m (19 ft) in depth (including 1.5 m (4 ft 11 in) underground). It weighs about 446 tons according to the latest data. It is made of Rapakivi granite . Its reddish mass includes large crystals of potassium feldspar surrounded by green rings of oligoclase . In 1943, sculptor Bronius Pundzius engraved portraits and quotes from last wills of Lithuanian pilots Steponas Darius and Stasys Girėnas for

78-451: A brave Lithuanian warrior Puntukas was killed and was burned (a usual pagan custom) on the stone; since then it is known as Puntukas stone. Other legends claim that the stone was a pagan shrine and that oaks growing around are relics of the sacred groves. On the road from Oniksht to Vilkomir there is a huge stone up to 40 ft circumference called Pantuke and which formerly served as an altar, Criwo-Cyrwaito or Pantukis, accused of blasphemy,

117-443: A groundmass of finely-divided clayey material sometimes called glacial flour . Lateral moraines are those formed at the side of the ice flow, and terminal moraines are those formed at the foot, marking the maximum advance of the glacier. Other types of moraine include ground moraines ( till -covered areas forming sheets on flat or irregular topography ) and medial moraines (moraines formed where two glaciers meet). The word moraine

156-452: A series of transverse ridges running across a valley behind a terminal moraine. They form perpendicular to the lateral moraines that they reside between and are composed of unconsolidated debris deposited by the glacier. They are created during temporary halts in a glacier's retreat. In permafrost areas an advancing glacier may push up thick layers of frozen sediments at its front. An arctic push moraine will then be formed. A medial moraine

195-502: A single moraine, and most moraines record a continuum of processes. Reworking of moraines may lead to the formation of placer deposits of gold as is the case of southernmost Chile . Moraines can be classified either by origin, location with respect to a glacier or former glacier, or by shape. The first approach is suitable for moraines associated with contemporary glaciers—but more difficult to apply to old moraines , which are defined by their particular morphology, since their origin

234-404: Is unstratified and unsorted debris ranging in size from silt -sized glacial flour to large boulders. The individual rock fragments are typically sub-angular to rounded in shape. Moraines may be found on the glacier's surface or deposited as piles or sheets of debris where the glacier has melted. Moraines may form through a number of processes, depending on the characteristics of sediment,

273-640: Is a ridge of moraine that runs down the center of a valley floor. It forms when two glaciers meet and the debris on the edges of the adjacent valley sides join and are carried on top of the enlarged glacier. As the glacier melts or retreats, the debris is deposited and a ridge down the middle of the valley floor is created. The Kaskawulsh Glacier in the Kluane National Park , Yukon , has a ridge of medial moraine 1 km wide. Supraglacial moraines are created by debris accumulated on top of glacial ice. This debris can accumulate due to ice flow toward

312-426: Is accumulated at the base of the ice as lodgment till with a thin and discontinuous upper layer of supraglacial till deposited as the glacier retreats. It typically is found in the areas between end moraines. Rogen moraines or ribbed moraines are a type of basal moraines that form a series of ribs perpendicular to the ice flow in an ice sheet . The depressions between the ribs are sometimes filled with water, making

351-399: Is any accumulation of unconsolidated debris ( regolith and rock ), sometimes referred to as glacial till , that occurs in both currently and formerly glaciated regions, and that has been previously carried along by a glacier or ice sheet. It may consist of partly rounded particles ranging in size from boulders (in which case it is often referred to as boulder clay) down to gravel and sand, in

390-428: Is any material which is not native to the immediate locale but has been transported from elsewhere. The most common examples of erratics are associated with glacial transport, either by direct glacier-borne transport or by ice rafting. However, other erratics have been identified as the result of kelp holdfasts, which have been documented to transport rocks up to 40 centimetres (16 in) in diameter, rocks entangled in

429-547: Is borrowed from French moraine [mɔ.ʁɛn] , which in turn is derived from the Savoyard Italian morena ('mound of earth'). Morena in this case was derived from Provençal morre ('snout'), itself from Vulgar Latin * murrum ('rounded object'). The term was introduced into geology by Horace Bénédict de Saussure in 1779. Moraines are landforms composed of glacial till deposited primarily by glacial ice. Glacial till, in turn,

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468-422: Is commonly used to refer to erratic blocks, which geologist Archibald Geikie describes as: "large masses of rock, often as big as a house, that have been transported by glacier ice, and have been lodged in a prominent position in the glacier valleys or have been scattered over hills and plains. And examination of their mineralogical character leads the identification of their sources...". In geology , an erratic

507-441: Is debated. Some moraine types are known only from ancient glaciers, while medial moraines of valley glaciers are poorly preserved and difficult to distinguish after the retreat or melting of the glacier. Lateral moraines are parallel ridges of debris deposited along the sides of a glacier. The unconsolidated debris can be deposited on top of the glacier by frost shattering of the valley walls or from tributary streams flowing into

546-401: Is deposited when the iceberg strands on the shore and subsequently melts, or drops out of the ice floe as it melts. Hence all erratic deposits are deposited below the actual high water level of the lake; however, the measured altitude of ice-rafted debris can be used to estimate the lake surface elevation. This is accomplished by recognizing that on a fresh-water lake, the iceberg floats until

585-425: Is material moved by geologic forces from one location to another, usually by a glacier. Erratics are formed by glacial ice erosion resulting from the movement of ice. Glaciers erode by multiple processes including: Evidence supports another possibility for the creation of erratics as well: rock avalanches onto the upper surface of the glacier ( supraglacial ). Rock avalanche – supraglacial transport occurs when

624-588: Is transported to the coast by glacier ice and released during the production, drift and melting of icebergs . The rate of debris release by ice depends upon the size of the ice mass in which it is carried as well as the temperature of the ocean through which the ice floe passes. Sediments from the late Pleistocene period lying on the floor of the North Atlantic show a series of layers (referred to as Heinrich layers ) which contain ice-rafted debris . They were formed between 14,000 and 70,000 years before

663-513: The Alps the subjects of special study, and Goethe, Charpentier as well as Schimper had even arrived at the conclusion that the erratic blocks of alpine rocks scattered over the slopes and summits of the Jura Mountains had been moved there by glaciers. Charles Darwin published extensively on geologic phenomena including the distribution of erratic boulders. In his accounts written during

702-585: The Canadian Prairies , Poland , England , Denmark and Sweden . One erratic megablock located in Saskatchewan is 30 by 38 kilometres (19 mi × 24 mi) (and up to 100 metres or 330 feet thick). Their sources can be identified by locating the bedrock from which they were separated; several rafts from Poland and Alberta were determined to have been transported over 300 kilometres (190 mi) from their source. In geology an erratic

741-454: The Swiss politician , jurist and theologian Bernhard Friedrich Kuhn  [ de ] saw glaciers as a possible solution as early as 1788. However, the idea of ice ages and glaciation as a geological force took a while to be accepted. Ignaz Venetz (1788–1859), a Swiss engineer, naturalist and glaciologist was one of the first scientists to recognize glaciers as a major force in shaping

780-603: The 10th anniversary of their deaths during the transatlantic flight with Lituanica ,the sculpting process took about 180 days. A local legend has it that velnias ( devil in the Lithuanian mythology ) carried the stone to destroy the Anykščiai Church , however a rooster crowed. The devil disappeared back into the underworld, leaving only Puntukas behind. The legend was featured in the famous poem Anykščių šilelis by Antanas Baranauskas . According to another story,

819-533: The Latin word errare ("to wander"), are carried by glacial ice, often over distances of hundreds of kilometres. Erratics can range in size from pebbles to large boulders such as Big Rock (16,500 metric tons) in Alberta . Geologists identify erratics by studying the rocks surrounding the position of the erratic and the composition of the erratic itself. Erratics are significant because: The term "erratic"

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858-589: The Rogen moraines look like tigerstripes on aerial photographs . Rogen moraines are named after Lake Rogen in Härjedalen , Sweden , the landform's type locality. Closely related to Rogen moraines, de Geer moraines are till ridges up to 5m high and 10–50m wide running perpendicular to the ice flow. They occur in large groups in low-lying areas. Named for Gerard De Geer , who first described them in 1889, these moraines may have developed from crevasses underneath

897-472: The dynamics on the ice, and the location on the glacier in which the moraine is formed. Moraine forming processes may be loosely divided into passive and active . Passive processes involve the placing of chaotic supraglacial sediments onto the landscape with limited reworking, typically forming hummocky moraines. These moraines are composed of supraglacial sediments from the ice surface. Active processes form or rework moraine sediment directly by

936-489: The earth. In the 19th century, many scientists came to favor erratics as evidence for the end of the ice age 10,000 years ago, rather than a flood. Geologists have suggested that landslides or rockfalls initially dropped the rocks on top of glacial ice. The glaciers continued to move, carrying the rocks with them. When the ice melted, the erratics were left in their present locations. Charles Lyell 's Principles of Geology (v. 1, 1830) provided an early description of

975-536: The erratic which is consistent with the modern understanding. Louis Agassiz was the first to scientifically propose that the Earth had been subject to a past ice age . In the same year, he was elected a foreign member of the Royal Swedish Academy of Sciences . Prior to this proposal, Goethe , de Saussure , Venetz , Jean de Charpentier , Karl Friedrich Schimper and others had made the glaciers of

1014-493: The glacier is advancing, receding or at equilibrium. The longer the terminus of the glacier stays in one place, the more debris accumulate in the moraine. There are two types of end moraines: terminal and recessional. Terminal moraines mark the maximum advance of the glacier. Recessional moraines are small ridges left as a glacier pauses during its retreat. After a glacier retreats, the end moraine may be destroyed by postglacial erosion. Recessional moraines are often observed as

1053-468: The glacier undercuts a rock face, which fails by avalanche onto the upper surface of the glacier. The characteristics of rock avalanche–supraglacial transport includes: Erratics provide an important tool in characterizing the directions of glacier flows, which are routinely reconstructed used on a combination of moraines , eskers , drumlins , meltwater channels and similar data. Erratic distributions and glacial till properties allow for identification of

1092-665: The ice dam broke during the Missoula floods , then the erratics are deposited where the ice finally releases its debris load. One of the more unusual examples is found far from its origin in Idaho at Erratic Rock State Natural Site just outside McMinnville, Oregon . The park includes a 40-short-ton (36 t) specimen, the largest erratic found in the Willamette Valley . [REDACTED] Media related to Glacial erratics at Wikimedia Commons Moraine A moraine

1131-449: The ice sheet. The Kvarken has a very high density of de Geer moraines. End moraines, or terminal moraines , are ridges of unconsolidated debris deposited at the snout or end of the glacier. They usually reflect the shape of the glacier's terminus . Glaciers act much like a conveyor belt, carrying debris from the top of the glacier to the bottom where it deposits it in end moraines. End moraine size and shape are determined by whether

1170-426: The movement of ice, known as glaciotectonism. These form push moraines and thrust-block moraines, which are often composed of till and reworked proglacial sediment. Moraine may also form by the accumulation of sand and gravel deposits from glacial streams emanating from the ice margin. These fan deposits may coalesce to form a long moraine bank marking the ice margin. Several processes may combine to form and rework

1209-449: The order of 100 to 1. These megablocks may be found partially exposed or completely buried by till and are clearly allochthonous , since they overlay glacial till . Megablocks can be so large that they are mistaken for bedrock until underlying glacial or fluvial sediments are identified by drilling or excavation. Such erratic megablocks greater than 1 square kilometre (250 acres) in area and 30 metres (98 ft) in thickness can be found on

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1248-628: The present. The deposited debris can be traced back to the origin by both the nature of the materials released and the continuous path of debris release. Some paths extend more than 3,000 kilometres (1,900 mi) distant from the point at which the ice floes originally broke free. The location and altitude of ice-rafted boulders relative to the modern landscape has been used to identify the highest level of water in proglacial lakes (e.g. Lake Musselshell in central Montana ) and temporary lakes (e.g. Lake Lewis in Washington state). Ice-rafted debris

1287-515: The roots of drifting logs, and even in transport of stones accumulated in the stomachs of pinnipeds during foraging. During the 18th century, erratics were deemed a major geological paradox. Geologists identify erratics by studying the rocks surrounding the position of the erratic and the rock of the erratic itself. Erratics were once considered evidence of a biblical flood , but in the 19th century scientists gradually came to accept that erratics pointed to an ice age in Earth's past. Among others,

1326-419: The source rock from which they derive, which confirms the flow direction, particularly when the erratic source outcrop is unique to a limited locality. Erratic materials may be transported by multiple glacier flows prior to their deposition, which can complicate the reconstruction of the glacial flow. Glacial ice entrains debris of varying sizes from small particles to extremely large masses of rock. This debris

1365-419: The surface in the ablation zone , melting of surface ice or from debris that falls onto the glacier from valley sidewalls. Washboard moraines , also known as minor or corrugated moraines , are low-amplitude geomorphic features caused by glaciers. They consist of low-relief ridges, 1 to 2 meters (3 ft 3 in to 6 ft 7 in) in height and around 100 meters (330 ft) apart, accumulated at

1404-580: The valley, or may be subglacial debris carried to the surface of the glacier, melted out, and transported to the glacier margin. Lateral moraines can rise up to 140 meters (460 ft) over the valley floor, can be up to 3 kilometers (1.9 mi) long, and are steeper close to the glacier margin (up to 80 degrees) than further away (where slopes are typically 29 to 36 degrees. Ground moraines are till-covered areas with irregular topography and no ridges, often forming gently rolling hills or plains, with relief of less than 10 meters (33 ft). Ground moraine

1443-725: The volume of its ice-rafted debris exceeds 5% of the volume of the iceberg. Therefore, a correlation between the iceberg size and the boulder size can be established. For example, a 1.5-metre-diameter (5 ft) boulder can be carried by a 3-metre-high (10 ft) iceberg and could be found stranded at higher elevations than a 2-metre (7 ft) boulder, which requires a 4-metre-high (13 ft) iceberg. Large erratics consisting of slabs of bedrock that have been lifted and transported by glacier ice to subsequently be stranded above thin glacial or fluvioglacial deposits are referred to as glacial floes, rafts (schollen) or erratic megablocks. Erratic megablocks have typical length to thickness ratios on

1482-461: The voyage of HMS  Beagle , Darwin observed a number of large erratic boulders of notable size south of the Strait of Magellan , Tierra del Fuego and attributed them to ice rafting from Antarctica . Recent research suggests that they are more likely the result of glacial ice flows carrying the boulders to their current locations. If glacial ice is "rafted" by a flood such as that created when

1521-414: Was executed there. Since Pagan times Punktukas boulder was known as a place where pagan rituals took place. 55°29′3″N 25°3′31″E  /  55.48417°N 25.05861°E  / 55.48417; 25.05861 Glacial erratic A glacial erratic is a glacially deposited rock differing from the type of rock native to the area in which it rests. Erratics, which take their name from

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