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39-694: It is the site name for the Saqqaq culture . It is located in the southwestern part of the Nuussuaq Peninsula , on the northern shore of Sullorsuaq Strait (known in Danish as Vaigat Strait), northwest of Ilulissat . Immediately northeast of Saqqaq is the Livets Top mountain (1,150 metres (3,773 ft)). Archaeological excavations in Qilakitsoq on the other side of Nuussuaq Peninsula on

78-543: A high degree of silicification due to hydrothermal interaction with seawater at low temperatures. Lithic fragments were replaced with microcrystalline quartz and protoliths were altered during silicification. The condition of silicification and the elements that were present suggested that the surface temperature and carbon dioxide contents were high during either or both syn-deposition and post-deposition. The Barberton Greenstone Belt in South Africa, specifically

117-506: A large-scale marine silica cycle that circulates silica through the ocean. Silica content is therefore high in active silica upwelling areas in the deep-marine sediments. Besides, carbonate shells that deposited in shallow marine environments enrich silica contents at continental shelf areas. The major component of the Earth's upper mantle is silica (SiO 2 ), which makes it the primary source of silica in hydrothermal fluids. SiO 2

156-580: A reference for further geological interpretations. In the Conception Bay in Newfoundland, Southeastern coast of Canada, a series of Pre-Cambrian to Cambrian-linked volcanic rocks were silicified. The rocks mainly consist of rhyolitic and basaltic flows, with crystal tuffs and breccia interbedded. Regional silicification was taken place as a preliminary alteration process before other geochemical processes occurred. The source of silica near

195-467: A syn- depositional or a post-depositional stage, commonly along layers marking changes in sedimentation such as unconformities or bedding planes . The sources of silica can be divided into two categories: silica in organic and inorganic materials. The former category is also known as biogenic silica , which is a ubiquitous material in animals and plants. The latter category is the second most abundant element in Earth's crust. Silicate minerals are

234-433: Is a stable component. It often appears as quartz in volcanic rocks . Some quartz that is derived from pre-existing rocks, appear in the form of sand and detrital quartz that interact with seawater to produce siliceous fluids. In some cases, silica in siliceous rocks are subjected to hydrothermal alteration and react with seawater at certain temperatures, forming an acidic solution for silicification of nearby materials. In

273-681: Is classic examples of silicified karsts. A portion of the carbonates are replaced by cherts in early diagenesis and the remaining portion is completely silicified in later stages. The source of silica in carbonates are usually associated with the presence of biogenetic silica; however, the source of silica in Mescal Limestone is from weathering of overlying basalts , which are extrusive igneous rocks that have high silica content. Silicification of woods usually occur in terrestrial conditions, but sometimes it could be done in aquatic environments. Surface water silicification can be done through

312-531: Is composed of silica spheres of different sizes arranged randomly. Mafic magma dominated the seafloor at around 3.9 Ga during the Hadean - Archean transition. Due to rapid silicification, the felsic continental crust began to form. In the Archean, the continental crust was composed of tonalite–trondhjemite–granodiorite (TTG) as well as granite– monzonite – syenite suites. The Mount Goldsworthy in

351-600: Is one of the very few demographically stable settlements in the Disko Bay region. Saqqaq culture The Saqqaq culture (named after the Saqqaq settlement, the site of many archaeological finds) was a Paleo-Eskimo culture in southern Greenland . Up to this day, no other people seem to have lived in Greenland continually for as long as the Saqqaq. The earliest known archaeological culture in southern Greenland,

390-431: Is the controlling value. Under a condition of pH lower than 9, silica precipitates out of the fluid; when the pH value is above 9, silica becomes highly soluble. In the silicification of woods, silica dissolves in hydrothermal fluid and seeps into lignin in cell walls. Precipitation of silica out of the fluids produces silica deposition within the voids, especially in the cell walls. Cell materials are broken down by

429-479: The Disko Bay are unique in that they are operated only during winter and spring. During summer and autumn, when the waters of the bay are navigable, communication between settlements is by sea only, serviced by Diskoline . The ferry links Saqqaq with Qeqertaq , Oqaatsut , and Ilulissat. The population of Saqqaq has increased by 60 percent relative to the 1990 levels, stabilizing in the following decade. Saqqaq

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468-653: The Inuit . On 21 November 2000 a large landslide at Paatuut , 40 kilometres (22 nmi; 25 mi) from Saqqaq, generated a megatsunami in Sullorsuaq (or Vaigat) Strait. Energy from the tsunami refracted after it struck Disko Island across the strait , generating a wave with a run-up height of 3 metres (9.8 ft) which destroyed boats at Saqqaq. Air Greenland serves the village as part of government contract, with winter-only helicopter flights between Saqqaq Heliport and Ilulissat Airport . Settlement flights in

507-532: The Pilbara Craton located in Western Australia holds one of the earliest silicification example with an Archean clastic meta-sedimentary rock sequence, revealing the surface environment of the Earth in the early times with evidence from silicification and hydrothermal alteration. The unearthed rocks are found to be SiO2 dominant in terms of mineral composition. The succession was subjected to

546-1249: The Yanjiahe Formation in South China. Some of them occur as sponge spicules and are associated with microcrystalline quartz or other carbonates after silicification. It could also be the main source of precipitative beds such as cherts beds or cherts in petrified woods. Diatoms , an important group of microalgae living in marine environments, contribute significantly to the source of diagenetic silica. They have cell walls made of silica, also known as diatom frustules . In some silicified sedimentary rocks, fossils of diatoms are unearthed. This suggests that diatoms frustules were sources of silica for silicification. Some examples are silicified limestones of Miocene Astoria Formation in Washington, silicified ignimbrite in El Tatio Geyser Field in Chile, and Tertiary siliceous sedimentary rocks in western pacific deep sea drills. The presence of biogenic silica in various species creates

585-418: The rock cycle , the chemical weathering of rocks also releases silica in the form of silicic acid as by-products . Silica from weathered rocks is washed into waters and deposit into shallow-marine environments. The presence of hydrothermal fluids is essential as a medium for geochemical reactions during silicification. In the silicification of different materials, different mechanisms are involved. In

624-553: The Eswatini Supergroup of around 3.5–3.2 Ga, is a suite of well-preserved silicified volcanic-sedimentary rocks. With the composition ranging from ultramafic to felsic, the silicified volcanic rocks are directly beneath the bedded chert layer. Rocks are more silicified near the bedded chert contact, suggesting a relationship between chert deposition and silicification. The silica altered zones reveal that hydrothermal activities, as in seawater circulation, actively circulate

663-585: The Saqqaq existed from around 2500 BCE until about 800 BCE. This culture coexisted with the Independence I culture of northern Greenland, which developed around 2400 BCE and lasted until about 1300 BCE. After the Saqqaq culture disappeared, the Independence II culture of northern Greenland and the Early Dorset culture of West Greenland emerged. There is some debate about the timeframe of

702-534: The Semail Nappe of Oman in the United Arb Emirates, silicified serpentinite was found. The occurrence of such geological features is rather unusual. It is a pseudomorphic alteration where the protolith of serpentinite was already silicified. Due to tectonic events, basal serpentinite was fractured and groundwater permeated along the faults, forming a large-scale circulation of groundwater within

741-413: The ancestors of the Saqqaq entered North America from Siberia through a distinct migration about 4000 BC, and that they subsequently remained largely genetically isolated from other North American populations. Silicification In geology, silicification is a petrification process in which silica -rich fluids seep into the voids of Earth materials , e.g., rocks, wood, bones, shells, and replace

780-407: The area was from hot siliceous fluids from rhyolitic flow under a static condition. A significant portion of silica appeared in the form of white chalcedonic quartz, quartz veins as well as granular quartz crystal. Due to the difference in rock structures, silica replaces different materials in rocks of close locations. The following table shows the replacement of silica at different localities: In

819-412: The difference in gradient, carbonates from the original rock dissolve into the fluid whereas silica precipitate out of it. The carbonate that dissolved is therefore pulled out from the system while the silica precipitated recrystallizes into various silicate minerals, depending on the silica phase. The solubility of silica strongly depends on the temperature and pH value of the environment where pH9

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858-421: The difficulty in digestion, harming the fitness of herbivores. However, evidence on the effects of silica on the wellbeing of animals and plants is still insufficient. Besides, sponges are another biogenic source of naturally occurring silica in animals. They belong to the phylum Porifera in the classification system. Silicious sponges are commonly found with silicified sedimentary layers , for example in

897-471: The faster silicification could take place. The same concept applies to the availability of hydrothermal fluids. The temperature and pH of the environment determine the condition for silicification to occur. This is closely connected to the burial depth or association with volcanic events. Interference of other diagenetic processes could sometimes create disturbance to silicification. The relative time of silicification to other geological processes could serve as

936-413: The fluid 3) Temperature and pH of silicification environment 4) Interference of other diagenetic processes These factors affect the silicification process in many ways. The rate of breakage of original cells controls the development of the mineral framework, hence the replacement of silica. Availability of silica directly determines the silica content in fluids. The higher the silica content,

975-505: The fluids, yet the structure remains stable due to the development of minerals. Cell structures are slowly replaced by silica. Continuous penetration of siliceous fluids results in different stages of silicification ie. primary and secondary. The loss of fluids over time leads to the cementation of silicified woods through late silica addition. The rate of silicification depends on a few factors: 1) Rate of breakage of original cells 2) Availability of silica sources and silica content in

1014-521: The form of silicified karsts. The Paleogene Madrid Basin in Central Spain is a foreland basin resulted from the Alpine uplift, an example of silicified carbonates in rock layers. The lithology consists of carbonate and detritus units that were formed in a lacustrine environment. The rock units are silicified where cherts, quartz, and opaline minerals are found in the layers. It is conformable with

1053-408: The major components of 95% of presently identified rocks. Biogenic silica is the major source of silica for diagenesis. One of the prominent examples is the presence of silica in phytoliths in the leaves of plants, ie. grasses, and Equisetaceae . Some suggested that silica present in phytoliths can serve as a defense mechanism against the herbivores, where the presence of silica in leaves increases

1092-408: The original materials with silica (SiO 2 ). Silica is a naturally existing and abundant compound found in organic and inorganic materials, including Earth's crust and mantle . There are a variety of silicification mechanisms. In silicification of wood, silica permeates into and occupies cracks and voids in wood such as vessels and cell walls. The original organic matter is retained throughout

1131-455: The precipitation of silica in silica-enriched hot springs. On the northern coast of central Japan, the Tateyama hot spring has a high silica content that contributes to the silicification of nearby fallen woods and organic materials. Silica precipitates rapidly out of the fluids and opal is the main form of silica. With a temperature of around 70°C and a pH value of around 3, the opal deposited

1170-470: The presence of diatoms. Karsts are carbonate caves formed from a dissolution of carbonate rocks such as limestones and dolomites . They are usually susceptible to groundwater and are dissolved in these drainage. Silicified karsts and cave deposits are formed when siliceous fluids enter karsts through faults and cracks. The Mid-Proterozoic Mescal Limestone from the Apache Group in central Arizona

1209-441: The process and will gradually decay through time. In the silicification of carbonates , silica replaces carbonates by the same volume. Replacement is accomplished through the dissolution of original rock minerals and the precipitation of silica. This leads to a removal of original materials out of the system. Depending on the structures and composition of the original rock, silica might replace only specific mineral components of

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1248-556: The remains of six Saqqaq individuals buried in Qeqertasussuk, Greenland between ca. 3000 BCE and 1900 BCE. The five samples of mitochondrial DNA (mtDNA) extracted belonged to haplogroups D2a1 (four samples) and D2a. These haplogroups also predominate in the Dorset culture , and are today found in high frequencies among Siberian Yupik and Aleut , with whom the Saqqaq are relatively closely related. The evidence suggested that

1287-715: The rock. Silicic acid (H 4 SiO 4 ) in the silica-enriched fluids forms lenticular, nodular, fibrous, or aggregated quartz , opal , or chalcedony that grows within the rock. Silicification happens when rocks or organic materials are in contact with silica-rich surface water, buried under sediments and susceptible to groundwater flow, or buried under volcanic ashes. Silicification is often associated with hydrothermal processes. Temperature for silicification ranges in various conditions: in burial or surface water conditions, temperature for silicification can be around 25°−50°; whereas temperatures for siliceous fluid inclusions can be up to 150°−190°. Silicification could occur during

1326-399: The shores of Uummannaq Fjord revealed the existence of an ancient Arctic culture, later named the Saqqaq culture , which inhabited the area of west-central Greenland between 2500 BCE and 800 BCE. Recent DNA samples from human hair suggest that the ancient Saqqaq people came from Siberia around 3,500 BCE and independent of the migration that gave rise to the modern Native Americans and

1365-564: The silicification of rock materials like carbonates, replacement of minerals through hydrothermal alteration is common; while the silicification of organic materials such as woods is solely a process of permeation. The replacement of silica involves two processes: 1) Dissolution of rock minerals 2) Precipitation of silica It could be explained through the carbonate-silica replacement. Hydrothermal fluids are undersaturated with carbonates and supersaturated with silica. When carbonate rocks get in contact with hydrothermal fluids, due to

1404-399: The strata. Through hydrothermal dissolution, silica precipitated and crystallized around the voids of serpentinite. Therefore, silicification can only be seen along groundwater paths. The silicification of serpentinite was formed under the condition where groundwater flow and carbon dioxide concentration are low. Silicified carbonates can appear as silicified carbonate rock layers, or in

1443-604: The transition from Saqqaq culture to Early Dorset in western Greenland. The Saqqaq culture came in two phases, the main difference of the two being that the newer phase adopted the use of sandstone. The younger phase of the Saqqaq culture coincides with the oldest phase of the Dorset culture. Frozen remains of a Saqqaq person dubbed " Inuk " were found in western Greenland ( Qeqertarsuaq ) and have been DNA sequenced. He had brown eyes, black hair, and shovel-shaped teeth . It has been determined that he lived about 4000 years ago, and

1482-422: The underlying evaporitic beds, also dated from similar ages. It is found that there were two stages of silicification within the rock strata. The earlier stage of silicification provided a better condition and site for the precipitation of silica. The source of silica is still uncertain. There are no biogenic silica detected from the carbonates. However, microbial films in carbonates are found, which could suggest

1521-654: Was related to native populations in northeastern Siberia. The Saqqaq people are not the ancestors of contemporary Kalaallit people, but instead are related to modern Chukchi and Koryak peoples. It is not known whether they crossed in boats or over ice. Saqqaq people lived in small tents and hunted seals, seabirds, and other marine animals. The people of the Saqqaq culture used silicified slate, agate, quartzite , and rock crystals as materials for their tools. A genetic study published in Science in August 2014 examined

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