Misplaced Pages

#998001

48-555: There is little recorded data found about the Pre-Mesolithic for this site, due to the fact that many of the burials were disturbed by the Neolithic and Meroitic occupations. However, around 90 bodies were excavated that can be attributed to the Pre-Mesolithic occupation of al-Khiday 2. They were distinguished through their extended and prone positions. The bodies were dated based on lack of collagen and prior stratigraphic data. This mound

96-441: A blue tinge. It has distinctive dark-black eyes, with a bright-yellow outer ring. One of the largest freshwater fishes , it reaches a maximum length of nearly 2 m (6 ft 7 in), weighing up to 200 kg (440 lb). Mature fish typically range from 1.21–1.37 m (4 ft 0 in – 4 ft 6 in), although many fish are caught before they can grow this large. Adult Nile perch occupy all habitats of

144-433: A high fat content (higher than cichlids), they need to be smoked to avoid spoiling. This has led to an increased demand for firewood in a region already hard-hit by deforestation , soil erosion , and desertification . The Academy Award -nominated documentary Darwin's Nightmare by Hubert Sauper (a French-Austrian-Belgian production, 2004) deals with the damage that has been caused by Nile perch introduction, including

192-591: A lake with sufficient oxygen concentrations, while juveniles are restricted to shallow or nearshore environments. A fierce predator that dominates its surroundings, the Nile perch feeds on fish (including its own species), crustaceans , molluscs , and insects ; the juveniles also feed on zooplankton . Nile perch use schooling as a mechanism to protect themselves from other predators. Nile perch have been introduced to many other lakes in Africa, including Lake Victoria and

240-409: A new equilibrium, neither its former state nor the state of fisheries on Lake Victoria can ever easily be brought back. Despite being a successful invasive species, the fish faces threats. Being a species of megafauna , the most obvious threats to the species are overfishing and the use of illegal fishing gear, as well as invasive water hyacinths . Prey depletion is also a factor, as it decreases

288-436: A section. The samples are analyzed to determine their detrital remanent magnetism (DRM), that is, the polarity of Earth's magnetic field at the time a stratum was deposited. For sedimentary rocks this is possible because, as they fall through the water column, very fine-grained magnetic minerals (< 17  μm ) behave like tiny compasses , orienting themselves with Earth's magnetic field . Upon burial, that orientation

336-416: Is a branch of geology concerned with the study of rock layers ( strata ) and layering (stratification). It is primarily used in the study of sedimentary and layered volcanic rocks . Stratigraphy has three related subfields: lithostratigraphy (lithologic stratigraphy), biostratigraphy (biologic stratigraphy), and chronostratigraphy (stratigraphy by age). Catholic priest Nicholas Steno established

384-431: Is also commonly used to delineate the nature and extent of hydrocarbon -bearing reservoir rocks, seals, and traps of petroleum geology . Chronostratigraphy is the branch of stratigraphy that places an absolute age, rather than a relative age on rock strata . The branch is concerned with deriving geochronological data for rock units, both directly and inferentially, so that a sequence of time-relative events that created

432-534: Is due to physical contrasts in rock type ( lithology ). This variation can occur vertically as layering (bedding), or laterally, and reflects changes in environments of deposition (known as facies change). These variations provide a lithostratigraphy or lithologic stratigraphy of the rock unit. Key concepts in stratigraphy involve understanding how certain geometric relationships between rock layers arise and what these geometries imply about their original depositional environment. The basic concept in stratigraphy, called

480-490: Is present within all periods. It is a tuberous plant which was very widespread throughout Africa especially near the Nile rivers, it excels at quickly spreading and thriving in these environments. No true evidence of the plant was found within the burials of the three periods, as it is very difficult to find preserved, however, was considered a staple of diets through associated communities and proxy evidence found. Chewing on purple nut sedge inhibits Streptococcus mutans , during

528-411: Is preserved. For volcanic rocks, magnetic minerals, which form in the melt, orient themselves with the ambient magnetic field, and are fixed in place upon crystallization of the lava. Oriented paleomagnetic core samples are collected in the field; mudstones , siltstones , and very fine-grained sandstones are the preferred lithologies because the magnetic grains are finer and more likely to orient with

SECTION 10

#1733085774999

576-635: The Congo , Nile , Senegal , Niger and Lake Chad , Volta , Lake Turkana , and other river basins. It also occurs in the brackish waters of Lake Maryut in Egypt . The Nile perch is a fish of substantial economic and food-security importance in East Africa. Originally described as Labrus niloticus, among the marine wrasses , the species has also been referred to as Centropomus niloticus . Common names include African snook, Victoria perch (a misleading trade name, as

624-431: The law of superposition , states: in an undeformed stratigraphic sequence, the oldest strata occur at the base of the sequence. Chemostratigraphy studies the changes in the relative proportions of trace elements and isotopes within and between lithologic units. Carbon and oxygen isotope ratios vary with time, and researchers can use those to map subtle changes that occurred in the paleoenvironment. This has led to

672-547: The natural remanent magnetization (NRM) to reveal the DRM. Following statistical analysis, the results are used to generate a local magnetostratigraphic column that can then be compared against the Global Magnetic Polarity Time Scale. This technique is used to date sequences that generally lack fossils or interbedded igneous rocks. The continuous nature of the sampling means that it is also a powerful technique for

720-520: The Mesolithic deposits around 90% is found to be fish, this is assumed to tie into the Mesolithic base camps close association with the flood-swamps, easy access to the Nile, and other productive aquatic habitats such as Jebel Baroka Lake. The most commonly identified aquatic species in the deposits is that of the Clarrid Catfish, which is a shallow water fish which lived within the shores of the Nile and

768-601: The Mesolithic findings contained a wide variety of decorations: incised wavy line, dotted wavy line, "lunula-shaped", alternately pivoting stamp, rocker stamp drops, rocker stamp drops deep, rocker stamp dotted zigzag, rocker stamp plain zigzag Optical Microscopy determined three types of paste at the al-Khiday sites, two of which are associated with the Mesolithic with no exceptions; Alkati-Felspar and Quartz-rich [117 samples] and Quartz Sand-rich [185 samples]. Image analysis of these three groups also found that, based on abundance, size and grain size distribution of inclusions, there

816-423: The Mesolithic small starch granules, plant fibers and micro-charcoal were found, the granules were small and displayed no signs of damage. This is estimated to be indicative of little to no external processing, such as heating, presence of water or roasting, they were most likely ingested raw. To greater determine diet the information gathered through the zooarchaeological record and lipid analysis of found pottery

864-449: The Mesolithic. These vessels saw no evidence that any aquatic products were cooked or processed and very little evidence of any ruminants within the analysis, despite most of the taxa from the deposits being either aquatic or ruminant, implying much more plant usage, of the 22 lipid-yielding vessels eight were ever used to process animal products and of those only three were solely for animal processes. The pottery found in association with

912-429: The Nile perch grows to 2.0 m (6 ft 7 in) long. The species is of great commercial importance as a food fish. The Nile perch is also popular with sport anglers , as it attacks artificial fishing lures , and it is also raised in aquaculture . The introduction of this species to Lake Victoria is one of the most cited examples of the negative effects alien species can have on ecosystems. The Nile perch

960-413: The actual Nile perch stocks. The Nile perch initially fed on native cichlids, but with decreasing availability of this prey, it now consumes mainly small shrimp and minnows . The alteration of the native ecosystem had disruptive socioeconomic effects on local communities bordering the lake. Many local people have been displaced from their traditional occupations in the fishing trade and brought them into

1008-588: The ambient field during deposition. If the ancient magnetic field were oriented similar to today's field ( North Magnetic Pole near the North Rotational Pole ), the strata would retain a normal polarity. If the data indicate that the North Magnetic Pole were near the South Rotational Pole , the strata would exhibit reversed polarity. Results of the individual samples are analyzed by removing

SECTION 20

#1733085774999

1056-468: The artificial Lake Nasser . The World Conservation Union 's Invasive Species Specialist Group considers L. niloticus one of the world's 100 worst invasive species. The state of Queensland in Australia levies heavy fines on anyone found in possession of a living Nile perch, since it competes directly with the native barramundi , which is similar and grows to 1.5 m (4 ft 11 in) long, while

1104-413: The cash economy, or before the establishment of export-oriented fisheries, turned them into economic refugees . At least initially, nets strong enough to hold adult Nile perch could not be manufactured locally and had to be imported for a high price. The introduction of Nile perch has also had additional ecological effects on shore. Native cichlids were traditionally sun-dried, but because Nile perch have

1152-731: The common Nile perch . The vessels found indicated evidence of use for carcass and plant production as well as some minor dairy exploitation, the residual analysis also saw much more ruminant animal production (it is unsure if domesticated or not). The vessels, as in the Mesolithic, contained a variety of decorations with some carrying on from the Mesolithic: burnishing, linear horizontal incisions, rocker stamp dotted zigzag, rocker stamp evenly spaced dots, rocker stamp unevenly spaced dots, horizontal dotted lines with alternately pivoting stamp technique, semi-circular concentric dotted line, scraping, incised fish scale, and black rimmed The paste group which

1200-483: The dental calculus analysis there was an exceptionally low quantity of this bacteria found indicating a potential correlation between the two. It is questioned why the consumption would have continued into the Neolithic and Meroitic periods where better C3 plants were present. One theory is the fact that as a tuber, purple nut sedge is not only nutritional and abundant, but also medicinal as described in various Grecian medical writings. Stratigraphy Stratigraphy

1248-557: The estimation of sediment-accumulation rates. Nile perch The Nile perch ( Lates niloticus ), also known as the African snook , Goliath perch , African barramundi , Goliath barramundi , Giant lates or the Victoria perch , is a species of freshwater fish in family Latidae of order Perciformes . It is widespread throughout much of the Afrotropical realm , being native to

1296-455: The flooded swamps nearby. Along with fish, mollusk shells and freshwater turtles were found, and in terms of non aquatic animals, small evidence for stork, geese and duck were discovered. The mammalian taxa contained a very diverse collection of animals which imply a lush Savannah environment, the main one being a large collection of Antelopes, but also baboon, hare, warthog and the rare large mammal; elephant, rhinoceros and hippopotamus. Within

1344-512: The gap may be due to removal by erosion, in which case it may be called a stratigraphic vacuity. It is called a hiatus because deposition was on hold for a period of time. A physical gap may represent both a period of non-deposition and a period of erosion. A geologic fault may cause the appearance of a hiatus. Magnetostratigraphy is a chronostratigraphic technique used to date sedimentary and volcanic sequences. The method works by collecting oriented samples at measured intervals throughout

1392-430: The import of weapons and ammunition in cargo planes from Europe, which are then used to export Nile perch, further exacerbating conflict and misery in the surrounding regions. Regardless of whether it is considered positive or negative, the trophic web of Lake Victoria appears to have been drastically impoverished by the introduction of this novel near- top-level predator . While the ecosystem seems to be moving towards

1440-409: The largest percentage of "char" on dental analysis associated with cooking and smoke compared to the other two periods. The deposits associated with this range saw a much smaller and more poorly preserved collection with the most significant finds being that of giraffe, antelope and some evidence of domesticates. There was also a lack of fish remains in the deposit with the most common one being that of

1488-521: The most common being a rectangular shaft that was dug east–west. The second most common was very similar to the prior, however it also contained a circular chamber on the west side. The final was one additional irregular/circular shaft burial on the southern side, it was the only one found but the fireplace C-14 dates attributes it to the same time period. The bodies found were oriented west with their faces turned north, traces of botanical remains were found above and below indicating mats surrounding them. There

Al-Khiday - Misplaced Pages Continue

1536-415: The mound, however, evidence demonstrates the fact that a Mesolithic group deliberately placed base camps on tops of ridges such as this one since at that time it would have been surrounded by seasonal flood-fed swamps. This establishment is what introduced the start of the accumulation of living floors on the site, the Mesolithic occupation as known know can be dated to around 6700 - 6300 cal years BC. Within

1584-555: The other cemeteries in Sudan from this time. It is estimated that the Neolithic occupation at this site lasted from around 4550 - 4250 cal years BC. The starch granules found which associated to this time period were all fairly large (~25mm) with no small ones present, the ones that were seen demonstrated alterations which resembled the possibility of heating. Many were cracked placing the theory that they were either ground or allowed to roast in dry heat. The Neolithic time period also displayed

1632-437: The rock layers. Strata from widespread locations containing the same fossil fauna and flora are said to be correlatable in time. Biologic stratigraphy was based on William Smith's principle of faunal succession , which predated, and was one of the first and most powerful lines of evidence for, biological evolution . It provides strong evidence for the formation ( speciation ) and extinction of species . The geologic time scale

1680-480: The rocks formation can be derived. The ultimate aim of chronostratigraphy is to place dates on the sequence of deposition of all rocks within a geological region, and then to every region, and by extension to provide an entire geologic record of the Earth. A gap or missing strata in the geological record of an area is called a stratigraphic hiatus. This may be the result of a halt in the deposition of sediment. Alternatively,

1728-405: The significance of strata or rock layering and the importance of fossil markers for correlating strata; he created the first geologic map of England. Other influential applications of stratigraphy in the early 19th century were by Georges Cuvier and Alexandre Brongniart , who studied the geology of the region around Paris. Variation in rock units, most obviously displayed as visible layering,

1776-402: The size of the fish and makes it vulnerable to larger predators, such as crocodiles. In 2021, The Uganda Fish Processors and Exporters Association called on the parliament to ban the local consumption of the species so as to protect its export. Nile perch were involved with the worship of Neith . As a result nile perch were sometimes mummified. A deposit of several thousand mummified perch

1824-516: The skull of a 10-year-old child. The adults were found with the larger vessels, however, two small feeding cups were found with infant burials. The investigations into the bodies found indicated that there was low dental caries, showing a low carbohydrate diet or plants which inhibit dental caries, there was also a high calculus rate which points to a protein diet. The studies also found indication of stress during childhood and evidence of healed injuries. Cyperus rotundus , also known as purple nut sedge,

1872-406: The specialized field of isotopic stratigraphy. Cyclostratigraphy documents the often cyclic changes in the relative proportions of minerals (particularly carbonates ), grain size, thickness of sediment layers ( varves ) and fossil diversity with time, related to seasonal or longer term changes in palaeoclimates . Biostratigraphy or paleontologic stratigraphy is based on fossil evidence in

1920-514: The species is not native to Lake Victoria , though they have been introduced there), and many local names in various African languages, such as the Luo name mbuta or mputa . In Tanzania , it is called sangara , sankara , or chenku . In Francophone African countries, it is known as capitaine . Its name in the Hausa language is giwan ruwa , meaning "water elephant". L. niloticus is silver in color with

1968-429: The theoretical basis for stratigraphy when he introduced the law of superposition , the principle of original horizontality and the principle of lateral continuity in a 1669 work on the fossilization of organic remains in layers of sediment. The first practical large-scale application of stratigraphy was by William Smith in the 1790s and early 19th century. Known as the "Father of English geology", Smith recognized

Al-Khiday - Misplaced Pages Continue

2016-517: Was introduced to Lake Victoria in East Africa in the 1950s, and has since been fished commercially. In 2003, Nile perch sales to the EU reached 169 million euros. Sport-fishing in the region of Uganda and Tanzania provided additional income from tourism. Its introduction was ecologically disruptive and is attributed with causing the extinction or near- extinction of several hundred native species, with some populations fluctuating with commercial fishing and

2064-525: Was developed during the 19th century, based on the evidence of biologic stratigraphy and faunal succession. This timescale remained a relative scale until the development of radiometric dating , which was based on an absolute time framework, leading to the development of chronostratigraphy. One important development is the Vail curve , which attempts to define a global historical sea-level curve according to inferences from worldwide stratigraphic patterns. Stratigraphy

2112-509: Was found through Optical Microscopy for the Neolithic was Fine sand-sized quartz-rich with around 58 samples, it was also confirmed to be different in abundance, size and grain size distribution of inclusions, through image analysis than the two groups associated with the Mesolithic. There were again no exceptions. Within the excavations 43 Meroitic graves were identified, these were deep graves which interrupted other burial phases and features. Among these 43 graves 3 distinct types were determined;

2160-529: Was likely chosen by Pre-Mesolithic people as a burial site due to its adjacency to the White Nile. An influential find of the Pre-Mesolithic occupation was the discovery of three prostatic stones found within the burial of an individual. These three Prostatic calculi with the occurrence of bacterial imprints link to evidence of a bacterial infection, that of lithiasis , the earliest known case. The cemetery at al-Khiday 2 found no evidence of Mesolithic burials in

2208-568: Was no substation difference between the two groups aforementioned associated with the Mesolithic At the site of al-Khiday 2 there are around 32 Neolithic burials which mark the movement of Neolithic peoples here following the base camps of the Mesolithic occupation, this occupation induces the beginning of the degradation of the Pre-Mesolithic graves. Many of the Neolithic burials are with burial goods such as Shaheinab Pottery and other datable material, they resemble many other ritualistic burials of

2256-399: Was no true pattern in spatial distribution of age, sex or gender except for a concentration of infant and children burials in the northeastern sector and an increase in burial goods within rounded graves. The grave goods found included 12 ceramic pots which were handmade and sand and straw tempered, these were buried with anklets, necklaces and other ornaments along with one iron arrowhead under

2304-462: Was used, these concentrations of lipids on vessels indicated that either plants or low lipid-yielding animal products were being processed in the vessels. The vessels were also found with a large accumulation of leaf or stem epicuticular waxes and a high abundance of diacids , more specifically cutin and suberin . The presence of these displays evidence that underground storage organs such as tubers were most likely processed in these vessels during

#998001