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48-693: The Cenozoic plate tectonics of the Indonesian region have generated a complex assemblage of micro-continental blocks and marginal ocean basins surrounded by extensional margins, subduction zones and major transcurrent faults. The island of Borneo and the Kutai basin are located on the Sunda micro-plate , which is bounded to the north and west by the Eurasian Plate , to the south by the Indo-Australian Plate and to

96-417: A deep marine depositional environment, while the western basin transitioned more slowly. A thick marine shale was deposited across much of the basin, while carbonate sedimentation continued on isolated high areas and basin margins. The sag phase marine shale has been observed to lie directly upon basement, and is a regional "blanket" over the syn-rift lithologies . Large carbonate platforms developed along

144-463: A global ocean model. These trajectories are of particles that move only on the surface of the ocean. The model outcome gives the probability of a particle at a certain grid point to end up somewhere else on the ocean's surface. With the model outcome a matrix can be created from which the Eigenvectors and Eigenvalues are taken. These Eigenvectors show regions of attraction, aka regions where things on

192-500: A particle on the ocean surface in a certain region is more likely to stay in the same region than to pass over to a different one. Depending on the chemical composition and the physical state, the Earth can be divided into three major components:  the mantle , the core , and the crust . The crust is referred to as the outside layer of the Earth. It is made of solid rock, mostly basalt and granite . The crust that lies below sea level

240-455: A punctuated fashion through the Miocene and Pliocene. A compressional regime is implied for the later inversion events with stresses transmitted from regional plate collisions. The high angle normal faults were reactivated as thrust faults , inverting the half-grabens. The locus of inversion shifted east with each event. Sedimentation in the Kutai basin has been relatively constant throughout

288-625: Is a mountain range in the Indonesian province of South Kalimantan ; it is located on Borneo island. The mountains run in a north-south arc that divides South Kalimantan province into two almost equal parts. Its highest peak is Mount Besar at 1,901 metres elevation. The mountains are inhabited by the "semi-nomadic" Meratus Dayak people. The mountains are surrounded at lower elevations by heavily disturbed lowland rain forest and lands converted to agriculture. The higher elevations are home to submontane and montane forests, which are separated from

336-551: Is a complex mosaic of geologic terrains, commonly interpreted as the product of primarily Mesozoic accretion of micro-continental fragments, island arc material, oceanic crustal material and marginal basin fill onto the Paleozoic core of the Schwaner Mountains in the southwest of the island. The Schwaner Mountain area consists of early-mid Cretaceous granitic batholiths intruded into Silurian to Permian age metamorphic units. NW of

384-558: Is active, re-activation along these faults produces detached, uplifted anticlines Three suites of intrusive and volcanic rocks are found in the Kutai Basin, and have been used to constrain the Tertiary stratigraphy . The felsic Nyaan volcanics, dated to 48-50 Ma may be related to the extensional tectonics that initiated basin formation. In some locations, the Nyaan volcanics and equivalents are at

432-541: Is affected not only by the volume of the ocean basin, but also by the volume of water in them. Factors that influence the volume of the ocean basins are: The Atlantic Ocean and the Arctic Ocean are good examples of active, growing oceanic basins, whereas the Mediterranean Sea is shrinking. The Pacific Ocean is also an active, shrinking oceanic basin, even though it has both spreading ridge and oceanic trenches. Perhaps

480-477: Is an accreted melange of upper cretaceous to Paleocene age that formed the central Kalimantan Ranges as the result of SW directed subduction beneath the continental core of Borneo. The Cenozoic evolution of Borneo is predominantly controlled by active regional and local tectonics and climate. In the Paleocene, Borneo was a promontory of SE Asia, partially separated by oceanic crust of the proto-South China Sea. There

528-574: Is anywhere on Earth that is covered by  seawater . Geologically , most of the ocean basins are large  geologic basins  that are below sea level . Most commonly the ocean is divided into basins following the continents distribution : the North and South Atlantic (together approximately 75 million km / 29 million mi ), North and South Pacific (together approximately 155 million km / 59 million mi ), Indian Ocean (68 million km / 26 million mi ) and Arctic Ocean (14 million km / 5.4 million mi ). Also recognized

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576-683: Is geologic evidence that suggests Borneo has rotated counter clock wise about 45° from its orentation at the end of the Oligocene while remaining to straddle the equator. This would indicate most of the Paleogene sediment in North Borneo was sourced from Indochina. In the Mid Eocene formation of the Celebes Sea and Makassar Strait rifted the eastern margin of Borneo while subduction of oceanic crust occurred on

624-532: Is known as the oceanic crust , while on land it is known as the continental crust . The former is thinner and is composed of relatively dense basalt, while the latter is less dense and mainly composed of granite. The lithosphere is composed of the crust (oceanic and continental) and the uppermost part of the mantle. The lithosphere is broken into sections called plates . Tectonic plates move very slowly (5 to 10 cm (2 to 4 inches) per year) relative to each other and interact along their boundaries. This movement

672-584: Is responsible for most of the Earth's seismic and volcanic activity. Depending on how the plates interact with each other, there are three types of boundaries. The Earth's deepest trench is the Mariana Trench which extends for about 2500 km (1600 miles) across the seabed. It is near the Mariana Islands , a volcanic archipelago in the West Pacific. Its deepest point is 10994 m (nearly 7 miles) below

720-583: Is the Southern Ocean (20 million km / 7 million mi ). All ocean basins collectively cover 71% of the Earth's surface, and together they contain almost 97% of all water on the planet. They have an average depth of almost 4 km (about 2.5 miles). "Limits of Oceans and Seas" , published by the International Hydrographic Office in 1953, is a document that defined the ocean's basins as they are largely known today. The main ocean basins are

768-792: The Atlantic and Arctic basins. The Atlantic Basin began to form around 180 million years ago, when the continent Laurasia (North America and Eurasia ) started to drift away from Africa and South America. The Pacific plate grew, and subduction led to a shrinking of its bordering plates. The Pacific plate continues to move northward. Around 130 million years ago the South Atlantic started to form, as South America and Africa started to separate. At around this time India and Madagascar rifted northwards, away from Australia and Antarctica, creating seafloor around Western Australia and East Antarctica. When Madagascar and India separated between 90 and 80 million years ago,

816-634: The Indonesian region. Many of these basins, including the Kutai, have formed in a back arc extensional setting, driven by passive or active subduction rollback. The mid Miocene episode of inversion in the Kutai can be linked to collision of continental fragments from the South China Sea with NW Borneo. The Pliocene inversion episode is contemporaneous with the collision of Australia with the Banda arc, with structural connections provided by strike-slip fault systems through Sulawesi . The basement rock of Borneo

864-589: The Kutai Basin in the Early Miocene. Large amounts of clastic sediment derived from the rising central mountains, and the now inverted Paleogene poured into the lower Kutai Basin. The proto-Mahakam river began to prograde eastward. Subsequent tectonic inversion events in the middle Miocene and Pliocene continued to shift the deltaic depocenter of the Mahakam river eastward into the Makassar Strait. Compression in

912-516: The Kutai basin at this location could be up to 15 kilometres (49,000 ft). The most prominent geologic structure in the Kutai Basin is the Samarinda anticlinorium—Mahakam foldbelt, a series of NNE-SSW trending folds and faults in Miocene deltaic strata that parallel the modern coast line. The tightly folded, asymmetric, and thrust fault bound anticlines range from 2–5 km wide and 20–50 km long and separated by broad, open synclines. Onshore,

960-605: The Mariana Islands. It is located far away from oceanic spreading centers, where oceanic crust is constantly created or destroyed. The oldest crust is estimated to be only around 200 million years old, compared to the age of Earth which is 4.6 billion years. 200 million years ago nearly all land mass was one large continent called Pangea , which started to split up. During the splitting process of Pangea, some ocean basins shrunk, such as the Pacific, while others were created, such as

1008-495: The Schwaner Mountains is a small area of older continental basement consisting of Permo-Triassic granite and metamorphic rocks. SE of the Schwaner Mountains, volcanic island arc and ophilitic rocks emplaced in the late Cretaceous comprise the Meratus Mountains. The basement terrain of eastern and northern Borneo is interpreted to be Cretaceous subduction melange, mostly covered by tertiary sediment. The basement of Western Borneo

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1056-602: The Sunda Plate and Pacific Plate in the Pliocene , creating a complex of subduction zones and island arcs . The Philippine Plate has been obliquely subducting the Sunda Plate for most of the Cenozoic. The complex interaction of the Sunda, Eurasian, Indo-Australian, Philippine and Pacific plates in the Cenozoic has controlled the evolution of approximately 60 Tertiary sedimentary basins in

1104-508: The Tertiary. Syn-rift deposition in the Eocene was focused in small, local depocenters within individual half-grabens. Lithology of the initial graben fill is highly variable due to the wide zone of rifting , and ranges from fully terrestrial in the western basin, to fully marine in the eastern basin. A typical initial graben fill in the Kutai basin is composed of coarse and poorly sorted basement derived material. Syn-rift sedimentation following

1152-452: The anticline crests are commonly eroded and breached, and the amount of erosion and structural complexity increase toward the west. A detached fold belt in the westernmost region of the anticlinorium transitions to thrust cored folds in the central region and simple symmetric/asymmetric structures in the easternmost offshore region. The tectonic origin of the fold belt has been attributed to a number of geodynamic processes. One explanation for

1200-452: The base of the Tertiary sedimentary succession, while at other locations bedded tuffs, agglomerates and reworked pyroclastics are part of the late Eocene succession. The Sintang Intrusive suite are mafic to felsic and have a fine crystalline nature which indicates high level emplacement. K-Ar dates of 41-8 Ma have been obtained from rocks assigned to the Sintang suite. Volcanics interpreted to be

1248-554: The basin can be divided into two parts. The western, or upper Kutai which has been inverted 1500-300' above sea level, and the eastern, or lower Kutai which is still receiving sediment. Basin formation was initiated in the middle Eocene as extension related to the opening of the Makassar straits and Celebes Sea rifted the crust of Eastern Borneo. This rifting created a broad system of half grabens that reverse polarity along NNE-SSW and N-S trending normal faults . Thermal subsidence in

1296-517: The basin margins as the result of shallowing marine environments in the early phases of the Late Oligocene tectonic uplift event and a marine regression. As tectonic uplift of central Borneo continued into the lower Miocene, the westernmost portion of the Kutai Basin was inverted above sea level, forming the Upper Kutai Basin. There was a significant change in the character of sedimentation in

1344-640: The best example of an inactive oceanic basin is the Gulf of Mexico, which formed in Jurassic times and has been doing nothing but collecting sediments since then. The Aleutian Basin is another example of a relatively inactive oceanic basin. The Japan Basin in the Sea of Japan which formed in the Miocene , is still tectonically active although recent changes have been relatively mild. Meratus mountains The Meratus Mountains

1392-399: The detachment folding is directly related to basement inversion along the rift stage normal faults, producing folding above a detachment surface in an underlying over-pressured shale. Another is the inversion of delta top grabben systems. These syn-depositional faults form in conjunction with delta toe thrust faults due to differential loading. When contraction occurs while delta progradation

1440-764: The eastern slope of the island of Borneo down from the central highlands, across the modern coastline to the basin floor of the Makassar Straits. It is bound to the North by the Mangkalihat High and the Central Kalimantan Ranges, to the south by the Paternoster Platform, Adang fault zone and the Schwaner and Meratus mountains . The Muller mountains form the western basin margin. In its present configuration,

1488-508: The evolution of several endemic species, including the birds Meratus blue flycatcher ( Cyornis kadayangensis ) and Meratus white-eye ( Zosterops meratusensis ). The area has been recognised as an Important Bird Area (IBA) by BirdLife International . In the 1990s the Borneo Orangutan Survival Foundation reintroduced 350 orangutans into the protected Meratus and Sungai Wain forests. Due to extensive deforestation

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1536-572: The individual ocean basins has fluctuated in the past due to, amongst other, tectonic plate movements. Therefore, an oceanic basin can be actively changing size and/or depth or can be relatively inactive. The elements of an active and growing oceanic basin include an elevated mid-ocean ridge , flanking abyssal hills leading down to abyssal plains and an oceanic trench . Changes in biodiversity, floodings and other climate variations are linked to sea-level, and are reconstructed with different models and observations (e.g., age of oceanic crust). Sea level

1584-449: The initial graben fill is variable across the basin, but several distinct facies tracts have been identified. Non marine, deltaic, shallow marine, deep marine and carbonate platform syn-rift deposits are found in the basin. Sag phase deposition begins in the upper Eocene to Oligocene. A more regional depocenter developed in response to marine inundation. The eastern basin, already influenced by marine conditions quickly transitioned to

1632-488: The late Eocene and early Oligocene induced minor reactivation along the existing faults. During the late Oligocene there was a brief renewal of extension and rifting along the northern margin of the basin, while the other basin margins experienced uplift. Inversion of the basin began in the Late Oligocene. Tectonic uplift of Borneo in the earliest Miocene inverted the Upper Kutai basin above sea level. Inversion continued in

1680-454: The line between the North and South Atlantic is set at the equator . The Antarctic or Southern Ocean, which reaches from 60° south to Antarctica had been omitted until 2000, but is now also recognized by the International Hydrographic Office. Nevertheless, and since ocean basins are interconnected, many oceanographers prefer to refer to one single ocean basin instead of multiple ones.   Older references (e.g., Littlehales 1930) consider

1728-414: The main mass of Borneo's montane rain forests in the centre and north of the island by approximately 300 km of lowland forest. The submontane and montane forests cover an area of approximately 2,460 km . Endemic plants include Gaultheria kalimantanensis (Ericaceae) and the carnivorous pitcher plant Nepenthes boschiana . The mountains' relative isolation from Borneo's other highlands has allowed for

1776-428: The middle Miocene produced a coast parallel anticlinorum into which the Mahakam river incised as the folds were inverted. This incision has prevented any lateral migration of the lowermost Mahakam river, creating a point source deltaic depocenter that has been active since the mid Miocene. Neogene sediments in the vicinity of the modern Mahakam delta are up to 9 kilometres (30,000 ft) thick. The total depth of

1824-406: The ocean is very slow compared to horizonal flow and observing the deep ocean is difficult. Defining the ocean basins based on connectivity of the entire ocean (depth and width) is therefore not possible. Froyland et al. (2014) defined ocean basins based on surface connectivity. This is achieved by creating a Markov Chain model of the surface ocean dynamics using short term time trajectory data from

1872-440: The oceanic basins to be the complement to the continents , with erosion dominating the latter, and the sediments so derived ending up in the ocean basins. This vision is supported by the fact that oceans lie lower than continents, so the former serve as sedimentary basins that collect sediment eroded from the continents, known as clastic sediments, as well as precipitation sediments. Ocean basins also serve as repositories for

1920-778: The ones named in the previous section. These main basins are divided into smaller parts. Some examples are: the Baltic Sea (with three subdivisions), the North Sea , the Greenland Sea , the Norwegian Sea , the Laptev Sea , the Gulf of Mexico , the South China Sea , and many more. The limits were set for convenience of compiling sailing directions but had no geographical or physical ground and to this day have no political significance. For instance,

1968-484: The sediment volume indicates that at least 6 km of crust was removed from the interior of Borneo in the Neogene. A period of punctuated compressional events beginning in the mid Miocene affected the continued evolution of these basins, deforming and inverting them. Igneous activity continued throughout the Cenozoic but was particularly more active in the northern region of Borneo in the Neogene. The Kutai basin traverses

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2016-455: The skeletons of carbonate - and silica -secreting organisms such as coral reefs , diatoms , radiolarians , and foraminifera . More modern sources (e.g., Floyd 1991) regard the ocean basins more as basaltic plains, than as sedimentary depositories, since most sedimentation occurs on the continental shelves and not in the geologically defined ocean basins. The flow in the ocean is not uniform but varies with depth. Vertical circulation in

2064-646: The spreading ridges in the Indian Ocean were reorganized. The northernmost part of the Atlantic Ocean was also formed at this time when Europe and Greenland separated. About 60 million years ago a new rift and oceanic ridge formed between Greenland and Europe, separating them and initiating the formation of oceanic crust in the Norwegian Sea and the Eurasian Basin in the eastern Arctic Ocean. The area occupied by

2112-491: The sub-aerial products of the Sintang intrusion are found to be interbedded with Late Oligocene to middle Miocene sediments, suggesting that volcanism occurred before and after the early miocene inversion event. The Metulang suite are mid to high-k calc-alkaline basalts and andesites with K-Ar ages between 2.4-1.7 Ma. They form high level intrusions and lava flows. Ocean basin In  hydrology , an  oceanic basin  (or ocean basin )

2160-484: The surface of the ocean (plastic, biomass, water etc.) become trapped. One of these regions is for example the Atlantic garbage patch . With this approach the five main ocean basins are still the North and South Atlantic, North and South Pacific and the Arctic Ocean, but with different boundaries between the basins. These boundaries show the lines of very little surface connectivity between the different regions which means that

2208-488: The surface of the sea. The Earth's longest trench runs alongside the coast of Peru and Chile, reaching a depth of 8065 m (26460 feet) and extending for approximately 5900 km (3700 miles). It occurs where the oceanic Nazca plate slides under the continental South American plate and is associated with the upthrust and volcanic activity of the Andes. The oldest oceanic crust is in the far western equatorial Pacific, east of

2256-736: The west by the Philippine and Pacific oceanic plates . In the Cenozoic, the Indo-Australian plate has been moving north and subducting under Eurasia. The collision of the Indian continent with Eurasia halted subduction and uplifted the Himalayas . In between the continents of India and Australia, the oceanic crust is still subducting under the Sunda Plate , forming the Sunda trench and Sunda Arc . Australia and Australian derived micro-plates collided with

2304-406: The western margin, producing deep basins on both sides. In the late Oligocene to Early Miocene, the central mountain ranges of Borneo began to rise. The equatorial perhumid climate provided intense chemical weathering and erosion of the newly uplifted rock and filled the marginal basins of Borneo with sediment. Neogene sediments are up to 9 km thick in sections of some basins. Reconstruction of

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