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52-534: The Carpinteria Tar Pits (also Carpinteria Oil Seeps ) are a series of natural asphalt lakes situated in the southern part of Santa Barbara County in southern California, US. The Carpinteria Tar Pits are a natural asphalt lake areas similar to Tierra de Brea Trinidad and Tobago , Lake Guanoco in Venezuela and the La Brea Tar Pits (Los Angeles) and McKittrick Tar Pits ( McKittrick ) both also located in

104-455: A fault-bend fold . Fault-propagation folds form at the tip of a thrust fault where propagation along the decollement has ceased, but displacement on the thrust behind the fault tip continues. The formation of an asymmetric anticline-syncline fold pair accommodates the continuing displacement. As displacement continues, the thrust tip starts to propagate along the axis of the syncline. Such structures are also known as tip-line folds . Eventually,

156-440: A fault created a fracture that tapped into an oil and gas reservoir deep within the crust. The oil and gas seeped upward to Earth's surface through the fracture over time, creating Pitch Lake. Due to this constant replenishment of the oil and gas, the lake has a slight current.  The current is largely unnoticed because the top layer of Pitch Lake is mostly solid. Tar pits are characteristic of their many fossils. This

208-464: A geologic fault . Additionally, in connection with subduction pressure can be created against underlying oil source rock . The oil moves towards the surface and slowly transforms into bitumen ; on the way through the lithosphere , it picks up clay and water and is cooled into asphalt. The Carpinteria pits are one of two in southern California. Although the La Brea pit is more well known, Carpinteria

260-403: A local rubbish dump. Tar pit Tar pits , sometimes referred to as asphalt pits , are large asphalt deposits. They form in the presence of petroleum , which is created when decayed organic matter is subjected to pressure underground. If this crude oil seeps upward via fractures, conduits, or porous sedimentary rock layers, it may pool up at the surface. The lighter components of

312-404: A sealant for waterproofing their tomols (plank-built boats) and other purposes. The area was named "La Carpinteria" (the carpentry) by a Spanish expedition under explorer Gaspar de Portolá , which arrived in the area on August 17, 1769. Initially, these tar pits were drilled for oil due to their ease of access of the natural resource. Starting around 1915, the tar pits were mined and the asphalt

364-409: A thrust that has propagated along the lower detachment, known as the floor thrust , cuts up to the upper detachment, known as the roof thrust , it forms a ramp within the stronger layer. With continued displacement on the thrust, higher stresses are developed in the footwall of the ramp due to the bend on the fault. This may cause renewed propagation along the floor thrust until it again cuts up to join

416-399: Is a fault or fracture in the overlying strata above the oil reserve, the oil may migrate to the surface. This is possible by capillary fringe and because oil is less dense than water. Tar pits are pools of asphalt. However, at the beginning of their formation, they were not always sticky and dense. The pools were composed of crude oil that originated below Earth's surface. Crude oil

468-605: Is a mixture of heteroatom compounds, hydrocarbons , metals , and inorganic compounds . Heteroatom compounds are organic molecules that contain elements that are not carbon or hydrogen, while hydrocarbons contain only carbon and hydrogen. Crude oil is less viscous than asphalt because it contains a higher percentage of light hydrocarbons. Light hydrocarbons include the following alkanes : methane , ethane , propane , and butane . These molecules have very low molecular weights . Crude oils may also contain some inorganic impurities, such as CO 2 , H 2 S, N 2 , and O 2 . At

520-502: Is both older and larger. Both pits were created in the same way, via this subduction along the San Andreas fault. The fossils collected here are that of more moderate temperature species such as ferns, indicating the climate of this region may have been much more temperate than what it is today. The Carpinteria Tar Pits were known to the Chumash people , who mined the asphalt and used it as

572-412: Is difficult to detect, especially in peneplain areas. Thrust faults, particularly those involved in thin-skinned style of deformation, have a so-called ramp-flat geometry. Thrusts mainly propagate along zones of weakness within a sedimentary sequence, such as mudstones or halite layers; these parts of the thrust are called decollements . If the effectiveness of the decollement becomes reduced,

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624-475: Is likely that the trees’ stomatal conductance and chloroplast demand for CO 2 was higher during this period to increase their carbon consumption. When moving into the following Interglacial Period, the Juniperus trees’ stomatal conductance and chloroplast demand for CO 2 decreased as a result of higher temperatures and higher CO 2 concentrations in the atmosphere. This response to fluctuating carbon levels

676-505: Is seen in plants over time. For example, increased stomatal conductance is observed in modern C3 plants grown in low CO 2 environments. It is also hypothesized that the wetter climate during the Last Glacial Period may have increased the nitrogen availability to plants, which therefore increased the concentration of nitrogen in leaves. This change may have increased the Juniperus trees’ photosynthetic capacities. A woman's body

728-630: Is seen on the surface is sourced from the Salt Lake Oil Field reservoir and the oil sands in the Repetto and Pico formations . These oil deposits were formed during the Miocene Epoch when marine plankton organisms accumulated in an ocean basin.  Over time, sediments buried the organisms 300 to 1000 meters below Earth's surface, subjecting them to high pressures. This process turned the organic matter into oil. The 6th Street Fault that cuts through

780-436: Is the case because the thick, sticky asphalt traps animals.   Once animals step into the tar, they become immobilized and begin sinking immediately if the asphalt is warm and sticky enough. Predators that see these helpless animals usually would advance into the tar pits with the hope of catching their next meal. As a result, prey are usually found beneath the predator during excavation projects. The bones and hard parts of

832-539: The Appalachians are prominent examples of compressional orogenies with numerous overthrust faults. Thrust faults occur in the foreland basin , marginal to orogenic belts. Here, compression does not result in appreciable mountain building, which is mostly accommodated by folding and stacking of thrusts. Instead, thrust faults generally cause a thickening of the stratigraphic section . When thrusts are developed in orogens formed in previously rifted margins, inversion of

884-656: The Carpinteria State Beach area in the southern part between the Santa Rosa and the San Miguel campsites. Most of the tar pits are located along a short stretch directly on the beach and generate from the underlying Carpinteria Offshore Oil Field . The Carpinteria Tar Pits most likely date from the Pleistocene epoch . The creation of an asphalt lake is typically the result of upwards migrations of hydrocarbons along

936-575: The Last Glacial Period were recovered from the La Brea Tar Pits, and they revealed that the ratio of intercellular and atmospheric CO 2 was similar between glacial and modern trees. Since the amount of carbon dioxide during the Last Glacial Period was between 180 and 200 ppm (409.8 ppm today), there was less carbon available for photosynthesis . The Juniperus trees had to enhance CO 2 uptake to survive under limiting carbon conditions. It

988-412: The ocean trench margin of subduction zones, where oceanic sediments are scraped off the subducted plate and accumulate. Here, the accretionary wedge must thicken by up to 200%, and this is achieved by stacking thrust fault upon thrust fault in a melange of disrupted rock, often with chaotic folding. Here, ramp flat geometries are not usually observed because the compressional force is at a steep angle to

1040-632: The Binagadi asphalt lake. It is estimated to be 96-120 thousand years old. It is on display at the Natural-Historical Museum of Azerbaijan in Baku , Azerbaijan . Pitch Lake in Trinidad and Tobago is a large, bowl-like depression filled with bitumen. The lake has a maximum depth of 250 feet with an area of 100 acres, making it the largest deposit of solid bitumen on Earth. The lake is cold and dense near

1092-442: The La Brea Tar Pits is the dire wolf , one of the most famous prehistoric carnivores that lived during the Pleistocene . Fossils from saber-toothed cats and coyotes were also abundant. Additional fossils are constantly being discovered through continued excavation projects. Life was found in a ca. 28,000-year-old sample of natural asphalt in the La Brea Tar Pits . Hundreds of new species of bacteria were discovered that have

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1144-724: The Salt Lake Oil Field is the conduit that feeds the La Brea Tar Pits. Petroleum migrated to the surface over time, trapping and preserving animals and plants for the past 50,000 years. The Carpinteria Tar Pits are located in Tar Pits Park in Carpinteria, California. These tar pits were predicted to have formed during the Pleistocene. During an excavation project, 25 plant species were recovered along with 55 species of birds and 26 species of mammals.  Springs of tar still ooze to

1196-524: The US state of California. These pits are all characterized by the large asphalt-based areas that seem to have trapped hundreds of fossils and slowed down decay over time. The Carpinteria Tar Pits are located in the southeastern extremity of Santa Barbara County about 20 km (12 mi) southeast of Santa Barbara in the town of Carpinteria . The area is a designated park, the Tar Pits Park , and lies within

1248-454: The ability to thrive in environments with little to no water or air. They contain special enzymes that can break down hydrocarbons and other petroleum products. The origin of the bacteria in these natural asphalt pits is unknown, but it is believed that they evolved from preexisting soil microorganisms that survived an asphalt seepage event thousands of years ago. The soil microorganisms had to adapt and undergo genetic changes to help tolerate

1300-604: The animals are well preserved because they are buried rapidly after the organism's death. Beneath the surface, the hard parts are engulfed with asphalt, and they are protected from climate variations like rain, wind, or snow that may accelerate weathering processes. Asphalt also lacks oxygen and water, so major decomposing organisms like aerobic fungi and bacteria are absent. In the La Brea Tar Pits, more than one million bones have been recovered since 1906. 231 vertebrate species, 234 invertebrate species, and 159 plant species have been identified. The most frequent large mammal found in

1352-559: The atmosphere are a result of anthropogenic emissions. Hydrocarbon seepage in urban or industrialized areas present a geologic hazard due to the explosive nature of hydrocarbons. On March 24, 1985, a pocket of methane gas passed through a small opening between the floor slab and foundation walls of a Ross clothing department store in Los Angeles , only about a mile north of the La Brea Tar Pits. This methane pocket created an explosion that injured 21 people. This event increased awareness of

1404-514: The buried paleo-rifts can induce the nucleation of thrust ramps. Foreland basin thrusts also usually observe the ramp-flat geometry, with thrusts propagating within units at very low angle "flats" (at 1–5 degrees) and then moving up-section in steeper ramps (at 5–20 degrees) where they offset stratigraphic units. Thrusts have also been detected in cratonic settings, where "far-foreland" deformation has advanced into intracontinental areas. Thrusts and duplexes are also found in accretionary wedges in

1456-418: The crude oil evaporate into the atmosphere, leaving behind a black, sticky asphalt. Tar pits are often excavated because they contain large fossil collections. Tar pits form above oil reserves, and these deposits are often found in anticlinal traps . In fact, about 80 percent of petroleum found on Earth has been found in anticlinal traps. Anticlines are folds in stratigraphic layers in which each half of

1508-458: The crust by thickening the section rather than by folding and deformation. Large overthrust faults occur in areas that have undergone great compressional forces. These conditions exist in the orogenic belts that result from either two continental tectonic collisions or from subduction zone accretion. The resultant compressional forces produce mountain ranges. The Himalayas , the Alps , and

1560-403: The displacement of the overlying block is large (often in the kilometer range) the fault is called an overthrust or overthrust fault . Erosion can remove part of the overlying block, creating a fenster (or window ) – when the underlying block is exposed only in a relatively small area. When erosion removes most of the overlying block, leaving island-like remnants resting on the lower block,

1612-414: The fold dips away from the crest. Such structures are usually developed above thrust faults or in tectonic regions where the land is bending and folding. If the structure above the concave-down fold (arch) is a non-porous rock or aquitard , such as shale , it is considered an anticlinal trap. The figure in this section is a cartoon cross-section diagram that shows oil stuck in an anticlinal trap. If there

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1664-586: The form of sulfides as their reducing agent. Other bacteria discovered in the tar pits were of the Rubrobacteraceae family. These bacteria are known for being some of the most radiation-resistant organisms on the planet.   Pitch Lake , another asphalt pit in Trinidad and Tobago , is also a habitat for microbial communities of archaea and bacteria. Bacterial microorganisms from the orders Burkholderiales and Enterobacteriales have been found living in microliter-sized droplets of water recovered from

1716-544: The harsh, new environment, which ultimately gave rise to new bacterial species. In one study, the predominant bacteria found in the La Brea Tar Pits were of the Gammaproteobacteria class in the Chromatiales order, more simply referred to as  purple sulfur bacteria . Purple sulfur bacteria do not use water as their reducing agent , so oxygen is not produced during respiration . Instead, they use sulfur in

1768-564: The highest along the 6th Street Fault, which is the conduit that feeds the tar pits with crude oil from the sediments underneath Earth's surface. It was also discovered that methane is evaporating out of the nearby soil, affecting the physiology of the native grasses. The La Brea Tar Pits have the highest natural gas flux measured for any onshore seepage zone in the United States.  On a global scale, geologic CH 4 and C 2 H 6 emissions estimates from gas seepage in sedimentary rock are in

1820-410: The horses, which dip away from the foreland. Occasionally, the displacement on the individual horses is more significant, such that each horse lies more or less vertically above the other; this is known as an antiformal stack or imbricate stack . If the individual displacements are still greater, the horses have a foreland dip. Duplexing is a very efficient mechanism of accommodating the shortening of

1872-564: The hydrocarbon lakes that are found on Titan. Tar pits are formed by the fractionation of crude oil at the surface. The lighter hydrocarbons of the crude oil, which include methane (CH 4 ), ethane (C 2 H 6 ), and propane (C 3 H 8 ), evaporate, leaving behind larger hydrocarbons that make up the chemical composition of asphalt. This is a concern because methane, ethane, and propane are either major greenhouse gases and/or photochemical pollutants . The La Brea Tar Pits emit about 500 kg of methane per day. The emissions are

1924-427: The initial volume just after a few days, forming asphalt as the resulting product. For medium crude oils, the volume may be reduced by 40%. Crude oils will evaporate differently depending on their chemical composition. The average composition of a bitumen sample by weight is 80.2% carbon, 7.5% hydrogen, 7.6% oxygen, 1.7% nitrogen, and 3.0% sulfur. The La Brea Tar Pits are located in Los Angeles . The petroleum that

1976-477: The lake. The biomass in Pitch Lake lake was reported up to 10 cells per gram of asphalt. Many of these microbes survive on sulfur, iron, methane , or other hydrocarbons. Ongoing research is being conducted in Pitch Lake because it mimics the environment found on the surface of Saturn ’s largest moon, Titan . The discovery of extremophiles in Pitch Lake provides insight into the possibilities for microbial life in

2028-545: The order of 50-70 Tg/year and 2-4 Tg/year respectively. These values are roughly half of the global CH 4 and C 2 H 6 emissions from anthropogenic fossil fuel combustion , which are approximately 100-150 Tg CH 4 /year and 6-8 Tg C 2 H 6 /year. These hydrocarbon emissions can be contributed to oil biodegradation and methanogenesis within the tar pits.   The natural geologic sources of methane and other hydrocarbons should be considered when modeling atmospheric greenhouse gases. Not all sources of hydrocarbons in

2080-432: The potential dangers of methane pockets and hydrocarbon seepage in the area. Tar pits are excellent preserving agents, and they also have the ability to provide carbon isotope data for trees that have fallen into the asphalt. Looking at carbon isotope data in prehistoric trees can reveal information about plant responses to different amounts of carbon dioxide in the paleoatmosphere . Samples of Juniperus trees from

2132-402: The propagating thrust tip may reach another effective decollement layer, and a composite fold structure will develop with fault-bending and fault-propagation folds' characteristics. Duplexes occur where two decollement levels are close to each other within a sedimentary sequence, such as the top and base of a relatively strong sandstone layer bounded by two relatively weak mudstone layers. When

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2184-659: The remnants are called klippen (singular klippe ). If the fault plane terminates before it reaches the Earth's surface, it is called a blind thrust fault. Because of the lack of surface evidence, blind thrust faults are difficult to detect until rupture. The destructive 1994 earthquake in Northridge, Los Angeles, California , was caused by a previously undiscovered blind thrust fault. Because of their low dip , thrusts are also difficult to appreciate in mapping, where lithological offsets are generally subtle and stratigraphic repetition

2236-400: The roof thrust. Further displacement then takes place via the newly created ramp. This process may repeat many times, forming a series of fault-bounded thrust slices known as imbricates or horses , each with the geometry of a fault-bend fold of small displacement. The final result is typically a lozenge-shaped duplex. Most duplexes have only small displacements on the bounding faults between

2288-847: The sedimentary layering. Thrust faults were unrecognised until the work of Arnold Escher von der Linth , Albert Heim and Marcel Alexandre Bertrand in the Alps working on the Glarus Thrust ; Charles Lapworth , Ben Peach and John Horne working on parts of the Moine Thrust in the Scottish Highlands ; Alfred Elis Törnebohm in the Scandinavian Caledonides and R. G. McConnell in the Canadian Rockies. The realisation that older strata could, via faulting, be found above younger strata

2340-420: The shores, and it has a top layer that can be walked on. Underneath this skin, the asphalt is continuously churning. The lake gets gradually softer and hotter near the center where the bitumen begins to bubble. The gas being released in the middle of the lake is largely methane and an ample amount of carbon dioxide. Pitch Lake formed thousands of years ago in the presence of tectonic activity. Movement along

2392-606: The surface through fractures in the underlying stratigraphic layers of marine shale. The Binagadi Asphalt Lake is located in Azerbaijan , or in the Caucasus, a region between the Black Sea and the Caspian Sea . This tar pit is known for preserving the heads and bodies of multiple cave lions , a mammal that flourished in the Pleistocene . A well-preserved horse skull was also found in

2444-461: The surface, these light molecules may evaporate out of the crude oil, leaving behind the heavier, stickier molecules. Asphalt, or bitumen, usually contains hydrocarbon molecule chains with 50+ carbon atoms. The longer the hydrocarbon chain, the more viscous it becomes, and the boiling point increases.   Evaporation is an important process in the formation of tar pits. A reservoir of light crude oil on Earth's surface can be reduced by up to 75% of

2496-409: The tar pits, they began mining and extracting the tar for roofing material in nearby towns. Thrust fault A thrust fault is a break in the Earth's crust, across which older rocks are pushed above younger rocks. A thrust fault is a type of reverse fault that has a dip of 45 degrees or less. If the angle of the fault plane is lower (often less than 15 degrees from the horizontal ) and

2548-438: The thrust will tend to cut up the section to a higher stratigraphic level until it reaches another effective decollement where it can continue as bedding parallel flat. The part of the thrust linking the two flats is known as a ramp and typically forms at an angle of about 15°–30° to the bedding. Continued displacement on a thrust over a ramp produces a characteristic fold geometry known as a ramp anticline or, more generally, as

2600-439: Was arrived at more or less independently by geologists in all these areas during the 1880s. Geikie in 1884 coined the term thrust-plane to describe this special set of faults. He wrote: By a system of reversed faults, a group of strata is made to cover a great breadth of ground and actually to overlie higher members of the same series. The most extraordinary dislocations, however, are those to which for distinction we have given

2652-549: Was recovered from the La Brea Tar Pits in 1914.  Only the skull and parts of the skeleton were preserved, and she was determined to have died about 9,000 years ago.   She was between the ages 18–24 at death, and she was 4 feet and 8-10 inches tall. This is the only reported instance of human remains found within tar pits. For thousands of years, Native Americans used tar from the La Brea Tar Pits as an adhesive and binding agent. They would use it as waterproof caulking to line their boats and baskets. When Europeans arrived at

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2704-491: Was used for building a coastal highway. In 1933, the area was designated a state beach and in 1941 it was formally opened to the public and all commercial activity stopped.. The tar pits have trapped and preserved hundreds of Pleistocene Age Mammals and birds. Some findings are on display at the Carpinteria Valley Museum of History , but no paleontological studies have been conducted because the tar pits were used as

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