Diagenesis is the process that describes physical and chemical changes in sediments first caused by water-rock interactions, microbial activity, and compaction after their deposition. Increased pressure and temperature only start to play a role as sediments become buried much deeper in the Earth's crust. In the early stages, the transformation of poorly consolidated sediments into sedimentary rock (lithification) is simply accompanied by a reduction in porosity and water expulsion, while their main mineralogical assemblages remain unaltered. As the rock is carried deeper by further deposition above, its organic content is progressively transformed into kerogens and bitumens. The process of diagenesis excludes surface alteration (weathering) and deep metamorphism. There is no sharp boundary between diagenesis and metamorphism, but the latter occurs at higher temperatures and pressures. Hydrothermal solutions, meteoric groundwater, rock porosity, permeability, dissolution/precipitation reactions, and time are all influential factors.
Petroleum geology is the study of origin, occurrence, movement, accumulation, and exploration of hydrocarbon fuels. It refers to the specific set of geological disciplines that are applied to the search for hydrocarbons.
Thermal history modelling is an exercise undertaken during basin modelling to evaluate the temperature history of stratigraphic layers in a sedimentary basin.
Kerogen is solid, insoluble organic matter in sedimentary rocks. Comprising an estimated 1016 tons of carbon, it is the most abundant source of organic compounds on earth, exceeding the total organic content of living matter 10,000-fold. It is insoluble in normal organic solvents and it does not have a specific chemical formula. Upon heating, kerogen converts in part to liquid and gaseous hydrocarbons. Petroleum and natural gas form from kerogen. Kerogen may be classified by its origin: lacustrine (e.g., algal), marine (e.g., planktonic), and terrestrial (e.g., pollen and spores). The name "kerogen" was introduced by the Scottish organic chemist Alexander Crum Brown in 1906, derived from the Greek for "wax birth" (Greek: κηρός "wax" and -gen, γένεση "birth").
Vitrinite is one of the primary components of coals and most sedimentary kerogens. Vitrinite is a type of maceral, where "macerals" are organic components of coal analogous to the "minerals" of rocks. Vitrinite has a shiny appearance resembling glass (vitreous). It is derived from the cell-wall material or woody tissue of the plants from which coal was formed. Chemically, it is composed of polymers, cellulose and lignin.
The Paleocene–Eocene thermal maximum (PETM), alternatively "Eocene thermal maximum 1" (ETM1), and formerly known as the "Initial Eocene" or "Late Paleocene thermal maximum", was a time period with a more than 5–8 °C global average temperature rise across the event. This climate event occurred at the time boundary of the Paleocene and Eocene geological epochs. The exact age and duration of the event is uncertain but it is estimated to have occurred around 55.5 million years ago (Ma).
Foraminifera are single-celled organisms, members of a phylum or class of amoeboid protists characterized by streaming granular ectoplasm for catching food and other uses; and commonly an external shell of diverse forms and materials. Tests of chitin are believed to be the most primitive type. Most foraminifera are marine, the majority of which live on or within the seafloor sediment, while a smaller number float in the water column at various depths, which belong to the suborder Globigerinina. Fewer are known from freshwater or brackish conditions, and some very few (nonaquatic) soil species have been identified through molecular analysis of small subunit ribosomal DNA.
The abiogenic petroleum origin hypothesis proposes that most of earth's petroleum and natural gas deposits were formed inorganically. Scientific evidence overwhelmingly supports a biogenic origin for most of the worlds petroleum deposits. Mainstream theories about the formation of hydrocarbons on earth point to an origin from the decomposition of long-dead organisms, though the existence of hydrocarbons on extraterrestrial bodies like Saturn's moon Titan indicates that hydrocarbons are sometimes naturally produced by inorganic means. A historical overview of theories of the abiogenic origins of hydrocarbons has been published.
In petroleum geology, the maturity of a rock is a measure of its state in terms of hydrocarbon generation. Maturity is established using a combination of geochemical and basin modelling techniques.
The Conodont Alteration Index (CAI) is used to estimate the maximum temperature reached by a sedimentary rock using thermal alteration of conodont fossils. Conodonts in fossiliferous carbonates are prepared by dissolving the matrix with weak acid, since the conodonts are composed of apatite and thus do not dissolve as readily as carbonate. The fossils are then compared to the index under a microscope. The index was first developed by Anita Epstein and colleagues at the United States Geological Survey.
Lukas Hottinger was a paleontologist, biologist and geologist. Hottinger collaborated with the Natural History Museum of Basel (Switzerland).
In petroleum geology, source rock is rock which has generated hydrocarbons or which could generate hydrocarbons. Source rocks are one of the necessary elements of a working petroleum system. They are organic-rich sediments that may have been deposited in a variety of environments including deep water marine, lacustrine and deltaic. Oil shale can be regarded as an organic-rich but immature source rock from which little or no oil has been generated and expelled. Subsurface source rock mapping methodologies make it possible to identify likely zones of petroleum occurrence in sedimentary basins as well as shale gas plays.
The McMurray Formation is a stratigraphic unit of Early Cretaceous age of the Western Canada Sedimentary Basin in northeastern Alberta. It takes the name from Fort McMurray and was first described from outcrops along the banks of the Athabasca River 5 kilometres (3.1 mi) north of Fort McMurray by F.H. McLearn in 1917. It is a well-studied example of fluvial to estuarine sedimentation, and it is economically important because it hosts most of the vast bitumen resources of the Athabasca Oil Sands region.
The Cretaceous Thermal Maximum (CTM), also known as Cretaceous Thermal Optimum, was a period of climatic warming that reached its peak approximately 90 million years ago (90 Ma) during the Turonian age of the Late Cretaceous epoch. The CTM is notable for its dramatic increase in global temperatures characterized by high carbon dioxide levels.
Carterinida is an order of multi-chambered foraminifera within the Globothalamea. Members of this order form hard tests out of thin calcite rods known as spicules, which are held together by a proteinaceous matrix.
Pyrobitumen is a type of solid, amorphous organic matter. Pyrobitumen is mostly insoluble in carbon disulfide and other organic solvents as a result of molecular cross-linking, which renders previously soluble organic matter insoluble. Not all solid bitumens are pyrobitumens, in that some solid bitumens are soluble in common organic solvents, including CS
2, dichloromethane, and benzene-methanol mixtures.
Bruce William Hayward is a New Zealand geologist, marine ecologist, and author. He is known as a leading expert on living and fossil foraminifera.
Foraminiferal tests are the tests of Foraminifera.
Global paleoclimate indicators are the proxies sensitive to global paleoclimatic environment changes. They are mostly derived from marine sediments. Paleoclimate indicators derived from terrestrial sediments, on the other hand, are commonly influenced by local tectonic movements and paleogeographic variations. Factors governing the earth climate system include plate tectonics, which controls the configuration of continents, the interplay between the atmosphere and the ocean, and the earth's orbital characteristics. Global paleoclimate indicators are established based on the information extracted from the analyses of geologic materials, including biological, geochemical and mineralogical data preserved in marine sediments. Indicators are generally grouped into three categories; paleontological, geochemical and lithological.
Felix M. Gradstein is a Dutch-Canadian academic and a pioneer in quantitative stratigraphy and geologic time scale. At the University of Utrecht, he studied paleontology and stratigraphy, obtaining his Ph.D. taking a novel biometrical approach in micropaleontology, under the supervision of Professor CW Drooger. In 1976, after working two years for an oil company in Calgary, Canada, he joined the Geological Survey of Canada in its eastern division at the Bedford Institute of Oceanography in Nova Scotia. During his research there, he was instrumental in developing a novel quantitative method for the analysis of stratigraphic events. In 1992 Felix moved to Norway where he currently has an office at the University of Oslo and is Visiting Research Fellow at, University of Portsmouth, UK. From 1985 - 1989, he was chairman of International Geoscience Project (IGCP) 181 on Quantitative Stratigraphy. From 2000 to 2008 he was chair of the International Commission on Stratigraphy (ICS) and in 2010 was instrumental in founding the Geologic Time Scale Foundation. For his fundamental work concerning the Geologic Time Scale, geochronology in general, quantitative stratigraphy, and micropaleontology, the European Geosciences Union awarded him in 2010 the Jean Baptiste Lamarck Medal. Prof. Gradstein, a world-renowned stratigrapher discussed debates over the Geologic Time Scale with the Anthropocene working Group.
