Sedimentary basin analysis

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Sedimentary basin analysis is a geologic method by which the formation and evolution history of a sedimentary basin is revealed, by analyzing the sediment fill and subsidence. Subsidence of sedimentary basins generates the spatial distribution of accommodation infilling sediments. Aspects of the sediment, namely its composition, primary structures, and internal architecture, can be synthesized into a history of the basin fill. Such a synthesis can reveal how the basin formed, how the sediment fill was transported or precipitated, and reveal sources of the sediment fill. From such syntheses models can be developed to explain broad basin formation mechanisms. Examples of such basin classifications include intracratonic, rift, passive margin, strike-slip, forearc, backarc-marginal sea, fold and thrust belt, and foreland basins.

Sedimentary basin analysis is largely conducted by two types of geologists who have slightly different goals and approaches. The petroleum geologist, whose ultimate goal is to determine the possible presence and extent of hydrocarbons and hydrocarbon-bearing rocks in a basin, and the academic geologist, who may be concerned with any or all facets of a basin's evolution. Petroleum industry basin analysis is often conducted on subterranean basins through the use of reflection seismology and data from well logging. Academic geologists study subterranean basins as well as those basins which have been exhumed and dissected by subsequent tectonic events. Thus academics sometimes use petroleum industry techniques, but in many cases they are able to study rocks at the surface. Techniques used to study surficial sedimentary rocks include: measuring stratigraphic sections, identifying sedimentary depositional environments and constructing a geologic map.

An important tool in sedimentary basin analysis is sequence stratigraphy, in which various sedimentary sequences are related to pervasive changes in sea level and sediment supply.

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Geology is a branch of natural science concerned with the Earth and other astronomical objects, the rocks of which it is composed, and the processes by which they change over time. Modern geology significantly overlaps all other Earth sciences, including hydrology. It is integrated with Earth system science and planetary science.

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.

<span class="mw-page-title-main">Sedimentary basin</span> Regions of long-term subsidence creating space for infilling by sediments

Sedimentary basins are region-scale depressions of the Earth's crust where subsidence has occurred and a thick sequence of sediments have accumulated to form a large three-dimensional body of sedimentary rock. They form when long-term subsidence creates a regional depression that provides accommodation space for accumulation of sediments. Over millions or tens or hundreds of millions of years the deposition of sediment, primarily gravity-driven transportation of water-borne eroded material, acts to fill the depression. As the sediments are buried, they are subject to increasing pressure and begin the processes of compaction and lithification that transform them into sedimentary rock.

Sedimentology encompasses the study of modern sediments such as sand, silt, and clay, and the processes that result in their formation, transport, deposition and diagenesis. Sedimentologists apply their understanding of modern processes to interpret geologic history through observations of sedimentary rocks and sedimentary structures.

<span class="mw-page-title-main">Stratigraphy</span> Study of rock layers and their formation

Stratigraphy 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, biostratigraphy, and chronostratigraphy.

<span class="mw-page-title-main">Rift</span> Geological linear zone where the lithosphere is being pulled apart

In geology, a rift is a linear zone where the lithosphere is being pulled apart and is an example of extensional tectonics. Typical rift features are a central linear downfaulted depression, called a graben, or more commonly a half-graben with normal faulting and rift-flank uplifts mainly on one side. Where rifts remain above sea level they form a rift valley, which may be filled by water forming a rift lake. The axis of the rift area may contain volcanic rocks, and active volcanism is a part of many, but not all, active rift systems.

<span class="mw-page-title-main">Los Angeles Basin</span> Sedimentary basin located along the coast of southern California

The Los Angeles Basin is a sedimentary basin located in Southern California, in a region known as the Peninsular Ranges. The basin is also connected to an anomalous group of east-west trending chains of mountains collectively known as the Transverse Ranges. The present basin is a coastal lowland area, whose floor is marked by elongate low ridges and groups of hills that is located on the edge of the Pacific Plate. The Los Angeles Basin, along with the Santa Barbara Channel, the Ventura Basin, the San Fernando Valley, and the San Gabriel Basin, lies within the greater Southern California region. The majority of the jurisdictional land area of the city of Los Angeles physically lies within this basin.

<span class="mw-page-title-main">Turbidite</span> Geologic deposit of a turbidity current

A turbidite is the geologic deposit of a turbidity current, which is a type of amalgamation of fluidal and sediment gravity flow responsible for distributing vast amounts of clastic sediment into the deep ocean.

Sequence stratigraphy is a branch of geology, specifically a branch of stratigraphy, that attempts to discern and understand historic geology through time by subdividing and linking sedimentary deposits into unconformity bounded units on a variety of scales. The essence of the method is mapping of strata based on identification of surfaces which are assumed to represent time lines, thereby placing stratigraphy in chronostratigraphic framework allowing understanding of the evolution of the earth's surface in a particular region through time. Sequence stratigraphy is a useful alternative to a purely lithostratigraphic approach, which emphasizes solely based on the compositional similarity of the lithology of rock units rather than time significance. Unconformities are particularly important in understanding geologic history because they represent erosional surfaces where there is a clear gap in the record. Conversely within a sequence the geologic record should be relatively continuous and complete record that is genetically related.

Back-stripping is a geophysical analysis technique used on sedimentary rock sequences. It is used to quantitatively estimate the depth that the basement would be in the absence of sediment and water loading. This depth provides a measure of the unknown tectonic driving forces that are responsible for basin formation. By comparing backstripped curves to theoretical curves for basin subsidence and uplift it is possible to deduce information on the basin forming mechanisms.

<span class="mw-page-title-main">Geology of the Falkland Islands</span>

The geology of the Falkland Islands is described in several publications. The Falkland Islands are located on a projection of the Patagonian continental shelf. In ancient geological time this shelf was part of Gondwana, which around 400 million years ago broke from what is now Africa and drifted westwards relative to Africa. Studies of the seabed surrounding the islands indicated the possibility of oil. Intensive exploration began in 1996, although there had been some earlier seismic surveys in the region.

Magnetostratigraphy is a geophysical correlation technique used to date sedimentary and volcanic sequences. The method works by collecting oriented samples at measured intervals throughout the section. The samples are analyzed to determine their characteristic remanent magnetization (ChRM), that is, the polarity of Earth's magnetic field at the time a stratum was deposited. This is possible because volcanic flows acquire a thermoremanent magnetization and sediments acquire a depositional remanent magnetization, both of which reflect the direction of the Earth's field at the time of formation. This technique is typically used to date sequences that generally lack fossils or interbedded igneous rock. It is particularly useful in high-resolution correlation of deep marine stratigraphy where it allowed the validation of the Vine–Matthews–Morley hypothesis related to the theory of plate tectonics.

<span class="mw-page-title-main">Stratigraphic column</span>

A stratigraphic column is a representation used in geology and its subfield of stratigraphy to describe the vertical location of rock units in a particular area. A typical stratigraphic column shows a sequence of sedimentary rocks, with the oldest rocks on the bottom and the youngest on top.

<span class="mw-page-title-main">Jeanne d'Arc Basin</span>

The Jeanne d'Arc Basin is an offshore sedimentary basin located about 340 kilometres to the basin centre, east-southeast of St. John's, Newfoundland and Labrador. This basin formed in response to the large scale plate tectonic forces that ripped apart the super-continent Pangea and also led to sea-floor spreading in the North Atlantic Ocean. This basin is one of a series of rift basins that are located on the broad, shallow promontory of continental crust known as the Grand Banks of Newfoundland off Canada's east coast. The basin was named after a purported 20 metres shoal labelled as "Ste. Jeanne d'Arc" on out-dated bathymetric charts and which was once thought to represent a local exposure of basement rocks similar to the Virgin Rocks.

Provenance in geology, is the reconstruction of the origin of sediments. The Earth is a dynamic planet, and all rocks are subject to transition between the three main rock types: sedimentary, metamorphic, and igneous rocks. Rocks exposed to the surface are sooner or later broken down into sediments. Sediments are expected to be able to provide evidence of the erosional history of their parent source rocks. The purpose of provenance study is to restore the tectonic, paleo-geographic and paleo-climatic history.

<span class="mw-page-title-main">Northern North Sea basin</span>

The North Sea is part of the Atlantic Ocean in northern Europe. It is located between Norway and Denmark in the east, Scotland and England in the west, Germany, the Netherlands, Belgium and France in the south.

<span class="mw-page-title-main">Himalayan foreland basin</span> Active collisional foreland basin in South Asia

The Himalayan foreland basin is an active collisional foreland basin system in South Asia. Uplift and loading of the Eurasian Plate on to the Indian Plate resulted in the flexure (bending) of the Indian Plate, and the creation of a depression adjacent to the Himalayan mountain belt. This depression was filled with sediment eroded from the Himalaya, that lithified and produced a sedimentary basin ~3 to >7 km deep. The foreland basin spans approximately 2,000 kilometres (1,200 mi) in length and 450 kilometres (280 mi) in width. From west to east the foreland basin stretches across five countries: Pakistan, India, Nepal, Bangladesh, and Bhutan.

<span class="mw-page-title-main">North German basin</span> Passive-active rift basin in central and west Europe

The North German Basin is a passive-active rift basin located in central and west Europe, lying within the southeasternmost portions of the North Sea and the southwestern Baltic Sea and across terrestrial portions of northern Germany, Netherlands, and Poland. The North German Basin is a sub-basin of the Southern Permian Basin, that accounts for a composite of intra-continental basins composed of Permian to Cenozoic sediments, which have accumulated to thicknesses around 10–12 kilometres (6–7.5 mi). The complex evolution of the basin takes place from the Permian to the Cenozoic, and is largely influenced by multiple stages of rifting, subsidence, and salt tectonic events. The North German Basin also accounts for a significant amount of Western Europe's natural gas resources, including one of the world's largest natural gas reservoir, the Groningen gas field.

The Officer Basin is an intracratonic sedimentary basin that covers roughly 320,000 km2 along the border between southern and western Australia. Exploration for hydrocarbons in this basin has been sparse, but the geology has been examined for its potential as a hydrocarbon reservoir. This basin's extensive depositional history, with sedimentary thicknesses exceeding 6 km and spanning roughly 350 Ma during the Neoproterozoic, make it an ideal candidate for hydrocarbon production.

The Laga Basin is the largest and youngest foreland basin of the Central Apennines fold and thrust belt. It is Messinian in age and serves as a link between an Early Miocene aged fold and thrust belt at the west of the Central Apennines and a younger belt to the east. In the 1980s and 1990s, it was the subject of numerous investigations for hydrocarbon resources, and since has become a valuable analogue with relation to clastic reservoirs developed in confined structural settings.

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