What is Allochthonous salt?
Allochthonous salt is defined as a “subhorizontal or moderately dipping, sheetlike salt diapir emplaced at stratigraphic levels above the autochthonous source layer” (Hudec & Jackson, 2011).
What is autochthonous salt?
102- On this line deepwater seismic line of Gulf of Mexico, autochthonous salt, that is to say, salt resting on the original strata on which it accumulated and allochthonous salt (salt emplaced at stratigraphic levels above the autochthonous source layer) are easily recognized.
What is the difference between a salt sheet and a salt canopy?
A salt sheet is allochthonous salt sourced from a single feeder. A salt canopy is a composite structure, formed through the coalescence of two or more salt sheets (Figure 6.1). Figure 6.1. A salt canopy is composed of two or more salt sheets that have coalesced to make a large composite allochthonous structure.
What is a salt weld?
A salt weld is a surface or thin zone marking a vanished salt body (Figure 9.1). The weld results from complete or nearly complete loss of salt by creep or dissolution. As such, a weld is a negative salt structure.
What is Halokinesis geology?
1. The movement of salt and salt bodies. The study of halokinesis includes subsurface flow of salt as well as the emplacement, structure, and tectonic influence of salt bodies. Another term used to refer to the study of salt bodies and their structures is “salt tectonics.”
How do salt diapirs form?
A mushroom-shaped or plug-shaped diapir made of salt, commonly having an overlying cap rock. Salt domes form as a consequence of the relative buoyancy of salt when buried beneath other types of sediment. The salt flows upward to form salt domes, sheets, pillars and other structures.
How do diapirs form?
A relatively mobile mass that intrudes into preexisting rocks. Diapirs commonly intrude vertically through more dense rocks because of buoyancy forces associated with relatively low-density rock types, such as salt, shale and hot magma, which form diapirs. The process is known as diapirism.
What are rising Diapirs?
Diapirs or piercement structures are structures resulting from the penetration of overlaying material. By pushing upward and piercing overlying rock layers, diapirs can form anticlines, salt domes and other structures capable of trapping petroleum and natural gas.
Where are salt domes in the US?
Pennsylvanian age salt of the Paradox Formation forms salt domes throughout the Paradox Basin in the US, which extends from eastern Utah, through southwestern Colorado into northwestern New Mexico. An example of an emergent salt dome is at Onion Creek, Utah / Fisher Towers near Moab, Utah.
What are allochthonous salt bodies?
Allochthonous salt bodies range in scale from local salt wings less than 5 km 2 in areal extent on the flanks of diapirs (e.g., Mohr, Warren, Kukla, Urai, & Irmen, 2007) to multilevel canopies covering > 100,000 km 2 and up to 10 km thick in places (e.g., Diegel, Karlo, Schuster, Shoup, & Tauvers, 1995 ).
What is allochthonous?
1. Originating or formed in a place other than where found: allochthonous rocks; an allochthonous population. 2. Ecology Not indigenous: an allochthonous organism.
What is allochthonous salt nappe?
Note that the allochthonous salt is emplaced at depth beneath a thick overburden. The term salt nappe was first applied to the Sigsbee Nappe in the northern Gulf of Mexico, the tip of which was thought to be over 100 km from the nearest vertical feeder ( Diegel et al., 1995) or over 200 km from its autochthonous source ( Peel et al., 1995 ).
How many Allochthons are there in the United States?
In the United States there are three notable allochthons; all of which were displaced nearly 50 km (31 miles) along thrust faults. The Golconda and Robert Mountains allochthon are both found in Nevada, a product of the Antler Orogeny in the Late-Devonian period.