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 (the rock cycle). 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.
In the modern geological lexicon, "sediment provenance" specifically refers to the application of compositional analyses to determine the origin of sediments. This is often used in conjunction with the study of exhumation histories, interpretation of drainage networks and their evolution, and forward-modelling of paleo-earth systems. In combination, these help to characterise the "source to sink" journey of clastic sediments from hinterland to sedimentary basin.
Introduction
Provenance (from the French provenir, "to come from"), is the place of origin or earliest known history of something. In geology (specifically, in sedimentary petrology), the term provenance deals with the question where sediments originate from. The purpose of sedimentary provenance studies is to reconstruct and to interpret the history of sediment from parent rocks at a source area to detritus at a burial place. The ultimate goal of provenance studies is to investigate the characteristics of a source area by analyzing the composition and texture of sediments. The studies of provenance involve the following aspects: "(1) the source(s) of the particles that make up the rocks, (2) the erosion and transport mechanisms that moved the particles from source areas to depositional sites, (3) the depositional setting and depositional processes responsible for sedimentation of the particles (the depositional environment), and (4) the physical and chemical conditions of the burial environment and diagenetic changes that occur in siliciclastic sediment during burial and uplift". Provenance studies are conducted to investigate many scientific questions, for example, the growth history of continental crust, collision time of Indian and Asian plates, Asian monsoon intensity, and Himalayan exhumation Meanwhile, the provenance methods are widely used in the oil and gas industry. "Relations between provenance and basin are important for hydrocarbon exploration because sand frameworks of contrasting detrital compositions respond differently to diagenesis, and thus display different trends of porosity reduction with depth of burial."
Source of detritus
All rock exposed at the Earth's surface is subjected to physical or chemical weathering and broken down into finer grained sediment. All three types of rocks (igneous, sedimentary and metamorphic rocks) can be the source of detritus.
Transportation of detritus
Rocks are transported downstream from higher elevation to lower elevation. Source rocks and detritus are transported by gravity, water, wind or glacial movement. The transportation process breaks rocks into smaller particles by physical abrasion, from big boulder size into sand or even clay size. At the same time minerals within the sediment can also be changed chemically. Only minerals that are more resistant to chemical weathering can survive (e.g. ultrastable minerals zircon, tourmaline and rutile). During the transportation, minerals can be sorted by their density, and as a result, light minerals like quartz and mica can be moved faster and further than heavy minerals (like zircon and tourmaline).
Accumulation of detritus
After a certain distance of transportation, detritus reaches a sedimentary basin and accumulates in one place. With the accumulation of sediments, sediments are buried to a deeper level and go through diagenesis, which turns separate sediments into sedimentary rocks (i.e. conglomerate, sandstone, mudrocks, limestone etc.) and some metamorphic rocks (such as quartzite) which were derived from sedimentary rocks. After sediments are weathered and eroded from mountain belts, they can be carried by stream and deposited along rivers as river sands. Detritus can also be transported and deposited in foreland basins and at offshore fans. The detrital record can be collected from all these places and can be used in provenance studies.