Terrigenous sediment

{{short description|Sediments derived from the erosion of rocks on land}} {{Use dmy dates|date=February 2016}} '''Terrigenous sediments''' are derived from the chemical and physical weathering and erosion of continental rocks and consists primarily of mud, sand, and silt that is carried to the ocean by rivers. Their composition is mainly rock fragments and silicate minerals like quartz, feldspar, and clay minerals. Terrigenous sediments are mostly found closest to continents in coastal environments and continental shelves. Finer grained sediments like clay may be carried into deep-sea abyssal plains.<ref name=":0">{{Citation |last1=Robert |first1=Christian M. |title=Chapter Ten Terrigenous Sediments |date=2008-01-01 |journal=Developments in Marine Geology |volume=3 |pages=329–363 |url=https://www.sciencedirect.com/science/chapter/bookseries/abs/pii/S1572548008002108 |access-date=2026-03-01 |publisher=Elsevier |doi=10.1016/S1572-5480(08)00210-8 |bibcode=2008DevMG...3..329R |isbn=978-0-444-51817-0 |language=en-US|url-access=subscription }}</ref> They can accumulate in a wide variety of depositional environments, including fluvial, coastal, eolian, and in deep marine settings. This reflects diverse transport mechanisms such as rivers, wind, glaciers, and turbidity currents.<ref name=":5">{{Cite web |title=Terrigenous Clastic Depositional Systems |url=https://www.researchgate.net/publication/279386089 |archive-url=http://web.archive.org/web/20231211030736/http://www.researchgate.net/publication/279386089_Terrigenous_Clastic_Depositional_Systems |archive-date=2023-12-11 |access-date=2026-02-22 |website=ResearchGate |language=en}}</ref>

== Source and transport of terrigenous sediment == thumb|432x432px|Simplified schematic diagram of transport of terrigenous sediment Weathering of igneous rocks, sedimentary rocks, and metamorphic rocks may result in terrigenous sediment.<ref name=":02">{{Citation |last1=Robert |first1=Christian M. |title=Chapter Ten Terrigenous Sediments |date=2008-01-01 |journal=Developments in Marine Geology |volume=3 |pages=329–363 |url=https://www.sciencedirect.com/science/chapter/bookseries/abs/pii/S1572548008002108 |access-date=2026-03-01 |publisher=Elsevier |doi=10.1016/S1572-5480(08)00210-8 |bibcode=2008DevMG...3..329R |isbn=978-0-444-51817-0 |language=en-US|url-access=subscription }}</ref><ref name=":13">{{Cite journal |last=Gibbs |first=Allan K. |date=1986 |title=<i>The Continental Crust: Its Composition and Evolution</i> Stuart Ross Taylor , Scott M. McLennan |url=https://doi.org/10.1086/629067 |journal=The Journal of Geology |volume=94 |issue=4 |pages=632–633 |doi=10.1086/629067 |issn=0022-1376|url-access=subscription }}</ref> Creation, transport, deposition and lithification of terrigenous sediment into sedimentary rocks make up an important part of the rock cycle.<ref name=":6">{{Cite news |title=Sedimentary rock {{!}} Definition, Formation, Examples, & Characteristics {{!}} Britannica |url=https://www.britannica.com/science/sedimentary-rock |archive-url=http://web.archive.org/web/20260219115505/https://www.britannica.com/science/sedimentary-rock |archive-date=2026-02-19 |access-date=2026-03-11 |work=Encyclopedia Britannica |language=en}}</ref> Weathering and erosion are two processes that generate terrigenous sediments.<ref name=":21">{{Cite web |title=5 Weathering, Erosion, and Sedimentary Rocks – An Introduction to Geology |url=https://opengeology.org/textbook/5-weathering-erosion-and-sedimentary-rocks/ |access-date=2026-04-27 |language=en}}</ref><ref>{{Cite book |url=https://doi.org/10.1002/9781394157365 |title=Weathering and Erosion Processes in the Natural Environment |date=2023-12-21 |publisher=Wiley |isbn=978-1-394-15733-4 |editor-last=Singh |editor-first=Virendra Bahadur |doi=10.1002/9781394157365 |editor-last2=Madhav |editor-first2=Sughosh |editor-last3=Pant |editor-first3=Naresh Chandra |editor-last4=Shekhar |editor-first4=Ravi}}</ref> Rocks are weathered once they are exhumed<ref name=":02" />. Mechanisms of erosion and the transport of sediment are water, wind, glaciers, or gravity to the ocean or other localized depocenter.<ref name=":7">{{Cite book |last1=Milliman |first1=John D. |url=https://doi.org/10.1017/cbo9780511781247 |title=River Discharge to the Coastal Ocean |last2=Farnsworth |first2=Katherine L. |date=2011-02-24 |publisher=Cambridge University Press |doi=10.1017/cbo9780511781247 |isbn=978-0-521-87987-3}}</ref>

=== Chemical weathering === Chemical weathering refers to the dissolution of rocks by weak acids present in water<ref name=":72">{{Cite book |last1=Milliman |first1=John D. |url=https://doi.org/10.1017/cbo9780511781247 |title=River Discharge to the Coastal Ocean |last2=Farnsworth |first2=Katherine L. |date=2011-02-24 |publisher=Cambridge University Press |doi=10.1017/cbo9780511781247 |isbn=978-0-521-87987-3}}</ref><ref name=":8">{{Cite journal |last1=Milliman |first1=John D. |last2=Syvitski |first2=James P. M. |date=1992 |title=Geomorphic/Tectonic Control of Sediment Discharge to the Ocean: The Importance of Small Mountainous Rivers |url=https://doi.org/10.1086/629606 |journal=The Journal of Geology |volume=100 |issue=5 |pages=525–544 |doi=10.1086/629606 |bibcode=1992JG....100..525M |issn=0022-1376|url-access=subscription }}</ref>. Chemical weathering can alter land-derived sediment by transforming primary minerals into secondary minerals such as clays. One example of this process is the chemical weathering of K-feldspar into kaolinite<ref name=":212">{{Cite web |title=5 Weathering, Erosion, and Sedimentary Rocks – An Introduction to Geology |url=https://opengeology.org/textbook/5-weathering-erosion-and-sedimentary-rocks/ |access-date=2026-04-27 |language=en}}</ref><ref name=":22">{{Citation |last=Velde |first=B. |title=Origin of clays |date=1992 |work=Introduction to Clay Minerals |pages=101–163 |url=https://doi.org/10.1007/978-94-011-2368-6_4 |access-date=2026-04-27 |place=Dordrecht |publisher=Springer Netherlands |doi=10.1007/978-94-011-2368-6_4 |isbn=978-0-412-37030-4|url-access=subscription }}</ref>. In general, incongruent dissolution is more common in nature and produces clays as a product of the dissolution<ref>{{Cite journal |last=Weaver |first=Charles E. |date=1956 |title=A Discussion on the Origin of Clay Minerals in Sedimentary Rocks |url=https://doi.org/10.1346/ccmn.1956.0050113 |journal=Clays and Clay Minerals (National Conference on Clays and Clay Minerals) |volume=5 |pages=159–173 |doi=10.1346/ccmn.1956.0050113 |bibcode=1956CCM.....5..159W |issn=2640-9364}}</ref><ref name=":22" />. The chemical alteration in sediments can increase sediment maturity and release dissolved ions.<ref name=":10">{{Cite journal |last1=Fu |first1=Yu |last2=Li |first2=Zhengkun |last3=Chew |first3=David |last4=Hollings |first4=Pete |last5=Peng |first5=Jinzhou |last6=Chen |first6=Jieyun |last7=Tan |first7=Bojue |last8=He |first8=Gaowen |last9=Liang |first9=Yongjia |last10=Huang |first10=Fei |last11=Tang |first11=Yayue |last12=Wang |first12=Rui |last13=Li |first13=Dengfeng |last14=Sun |first14=Xiaoming |date=2025 |title=Deep-sea rare earth element-rich sediments: A review of distribution, carriers and petrogenesis |url=https://doi.org/10.1016/j.gloplacha.2025.104870 |journal=Global and Planetary Change |volume=252 |article-number=104870 |doi=10.1016/j.gloplacha.2025.104870 |bibcode=2025GPC...25204870F |issn=0921-8181|url-access=subscription }}</ref> Carbonic acid formed from the dissolution of carbon dioxide from the atmosphere into rainwater to produce carbonic acid<ref>{{Cite journal |last1=Kump |first1=Lee R. |last2=Brantley |first2=Susan L. |last3=Arthur |first3=Michael A. |date=2000 |title=Chemical Weathering, Atmospheric CO₂, and Climate |url=https://doi.org/10.1146/annurev.earth.28.1.611 |journal=Annual Review of Earth and Planetary Sciences |volume=28 |issue=1 |pages=611–667 |doi=10.1146/annurev.earth.28.1.611 |bibcode=2000AREPS..28..611K |issn=0084-6597|url-access=subscription }}</ref>. Precipitated carbonic acid enriched rainwater falls and runs over exposed silicate or carbonate minerals creating a fully dissolved fluvial load (congruent weathering) or partly dissolved load (incongruent weathering)<ref name=":22" />. It is also possible in some environments for the production of sulfuric acid as a result of the oxidation of sulfur minerals that leads to the weathering of carbonate minerals<ref>{{Cite journal |last=Berner |first=R. A. |date=2001-02-01 |title=GEOCARB III: A revised model of atmospheric CO2 over Phanerozoic time |url=https://doi.org/10.2475/ajs.301.2.182 |journal=American Journal of Science |volume=301 |issue=2 |pages=182–204 |doi=10.2475/ajs.301.2.182 |bibcode=2001AmJS..301..182B |issn=0002-9599}}</ref>. Other organic acids are also capable of rock dissolution<ref>{{Cite journal |last1=HUANG |first1=W. H. |last2=KELLER |first2=W. D. |date=1972 |title=Organic Acids as Agents of Chemical Weathering of Silicate Minerals |url=https://doi.org/10.1038/physci239149a0 |journal=Nature Physical Science |volume=239 |issue=96 |pages=149–151 |doi=10.1038/physci239149a0 |bibcode=1972NPhS..239..149H |issn=0300-8746|url-access=subscription }}</ref><ref>{{Cite journal |last1=Perez-Fodich |first1=Alida |last2=Derry |first2=Louis A. |date=2019 |title=Organic acids and high soil CO2 drive intense chemical weathering of Hawaiian basalts: Insights from reactive transport models |url=https://doi.org/10.1016/j.gca.2019.01.027 |journal=Geochimica et Cosmochimica Acta |volume=249 |pages=173–198 |doi=10.1016/j.gca.2019.01.027 |issn=0016-7037}}</ref><ref>{{Cite journal |last1=Lawrence |first1=Corey |last2=Harden |first2=Jennifer |last3=Maher |first3=Kate |date=2014 |title=Modeling the influence of organic acids on soil weathering |url=https://doi.org/10.1016/j.gca.2014.05.003 |journal=Geochimica et Cosmochimica Acta |volume=139 |pages=487–507 |doi=10.1016/j.gca.2014.05.003 |bibcode=2014GeCoA.139..487L |issn=0016-7037|url-access=subscription }}</ref>. Climatic changes (changes in long-term precipitation and temperature patterns) effect the rate of chemical weathering in a given region. Increased precipitation and increased temperature (through increased greenhouse gases or increased solar irradiance) yield higher rates of chemical weathering<ref>{{Cite web |last=Miller |first=Nahgeib |title=Weathering and Soils |url=https://pressbooks.senecapolytechnic.ca/millergeolgeomorph/chapter/weathering-and-soils/ |language=en}}</ref>. Age functions as an inverse to chemical weathering rates, meaning that as soils and sediment get older, the rate of mineral dissolution decreases because of the decrease in reactive materials.<ref>{{Cite journal |last=Colman |first=Steven M. |date=1981 |title=Rock-Weathering Rates as Functions of Time |url=https://doi.org/10.1016/0033-5894(81)90029-6 |journal=Quaternary Research |volume=15 |issue=3 |pages=250–264 |doi=10.1016/0033-5894(81)90029-6 |bibcode=1981QuRes..15..250C |issn=0033-5894|url-access=subscription }}</ref><ref>{{Cite journal |last=Maher |first=K. |date=2010 |title=The dependence of chemical weathering rates on fluid residence time |url=https://doi.org/10.1016/j.epsl.2010.03.010 |journal=Earth and Planetary Science Letters |volume=294 |issue=1–2 |pages=101–110 |doi=10.1016/j.epsl.2010.03.010 |bibcode=2010E&PSL.294..101M |issn=0012-821X|url-access=subscription }}</ref>. Sediment grain surface area increase with decreasing grain size as unstable components of the grain are dissolved away. Weathering of terrigenous sediment supplies the salt ions that give the ocean its salinity<ref name=":72" /><ref name=":03">{{Citation |last1=Robert |first1=Christian M. |title=Chapter Ten Terrigenous Sediments |date=2008-01-01 |journal=Developments in Marine Geology |volume=3 |pages=329–363 |url=https://www.sciencedirect.com/science/chapter/bookseries/abs/pii/S1572548008002108 |access-date=2026-03-01 |publisher=Elsevier |doi=10.1016/S1572-5480(08)00210-8 |bibcode=2008DevMG...3..329R |isbn=978-0-444-51817-0 |language=en-US|url-access=subscription }}</ref>. Accumulation of salt cation and anions accumulate in seawater, where their residence time can span hundreds of years to thousands of years<ref name=":72" /><ref>{{Cite journal |last=Lécuyer |first=Christophe |date=2016 |title=Seawater residence times of some elements of geochemical interest and the salinity of the oceans |url=https://doi.org/10.2113/gssgfbull.187.6.245 |journal=Bulletin de la Société Géologique de France |volume=187 |issue=6 |pages=245–260 |doi=10.2113/gssgfbull.187.6.245 |bibcode=2016BSGF..187..245L |issn=0037-9409|url-access=subscription }}</ref>.

=== Physical weathering === Physical weathering refers to the breakup of large rocks into smaller pieces<ref name=":72" /><ref name=":212" />. The physical rupture of parent rock material exposes new, unweathered rock to the atmosphere where it can begin to be weathered. Tectonics plays a critical role in uplifting new lithosphere to be exposed to weathering. Increased tectonic uplift functions as a direct relationship with chemical weathering rates<ref>{{Cite journal |last1=WEST |first1=A |last2=GALY |first2=A |last3=BICKLE |first3=M |date=2005-06-30 |title=Tectonic and climatic controls on silicate weathering |url=https://doi.org/10.1016/j.epsl.2005.03.020 |journal=Earth and Planetary Science Letters |volume=235 |issue=1–2 |pages=211–228 |doi=10.1016/j.epsl.2005.03.020 |issn=0012-821X|url-access=subscription }}</ref>, which results in increased terrigenous sediment production. There is also evidence that the climatic regime is important for determining chemical weathering rates<ref>{{Cite journal |last1=Willenbring |first1=Jane K. |last2=von Blanckenburg |first2=Friedhelm |date=2010 |title=Long-term stability of global erosion rates and weathering during late-Cenozoic cooling |url=https://doi.org/10.1038/nature09044 |journal=Nature |volume=465 |issue=7295 |pages=211–214 |doi=10.1038/nature09044 |pmid=20463736 |bibcode=2010Natur.465..211W |issn=0028-0836|url-access=subscription }}</ref><ref>{{Cite journal |last1=Willenbring |first1=Jane K. |last2=Jerolmack |first2=Douglas J. |date=2015-12-15 |title=The null hypothesis: globally steady rates of erosion, weathering fluxes and shelf sediment accumulation during Late Cenozoic mountain uplift and glaciation |url=https://doi.org/10.1111/ter.12185 |journal=Terra Nova |volume=28 |issue=1 |pages=11–18 |doi=10.1111/ter.12185 |issn=0954-4879}}</ref>.

Tectonic processes like continental collision, faulting, and crustal thickening can increase the production of land-derived sediments because these processes all push the crust upward and create orogens. Resulting high topography and steep slopes increase erosion and controls river gradients in mountainous regions<ref name=":3">{{Cite journal |last1=Jia |first1=Jianliang |last2=Wu |first2=Yanjia |last3=Miao |first3=Changsheng |last4=Fu |first4=Changlei |last5=Xie |first5=Wenquan |last6=Qin |first6=Jianyi |last7=Wang |first7=Xiaoming |date=2021 |title=Tectonic Controls on the Sedimentation and Thermal History of Supra-detachment Basins: A Case Study of the Early Cretaceous Fuxin Basin, NE China |url=https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2020TC006535 |journal=Tectonics |language=en |volume=40 |issue=5 |article-number=e2020TC006535 |doi=10.1029/2020TC006535 |bibcode=2021Tecto..4006535J |issn=0278-7407|url-access=subscription }}</ref>. Tectonic activity that lead to the weathering of mountain belts mobilize sediment from land to different marine depositional environments. For example, erosion of sediments from the Himalayas feeds directly into the Bengal Fan <ref name=":62">{{Cite news |title=Sedimentary rock {{!}} Definition, Formation, Examples, & Characteristics {{!}} Britannica |url=https://www.britannica.com/science/sedimentary-rock |archive-url=http://web.archive.org/web/20260219115505/https://www.britannica.com/science/sedimentary-rock |archive-date=2026-02-19 |access-date=2026-03-11 |work=Encyclopedia Britannica |language=en}}</ref>. Without tectonics, continents would be low, erosion rates would drop, and terrigenous sediment supply to the oceans would decrease <ref name=":3" />.

=== Determining sources and fate of solute and sediment transport === Sources of solutes and their behavior as a function of changing discharge produced from weathering for a catchment basin can be using power law relationship (assuming steady-state):

<math>C=a*R^b</math>

Where ''C'' is concentration of solute, ''a'' is catchment characteristic variable, ''R'' is runoff, which is discharge normalized to basin area, and ''b'' is the slope of the relationship between concentration and runoff<ref>{{Cite journal |last1=Godsey |first1=Sarah E. |last2=Kirchner |first2=James W. |last3=Clow |first3=David W. |date=2009-05-07 |title=Concentration–discharge relationships reflect chemostatic characteristics of US catchments |url=https://doi.org/10.1002/hyp.7315 |journal=Hydrological Processes |volume=23 |issue=13 |pages=1844–1864 |doi=10.1002/hyp.7315 |bibcode=2009HyPr...23.1844G |issn=0885-6087|url-access=subscription }}</ref><ref name=":4">{{Cite journal |last1=Godsey |first1=Sarah E. |last2=Hartmann |first2=Jens |last3=Kirchner |first3=James W. |date=2019-09-11 |title=Catchment chemostasis revisited: Water quality responds differently to variations in weather and climate |url=https://doi.org/10.1002/hyp.13554 |journal=Hydrological Processes |volume=33 |issue=24 |pages=3056–3069 |doi=10.1002/hyp.13554 |bibcode=2019HyPr...33.3056G |issn=0885-6087|url-access=subscription }}</ref><ref>{{Cite journal |last1=Thompson |first1=S. E. |last2=Basu |first2=N. B. |last3=Lascurain |first3=J. |last4=Aubeneau |first4=A. |last5=Rao |first5=P. S. C. |date=2011 |title=Relative dominance of hydrologic versus biogeochemical factors on solute export across impact gradients |url=https://doi.org/10.1029/2010wr009605 |journal=Water Resources Research |volume=47 |issue=10 |article-number=2010WR009605 |doi=10.1029/2010wr009605 |bibcode=2011WRR....47.0J05T |issn=0043-1397}}</ref>. The slope or b-value can be interpreted as:

If ''b = 0'', then the supply of sediment and transport exhibit chemostatic behavior

If ''b > 0'', then the supply of sediment exceeds the transport capacity

If ''b < 0'', then the transport capacity exceeds the supply of sediment

Total sediment flux to the ocean can be calculated by the following equation (assuming steady-state):

<math>Qs=\alpha R^{3/2} A^{1/2} e^{KT}</math>

Where ''Qs'' is total sediment flux, ''α'' and ''K'' are climate zone constants, ''R'' is relief relative to sea level, ''A'' is catchment area, and ''T'' is temperature<ref>{{Cite journal |last1=Syvitski |first1=James P. |last2=Morehead |first2=Mark D. |last3=Bahr |first3=David B. |last4=Mulder |first4=Thierry |date=2000 |title=Estimating fluvial sediment transport: The rating parameters |url=https://doi.org/10.1029/2000wr900133 |journal=Water Resources Research |volume=36 |issue=9 |pages=2747–2760 |doi=10.1029/2000wr900133 |bibcode=2000WRR....36.2747S |issn=0043-1397}}</ref><ref>{{Cite journal |last1=Rustomji |first1=P. |last2=Wilkinson |first2=S. N. |date=2008 |title=Applying bootstrap resampling to quantify uncertainty in fluvial suspended sediment loads estimated using rating curves |url=https://doi.org/10.1029/2007wr006088 |journal=Water Resources Research |volume=44 |issue=9 |article-number=2007WR006088 |doi=10.1029/2007wr006088 |bibcode=2008WRR....44.9435R |issn=0043-1397}}</ref>.

== Depositional environments == thumb|447x447px|Global distribution of sediment on the seafloorTerrigenous sediment mainly accumulates on continental shelves near continental masses<ref name=":04">{{Citation |last1=Robert |first1=Christian M. |title=Chapter Ten Terrigenous Sediments |date=2008-01-01 |journal=Developments in Marine Geology |volume=3 |pages=329–363 |url=https://www.sciencedirect.com/science/chapter/bookseries/abs/pii/S1572548008002108 |access-date=2026-03-01 |publisher=Elsevier |doi=10.1016/S1572-5480(08)00210-8 |bibcode=2008DevMG...3..329R |isbn=978-0-444-51817-0 |language=en-US|url-access=subscription }}</ref><ref name=":52">{{Cite web |title=Terrigenous Clastic Depositional Systems |url=https://www.researchgate.net/publication/279386089 |archive-url=http://web.archive.org/web/20231211030736/http://www.researchgate.net/publication/279386089_Terrigenous_Clastic_Depositional_Systems |archive-date=2023-12-11 |access-date=2026-02-22 |website=ResearchGate |language=en}}</ref><ref name=":82">{{Cite journal |last1=Milliman |first1=John D. |last2=Syvitski |first2=James P. M. |date=1992 |title=Geomorphic/Tectonic Control of Sediment Discharge to the Ocean: The Importance of Small Mountainous Rivers |url=https://doi.org/10.1086/629606 |journal=The Journal of Geology |volume=100 |issue=5 |pages=525–544 |doi=10.1086/629606 |bibcode=1992JG....100..525M |issn=0022-1376|url-access=subscription }}</ref>. Large build up of terrigenous sediment form the continental shelves and beaches over millions of years of weathering and erosion<ref name=":04" />. Terrigenous sediment found in the deep ocean are fine-grained clays, typically red clays rich in iron.

=== Turbidity currents === thumb|445x445px|Simplified sediment density flow in Monterey Canyon Terrigenous sediments on the continental shelf are subject to processes that are dominate in shallow marine environments like rivers, waves, and tidal currents. Turbidity currents are gravity-driven, underwater currents that rapidly move down slope and transport near-shore sediment deeper in the marine environment. They are one of the primary mechanisms of transport down the continental slope and into deep ocean basins. Turbidity currents enhance carbon burial efficiency by transporting sediment to deep-marine environments, which will reduce oxygen exposure and rapid sedimentation can increase long-term carbon preservation <ref>{{Cite journal |last1=Hage |first1=S. |last2=Galy |first2=V.V. |last3=Cartigny |first3=M.J.B. |last4=Acikalin |first4=S. |last5=Clare |first5=M.A. |last6=Gröcke |first6=D.R. |last7=Hilton |first7=R.G. |last8=Hunt |first8=J.E. |last9=Lintern |first9=D.G. |last10=McGhee |first10=C.A. |last11=Parsons |first11=D.R. |last12=Stacey |first12=C.D. |last13=Sumner |first13=E.J. |last14=Talling |first14=P.J. |date=2020-05-29 |title=Efficient preservation of young terrestrial organic carbon in sandy turbidity-current deposits |url=https://pubs.geoscienceworld.org/gsa/geology/article/48/9/882/586768/Efficient-preservation-of-young-terrestrial |journal=Geology |language=en |volume=48 |issue=9 |pages=882–887 |doi=10.1130/G47320.1 |bibcode=2020Geo....48..882H |issn=0091-7613 |archive-url=http://web.archive.org/web/20240919033554/https://pubs.geoscienceworld.org/gsa/geology/article/48/9/882/586768/Efficient-preservation-of-young-terrestrial |archive-date=2024-09-19|hdl=1912/26337 |hdl-access=free }}</ref>.

=== Eolian dunes === Eolian dunes are formed by sediments transported by wind. This is common in deserts and coastal areas because siliciclastic minerals erode, transport, and deposit sand to form dunes and other formations <ref>{{Cite web |title=Eolian sediments {{!}} U.S. Geological Survey |url=https://www.usgs.gov/publications/eolian-sediments-0 |access-date=2026-03-04 |website=www.usgs.gov |language=en}}</ref>.

The siliciclastic minerals are transported through three methods called saltation, traction, and suspension. Saltation is the action of fine-grained material bouncing while being carried in turbulent air. Traction is the transport of larger grains rolling or sliding across a surface, usually results in saltation and erosion. Suspension is the process where wind lifts and carries these fine particles high into the atmosphere over vast distances <ref>{{Cite journal |last1=Jackson |first1=Nancy L. |last2=Nordstrom |first2=Karl F. |date=2011-11-01 |title=Aeolian sediment transport and landforms in managed coastal systems: A review |url=https://www.sciencedirect.com/science/article/pii/S1875963711000309 |journal=Aeolian Research |volume=3 |issue=2 |pages=181–196 |doi=10.1016/j.aeolia.2011.03.011 |bibcode=2011AeoRe...3..181J |issn=1875-9637|url-access=subscription }}</ref>.

Some common examples would be the Sahara Desert, Loess Plateau, and the Outer Banks. Many of these examples are created from different transport mechanisms. The dunes in the Saharan Deserts are often quartz-rich from weathered old rocks and recycling of older sediments.<ref>{{Cite journal |last1=Pastore |first1=Guido |last2=Baird |first2=Thomas |last3=Vermeesch |first3=Pieter |last4=Bristow |first4=Charles |last5=Resentini |first5=Alberto |last6=Garzanti |first6=Eduardo |date=2021 |title=Provenance and recycling of Sahara Desert sand |url=https://linkinghub.elsevier.com/retrieve/pii/S0012825221001069 |journal=Earth-Science Reviews |language=en |volume=216 |article-number=103606 |doi=10.1016/j.earscirev.2021.103606 |bibcode=2021ESRv..21603606P |hdl=10281/324362 |hdl-access=free }}</ref>. The Loess Plateau is fine-grained silt that is transported by wind that forms thick blankets of sediment far from the original source <ref>{{Citation |last=Muhs |first=D.R. |title=Loess Deposits, Origins and Properties |date=2007 |encyclopedia=Encyclopedia of Quaternary Science |pages=1405–1418 |url=https://linkinghub.elsevier.com/retrieve/pii/B0444527478001587 |access-date=2026-04-08 |publisher=Elsevier |language=en |doi=10.1016/b0-44-452747-8/00158-7 |bibcode=2007enqu.book.1405M |isbn=978-0-444-52747-9|url-access=subscription }}</ref>. Lastly, the Outer Banks' sand originated from weathered material that is delivered by rivers to beaches and then reworked into the dunes <ref>{{Cite journal |last1=Counts |first1=John W. |last2=Gooley |first2=Jared T. |last3=Long |first3=Joshua H. |last4=Craddock |first4=William H. |last5=O'Sullivan |first5=Paul |date=2024-11-01 |title=Discerning sediment provenance in the Outer Banks (USA) through detrital zircon geochronology |url=https://www.sciencedirect.com/science/article/pii/S0025322724001932 |journal=Marine Geology |volume=477 |article-number=107409 |doi=10.1016/j.margeo.2024.107409 |bibcode=2024MGeol.47707409C |issn=0025-3227|doi-access=free }}</ref>.

=== Fluvial environments === thumb|433x433px|Potential mechanisms of transport of sediment during river flow Fluvial environments are rivers and streams that can carry sediment from continents to oceans. This is a crucial link in source-to-sink sedimentary cycle. Rivers are high energy, turbulent flows that erode, transport, and deposit sediments based on flow velocity and grain size <ref name=":1">{{Cite journal |last=L. G. Kessler, II |date=1974 |title=Braided Rivers and Related Terrigenous Depositional Systems--Useful But Enigmatic Exploration Models: ABSTRACT |url=http://search.datapages.com/data/doi/10.1306/83D91579-16C7-11D7-8645000102C1865D |journal=AAPG Bulletin |language=en |volume=58 |doi=10.1306/83D91579-16C7-11D7-8645000102C1865D |issn=0149-1423}}</ref>. Transport processes influence sediment characteristics such as grain size, sorting, and composition.

Sediment can be transported through two methods called bed load or bed material and suspended load or suspended sediment. Bed load carries the coarser, heavier sediment like gravel and sand by rolling, sliding, or saltating <ref name=":1" />. Suspended load carries finer sediment like silt and clay through the water column shown in Figure 4.

== Methods of sediment source tracing == Sediment-tracing technology began in the early 1960s with research on sediment patterns, which include erosional and depositional rates and mass sediment accumulation<ref>{{Citation |last=Appleby |first=P. G. |title=Chronostratigraphic Techniques in Recent Sediments |series=Developments in Paleoenvironmental Research |date=2002 |volume=1 |pages=171–203 |url=https://doi.org/10.1007/0-306-47669-x_9 |access-date=2026-05-01 |place=Dordrecht |publisher=Kluwer Academic Publishers |doi=10.1007/0-306-47669-x_9 |isbn=0-7923-6482-1|url-access=subscription }}</ref><ref>{{Citation |last1=McLennan |first1=S. M. |title=Geochemical approaches to sedimentation, provenance, and tectonics |date=1993 |journal=Geological Society of America Special Papers |pages=21–40 |url=https://doi.org/10.1130/spe284-p21 |access-date=2026-05-01 |publisher=Geological Society of America |isbn=0-8137-2284-5 |last2=Hemming |first2=S. |last3=McDaniel |first3=D. K. |last4=Hanson |first4=G. N. |volume=284 |doi=10.1130/spe284-p21 |bibcode=1993GSASP.284...21M |url-access=subscription }}</ref>. To determine the origin and transport routes of terrigenous sediments, scientists employ a variety of geochemical and biological techniques, such as radiogenic isotopes, grain size-analysis, biomarkers and compound specific stable isotopes, rare earth element (REE) patterns, paleomagnetism, fossil pollen, and radionuclides<ref name=":11">{{Cite journal |last1=Rodrigo-Gámiz |first1=M. |last2=Martínez-Ruiz |first2=F. |last3=Chiaradia |first3=M. |last4=Jiménez-Espejo |first4=F.J. |last5=Ariztegui |first5=D. |date=2015 |title=Radiogenic isotopes for deciphering terrigenous input provenance in the western Mediterranean |url=https://linkinghub.elsevier.com/retrieve/pii/S0009254115002910 |journal=Chemical Geology |language=en |volume=410 |pages=237–250 |doi=10.1016/j.chemgeo.2015.06.004 |bibcode=2015ChGeo.410..237R }}</ref><ref>{{Citation |last1=Bierman |first1=Paul R. |title=Erosion, Weathering, and Sedimentation |date=1998 |work=Isotope Tracers in Catchment Hydrology |pages=647–678 |url=https://doi.org/10.1016/b978-0-444-81546-0.50026-4 |access-date=2026-05-01 |publisher=Elsevier |isbn=978-0-444-81546-0 |last2=Albrecht |first2=Achim |last3=Bothner |first3=Michael H. |last4=Brown |first4=Erik T. |last5=Bullen |first5=Thomas D. |last6=Gray |first6=Leda Beth |last7=Turpin |first7=Laurent |doi=10.1016/b978-0-444-81546-0.50026-4 |bibcode=1998itch.book..647B |url-access=subscription }}</ref><ref>{{Cite journal |last=Hilton |first=J. |date=1990 |title=Greigite and the magnetic properties of sediments |journal=Limnology and Oceanography |volume=35 |issue=2 |pages=509–520 |doi=10.4319/lo.1990.35.2.0509 |doi-access=free |bibcode=1990LimOc..35..509H |issn=0024-3590}}</ref><ref>{{Cite journal |last1=Nittrouer |first1=C.A. |last2=Sternberg |first2=R.W. |last3=Carpenter |first3=R. |last4=Bennett |first4=J.T. |date=1979 |title=The use of Pb-210 geochronology as a sedimentological tool: Application to the Washington continental shelf |url=https://doi.org/10.1016/0025-3227(79)90039-2 |journal=Marine Geology |volume=31 |issue=3–4 |pages=297–316 |doi=10.1016/0025-3227(79)90039-2 |bibcode=1979MGeol..31..297N |issn=0025-3227|url-access=subscription }}</ref><ref name=":2">{{Cite journal |last1=Bayon |first1=Germain |last2=Lambert |first2=Thibault |last3=Vigier |first3=Nathalie |last4=De Deckker |first4=Patrick |last5=Freslon |first5=Nicolas |last6=Jang |first6=Kwangchul |last7=Larkin |first7=Christina S. |last8=Piotrowski |first8=Alexander M. |last9=Tachikawa |first9=Kazuyo |last10=Thollon |first10=Maude |last11=Tipper |first11=Edward T. |date=2020 |title=Rare earth element and neodymium isotope tracing of sedimentary rock weathering |url=https://doi.org/10.1016/j.chemgeo.2020.119794 |journal=Chemical Geology |volume=553 |article-number=119794 |doi=10.1016/j.chemgeo.2020.119794 |bibcode=2020ChGeo.55319794B |issn=0009-2541}}</ref><ref name=":9">{{Citation |last1=Tripathy |first1=Gyana Ranjan |title=Sr and Nd Isotopes as Tracers of Chemical and Physical Erosion |date=2011-06-30 |work=Advances in Isotope Geochemistry |pages=521–552 |url=https://doi.org/10.1007/978-3-642-10637-8_26 |access-date=2026-05-01 |place=Berlin, Heidelberg |publisher=Springer Berlin Heidelberg |isbn=978-3-642-10636-1 |last2=Singh |first2=Sunil Kumar |last3=Krishnaswami |first3=S. |doi=10.1007/978-3-642-10637-8_26 |url-access=subscription }}</ref>, among others. Often times, lacustrine (lake) systems are particularly valuable because they preserve continuous sediment records, unlike some marine records<ref name=":12">{{Cite journal |last=Tucker |first=Maurice |date=1995 |title=Principles of sedimentology and stratigraphy |url=https://doi.org/10.1016/0012-8252(95)90009-8 |journal=Earth-Science Reviews |volume=39 |issue=1–2 |pages=117–118 |doi=10.1016/0012-8252(95)90009-8 |bibcode=1995ESRv...39..117T |issn=0012-8252|url-access=subscription }}</ref>.

=== Radiogenic isotopes === Sediments created by weathering and erosion frequently preserve radiogenic isotopic signatures because rocks from various geographical locations and geological eras have unique isotope compositions <ref name=":11" />. These isotopic compositions act as geochemical signatures that reflect their source regions based on local geology. By analyzing isotope ratios and comparing them with potential continental sources, scientists can determine the origin and transport pathways of sediments <ref name=":14">{{Citation |last1=Goldstein |first1=S.L. |title=Long-lived Isotopic Tracers in Oceanography, Paleoceanography, and Ice-sheet Dynamics |date=2003 |journal=Treatise on Geochemistry |pages=453–489 |url=https://doi.org/10.1016/b0-08-043751-6/06179-x |access-date=2026-04-10 |publisher=Elsevier |isbn=978-0-08-043751-4 |last2=Hemming |first2=S.R. |volume=6 |doi=10.1016/b0-08-043751-6/06179-x |bibcode=2003TrGeo...6..453G |url-access=subscription }}</ref><ref>{{Cite web |title=Principles and Applications of Isotopes |url=https://webapps.unitn.it/Biblioteca/it/Web/EngibankFile/Isotopes%20-%20principles%20and%20applications.pdf |archive-url=http://web.archive.org/web/20240214183555/https://webapps.unitn.it/Biblioteca/it/Web/EngibankFile/Isotopes%20-%20principles%20and%20applications.pdf |archive-date=2024-02-14 |access-date=2026-04-10 |website=webapps.unitn.it}}</ref><ref>{{Citation |last1=Goldstein |first1=S.L. |title=Long-lived Isotopic Tracers in Oceanography, Paleoceanography, and Ice-sheet Dynamics |date=2003 |journal=Treatise on Geochemistry |pages=453–489 |url=https://doi.org/10.1016/b0-08-043751-6/06179-x |access-date=2026-05-01 |publisher=Elsevier |isbn=978-0-08-043751-4 |last2=Hemming |first2=S.R. |volume=6 |doi=10.1016/b0-08-043751-6/06179-x |bibcode=2003TrGeo...6..453G |url-access=subscription }}</ref>. Sediment tracing may use a combination of isotope tracers, such as strontium (Sr), neodymium (Nd), and lead (Pb)<ref>{{Cite journal |last1=Allègre |first1=Claude J. |last2=Dupré |first2=Bernard |last3=Négrel |first3=Philippe |last4=Gaillardet |first4=Jérôme |date=1996 |title=SrNdPb isotope systematics in Amazon and Congo River systems: constraints about erosion processes |url=https://doi.org/10.1016/0009-2541(96)00028-9 |journal=Chemical Geology |volume=131 |issue=1–4 |pages=93–112 |doi=10.1016/0009-2541(96)00028-9 |bibcode=1996ChGeo.131...93A |issn=0009-2541|url-access=subscription }}</ref>. It is possible to determine the origin and mode of transportation of sediments by analyzing radiogenic isotope ratios in sediments and comparing them with possible source regions<ref name=":11" /><ref name=":9" /><ref name=":15">{{Cite journal |last1=Pearce |first1=Christopher R. |last2=Parkinson |first2=Ian J. |last3=Gaillardet |first3=Jérôme |last4=Charlier |first4=Bruce L.A. |last5=Mokadem |first5=Fatima |last6=Burton |first6=Kevin W. |date=2015 |title=Reassessing the stable (δ88/86Sr) and radiogenic (87Sr/86Sr) strontium isotopic composition of marine inputs |url=https://doi.org/10.1016/j.gca.2015.02.029 |journal=Geochimica et Cosmochimica Acta |volume=157 |pages=125–146 |doi=10.1016/j.gca.2015.02.029 |issn=0016-7037}}</ref><ref>{{Cite journal |last=Frank |first=Martin |date=2002 |title=Radiogenic Isotopes: Tracers of Past Ocean Circulation and Erosional Input |url=https://doi.org/10.1029/2000rg000094 |journal=Reviews of Geophysics |volume=40 |issue=1 |page=1001 |doi=10.1029/2000rg000094 |bibcode=2002RvGeo..40.1001F |issn=8755-1209|url-access=subscription }}</ref><ref name=":23">{{Cite journal |last1=Dia |first1=Aline |last2=Dupré |first2=Bernard |last3=Allègre |first3=Claude Jean |date=1992 |title=Nd isotopes in Indian Ocean sediments used as a tracer of supply to the ocean and circulation paths |url=https://doi.org/10.1016/0025-3227(92)90025-d |journal=Marine Geology |volume=103 |issue=1–3 |pages=349–359 |doi=10.1016/0025-3227(92)90025-d |bibcode=1992MGeol.103..349D |issn=0025-3227|url-access=subscription }}</ref>.

==== Strontium ==== One of the most widely utilized tracers in sediment origin research is the ratio of <chem>^{87}_Sr</chem> to <chem>^{86}_Sr</chem> (<chem>^{87}_Sr</chem>/<chem>^{86}_Sr</chem>)<ref name=":9" /><ref name=":15" />. Sediments formed from rocks of various ages and compositions tend to retain these signatures during weathering and transportation because these rocks develop varied ratios of <chem>^{87}_Sr</chem> to <chem>^{86}_Sr</chem><ref name=":9" />. Thus, measurements of strontium isotopes in natural waters and sediments enable researchers to track the flow of terriginous material from land to the ocean and determine the sources of sediment <ref name=":15" />.

==== Neodymium ==== Neodymium (Nd) isotopes are also widely used in sediment tracing. The isotopic composition of neodymium is typically expressed using epsilon notation (εNd), which reflects deviations from a standard reference and varies depending on the geological characteristics of source regions <ref name=":14" /><ref name=":16">{{Cite journal |last1=van de Flierdt |first1=Tina |last2=Griffiths |first2=Alexander M. |last3=Lambelet |first3=Myriam |last4=Little |first4=Susan H. |last5=Stichel |first5=Torben |last6=Wilson |first6=David J. |date=2016-11-28 |title=Neodymium in the oceans: a global database, a regional comparison and implications for palaeoceanographic research |url=https://doi.org/10.1098/rsta.2015.0293 |journal=Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences |volume=374 |issue=2081 |pages=20150293 |doi=10.1098/rsta.2015.0293 |pmid=29035258 |pmc=5069528 |bibcode=2016RSPTA.37450293V |issn=1364-503X}}</ref>.

Radiogenic Nd isotopes (<chem>^{143}_Nd</chem>/<chem>^{144}_Nd</chem>) are particularly useful because they retain the geochemical signature of their source rocks and are widely used to trace sediment provenance and mixing processes <ref name=":23" /><ref name=":16" /><ref>{{Citation |last1=McLennan |first1=S. M. |title=Geochemical approaches to sedimentation, provenance, and tectonics |date=1993 |journal=Geological Society of America Special Papers |pages=21–40 |url=https://doi.org/10.1130/spe284-p21 |access-date=2026-04-10 |publisher=Geological Society of America |isbn=0-8137-2284-5 |last2=Hemming |first2=S. |last3=McDaniel |first3=D. K. |last4=Hanson |first4=G. N. |volume=284 |doi=10.1130/spe284-p21 |bibcode=1993GSASP.284...21M |url-access=subscription }}</ref><ref name=":17">{{Cite journal |last1=Bai |first1=Jianghao |last2=Luo |first2=Kai |last3=Wu |first3=Chao |last4=Wang |first4=Zhibing |last5=Zhang |first5=Le |last6=Yan |first6=Shuang |last7=Zhong |first7=Songxiong |last8=Ma |first8=Jinlong |last9=Wei |first9=Gangjian |date=2023 |title=Stable neodymium isotopic fractionation during chemical weathering |url=https://doi.org/10.1016/j.epsl.2023.118260 |journal=Earth and Planetary Science Letters |volume=617 |article-number=118260 |doi=10.1016/j.epsl.2023.118260 |bibcode=2023E&PSL.61718260B |issn=0012-821X|url-access=subscription }}</ref>. Different geological regions exhibit distinct εNd values, allowing scientists to distinguish between sediment sources<ref name=":2" /><ref name=":9" />. Radiogenic Nd isotopes do not significantly fractionate during weathering and transport, making them reliable indicators of source rock composition. However, studies have shown that stable Nd isotopes may exhibit minor fractionation under certain weathering conditions, but it does not largely affect their use in analysis <ref name=":17" />.

==== Lead ==== Lead (Pb) isotopes are used to trace both natural and anthropogenic sources of sediments. Variations in Pb isotope ratios arise from the radioactive decay of uranium and thorium in source rocks, producing distinct geochemical signatures <ref name=":18">{{Cite journal |last1=Komárek |first1=Michael |last2=Ettler |first2=Vojtěch |last3=Chrastný |first3=Vladislav |last4=Mihaljevič |first4=Martin |date=2008 |title=Lead isotopes in environmental sciences: A review |url=https://doi.org/10.1016/j.envint.2007.10.005 |journal=Environment International |volume=34 |issue=4 |pages=562–577 |doi=10.1016/j.envint.2007.10.005 |pmid=18055013 |bibcode=2008EnInt..34..562K |issn=0160-4120|url-access=subscription }}</ref>. In addition to natural sources from rock weathering, lead isotopes can indicate anthropogenic disturbances such as industrial pollution, mining activity, and the historical use of leaded gasoline<ref>{{Cite journal |last1=Komárek |first1=Michael |last2=Ettler |first2=Vojtěch |last3=Chrastný |first3=Vladislav |last4=Mihaljevič |first4=Martin |date=2008 |title=Lead isotopes in environmental sciences: A review |url=https://doi.org/10.1016/j.envint.2007.10.005 |journal=Environment International |volume=34 |issue=4 |pages=562–577 |doi=10.1016/j.envint.2007.10.005 |pmid=18055013 |bibcode=2008EnInt..34..562K |issn=0160-4120|url-access=subscription }}</ref>. These human-derived signatures allow researchers to detect contamination and environmental changes within sediment records <ref name=":18" />.

Rare earth elements (REEs) are a group of chemically similar trace metals that include the lanthanides from lanthanum (La) to lutetium (Lu). Although they occur in low concentrations (nanogram per gram concentrations), their relative abundance patterns in sediments can reflect the composition of the original source rocks<ref name=":102">{{Cite journal |last1=Fu |first1=Yu |last2=Li |first2=Zhengkun |last3=Chew |first3=David |last4=Hollings |first4=Pete |last5=Peng |first5=Jinzhou |last6=Chen |first6=Jieyun |last7=Tan |first7=Bojue |last8=He |first8=Gaowen |last9=Liang |first9=Yongjia |last10=Huang |first10=Fei |last11=Tang |first11=Yayue |last12=Wang |first12=Rui |last13=Li |first13=Dengfeng |last14=Sun |first14=Xiaoming |date=2025 |title=Deep-sea rare earth element-rich sediments: A review of distribution, carriers and petrogenesis |url=https://doi.org/10.1016/j.gloplacha.2025.104870 |journal=Global and Planetary Change |volume=252 |article-number=104870 |doi=10.1016/j.gloplacha.2025.104870 |bibcode=2025GPC...25204870F |issn=0921-8181|url-access=subscription }}</ref><ref name=":24">{{Cite journal |last1=Bayon |first1=Germain |last2=Lambert |first2=Thibault |last3=Vigier |first3=Nathalie |last4=De Deckker |first4=Patrick |last5=Freslon |first5=Nicolas |last6=Jang |first6=Kwangchul |last7=Larkin |first7=Christina S. |last8=Piotrowski |first8=Alexander M. |last9=Tachikawa |first9=Kazuyo |last10=Thollon |first10=Maude |last11=Tipper |first11=Edward T. |date=2020 |title=Rare earth element and neodymium isotope tracing of sedimentary rock weathering |url=https://doi.org/10.1016/j.chemgeo.2020.119794 |journal=Chemical Geology |volume=553 |article-number=119794 |doi=10.1016/j.chemgeo.2020.119794 |bibcode=2020ChGeo.55319794B |issn=0009-2541}}</ref>.

REEs are adsorbed onto clay minerals and other fine sediment particle surfaces during weathering and erosion. Their distribution patterns are frequently maintained because they are comparatively resistant to chemical change during transportation. Therefore, it is possible to identify sediment dispersal using differences in rare earth element patterns, such as the relative abundance of light vs. heavy REEs or anomalies in elements like cerium and europium <ref name=":102" />.

=== Biomarkers === Biomarkers are organic molecules derived from specific biological sources that can be preserved in sediments over long periods of time. Some biomarkers originate from terrestrial plants, soils, or microbes, indicating that continental organic matter has been incorporated into marine or lacustrine sediments <ref name=":19">{{Cite book |last1=Peters |first1=K. E. |url=https://doi.org/10.1017/cbo9781107326040 |title=The Biomarker Guide |last2=Walters |first2=C. C. |last3=Moldowan |first3=J. M. |date=2004-12-16 |publisher=Cambridge University Press |doi=10.1017/cbo9781107326040 |isbn=978-0-521-83762-0}}</ref><ref name=":20">{{Cite journal |last=Meyers |first=Philip A. |date=1997 |title=Organic geochemical proxies of paleoceanographic, paleolimnologic, and paleoclimatic processes |url=https://doi.org/10.1016/s0146-6380(97)00049-1 |journal=Organic Geochemistry |volume=27 |issue=5–6 |pages=213–250 |doi=10.1016/s0146-6380(97)00049-1 |bibcode=1997OrGeo..27..213M |issn=0146-6380|url-access=subscription }}</ref><ref>{{Cite book |last1=Peters |first1=K. E. |url=https://doi.org/10.1017/cbo9780511524868 |title=The Biomarker Guide |last2=Walters |first2=C. C. |last3=Moldowan |first3=J. M. |date=2004-12-16 |publisher=Cambridge University Press |doi=10.1017/cbo9780511524868 |isbn=978-0-521-78158-9}}</ref>.

Terrigenous organic matter is frequently traced using substances like leaf wax lipids, lignin phenols, and other humic substances produced from plants<ref name=":19" /><ref name=":20" />. The presence of these molecules in marine or coastal sediments can reveal the contribution of terrestrial material carried by rivers, wind, or coastal processes since they are linked to certain biological sources <ref name=":19" />. Specific biomarkers, such as lignin-derived compounds, are widely used indicators of terrestrial input because they are relatively resistant to degradation<ref name=":20" />. Biomarkers can also provide insight to environmental conditions at the time of deposition. For example, carbon isotope variations can distinguish between different plant types and climate conditions <ref name=":20" />. Biomarkers are often used alongside geochemical tracers to better understand the sources and transport pathways of terrigenous sediments <ref name=":19" />.

==References== <references /> Category:Sedimentary rocks Category:Sedimentology Category:Marine geology Category:Oceanography Category:Soil Category:Weathering