This section needs additional citations for verification. Please help improve this article by adding citations to reliable sourcesin this section. Unsourced material may be challenged and removed. ( November 2023) ( Learn how and when to remove this template message) Relationships of unconformities – Geologic features representing periods of erosion or non-deposition, indicating non-continuous sediment deposition.

Zalasiewicz, Jan; Waters, Colin N.; Ellis, Erle C.; Head, Martin J.; Vidas, Davor; Steffen, Will; Thomas, Julia Adeney; Horn, Eva; Summerhayes, Colin P.; Leinfelder, Reinhold; McNeill, J. R. (2021). "The Anthropocene: Comparing Its Meaning in Geology (Chronostratigraphy) with Conceptual Approaches Arising in Other Disciplines". Earth's Future. 9 (3). Bibcode: 2021EaFut...901896Z. doi: 10.1029/2020EF001896. ISSN 2328-4277. S2CID 233816527. Intermediate is a composition between felsic and mafic. It usually contains roughly-equal amounts of light and dark minerals, including light grains of plagioclase feldspar and dark minerals like amphibole. It is intermediate in silica in the 55-60% range. Acastan Period/System ( 4030–3810 Ma) – named after the Acasta Gneiss, one of the oldest preserved pieces of continental crust. [57] [70] The definition of an economic mineral is broader. Economic minerals are extracted from the Earth by quarrying, mining and pumping and used in a wide range of applications related to construction, manufacturing, agriculture and energy supply. They include: Williams, Joshua J.; Mills, Benjamin J. W.; Lenton, Timothy M. (2019). "A tectonically driven Ediacaran oxygenation event". Nature Communications. 10 (1): 2690. Bibcode: 2019NatCo..10.2690W. doi: 10.1038/s41467-019-10286-x. ISSN 2041-1723. PMC 6584537. PMID 31217418.Cox, Simon J. D.; Richard, Stephen M. (2014). "A geologic timescale ontology and service". Earth Science Informatics. 8: 5–19. doi: 10.1007/s12145-014-0170-6. S2CID 42345393. Further cooling of the climate. Giant terror birds go extinct. Spread of Homo erectus across Afro-Eurasia. Head, Martin J.; Steffen, Will; Fagerlind, David; Waters, Colin N.; Poirier, Clement; Syvitski, Jaia; Zalasiewicz, Jan A.; Barnosky, Anthony D.; Cearreta, Alejandro; Jeandel, Catherine; Leinfelder, Reinhold (15 November 2021). "The Great Acceleration is real and provides a quantitative basis for the proposed Anthropocene Series/Epoch". Episodes. 45 (4): 359–376. doi: 10.18814/epiiugs/2021/021031. ISSN 0705-3797. S2CID 244145710.

When any given stratum was being formed, all the matter resting on it was fluid and, therefore, when the lowest stratum was being formed, none of the upper strata existed. Iizuka, Tsuyoshi; Komiya, Tsuyoshi; Maruyama, Shigenori (2007), Chapter 3.1 the Early Archean Acasta Gneiss Complex: Geological, Geochronological and Isotopic Studies and Implications for Early Crustal Evolution, Developments in Precambrian Geology, vol.15, Elsevier, pp.127–147, doi: 10.1016/s0166-2635(07)15031-3, ISBN 978-0-444-52810-0 , retrieved 1 May 2022 kiloyear event, Holocene climatic optimum. Sea level flooding of Doggerland and Sundaland. Sahara becomes a desert. End of Stone Age and start of recorded history. Humans finally expand into the Arctic Archipelago and Greenland.

Sivin, Nathan (1995). Science in ancient China: researches and reflections. Variorum. ISBN 0-86078-492-4. OCLC 956775994. Luster is a property that is more commonly used in the identification of minerals. It describes the way light reflects off of a surface and can be very useful for description and identification.

Strachan, R.; Murphy, J.B.; Darling, J.; Storey, C.; Shields, G. (2020), "Precambrian (4.56–1 Ga)", Geologic Time Scale 2020, Elsevier, pp.481–493, doi: 10.1016/b978-0-12-824360-2.00016-4, ISBN 978-0-12-824360-2, S2CID 229513433 , retrieved 9 April 2022 Gradstein, Felix M.; Ogg, James G.; Smith, Alan G.; Bleeker, Wouter; Laurens, Lucas, J. (June 2004). "A new Geologic Time Scale, with special reference to Precambrian and Neogene". Episodes. 27 (2): 83–100. doi: 10.18814/epiiugs/2004/v27i2/002. {{ cite journal}}: CS1 maint: multiple names: authors list ( link)

See also: Stratigraphy, Chronostratigraphy, Biostratigraphy, Magnetostratigraphy, Lithostratigraphy, and Geochronology The granitoids all center around granite, a fairly equal mixture of quartz, alkali feldspar, and plagioclase feldspar. As you remove alkali feldspar from proper granite, it becomes granodiorite and then tonalite (mostly plagioclase with less than 10% K-feldspar). Recognizing tonalite takes a close look with a magnifier to be sure that alkali feldspar is truly absent and quartz is abundant. Most tonalite also has abundant dark minerals, but this example is almost white (leucocratic), making it a plagiogranite. Trondhjemite is a plagiogranite whose dark mineral is biotite. This specimen's dark mineral is pyroxene, so it's plain old tonalite. Butcher, Andy (26 May 2004). "Re: Ediacaran". LISTSERV 16.0 - AUSTRALIAN-LINGUISTICS-L Archives. Archived from the original on 23 October 2007 . Retrieved 19 July 2011.

Montenari, Michael (2020). Carbon Isotope Stratigraphy (1sted.). Amsterdam: Academic Press (Elsevier). ISBN 978-0-12-820991-2.Greenland ice sheet develops [79] as the cold slowly intensifies towards the Pleistocene. Atmospheric O 2 and CO 2 content reaches present-day levels while landmasses also reach their current locations (e.g. the Isthmus of Panama joins the North and South Americas, while allowing a faunal interchange). The last non-marsupial metatherians go extinct. Australopithecus common in East Africa; Stone Age begins. [80] A Global Standard Stratigraphic Age (GSSA) [11] is a numeric only, chronologic reference point used to define the base of geochronologic units prior to the Cryogenian. These points are arbitrarily defined. [7] They are used where GSSPs have not yet been established. Research is ongoing to define GSSPs for the base of all units that are currently defined by GSSAs. From the Greek words παλιός ( palaiós) meaning 'old', πρότερος ( próteros) meaning 'former' or 'earlier', and ζωή ( zōḗ) meaning 'life'.