Editing Geography of Qatar (section)

==Geology and mineral deposits==
[[File:Nakhsh mountain in Qatar.jpg|thumb|Fenced-off area of [[Jebel Nakhsh]] (Nakhsh Mountain)]]
[[File:Hillock at northern end of Al Khor Island.jpg|thumb|Limestone hillock on northern end of [[Al Khor Island]]]]
{| class="wikitable sortable"
! Era<ref>Casey & Vine (1991), p. 73</ref><ref>{{cite book|last=Al-Kubaisi|first=Mohammed Ali M.|title=Industrial development in Qatar: a geographical assessment|url=http://etheses.dur.ac.uk/7144/1/7144_4326.PDF?UkUDh:CyT|publisher=Durham E-Theses, Durham University|year=1984|page=12}}</ref>
! Period
! Formation
! Member
! Mineral deposits and resources
|-
| rowspan="2"|[[Paleozoic]] || [[Cambrian]] || Hormuz Formation || [[Dolomite (rock)|Dolomite]], [[sandstone]] || [[Hematite]], [[carbonate]]s, [[asbestos]]
|- 
| [[Permian]] <br /> [[Carboniferous]] || Khuff Formation || || [[Petroleum]]
|-
| rowspan="2"|[[Mesozoic]] || [[Jurassic]] || Uwainat Limestone Formation, Arab Formation || [[Dolomite (rock)|Dolomite]], [[limestone]], [[evaporite]], [[shale]] || [[Petroleum]]
|- 
| [[Cretaceous]] || Shuaiba Formation || [[Marl]]stone, [[limestone]], [[shale]] || [[Petroleum]]
|-
| rowspan="7"|[[Cenozoic]] || [[Paleocene]] || Umm Er Radhuma Formation || colspan="2"|
|- 
| rowspan="2"|[[Eocene|Lower Eocene]] || Rus Formation || [[Chalk]] || [[Celestine (mineral)|Celestine]], [[gypsum]]
|-
| Lower Dammam Formation || Dukhan limestone, Midra shale, Rudjm Aid limestone || [[Palygorskite]], [[pyrite]]
|- 
| [[Eocene|Middle Eocene]] || Upper Dammam Formation || Umm Bab chalk, Simaisma dolomites || [[Dolomite (rock)|Dolomite]], [[limestone]]
|-
| [[Miocene]] || Upper and Lower Dam Formation || [[Clay]], [[limestone]], [[gypsum]] || [[Clay]], [[limestone]], [[Celestine (mineral)|celestine]]
|- 
| [[Pliocene]] || Hofuf Formation || Sandy clay, [[sandstone]] || [[Sand]], [[gravel]]
|-
| [[Pleistocene]] || || [[wikt:miliolite|Miliolite]] limestone || [[Limestone]]
|}

Most  of Qatar's surface lies on [[Cenozoic]] [[stratum|strata]]. These strata have an abundance of mineral resources, most of which have not yet been exploited, such as [[limestone]] and [[clay]].<ref>{{cite book|last=Al-Kubaisi|first=Mohammed Ali M.|title=Industrial development in Qatar: a geographical assessment|url=http://etheses.dur.ac.uk/7144/1/7144_4326.PDF?UkUDh:CyT|publisher=Durham E-Theses, Durham University|year=1984|pages=10–11}}</ref> The Upper Dammam Formation in the [[Eocene|Middle Eocene]] period is the most predominant surface layer. It is constituted by [[limestone]] and [[Dolomite (rock)|Dolomite]].<ref>{{cite journal|last=Al-Saad|first=Hamad|url=https://www.researchgate.net/publication/222367100|title=Lithostratigraphy of the Middle Eocene Dammam Formation in Qatar, Arabian Gulf: effects of sea-level fluctuations along a tidal environment|journal=Journal of Asian Earth Sciences|year=2015|page=Abstract|access-date=27 July 2015|doi=10.1016/j.jseaes.2004.07.009|volume=25|issue=5}}</ref> The northern zone of Qatar, which comprises the most significant source of fresh groundwater in the peninsula, primarily draws its water from the Umm Err Radhuma Formation and Rus Formation dating to the [[Paleocene]] and [[Eocene|Lower Eocene]] periods, respectively.<ref>{{cite web|url=http://waterinventory.org/groundwater/umm-er-radhuma-dammam-aquifer-system-centre|title=Umm er Radhuma-Dammam Aquifer System (Centre)|publisher=Inventory of Shared Water Resources in Western Asia|access-date=27 July 2015}}</ref> The [[Mesozoic]] strata are the most important layers as they contain [[petroleum]]. The first substantial deposit of crude oil was discovered in 1940 in the [[Jurassic]] period Arab Formation.<ref>{{cite book|last=Al-Kubaisi|first=Mohammed Ali M.|title=Industrial development in Qatar: a geographical assessment|url=http://etheses.dur.ac.uk/7144/1/7144_4326.PDF?UkUDh:CyT|publisher=Durham E-Theses, Durham University|year=1984|page=11}}</ref>