Main Page
From Wikipedia, the free encyclopedia.
Welcome to Wikipedia, the free encyclopedia that anyone can edit.
In this English version, started in 2001, we are currently working on 802,285 articles.
Wikipedia FAQs - Browse - A–Z - Portals - Ask a question
Culture | Geography | History | Mathematics | People | Science | Society | Technology
Today's featured articleThe geology of the Grand Canyon area exposes one of the most complete sequences of rock anywhere, representing a period of 1.4 billion years of the Earth's history in that part of North America. The major sedimentary rock layers exposed in the Grand Canyon and in the Grand Canyon National Park area range in age from 2 billion to about 200 million years old. Most were deposited in warm, shallow seas and near ancient, long-gone sea shores. Both marine and terrestrial sediments are represented, including fossilized sand dunes from an extinct desert. Uplift of the region started about 75 million years ago in the Laramide orogeny, a mountain-building event that is largely responsible for creating the Rocky Mountains to the east. The canyon did not start to form until 5.3 million years ago when the Gulf of California opened up and thus lowered the river's base level (its lowest point) from that of large inland lakes to sea level. About 2 million years ago volcanic activity started to deposit ash and lava over the area. The nearly 40 identified rock layers and 14 major unconformities (gaps in the geologic record) of the Grand Canyon form one of the most studied sequences of rock in the world. Recently featured: Eigenvalue, eigenvector and eigenspace – Gray Wolf – Speaker of the House of Commons Selected anniversariesNovember 2: All Souls Day in Catholicism; Day of the Dead in Mexico.
Recent days: November 1 – October 31 – October 30 |
In the news
Did you know...From Wikipedia's newest articles:
|
Wikipedia in other languages
You may read and edit articles in many different languages:
- Wikipedia encyclopedia languages with over 100,000 articles
- Deutsch (German) · Français (French) · Italiano (Italian) · 日本語 (Japanese) · Nederlands (Dutch) · Polski (Polish) · Svenska (Swedish)
- Wikipedia encyclopedia languages with over 10,000 articles
- Български (Bulgarian) · Català (Catalan) · Česká (Czech) · Dansk (Danish) · Eesti (Estonian) · Español (Spanish) · Esperanto · עברית (Hebrew) · Hrvatski (Croatian) · Ido · Bahasa Indonesia (Indonesian) · 한국어 (Korean) · Magyar (Hungarian) · Norsk bokmål (Norwegian) · Norsk nynorsk (Norwegian) · Português (Portuguese) · Română (Romanian) · Русский (Russian) · Slovenčina (Slovak) · Slovenščina (Slovenian) · Српски (Serbian) · Suomi (Finnish) · Українська (Ukrainian) · 中文 (Chinese)
- Wikipedia encyclopedia languages with over 1,000 articles
- Alemannisch (Alemannic) · Afrikaans · العربية (Arabic) · Asturianu (Asturian) · Bân-lâm-gú (Min Nan) · Беларуская (Belarusian) · Bosanski (Bosnian) · Brezhoneg (Breton) · Чăваш чěлхи (Chuvash) · Corsu (Corsican) · Cymraeg (Welsh) · Ελληνικά (Greek) · Euskara (Basque) · فارسی (Persian) · Føroyskt (Faroese) · Frysk (Western Frisian) · Gaeilge (Irish) · Gàidhlig (Scots Gaelic) · Galego (Galician) · हिन्दी (Hindi) · Interlingua · Íslenska (Icelandic) · Basa Jawa (Javanese) · ქართული (Georgian) · ಕನ್ನಡ (Kannada) · Kurdî / كوردی (Kurdish) · Latina (Latin) · Latviešu (Latvian) · Lëtzebuergesch (Luxembourgish) · Lietuvių (Lithuanian) · Limburgs (Limburgish) · Македонски (Macedonian) · मराठी (Marathi) · Bahasa Melayu (Malay) · Occitan · Ирон (Ossetic) · Plattdüütsch (Low Saxon) · Scots · Sicilianu (Sicilian) · Simple English · Shqip (Albanian) · Srpskohrvatski/Српскохрватски (Serbo–Croatian) · தமிழ் (Tamil) · Tagalog · ภาษาไทย (Thai) · Türkçe (Turkish) · Tatarça (Tatar) · తెలుగు (Telugu) · Tiếng Việt (Vietnamese) · Walon (Walloon)
Complete list · Multilingual coordination · Start a Wikipedia in another language
Wikipedia's sister projects
Wikipedia is hosted by the non-profit Wikimedia Foundation, which operates several other multilingual and free-content projects:
Wiktionary Dictionary and thesaurus |
Wikibooks Free textbooks and manuals |
Wikiquote Collection of quotations |
Wikisource The free library |
||||
Wikispecies Directory of species |
Wikinews Free content news source |
Commons Shared media repository |
Meta-Wiki Wikimedia project coordination |