Question: When did the country for which the Ferronigerite-2N1S is named become a member of OPEC?

full_context: Document 1: Oil reserves in Saudi Arabia: The proven oil reserves in Saudi Arabia are the 2nd largest in the world, estimated to be (Gbbl hereafter), including 2.5 Gbbl in the Saudi–Kuwaiti neutral zone. They are predominantly found in the Eastern Province. These reserves were the largest in the world until Venezuela announced they had increased their proven reserves to 297 Gbbl in January 2011. The Saudi reserves are about one-fifth of the world's total conventional oil reserves, a large fraction of these reserves comes from a small number of very large oil fields, and past production amounts to 40% of the stated reserves.
Document 2: Agbaja mine: The Agbaja mine is a large iron mine located in central Nigeria in the Kogi State. Agbaja represents one of the largest iron ore reserves in Nigeria and in the world having estimated reserves of 1.25 billion tonnes of ore grading 48% iron metal.
Document 3: Nigeria: The Niger Delta Nembe Creek Oil field was discovered in 1973 and produces from middle Miocene deltaic sandstone-shale in an anticline structural trap at a depth of 2–4 km. In June 2013, the company announced a strategic review of its operations in Nigeria, hinting that assets could be divested. While many international oil companies have operated there for decades, by 2014 most were making moves to divest their interests, citing a range of issues including oil theft. In August 2014, Shell Oil Company said it was finalising its interests in four Nigerian oil fields.
Document 4: Oil reserves in Saudi Arabia: The proven oil reserves in Saudi Arabia are the second largest in the world, estimated to be 268 billion barrels (43 × 10 ^ m) (Gbbl hereafter), including 2.5 Gbbl in the Saudi -- Kuwaiti neutral zone. They are predominantly found in the Eastern Province. These reserves were the largest in the world until Venezuela announced they had increased their proven reserves to 297 Gbbl in January 2011. The Saudi reserves are about one - fifth of the world's total conventional oil reserves, a large fraction of these reserves comes from a small number of very large oil fields, and past production amounts to 40% of the stated reserves.
Document 5: OPEC: Organization of the Petroleum Exporting Countries (OPEC, / ˈoʊpɛk / OH - pek, or OPEP in several other languages) is an intergovernmental organization of 14 nations as of May 2017, founded in 1960 in Baghdad by the first five members (Iran, Iraq, Kuwait, Saudi Arabia, Venezuela), and headquartered since 1965 in Vienna. As of 2016, the 14 countries accounted for an estimated 44 percent of global oil production and 73 percent of the world's ``proven ''oil reserves, giving OPEC a major influence on global oil prices that were previously determined by American - dominated multinational oil companies.
Document 6: Niobium: Columbium (symbol "Cb") was the name originally bestowed by Hatchett upon his discovery of the metal in 1801. The name reflected that the type specimen of the ore came from America (Columbia). This name remained in use in American journals—the last paper published by American Chemical Society with columbium in its title dates from 1953—while niobium was used in Europe. To end this confusion, the name niobium was chosen for element 41 at the 15th Conference of the Union of Chemistry in Amsterdam in 1949. A year later this name was officially adopted by the International Union of Pure and Applied Chemistry (IUPAC) after 100 years of controversy, despite the chronological precedence of the name columbium.  This was a compromise of sorts; the IUPAC accepted tungsten instead of wolfram in deference to North American usage; and niobium instead of columbium in deference to European usage. While many US chemical societies and government organizations typically use the official IUPAC name, some metallurgists and metal societies still use the original American name, "columbium".
Document 7: Nigeria: The name "" was taken from the Niger River running through the country. This name was coined in the late 19th century by British journalist Flora Shaw, who later married Lord Lugard, a British colonial administrator. The origin of the name "Niger", which originally applied only to the middle reaches of the Niger River, is uncertain. The word is likely an alteration of the Tuareg name "egerew n-igerewen" used by inhabitants along the middle reaches of the river around Timbuktu prior to 19th-century European colonialism.
Document 8: MENA: The MENA region has vast reserves of petroleum and natural gas that make it a vital source of global economic stability. According to the Oil and Gas Journal (January 1, 2009), the MENA region has 60% of the world's oil reserves (810.98 billion barrels (128.936 km3)) and 45% of the world's natural gas reserves (  2,868,886 billion cubic feet (81,237.8 km3)  ).As of 2011, 8 of the 15 OPEC nations are within the MENA region.
Document 9: OPEC: Country Region Membership Years Population (2016 est.) Area (km) Oil Production (bbl / day, 2016) Proven Reserves (bbl, 2016) Algeria North Africa 1969 -- 40,606,052 2,381,740 1,348,361 12,200,000,000 Angola Southern Africa 2007 -- 28,813,463 1,246,700 1,769,615 8,423,000,000 Ecuador Americas 1973 -- 1992, 2007 -- 16,385,068 283,560 548,421 8,273,000,000 Equatorial Guinea Western Africa 2017 -- 1,221,490 28,051 227,000 1,100,000,000 Gabon Western Africa 1975 -- 1995, 2016 -- 1,979,786 267,667 210,820 2,000,000,000 Iran Middle East 1960 -- 80,277,428 1,648,000 3,990,956 157,530,000,000 Iraq Middle East 1960 -- 37,202,572 437,072 4,451,516 143,069,000,000 Kuwait Middle East 1960 -- 4,052,584 17,820 2,923,825 101,500,000,000 Libya North Africa 1962 -- 6,293,253 1,759,540 384,686 48,363,000,000 Nigeria Western Africa 1971 -- 185,989,640 923,768 1,999,885 37,070,000,000 Qatar Middle East 1961 -- 2,569,804 11,437 1,522,902 25,244,000,000 Saudi Arabia Middle East 1960 -- 32,275,687 2,149,690 10,460,710 266,578,000,000 United Arab Emirates Middle East 1967 -- 9,269,612 83,600 3,106,077 97,800,000,000 Venezuela Americas 1960 -- 31,568,179 912,050 2,276,967 299,953,000,000 OPEC Total 478,498,000 12,150,695 35,221,740 1,209,103,000,000 World Total 7,588,065,000 510,072,000 80,622,287 1,650,585,000,000 OPEC Percent 6% 2% 44% 73%
Document 10: Ferronigerite-2N1S: Ferronigerite-2N1S was first discovered in the Kabba provence of central Nigeria in 1944; it was originally named Nigerite. Its name was later changed to nigerite-6H then to nigerite-6T and in 2003 ferronigertie-2N1S was approved by the International Mineralogical Association.
Document 11: OPEC: OPEC's stated mission is ``to coordinate and unify the petroleum policies of its member countries and ensure the stabilization of oil markets, in order to secure an efficient, economic and regular supply of petroleum to consumers, a steady income to producers, and a fair return on capital for those investing in the petroleum industry. ''The organization is also a significant provider of information about the international oil market. As of May 2017, OPEC's members are Algeria, Angola, Ecuador, Equatorial Guinea, Gabon, Iran, Iraq, Kuwait, Libya, Nigeria, Qatar, Saudi Arabia (the de facto leader), United Arab Emirates, and Venezuela, while Indonesia is a former member. Two - thirds of OPEC's oil production and reserves are in its six Middle Eastern countries that surround the oil - rich Persian Gulf.
Document 12: Oil reserves: Based on data from OPEC at the beginning of 2013 the highest proved oil reserves including non-conventional oil deposits are in Venezuela (20% of global reserves), Saudi Arabia (18% of global reserves), Canada (13% of global reserves), and Iran (9%).
Document 13: Sial: The name 'sial' was taken from the first two letters of silica and of alumina. The sial is often contrasted to the 'sima,' the next lower layer in the Earth, which is often exposed in the ocean basins; and the nickel - iron alloy core, sometimes referred to as the ``Nife ''. These geochemical divisions of the Earth's interior (with these names) were first proposed by Eduard Suess in the 19th century. This model of the outer layers of the earth has been confirmed by petrographic, gravimetric, and seismic evidence.
Document 14: OPEC: Country Region Membership Years Population (2016 est.) Area (km) Oil Production (bbl / day, 2016) Proven Reserves (bbl, 2016) Algeria North Africa 1969 -- 40,606,052 2,381,740 1,348,361 12,200,000,000 Angola Southern Africa 2007 -- 28,813,463 1,246,700 1,769,615 8,423,000,000 Ecuador South America 1973 -- 1992, 2007 -- 16,385,068 283,560 548,421 8,273,000,000 Equatorial Guinea Central Africa 2017 -- 1,221,490 28,051 227,000 1,100,000,000 Gabon Central Africa 1975 -- 1995, 2016 -- 1,979,786 267,667 210,820 2,000,000,000 Iran Middle East 1960 -- 80,277,428 1,648,000 3,990,956 157,530,000,000 Iraq Middle East 1960 -- 37,202,572 437,072 4,451,516 143,069,000,000 Kuwait Middle East 1960 -- 4,052,584 17,820 2,923,825 101,500,000,000 Libya North Africa 1962 -- 6,293,253 1,759,540 384,686 48,363,000,000 Nigeria West Africa 1971 -- 185,989,640 923,768 1,999,885 37,070,000,000 Qatar Middle East 1961 -- 2,569,804 11,437 1,522,902 25,244,000,000 Saudi Arabia Middle East 1960 -- 32,275,687 2,149,690 10,460,710 266,578,000,000 United Arab Emirates Middle East 1967 -- 9,269,612 83,600 3,106,077 97,800,000,000 Venezuela South America 1960 -- 31,568,179 912,050 2,276,967 299,953,000,000 OPEC Total 478,498,000 12,150,695 35,221,740 1,209,103,000,000 World Total 7,618,511,000 510,072,000 80,622,287 1,650,585,000,000 OPEC Percent 6% 2% 44% 73%
Document 15: Nigeria: The name Nigeria was taken from the Niger River running through the country. This name was allegedly coined in the late 19th century by British journalist Flora Shaw, she was inspired by the name of the river, in preference to terms such as "Central Sudan". The origin of the name ''Nigeria'' came from the name of the Niger River. The word ( Niger )  is an alteration of the Tuareg name egerew n-igerewen used by inhabitants along the middle reaches of the river around Timbuktu prior to 19th-century European colonialism. Egerew n-igerewen means River of the Rivers.
ground_truth: 1971
sub_queries: Who is the Ferronigerite-2N1S named after? Answer: Nigeria
when did Nigeria become a member of opec Answer: 1971