zone = Cameroun
Données géochimiques des échantillons de type "CAB" du domaine "Afrique" dans la zone "Cameroun" :
| Centre
Paris-Saclay
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Univ. Paris-Saclay

Données géochimiques des échantillons de type "CAB" du domaine "Afrique" dans la zone "Cameroun" :



Jean-Louis JORON et Michel TREUIL
Laboratoire Pierre Süe
Centre d’Études de Saclay – France
Laboratoire Pierre Sue

Les analyses en éléments traces fournies ci-dessous concernent des roches prélevées par carottage terrestre, dragage ou forage océanique profond. Elles ont toutes été réalisées par la même technique : l’analyse par activation neutronique purement instrumentale(*) et en utilisant les mêmes données standards de calibration. La technique a été développée au Laboratoire Pierre Süe (CE Saclay).
*sans nécessité de mise en solution, source d'imprécisions dans le cas d'analyse de roches, du fait de la présence de minéraux "non solubles".

Référence :

Lexique :

  • CAB : calk-alkaline basalt / Basaltes calco-alcalins
  • CFB (Continental Flood Basalt) ou Trapps,
  • MORB : Middle Oceanic Ridge Basalt / Basaltes des rides médio-océaniques
  • OIB : Ocean Island Basalt / Basaltes des îles océaniques intraplaques
  • Subduction : roches issues de zones de subduction, lieu de destruction de la croûte océanique. Lorsqu’une plaque se heurte à une autre plaque, elle retourne dans le manteau en formant une zone de suduction.
  • Volcanisme d’arc insulaire : les arcs insulaires, répartis en bordure des zones de subduction, résultent de la formation de nouvelle croûte similaire à celle des continents
  • Volcanisme arrière-arc : en arrière d'un arc insulaire, formation de petits bassins dits "arrière-arcs". L’ouverture de ces bassins serait le signe précurseur de la formation d’un bassin océanique.
  • Ophiolite : roches correspondant à la lithosphère océanique, charriée sur un continent par obduction lors de la convergence de deux plaques lithosphériques
  • Magmatisme ancien Magmatisme antérieur à la tectonique des plaques actuelle (antérieur à 500 millions d'années)
    • Archéen : éon précédent le Protérozoïque (de - 4 à - 2.5 milliards d’années).
    • Basalte : roche magmatique rapidement refroidie. C'est le constituant principal de la croûte océanique.
    • Protérozoïque : éon (ou période géochronologique) de la fin du précambrien (de - 2,5 à - 0,541 milliards d’années).
    • Komatiite : roches témoins direct du manteau archéen à olivine et pyroxène.
    • Gabbro : roche magmatique, constituant principal de la couche inférieure de la croûte océanique.
    • Ophite : roche magmatique intermédiaire entre le gabbro et le basalte, qui résulte de la cristallisation d'un magma sans contact avec l'atmosphère .
  • Birimien : âge stratigra^phique équivalent à l'époque paléoprotérozoïque du précambrien (-2.5 à -1.6 Milliards d'années).
  • Les roches de cet âge morceau de croûte terrestre (terrane), essentiellement composé de granites alcalins, agrégé à l'aire continentale sud (craton) de l'Afrique de l'Ouest, âgé de
  • Shale : roche sédimentaire n'ayant pas subi de transformation (métamorphisme) et censée représenter la composition de la croûte continentale primitive.
  • Chondrite et achondrite : météorites avec ou sans "chondres", petites billes composées de silicates, traduisant leur origine primitive ou issue d'astéroïdes.
Echelle des temps géologiques du BRGM.

NB : les références des échantillons suivies de "(d)" indiquent de nouvelles analyses sur des échantillons, précédemment analysés.

TypeDomaineZoneLieuMissionMethode, Age, Eruption, CommentaireFichier localisationÉchantillon / SampleScCrCoNiRbSrZrSbCsBaLaCeNdSmEuTbYbHfTaThUWAsMoBrAu (ppb)Ag (ppb)ZnNa (%)Fe (%)
CABAfriqueCamerounAdamaouaCA1W31.7024561.0012237.49693320.07000.320044745.180.87.363.3200.972.167.0005.2005.1001.52.210.46
CABAfriqueCamerounAdamaouaCA1W(d)32.5026562.1011938.77373340.10600.360045647.2198.39.573.3000.992.047.0205.3105.2001.61.073.751.271.41.697.37
CABAfriqueCamerounAdamaouaCA2L27.6017747.00936811784550.08000.5500612621019.614.0801.22.458.9007.1006.80022.739.46
CABAfriqueCamerounAdamaouaCA2L(d)27.4018945.809167.99533750.13400.510059462.09125.811.73.8501.202.368.3006.9106.8301.970.934.750.482.32.639.27
CABAfriqueCamerounAdamaouaCA1X30.0055766.00479789992910.06000.780044748.8886.82.7400.871.555.5004.6005.6003.81.679.16
CABAfriqueCamerounAdamaouaCA1X(d)30.1063464.8046579.76302620.10200.750044049.4298.28.352.6900.892.065.5604.5305.5701.410.592.320.241.51.629.03
CABAfriqueCamerounAdamaouaCA4E5.8057.409.573.512843860.12400.6100154488.6118711.94.6001.222.78.63010.0108.5102.331.392.312.04.063.93
CABAfriqueCamerounBambuto3118.801431.8015.841.69844550.13500.430048056.04143.511.93.7701.202.669.5606.9506.7902.080.91.154.862.211.11253.178.80
CABAfriqueCamerounBambuto3271.2242.113.12959314271.06003.5500104.269.39114.20.4900.222.3522.7705.54046.50014.60.79.15.4716.00.81057.231.92
CABAfriqueCamerounBambuto21124.9042952.3026132.79502510.14000.410072137.2988.58.242.8100.891.895.1204.1304.4601.220.70.953.42.212.51152.268.20
CABAfriqueCamerounBambuto77.60100.492.21622818500.34001.000073.2266.256133.14.4303.7811.940.90024.62038.5007.960.70.416.13.83103.764.73
CABAfriqueCamerounBambuto3074.13174.662.52082296190.02401.24001387191.838117.11.8500.941.1914.0001.44051.5601.630.20.112.050.341.91151.522.39
CABAfriqueCamerounBambuto3161.1741.980.26117.8216830.21001.1600159999.317710.72.7801.143.6613.4009.72013.0902.780.61.374.30.79634.63.52
CABAfriqueCamerounBambuto32321.4010034.8047.639.912312510.08600.780082044.395.99.383.3101.012.175.5604.5404.3201.210.50.654.272.432.11263.298.40
CABAfriqueCamerounBambuto32127.3018044.5082.429.213532360.06700.3500105642.995.29.923.6001.031.955.0604.0103.8801.010.62.880.82.21142.49.03
CABAfriqueCamerounBambuto30934.2028257.4012727.37163110.08500.280030839.7789.89.513.0001.052.196.9304.4604.0501.140.50.672.340.781.71251.969.94
CABAfriqueCamerounBambuto32023.9027144.5013549.511032610.09600.500075452.42106.99.123.1100.952.085.5105.0805.9501.430.91.098.616.315.11232.938.06
CABAfriqueCamerounBambuto31223.4010138.106136.511702510.08200.390075443.9892.49.343.3401.012.095.8304.2404.3201.134.390.571362.568.58
CABAfriqueCamerounBambuto32218.507229.7030.23912292950.09700.450089651.9611010.03.4101.062.416.5505.3105.2101.550.91.13.972.981383.58.01
CABAfriqueCamerounBambuto4713.4070.410.489.31309000.13000.32001872102.4215.417.55.3201.885.2319.1706.57011.2202.531.00.76.81.21473.724.55
CABAfriqueCamerounBambuto32813.103220.5020.981.911294260.17000.930086769.1136.79.743.0100.962.588.6507.26010.4302.451.21.449.276.021.1784.096.28
CABAfriqueCamerounBambuto6729.5042958.8030326.310242070.06300.650052235.6574.48.512.9900.891.784.2103.6103.4600.932.30.952.50.42811.71052.058.93
CABAfriqueCamerounBambuto30410.602714.2010.9167.5423170.01402.23001780136.727614.72.9500.941.568.8802.61020.0602.582.670.471931412.794.60
CABAfriqueCamerounBambuto2127.30240.490.1143.1215420.38002.64005222744227.15.2402.859.5632.90023.70028.0006.791.238.771772514.953.41
CABAfriqueCamerounBambuto32525.9082682.1051913.710971770.05300.420080638.8478.67.862.7400.821.63.9204.1504.1600.931.60.632.1301051.339.88
CABAfriqueCamerounBambuto3310.70217.415.21953057170.00811.7400149327642226.12.9601.82.5415.6903.03046.4002.411.70.350.792491312.493.55
CABAfriqueCamerounBambuto30226.907546.0048.724.68632290.08200.170041237.5482.58.672.8600.902.025.5003.7703.3200.950.632.051551.01111.979.95
CABAfriqueCamerounBambuto596.9380.221.1141.515570.42000.30004127641331.65.28038.0632.80023.28027.8106.220.9971241094.93.23
CABAfriqueCamerounBambuto3242.3662.650.1115.9886220.29000.9900127895.81718.82.6800.832.9512.19012.01015.5804.251.7512.011.6841085.13.80
CABAfriqueCamerounBambuto3116.6570.320.58123.5310610.32001.5200401673382.972.9602.277.6222.67017.00019.5505.220.781.692122144.783.61
CABAfriqueCamerounBambuto3170.692.50.660.128314612850.84002.2900104120.61865.490.7300.684.2122.41013.78038.33010.63.25.9612.318.41271.41166.612.25
CABAfriqueCamerounBambuto31021.6031148.10238369452490.09600.420075339.5482.37.922.7800.831.95.1504.2104.7301.271.70.963.731.5912.71132.638.23
CABAfriqueCamerounBambuto30523.3026145.8017836.914732210.08500.550083546.397.29.593.3400.951.95.1004.9104.8501.310.613.652.251081.21112.938.12
CABAfriqueCamerounBénouéNC4P23.2022050.8019730.79423290.13801.170065871.36132.710.53.2301.081.777.6507.2408.5002.11.255.891.611.23.38.92
CABAfriqueCamerounEtindéC1K24.404933.009.18121317760.21000.770090621036720.27.9001.873.9812.66018.09022.8005.123.158.62
CABAfriqueCamerounEtindéM4625.008839.00254222468930.58000.3000106826646024.210.1002.484.4814.80024.11017.7903.871.1810.11
CABAfriqueCamerounKapsikiCN1G21.507938.704427.89303260.08200.240042050.13105.710.93.9001.232.697.5404.7004.5101.240.853.331.443.5110.00
CABAfriqueCamerounKapsikiCN1D27.6026450.9022832.311663740.09300.400050056.59120.611.23.8801.192.247.8206.1706.6902.031.214.922.1442.819.29
CABAfriqueCamerounMt CamerounMC00115.002324.1014.349.912084610.20000.630062591.518713013.84.2101.312.839.2508.93010.4202.621.66.554.953.51001083.656.91
CABAfriqueCamerounMt CamerounMC00224.8016140.308136.810063700.16000.470046669.5143.710411.23.4901.082.377.7006.6407.8902.11.21.254.653.815.11341103.158.32
CABAfriqueCamerounMt CamerounC8N33.6044652.1017735.510063840.14800.408045075.5155.612.23.4901.112.418.4406.9907.8402.111.51.253.573.712.51132.69.49
CABAfriqueCamerounMt CamerounC8N(d)32.9043250.8017634.99923730.13500.410044075.7152.912.03.4901.102.358.2806.8507.7202.151.11.353.83.622.31071122.649.33
CABAfriqueCamerounMt CamerounCA8C1B21.101934.004940.410994270.16300.464051980.3163.112.43.6701.192.728.6307.6408.6602.281.11.624.214.712.81033.358.04
CABAfriqueCamerounMt CamerounCA8C1B(d)20.801633.504739.910874080.16200.478051279.216112.43.7701.182.658.5907.5308.5102.431.01.324.094.432.61223.317.94
CABAfriqueCamerounMt CamerounC10W26.301541.105531.59573490.12700.369040262.7128.410.73.2101.062.397.5305.8206.5801.761.11.053.123.684.41102.849.09
CABAfriqueCamerounMt CamerounC10W(d)26.901242.505732.89903300.12600.387041563.513111.03.2901.092.427.8005.9706.7601.791.263.263.6641312.929.29
CABAfriqueCamerounMt CamerounC10F18.70930.703041.311073980.15300.496051977.6159.512.63.7801.222.738.8407.5608.3902.311.11.384.434.232.1701073.497.71
CABAfriqueCamerounMt CamerounC10F(d)18.50630.70314110974260.14000.487051278.3158.312.73.8101.22.758.6807.4908.3402.331.41.434.453.832.2851243.487.66
CABAfriqueCamerounMt CamerounC1D24.3011939.0055358033700.11000.380041363.31068.73.5501.11.997.6806.3306.6101.793.138.70
CABAfriqueCamerounMt CamerounC1E24.1011738.0056288223820.10000.300040361.41058.83.5801.12.637.6606.1306.7601.812.588.53
CABAfriqueCamerounMt CamerounC1F33.5042156.00248179333080.05000.240026639.6706.732.9400.891.935.7703.8204.1301.192.048.87
CABAfriqueCamerounMt CamerounC1F(d)33.8047456.8025319.96902720.06000.220028839.986.38.252.8500.891.875.8803.9304.3301.192.779.02
CABAfriqueCamerounMt CamerounC1N41.0030151.001442910953470.12000.3900394671079.233.6701.042.467.5006.1406.82022.239.26
CABAfriqueCamerounMt CamerounC5B34.1046254.002063412864120.11000.3500410731409.64.1301.032.747.8707.4807.1201.962.579.72
CABAfriqueCamerounMt CamerounC5M28.9090370.00477159541690.06000.150021729.8585.32.2600.721.654.3603.3003.2600.841.889.10
CABAfriqueCamerounMt CamerounC5M(d)29.1083369.6043916.85352100.05500.220024129.7367.16.592.3300.731.54.6903.0803.4400.880.672.21.899.13
CABAfriqueCamerounMt CamerounC5W32.0039553.001844314374570.12000.47004668415910.74.3701.133.048.7608.7308.2602.272.7910.00
CABAfriqueCamerounMt CamerounNA233.5030750.0015835.714004140.12000.2500438741219.73.6201.212.378.2306.8607.8502.152.579.39
CABAfriqueCamerounMt CamerounN4H32.6035252.6018325.111702560.07000.32003885985.52.757.60012.886.5205.3906.6801.651.78.79
CABAfriqueCamerounMt CamerounN4H(d)31.9041153.3019425.38262500.06300.240036961.2120.79.352.7900.892.026.4605.4206.5301.670.72.880.597.91.848.76
CABAfriqueCamerounMt CamerounN4J28.6026244.6013027.510743380.10000.410034253807.62.99013.086.5205.2405.8601.492.378.30
CABAfriqueCamerounMt CamerounN4U26.3010239.0038438434100.12000.57004937112110.23.8801.22.888.5807.0009.1102.452.628.69
CABAfriqueCamerounMt CamerounN4U(d)27.908640.804142.69644070.13100.560051371161.512.84.0301.252.938.9107.2209.4202.490.715.481.221.42.628.99
CABAfriqueCamerounMt CamerounN6P23.606043.00393912353910.13000.22003916512010.34.1101.262.598.4706.3606.4002.022.39.79
CABAfriqueCamerounMt CamerounN4V17.706431.002145.710434760.20500.510055286.52175.612.84.1001.252.818.7808.5309.7202.561.213.873.671.93.547.96
CABAfriqueCamerounMt CamerounNG2730.3026547.001292710033720.08000.390042258988.93.5001.13.087.5305.8306.5301.482.118.78
CABAfriqueCamerounMt CamerounNG2228.1012843.0064267303110.06000.280034650908.13.3201.052.717.1905.0605.8301.462.368.85
CABAfriqueCamerounMt CamerounNG22(d)29.7013844.607124.38413510.07200.230036351.7112.810.43.5801.102.77.3105.2705.9801.530.62.250.891.42.469.17
CABAfriqueCamerounMt CamerounM671.5856.100.2517649527660.23002.65003219186246524.81.3200.371.767.6907.25013.0009.730.80.595.0410.82.5672136.854.06
CABAfriqueCamerounMt CamerounM10026.10844.801146.428716790.62000.2100656472.7112437549.314.6803.414.8614.90047.80063.7009.435.894.461.3222571852.3810.97
CABAfriqueCamerounMt CamerounM8316.201228.601693.328817160.27000.8500124125547215926.57.7401.984.7312.10023.70023.0006.371.82.243.563.4711273.637.74
CABAfriqueCamerounMt CamerounM11314.30529.901021961355770.02802.990045824143715023.16.6901.683.979.88018.90021.7405.430.635.322.261.4681323.227.21
CABAfriqueCamerounMt CamerounM182.7057.200.218659998860.67002.44002948122.615330.25.652.1100.7749.9207.0006.0809.681.02.164.46104.5941896.684.45
CABAfriqueCamerounOkuLJ0130.2039355.6024728.98551770.06900.470063032.5672.437.97.722.7300.851.814.8303.6103.7000.980.30.862.491.73581012.079.67
CABAfriqueCamerounOkuL7017.4055.500.589.53277700.14000.260080093197.78216.03.7601.644.517.2006.6708.2702.360.41.2562.0481593.596.13
CABAfriqueCamerounOkuLJ0826.0020251.9015632.28812150.07900.460059341.6787.339.78.683.1000.955.4704.3604.5601.20.60.893.141.851.11192.939.41
CABAfriqueCamerounOkuLJ04C28.7019651.001112614382210.05200.260052836.2581.343.59.023.4300.891.65.1203.5203.0200.90.432.10.721132.4610.11
CABAfriqueCamerounOkuLJ04K23.9018846.6013465.611162710.08000.520068950.5910851.910.73.6901.102.116.6205.3305.3301.411.40.93.481.261282.959.40
CABAfriqueCamerounOkuLJ07J0.54480.110.5142.128100.31001.470017217334213824.30.6102.588.419.91011.67021.4605.022.90.540.466723.190.41
CABAfriqueCamerounOkuL7724.8036254.6028031.28132240.06500.370055039.583418.393.0900.962.255.0104.2704.3701.060.50.672.310.361041.829.26
CABAfriqueCamerounOkuLJ03JJ27.3052658.7034943.99572260.07000.500055939.382.9408.322.9100.911.785.1304.2404.3101.10.922.30.931131.759.41
CABAfriqueCamerounOkuL5626.1018553.5014435.99202510.07900.490063445.39441.59.183.2600.991.945.8504.6604.9501.270.91.013.792.71252.569.57
CABAfriqueCamerounOkuL4120.9036745.4021828.312342490.07600.240069344.794.639.68.472.9800.831.685.4504.2204.3201.290.30.782.91.431142.588.27
CABAfriqueCamerounOkuL7129.3054055.8026520.912501960.06900.240044934.779.143.59.093.2700.931.74.7003.3902.9000.860.642.250.561081.918.77
CABAfriqueCamerounOkuL918.70534.901.636.76904030.10000.180088063.7137.265.713.74.4201.453.419.6105.3405.3101.530.50.584.351633.149.13
CABAfriqueCamerounOkuL7323.6014942.108642.69393320.14400.480055857.6114.445.89.963.3301.062.367.1005.6206.3101.881.11.344.161.941273.148.76
CABAfriqueCamerounOkuL2534.7033280.9032011.712121510.02700.140032124.456.835.97.232.8400.771.424.0302.6901.5700.4420.251.11161.9611.12
CABAfriqueCamerounOkuL45.9650.100.289.61.89420.19701.410083.6133.727.111222.05.0902.315.5620.60011.15012.0102.871.30.291.521.6984.882.71
CABAfriqueCamerounOkuLJ02K24.7018847.9013251.711463340.10000.520071654.2113.84811.33.7601.162.327.1205.6205.7901.540.90.894.242.951.21273.39.73
CABAfriqueCamerounOkuLJ05K0.91210.201.45.82112481.41000.660011.865.82855717.21.2602.558.1629.60014.94024.5103.866.51.091.840.2870.101.14
CABAfriqueCamerounOkuLJ01G20.40236.3026.438.513533010.08900.300065147.2103.14910.13.4301.032.146.4804.7604.7301.370.723.250.790.71182.578.67
CABAfriqueCamerounOkuLJ04GG27.0065763.2041726.78922210.05600.360049633.472.833.47.752.6000.821.574.6103.5603.6200.950.692.271.91.31072.49.28
CABAfriqueCamerounOkuL1050.90590.050.3134.2716710.39000.760014.6157.222512122.60.7202.347.9535.40015.52025.7705.091.41.199.10.9951764.352.93
CABAfriqueCamerounOkuLJ05G25.9020051.8014928.88952350.08000.450059542.587.133.88.793.0600.961.895.6104.3704.6601.230.41.083.321.311192.599.32
CABAfriqueCamerounOkuLJ01K25.3012547.8011213.712513570.07500.450074157.8119.25511.63.5901.212.637.8506.1006.6201.640.40.982.040.460.81352.149.99
CABAfriqueCamerounOkuL4027.7028353.8021326.614942050.04500.270063737.88540.59.883.5600.981.764.6403.7003.0600.870.672.560.660.81192.59.41
CABAfriqueCamerounOkuL890.9960.051.2115.677690.19800.4700100287.22017620.13.8902.747.2616.6206.97012.6303.497.10.54.660.980763.710.68
CABAfriqueCamerounOkuL10310.8051.920.3109.2828280.16700.6300170192.12007215.54.0301.665.0917.5607.40015.2703.291.286.820.311413.544.71
CABAfriqueCamerounOkuLJ02F2.0050.100.42912.644571.20002.060043.744782328262.83.5807.0425.2103.60056.80078.50018.84.44.328.360.893633.965.11
CABAfriqueCamerounOkuL728.1019743.709427.711972550.05900.350068243.994.9469.873.4501.041.965.5104.4803.8701.120.70.83.71.91072.258.85
CABAfriqueCamerounOkuL1081.4440.050.313610710.33001.230031.8167.130114427.62.5703.037.8224.35012.74020.1205.372.03.086.220.251034.21.89
CABAfriqueCamerounOkuLJ04F2.461610.430.5120.320790.23000.270071123.329613719.41.3501.583.5348.50026.94033.9503.410.60.72.240.91363.984.82
CABAfriqueCamerounOkuL1010.7750.020.1123.210800.12400.240032.1124.858.59612.51.6101.365.7123.50012.59018.3601.420.431.541714.323.55
CABAfriqueCamerounOkuLJ04E2.0641.010.22363329941.12003.060098315.599726847.62.2006.0718.470.70032.64052.04016.32.52.73.161.222043.353.02
CABAfriqueCamerounOkuLJ09D22.5011735.405836.810712830.07500.280063142.590.1498.793.2300.941.896.1804.2004.5301.290.80.794.071.550.91142.918.28
CABAfriqueCamerounOkuLJ01P1.96821.470.21941120050.39000.64006582.7176.712010.40.6301.3710.351.10029.18041.4206.920.84.383.980.872924.163.52
CABAfriqueCamerounOkuLJ04HH12.1043.470.292.94807850.18000.5900141894.119210015.04.5801.624.6117.1007.7409.7402.751.557.20.91451573.85.62
CABAfriqueCamerounOkuL1060.8620.140.218018214930.32004.21001543.484.95713.00.5602.7310.333.00014.73025.0104.451.00.481.74553.941.63
CABAfriqueCamerounOkuLJ01E4.6320.520.2187219710.36000.270037.623750824536.02.5903.86.9446.10026.52032.3505.861.838.71.41544.854.81
CABAfriqueCamerounOkuLJ08J10.6924.284.775.81744870.12000.4900180267.71456612.54.6201.423.8311.2005.6308.4802.161.316.2711194.035.00
CABAfriqueCamerounOkuL337.3450.16179.4619840.09900.220013.3141.125814324.25.5902.283.8423.20013.91017.2802.370.50.332.451.190.7904.535.18
CABAfriqueCamerounOkuLJ09J11.0854.284.866.2864680.10800.1900187368.41468512.74.8101.423.8611.3005.6308.4102.190.40.575.751134.014.65
CABAfriqueCamerounOkuL821.7240.991297.92820230.55001.490010531.975.85.090.3700.63451.00028.73045.6007.141.72.254.771.452972.146.82
CABAfriqueCamerounOkuLJ05HH3.0550.440.22001534750.55000.44006436454735848.25.5705.3313.279.10041.80057.600136.6722.62064.515.34
CABAfriqueCamerounOkuL1001.8350.560.2123.358260.27000.590019416431015322.21.8202.285.1219.3009.58017.4204.633.50.66.54101464.071.14
TypeDomaineZoneLieuMissionMethode, Age, Eruption, CommentaireFichier localisationÉchantillon / SampleScCrCoNiRbSrZrSbCsBaLaCeNdSmEuTbYbHfTaThUWAsMoBrAu (ppb)Ag (ppb)ZnNa (%)Fe (%)

Jean-Louis JORON et Michel TREUIL
Laboratoire Pierre Süe
Centre d’Études de Saclay – France
Laboratoire Pierre Sue

Lexique :

  • CAB : calk-alkaline basalt / Basaltes calco-alcalins
  • CFB (Continental Flood Basalt) ou Trapps,
  • MORB : Middle Oceanic Ridge Basalt / Basaltes des rides médio-océaniques
  • OIB : Ocean Island Basalt / Basaltes des îles océaniques intraplaques
  • Subduction : roches issues de zones de subduction, lieu de destruction de la croûte océanique. Lorsqu’une plaque se heurte à une autre plaque, elle retourne dans le manteau en formant une zone de suduction.
  • Volcanisme d’arc insulaire : les arcs insulaires, répartis en bordure des zones de subduction, résultent de la formation de nouvelle croûte similaire à celle des continents
  • Volcanisme arrière-arc : en arrière d'un arc insulaire, formation de petits bassins dits "arrière-arcs". L’ouverture de ces bassins serait le signe précurseur de la formation d’un bassin océanique.
  • Ophiolite : roches correspondant à la lithosphère océanique, charriée sur un continent par obduction lors de la convergence de deux plaques lithosphériques
  • Magmatisme ancien Magmatisme antérieur à la tectonique des plaques actuelle (antérieur à 500 millions d'années)
    • Archéen : éon précédent le Protérozoïque (de - 4 à - 2.5 milliards d’années).
    • Basalte : roche magmatique rapidement refroidie. C'est le constituant principal de la croûte océanique.
    • Protérozoïque : éon (ou période géochronologique) de la fin du précambrien (de - 2,5 à - 0,541 milliards d’années).
    • Komatiite : roches témoins direct du manteau archéen à olivine et pyroxène.
    • Gabbro : roche magmatique, constituant principal de la couche inférieure de la croûte océanique.
    • Ophite : roche magmatique intermédiaire entre le gabbro et le basalte, qui résulte de la cristallisation d'un magma sans contact avec l'atmosphère .
  • Birimien : âge stratigra^phique équivalent à l'époque paléoprotérozoïque du précambrien (-2.5 à -1.6 Milliards d'années).
  • Les roches de cet âge morceau de croûte terrestre (terrane), essentiellement composé de granites alcalins, agrégé à l'aire continentale sud (craton) de l'Afrique de l'Ouest, âgé de
  • Shale : roche sédimentaire n'ayant pas subi de transformation (métamorphisme) et censée représenter la composition de la croûte continentale primitive.
  • Chondrite et achondrite : météorites avec ou sans "chondres", petites billes composées de silicates, traduisant leur origine primitive ou issue d'astéroïdes.
Echelle des temps géologiques du BRGM.

NB : les références des échantillons suivies de "(d)" indiquent de nouvelles analyses sur des échantillons, précédemment analysés.

 

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