زمين شيمي، خاستگاه و بررسي رفتار عناصر كمياب در لاتريت نيكل چاه غيب، قادر آباد، استان فارس

Geochemistry, genesis and behavior of the rare elements in Chah-Gheib laterite deposit, Ghader Abad, Fars Province

ﮐﺎﻧﺴﺎرﻻﺗﺮﯾﺖ ﭼﺎه ﻏﯿﺐ ﺗﺤﺖ ﺗﺄﺛﯿﺮ ﻓﺮاﯾﻨﺪﻫﺎي ﻫﻮازدﮔﯽ ﭘﺮﯾﺪوﺗﯿﺖﻫﺎي ﺳﺮﭘﺎﻧﺘﯿﻨﯽ ﺷﺪه ﻣﺮﺑﻮط ﺑﻪ ﻣﺠﻤﻮﻋﻪ اﻓﯿﻮﻟﯿﺘﯽ- رادﯾﻮﻻرﯾﺘﯽ ﻧﯿﺮﯾﺰ ﺗﺸﮑﯿﻞ ﺷﺪه اﺳﺖ ﮐﻪ در ﺑﺨﺶ زﯾﺮﯾﻦ آﻫﮏ دوﻟﻮﻣﯿﺘﯽ ﺟﻬﺮم ﺑﻪ ﺳﻦ اﺋﻮﺳﻦ ﻗﺮار دارد. از ﭘﺎﯾﯿﻦ ﺑﻪ ﺑﺎﻻ ﺷﺎﻣﻞ ﭘﺮﯾﺪوﺗﯿﺖﻫﺎي ﺳﺮﭘﺎﻧﺘﯿﻨﯽ، زونﻫﺎي اﻧﺘﻘﺎﻟﯽ، ﻟﯿﻤﻮﻧﯿﺖ، ﻫﻤﺎﺗﯿﺖ و ﻻﺗﺮﯾﺖ ﻣﯽﺑﺎﺷﺪ. ﺑﺮ اﺳﺎس ﻧﺘﺎﯾﺞ ﮐﺎﻧﯽ ﺷﻨﺎﺳﯽ، XRD و EPMAﮐﺎﻧﯿﻬﺎي ﻫﻤﺎﺗﯿﺖ، ﮔﻮﺗﯿﺖ، ﮐﻮارﺗﺰ، ﻣﻮﻧﺖ ﭘﺎﻟﯿﮕﻮرﺳﮑﯿﺖ و اﻟﯿﻮﯾﻦ از ﮐﺎﻧﯽﻫﺎي اﺻﻠﯽ ﺳﺎزﻧﺪه اﯾﻦ ﮐﺎﻧﺴﺎر ﻣﯽﺑﺎﺷﻨﺪ. ﻫﻤﭽﻨﯿﻦ ﺑﺎ ﻣﻄﺎﻟﻌﻪ EPMA ﻣﺸﺨﺺ ﺷﺪ، ﻃﻼ در زون ﻟﯿﻤﻮﻧﯿﺖ ﺑﻪ ﻫﻤﺮاه ﮐﺎﻧﯿﻬﺎي ﺳﯿﻠﯿﺲ ﯾﺎﻓﺖ ﻣﯽ ﺷﻮد. ﺑﺮ اﺳﺎس ﻧﺘﺎﯾﺞ آزﻣﺎﯾﺸﺎت زﻣﯿﻦ ﺷﯿﻤﯽ )ICP-MS(، ﺑﯿﺸﺘﺮﯾﻦ ﻣﻘﺪار ﻧﯿﮑﻞ )ppm( 10870 در زون ﻻﺗﺮﯾﺖ و ﮐﻤﺘﺮﯾﻦ ﻣﻘﺪار )ppm( 2066 در زون اﻧﺘﻘﺎﻟﯽ ﻣﯽﺑﺎﺷﺪ. ﺑﺮرﺳﯽ ﻫﻤﺒﺴﺘﮕﯽ ﺑﯿﻦ ﻋﻨﺎﺻﺮ ﻧﺸﺎن ﻣﯿﺪﻫﺪ ﮐﻪ ﻧﯿﮑﻞ داراي ﻫﻤﺒﺴﺘﮕﯽ ﻣﺜﺒﺖ ﻗﻮي ﺑﺎ ﻋﻨﺼﺮ آﻫﻦ ﻣﯽﺑﺎﺷﺪ ﮐﻪ ﺧﻮد ﮔﻮاﻫﯽ ﺑﺮ ﺣﻀﻮر ﻋﻨﺼﺮ ﻧﯿﮑﻞ در اﮐﺴﯿﺪ ﻫﺎي آﻫﻦ ﺑﻮده اﺳﺖ. ﺑﺮ اﺳﺎس ﻧﻤﻮدار ﺳﻪ ﺗﺎﯾﯽ Al2O3-Fe2O3-SiO2 درﺻﺪ ﻫﻮازدﮔﯽ در ﮐﺎﻧﺴﺎر ﭼﺎه ﻏﯿﺐ درﺟﻪ ﻗﻮي ﺗﺎ ﻣﺘﻮﺳﻂ ﻣﯽ ﺑﺎﺷﺪ. ﻣﻘﺪار ﻋﻨﺎﺻﺮ ﻧﺎدر ﺧﺎﮐﯽ از ﺳﺮﭘﺎﻧﺘﯿﻨﯿﺖ )ﺳﻨﮓ ﻣﻨﺸﺎ( )ppm( 8/97 ﺑﻪ ﺳﻤﺖ زون ﻻﺗﺮﯾﺖ )ppm(18/41 روﻧﺪ اﻓﺰاﯾﺸﯽ را ﻧﺸﺎن ﻣﯽدﻫﻨﺪ.. ﻣﻘﺪار *Ce/Ce از 0/65 درزون ﺳﺮﭘﺎﻧﺘﯿﻨﯿﺖ ﺗﺎ 1/56 در زون ﻻﺗﺮﯾﺖ ﺗﻐﯿﯿﺮ ﻣﯽﮐﻨﺪ. ﻣﻘﺪار*Eu/Eu ﮐﻪ از 0/13در ﺳﺮﭘﺎﻧﺘﯿﻨﯿﺖ ﺗﺎ 0/98در زون ﻻﺗﺮﯾﺖ ﺗﻐﯿﯿﺮ ﻣﯽﮐﻨﺪ ﻧﺸﺎن دﻫﻨﺪه ﺑﯽﻫﻨﺠﺎري ﺗﻘﺮﯾﺒﺎ ﻣﻨﻔﯽ ﯾﻮروﭘﯿﻢ ﺑﻮده و ﻧﺸﺎن دﻫﻨﺪه اﮐﺴﯿﺪي و اﺳﯿﺪي ﺑﻮدن ﻣﺤﯿﻂ ﺗﺸﮑﯿﻞ ﻻﺗﺮﯾﺖ ﻣﯽﺑﺎﺷﺪ. ﺑﺮاي ﭘﯽ ﺑﺮدن ﺑﻪ ﺧﺎﺳﺘﮕﺎه از ﻧﻤﻮدار ﺳﻪﺗﺎﯾﯽ Zr-Ga-Crاﺳﺘﻔﺎده ﺷﺪ ﮐﻪ ﻧﺸﺎندﻫﻨﺪه آن اﺳﺖ ﮐﻪ ﻻﺗﺮﯾﺖ ﭼﺎه ﻏﯿﺐ در ﻣﺤﺪوده ﺳﻨﮓﻫﺎي آذرﯾﻦ اوﻟﺘﺮاﻣﺎﻓﯿﮏ ﻗﺮار دارد.

The Chah-Gheib laterite deposit is formed as a result of the weathering of serpantinized peridotite of the radiolarite-ophiolite Neyriz complex. occurs in the lower part of the dolomitic limestone of the Eocene Jahrum Formation which from the bottom to top includes; serpantinized peridotite transitional, limonite, hematite and laterite zones. Based on the mineralogical investigations coupled withXRD and EPMA results, the main minerals consist of hematite, goethite, quartz montmorillonite, palygorskite and olivine. . Based investigations EPMA results Gold is accompanied with silica minerals in the limonite zone. Based on the geochemical analysis (ICP-MS), the highest content of nickel is 10870 (ppm), which is related to the laterite zone and lowest one is 2066 (ppm), related to the transitional zone. There is a positive correlation coefficient between nickel and iron, which reflecting the presence of nickel in iron oxides. Based on Al2O3-Fe2O3-SiO2 diagram, the weathering in the Chah-Gheib laterite deposit ranges from strong to middle. Based on the geochemical analysis and correlation coefficient The rare earth elements show an increasing trend from serpentinite (8.97 ppm) to the laterite zones (18.41ppm. The amounts of Ce/Ce* range from 0.65 to 1.56 in the serpentinite and laterite zones, respectively. This indicates oxidized acidic conditions for the laterite zone. The Eu/Eu* increases from serpentines (0.13) to laterite zone (0.98) ref