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The distribution and geochemical significance of dibenzofurans,phenyldibenzofurans and benzo[b]napthofurans in source rocks from Niger Delta basin,Nigeria,were investigated by Rock-Eval pyrolysis and gas chromatography-mass spectrometry (GC-MS).The data obtained from the source rocks evaluation showed that the rock samples contained type Ⅱ/Ⅲ kerogen capable of generating oil and gas and were within immature to early mature stage.The relative abundance of the C0-,C1-and C2-dibenzofurans range from 1.75％ to 29.82％,27.60％ to 40.52％ and 29.66％ to 68.89％,respectively.The dibenzofurans were dominated by C2-dibenzofurans.Among the C1-dibenzofurans,2-+3-methyldibenzofuran was the most abundant in the rock samples while 1-methyldibenzofuran appeared to be the least.The relative abundance of benzo[b]naphtho[1,2-d]furan ([1,2]BNF),benzo[b]naphtha[2,1-d]furan ([2,1]BNF) and benzo[b]naphtha[2,3-d]furan ([2,3]BNF) in the rock extracts range from 12.01％ to 52.58％,32.61％ to 75.21％ and 10.27％ to 52.43％.The wide range of values recorded for the three isomers of benzo[b]napthofurans in the samples suggest source rocks formed from mixed organic matter.Among the phenyldibenzofuran isomers,4-phenyldibenzofuran was the most abundant while 1-phenyldibenzofuran was the least.Phenyldibenzofuran ratio-1 (PhFR-1) and phenyldibenzofuran ratio-2 (PhFR-2) values range from 0.13 to 1.20 and 0.11 to 2.11,respectively.The results showed that the relative abundance of PhFR-1 and PhFR-2 increase gradually with increasing burial depth and maturity (VR0 ≤ 0.77％,MPI-1 ≤ 0.62,Tmax ≤ 443 ℃),and have a good correlations with calculated vitrinite reflectance,MPI-1 and maximum Temperature (Tmax).This range of values suggested immature to early mature source rocks.The source rocks were found to have shale and coal lithologies and deposited in a lacustrine/fluvial/deltaic settings within immature to early mature stages based on the distribution of dibenzofurans,phenyldibenzofurans and benzo[b]naphthofurans in the source rocks.This study showed that dibenzofurans,phenyldibenzofurans and benzo[b]naphthofurans were effective in determining the origin,depositional environment and thermal maturity of source rocks in Niger Delta basin,Nigeria.