Numerous studies on source rocks around the world has proven the Cretaceous era to be a significant stratigraphic interval for petroleum formation.As a Cretaceous basin located within the southern coast of Ghana,Tano basin is among the key hydrocarbon spot in West Africa.Previous hydrocarbon assessment of the Tano basin primarily focused on the bulk geochemical properties of lower Cretaceous rocks（Turonian-Albian）and trace element distribution in the basin’s oil.Up until now,there is no comprehensive information about the organic geochemistry and petrology of each sedimentary bed.This has placed a limitation on our current understanding of the Petroleum systems in the Tano basin.Using various bulk and specific geochemical parameters,organic petrological and a 1D basin modeling technique,an in-depth information about the hydrocarbon potential,sedimentary environments,organic matter type,lithology,oil-oil correlation,and oil-source correlation of the Paleocene to Albian strata,of the Tano basin has been established in this study through the sampling of sixty rock cuttings from three discovery wells and six oil samples from the basin’s Jubilee and TEN field.Integrating geochemical,maceral composition,and basin modelling results,the rocks in the Tano basin have been put into four main groups,namely;1)Mature Marine Source rocks;comprising of the Turonian,Cenomanian and Albian strata claystones 2)Potential marine source rocks;representing the Paleocene unit 3)Potential Non-marine Source rocks consisting of Lower Campanian-Coniacian horizon claystones and 4)Immature Non-Marine Source rocks comprising of the Maastrichtian strata.The Cenomanian claystones,featuring Type II kerogen is the richest strata in the Mature Marine group with an average TOC of 3.28 wt./%;S1+S2:～10.85 mg/g;HI:～251 mg/g;Tmax～442 ℃;followed by the Turonian Type II kerogen S.R with an Av.TOC of 1.76 wt./%;S1+S2of 5.43 mg/g,HI:～242 mg/g;and Tmax:437 ℃.The Type II and III Albian rocks being the organic lean sequence in this group has an Av.TOC of～1.1 wt./%;S1+S2:2.38 mg/g;HI:117 mg/g;and Tmax:440 ℃.Both biomarker and petrographic data supports that,lower organisms mainly algae and foraminifera and some land plants contributed towards the organic matter formation in these rocks.The ratios of C3122S/22S+22R,C2920S/20S+20R,and Ts/（Ts+Tm）in these rocks are≥O.60,≥0.3,and≥0.4 respectively corresponding to the lower mature phase（with an estimated VRo.of≥0.63～0.75%）.The marine anoxic redox sedimentary environment for these rocks was supported by their low Pr/Ph ratio,preservation of B-Carotane,elevated C23tricyclic terpane peak in the terpenoids series,high abundance of dolomites,pyrites,presence of marine Foraminiferas,and an averageδ13CSatvalues of 28.24at a range of 28.63 to 27.62.The potential non-marine source rocks（Santonian-Coniacian）comprising of Type II kerogen have an average TOC of 1.68 wt./%and 2.33;S1+S2:～7.14mg/g and 10.79 mg/g;HI:～303 mg/g and 280 mg/g;and Tmaxof～437 ℃ and～435 ℃,respectively.Phytoplankton and some little land plant contribution are the main biological precursors for the organic matter in the Coniacian and Santonian strata and they are represented by the high predominance of C27peak in their regular sterane distribution pattern,presence of vitrinite and semifusinites in their maceral composition.The non-marine oxidizing sedimentary environment for the Santonian-Coniacian rocks was proven by their relatively high average Pr/Ph ratios（＞2）and high C24Te T/C26TT ratios,presence of limonite and higher negativeδ13CPDB（‰）Sataverage values of-35.69 and-36.76 respectively.The ratios of molecular parameters C3122S/（22S+22R）,C2920S/（20S+20R）,Ts/（Ts+Tm）,C23/C21TT in the potential source rocks is slightly lower than that of the mature marine source rocks with an estimated VRo of 0.55-0.62%.The Paleocene and Maastrichtian strata possess an average TOC of 2.18 wt./%and 1.89 wt./%,S1+S2:～4.62 mg HC/g rock and 6.44mg HC/g rock;HI:～175 mg HC/g TOC and 211 mg HC/g TOC and Tmax:～429 ℃ and 410℃.The ratios of C2920S/（20S+20R）,C3122S/22S+22R,and Ts/（Ts+Tm）in the immature source rocks are＜0.3,＜0.5,and＜0.4 respectively conforming to vitrinite reflectance less than 0.55%.Additionally,The Paleocene strata has similar organic matter source and sedimentary environment as the Lower Cretaceous sources rocks whereas the Maastrichtian strata also exhibit similar origin as the Santonian and Coniacian rocks as shown in their biomarker distribution andδ13CPDBvalues.The hydrocarbon potential of the source rocks in the Tano basin as ranked from the highest to the lowest is in the order:Cenomanian＞Albian＞Turonian＞Coniacian＞Santonian＞Paleocene＞Maastrichtian.Regarding oil geochemistry and Oil to Source correlation,the molecular distribution and ratios of Pr/Ph,B-Carotane,OEP,CPI,C3122S/（22S+22R）,C2920S/（20S+20R）,regular sterane distribution pattern andδ13CPDB（‰）Satandδ13CPDB（‰）Arovalues confirms that the oil from both jubilee and TEN field have a common origin as marine anoxic environment with high algae input most likely to be originated from lower mature OAE2 source rocks（Turonian,Cenomanian and Albian）as shown by theirδ13CPDB（‰）Satandδ13CPDB（‰）Arovalue,unusual predominance of C23TT and C28to C31Tricyclic terpane in the Terpenoids series and the cross plot of(C19+C20)/(C23+C24)TT;(C19+C20)/C23TT;and C23/C21TT).The oils exhibit slight differences in the Ts/（Ts+Tm）ratio which may be attributed to different migration distances from the source.In conclusion,results from biomarker geochemistry,maceral composition and basin modeling affirm that the hydrocarbon potential of the source rocks in the Tano basin is generally controlled by burial depth.The results revealed that most of the organic rich marine anoxic Type II and humic kerogen Turonian-Albian rocks are already in the early-peak mature hydrocarbon generation stage and they constitute the most effective source rock interval in the Tano basin with the highest potential for oil and gas.With sufficient burial（approximately,3500-4000m deep）,especially in the southern part of the basin,the good Type II marine anoxic Paleocene claystones with similar characteristics as the Lower.Cretaceous rocks and the moderately rich non-marine Type II lower Campanian-Coniacian claystones could be a potential source rock interval in the Tano basin.