An earlier study of GC-MS analysis on bitumen samples from the Agbabu area in Western Niger Delta showed the significant presence of gammacerane and no Oleanane and is suggested to be generated from the Lower Cretaceo...An earlier study of GC-MS analysis on bitumen samples from the Agbabu area in Western Niger Delta showed the significant presence of gammacerane and no Oleanane and is suggested to be generated from the Lower Cretaceous (Neocomian) source rock, however, twelve core samples were obtained from the geological survey of Nigeria for both optical geochemical and biomarker analysis, two of the samples from Isan-9 well indicated the presence of Botryococcus braunii a freshwater alga which is characteristic of a lacustrine lake type environment. The extracts from the same core showed m/z = 191 chromatogram with the significant presence of gammacerane which is diagnostic for stratified water columns and characterizes a typical lake environment. However, the m/z = 191 chromatogram also shows the presence of Oleanane which is diagnostic for vascular plant materials, this doesn’t corroborate with that of the Ise-2 well. The Isan-9 well source rock is suggested to have occurred due to the evolving structural geology of the continental shelf after the onset of the rifting, whereby the dominant lake-type environment in the Early Cretaceous was accompanied by a sediment fill of continental runoffs containing vascular plant materials. This implies that an ancient lacustrine lake system was gradually modified as a result of sedimentary infill. And that the bitumen is sourced from the lower Cretaceous Neocomian source rocks.展开更多
A new genus and species of Rhachiberothidae, Raptorapax terribilissima gen. et sp. nov. from the Cretaceous amber of Lebanon is described. The new genus is assigned to the subfamily Paraberothinae. The new material co...A new genus and species of Rhachiberothidae, Raptorapax terribilissima gen. et sp. nov. from the Cretaceous amber of Lebanon is described. The new genus is assigned to the subfamily Paraberothinae. The new material confirms the great diversity of the group in the Cretaceous age and its decrease in diversity in recent times.展开更多
文摘An earlier study of GC-MS analysis on bitumen samples from the Agbabu area in Western Niger Delta showed the significant presence of gammacerane and no Oleanane and is suggested to be generated from the Lower Cretaceous (Neocomian) source rock, however, twelve core samples were obtained from the geological survey of Nigeria for both optical geochemical and biomarker analysis, two of the samples from Isan-9 well indicated the presence of Botryococcus braunii a freshwater alga which is characteristic of a lacustrine lake type environment. The extracts from the same core showed m/z = 191 chromatogram with the significant presence of gammacerane which is diagnostic for stratified water columns and characterizes a typical lake environment. However, the m/z = 191 chromatogram also shows the presence of Oleanane which is diagnostic for vascular plant materials, this doesn’t corroborate with that of the Ise-2 well. The Isan-9 well source rock is suggested to have occurred due to the evolving structural geology of the continental shelf after the onset of the rifting, whereby the dominant lake-type environment in the Early Cretaceous was accompanied by a sediment fill of continental runoffs containing vascular plant materials. This implies that an ancient lacustrine lake system was gradually modified as a result of sedimentary infill. And that the bitumen is sourced from the lower Cretaceous Neocomian source rocks.
基金a contribution to the ANR project: AMBRACE(BLAN 07-1-184190)the scientific project‘The Study of the Fossil Insects in Lebanon and their Outcrops: Geology of the Outcrops - Historical and Biodiversity Evolution' financed by the Lebanese University to DA.JFP thanks the National Research Council of Argentina(CONICET) for the funds provided for this research:grant PIP 6393,PIP 11420090100377 and BEJI
文摘A new genus and species of Rhachiberothidae, Raptorapax terribilissima gen. et sp. nov. from the Cretaceous amber of Lebanon is described. The new genus is assigned to the subfamily Paraberothinae. The new material confirms the great diversity of the group in the Cretaceous age and its decrease in diversity in recent times.
