摘要
This work is the subject of the biostratigraphic and palaeoenvironmental study of the North Deep Sea area of the Congolese Miocene Atlantic Basin. This study is made from samples of lateral cores, drill cuttings and electrical logs. Lithology generally exhibits an irregular alternation of weakly indurated grey clay, light grey siltstones, and whitish, quartzitic sand, medium to coarse-grained, sub-angular to rounded. The presence of glaucony indicates that sediments have been deposited in a calm and reducing environment. The entire formation is fossiliferous. Micropaleontological analysis revealed 120 species of foraminifera including 98 planktonic (81.67%) and 22 benthic (18.33%) species used for biozonation, dating and interpretation of palaeoenvironments. Similarly, the bio-events of plankton foraminiferal, characterized by the level of the first appearance of certain species, have made it possible to identify fifteen biozones (<i>Globorotalia plesiotumida</i>,<i> Globorotalia merotumida</i>,<i> Globorotalia acostaensis</i>,<i> Globorotalia menardii</i>,<i> Globigerina nepenthes</i>,<i> Globorotalia siakensis</i>,<i> Globorotalia fohsi</i>,<i> Globorotalia praefohsi, Globorotalia peripheroacuta</i>,<i> Globorotalia peripheroronda</i>,<i> Praeorbulina sicana</i>,<i> Catapsydrax dissimilis</i>,<i> Globigerinatella insueta, Paragloborotalia kugleri </i>and<i> Globorotalia kugleri</i>) corresponding to age between Aquitanian and Lower Pliocene. Biofacies analysis of foraminifera has identified palaeoenvironments that vary from open marine environments, bathyal to abyssal. <p> <br /> </p>
This work is the subject of the biostratigraphic and palaeoenvironmental study of the North Deep Sea area of the Congolese Miocene Atlantic Basin. This study is made from samples of lateral cores, drill cuttings and electrical logs. Lithology generally exhibits an irregular alternation of weakly indurated grey clay, light grey siltstones, and whitish, quartzitic sand, medium to coarse-grained, sub-angular to rounded. The presence of glaucony indicates that sediments have been deposited in a calm and reducing environment. The entire formation is fossiliferous. Micropaleontological analysis revealed 120 species of foraminifera including 98 planktonic (81.67%) and 22 benthic (18.33%) species used for biozonation, dating and interpretation of palaeoenvironments. Similarly, the bio-events of plankton foraminiferal, characterized by the level of the first appearance of certain species, have made it possible to identify fifteen biozones (<i>Globorotalia plesiotumida</i>,<i> Globorotalia merotumida</i>,<i> Globorotalia acostaensis</i>,<i> Globorotalia menardii</i>,<i> Globigerina nepenthes</i>,<i> Globorotalia siakensis</i>,<i> Globorotalia fohsi</i>,<i> Globorotalia praefohsi, Globorotalia peripheroacuta</i>,<i> Globorotalia peripheroronda</i>,<i> Praeorbulina sicana</i>,<i> Catapsydrax dissimilis</i>,<i> Globigerinatella insueta, Paragloborotalia kugleri </i>and<i> Globorotalia kugleri</i>) corresponding to age between Aquitanian and Lower Pliocene. Biofacies analysis of foraminifera has identified palaeoenvironments that vary from open marine environments, bathyal to abyssal. <p> <br /> </p>
作者
Nehl Dorland Kobawila
Hilaire Elenga
Louis Richard Ngatse
Nehl Dorland Kobawila;Hilaire Elenga;Louis Richard Ngatse(Department of Geology, Faculty of Science and Technology, Marien Ngouabi University, Brazzaville, Republic of Congo;Geological and Mining Research Center, Brazzaville, Republic of Congo;National Petroleum Society of the Congo, Brazzaville, Republic of Congo)