scholarly journals High-Resolution Biostratigraphic Studies of Step-1 Well, Offshore, Western Niger Delta

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
M. E. Nton ◽  
S. O. Famori
Keyword(s):  
High Resolution ◽  
Late Miocene ◽  
Niger Delta ◽  
Calcareous Nannofossils ◽  
Early Pliocene ◽  
Sequence Stratigraphic ◽  
Foraminiferal Species ◽  
Stratigraphic Model ◽  
Niger Delta Basin ◽  
Preparation Techniques

Abstract A high-resolution biostratigraphic study of the STEP-1 well, offshore Western Niger Delta Basin, Nigeria, was carried out using foraminifera, calcareous nannofossils and palynomorphs. The study was aimed at identifying the biostratigraphic zones, age deductions as well as palaeoenvironmental and palaeoclimatic reconstructions. From the studied well section of 609 m (1,829–2,438 m), 50 ditch cuttings were used for foraminifera and calcareous nannofossils, while 25 samples were used for palynological studies at 12 m and 24 m intervals, respectively. Standard laboratory preparation techniques were employed for the three microfossil groups. Due to the occurrence of some forms such as Globigerina praebulloides, Haplophragmoides spp, Bolivina scalprata miocenica, Valvulina flexilis and Cyclammina cf. minima, two planktonic and one benthonic foraminifera zones were identified as follows: Lower N18, Upper N17 zone (early Pliocene, late Pliocene) and Cyclammina minima zone (late Miocene), respectively. Two biozones were recognized for the nannofossils and include NN12 (Ceratolithus cristatus zone) and NN11 (Discoaster berggrenii zone). These zones were assigned to early Pliocene and late Miocene, respectively. Other forms include Discoaster pentaradiatus, Sphenolithus abies and Ceratolithus armatus. Echitricolporites spinosus/P800zone has been assigned for the Palynomorph assemblages and was dated late Miocene due to the quantitative occurrence of Cyperaceaepollis spp. Four identified major condensed sections include intervals at 1,926, 1,987, 2,097 and 2,316 m, which have been dated 5.0, 5.8, 6.3 and 7.0 Ma, respectively. Based on the benthonic foraminiferal species and Palynological Marine Index, a shallow marine environment is deduced for the studied interval which was interpreted to be deposited under both wet and dry palaeoclimatic conditions. The findings, no doubt could serve as a template for a sequence stratigraphic model, generally beyond the resolution of seismic stratigraphy.

scholarly journals Late Miocene–Early Pliocene planktic foraminiferal biostratigraphy of deep offshore southwestern Niger Delta

2021 ◽  
Vol 3 (3) ◽  
Author(s):  
Bamidele Adeniyi Adebambo ◽  
Suyi Lawrence Fadiya
Keyword(s):  
Late Miocene ◽  
Niger Delta ◽  
Early Pliocene ◽  
Foraminiferal Species ◽  
Processing Techniques ◽  
Foraminiferal Biostratigraphy

AbstractThe planktic foraminiferal biostratigraphy of the deep offshore southwestern Niger Delta has been studied from three wells (DPW-1, DPW-2 and DPW-3). A total of 418 ditch cutting samples (104 samples from DPW-1, 165 from DPW-2 and 149 from DPW-3) taken at 18-m intervals were subjected to standard micropaleontological processing techniques. In total, 42, 52 and 40 planktic foraminiferal species were identified from DPW-1, DPW-2 and DPW-3, respectively. The identified planktic species allow the delineation of the studied section into four biozones—Globorotalia acostaensis (N16), Globigerinoides obliquus extremus/Globorotalia merotumida (N17), Globorotalia margaritae primitiva (N18) and Globorotalia margaritae evoluta/Globigerina nepenthes (N19) zones, based on the first appearance datums (FADs), last appearance datums (LADs) of the nominate taxa and associated assemblages. The well sections dated Late Miocene to Early Pliocene based on the occurrence of certain diagnostic planktic foraminiferal datums such as FADs Globorotalia acostaensis, Globigerinoides obliquus extremus, Globorotalia merotumida/plesiotumida, Globorotalia margaritae primitiva and the LADs Globigerina nepenthes, Globorotalia margaritae primitiva and Globorotalia margaritae evoluta. The Miocene/Pliocene boundary was placed at the FAD Globorotalia margaritae primitiva. In the Niger Delta, this boundary is commonly placed at the FADs Globorotalia margaritae margaritae and Globorotalia crassaformis probably due to nonrecovery of Globorotalia margaritae primitiva. However, in this studied section of the deep offshore southwestern Niger Delta, FAD Globorotalia margaritae primitiva occurs consistently in the three study wells and is therefore considered an appropriate datum for the placement of the Miocene/Pliocene boundary.

scholarly journals Foraminiferal biostratigrpahy of oshi-13 field, coastal and central swamp depobelt, Niger delta basin, Nigeria

2018 ◽  
Vol 6 (1) ◽  
pp. 127
Author(s):  
J R. Nimnu ◽  
G O Aigbadon ◽  
F Ogbikaya
Keyword(s):  
High Resolution ◽  
Niger Delta ◽  
Middle Miocene ◽  
Hydrocarbon Saturation ◽  
Using Data ◽  
Niger Delta Basin

A high resolution Foraminiferal biostratigrpahic study has been carried out using data from three wells located in the Coastal and Central Swamp depobelts of Niger Delta.The study defined six (N6-N15) Foraminiferal zones for the early to middle Miocene Niger Delta on the basis of index Foraminiferal and this was correlated to Blow, 1969 and Bergreen et al., 1995. Foraminiferal analysis shows that Oshi-13Field is very rich in calcareous and araneceous benthics, calcareous and planktic foraminiferal. The abudance of fossils and index fossils are responsible for constructing the biostratigraphic chart and hydrocarbon saturation in the field. The biostratigraphy chart constructed act as a basis in establishing the ages of sediments/ sequence in the  studied field.   

Late Neogene carbonate productivity and terrigenous input in the central Western Pacific Warm Pool (IODP Site U1488)

2020 ◽  
Author(s):  
Anna Joy Drury ◽  
Thomas Westerhold ◽  
Ana Christina Ravelo ◽  
Ivano Aiello ◽  
Roy Wilkens ◽  
...  
Keyword(s):  
High Resolution ◽  
Late Miocene ◽  
Warm Pool ◽  
Western Pacific ◽  
Early Pleistocene ◽  
Western Pacific Warm Pool ◽  
Early Pliocene ◽  
Pacific Warm Pool ◽  
Late Neogene ◽  
Regional Processes

<p>As the largest modern reservoir of oceanic heat, the Western Pacific Warm Pool (WPWP) plays an important role in atmospheric and oceanic circulation patterns. Little is known about how regional deposition patterns have changed over the past 10 Ma. To understand the interplay between regional processes and global climate evolution in the WPWP, we explore the late Neogene evolution of biogenic (carbonate/siliceous) versus terrigenous deposition.</p><p>We collected high-resolution (2 cm/~0.5 kyr) X-Ray fluorescence (XRF) core scanning data at IODP Site U1488 (Exp. 363) in the central WPWP. These data were especially useful for estimating the carbonate, siliceous and terrigenous components below 65 m CCSF, where the shipboard track data were less robust. The shipboard splice was verified and revised using the Ba/Sr ratio to ensure a continuous composite section down to ~330 m revised CCSF-A at Site U1488. Fe and Si likely reflect terrigenous and partially biogenic silica components. We calibrated the high-resolution ln(Ca/K) record to %CaCO<sub>3</sub> using discrete shipboard %CaCO<sub>3</sub> measurements.</p><p>Fe and Si decrease, whilst ln(Ca/K) increases downcore, in agreement with shipboard data showing increasing %CaCO<sub>3</sub> and decreasing terrigenous/siliceous input­. During the late Pleistocene, the site shows high amplitude %CaCO<sub>3</sub>, Fe and Si cycles superimposed on low carbonate. The amplitude decreases during the early Pleistocene-mid Pliocene, although clear variability remains. The early Pliocene-late Miocene is dominated by high CaCO<sub>3</sub> (80-90%). The %CaCO<sub>3</sub>, Fe and Si variability is considerably reduced, although clear obliquity-precession interference patterns are visible, in addition to longer-term ~400 kyr eccentricity modulation. The high-carbonate interval at IODP Site U1488 likely reflects the early Pliocene to late Miocene Biogenic Bloom (LMBB). The expression of the LMBB in the WPWP is distinctly different to the Atlantic and eastern equatorial Pacific. This indicates that although productivity was enhanced during the late Miocene-early Pliocene, regional processes determined the exact expression and timing of the LMBB in different areas.</p>

Sign in / Sign up

Export Citation Format

Share Document