Use of spectral gamma-ray data to refine subsurface fluvial stratigraphy: late Cretaceous strata in the Book Cliffs, Utah, USA

2005 ◽  
Vol 162 (4) ◽  
pp. 603-621 ◽  
Author(s):  
Gary J. Hampson ◽  
William Davies ◽  
Sarah J. Davies ◽  
John A. Howell ◽  
Keith R. Adamson
Keyword(s):  
Late Cretaceous ◽  
Gamma Ray ◽  
Book Cliffs

scholarly journals Late Cretaceous Palynostratigraphy of Subsurface Sediments of Southern Bornu Basin, Nigeria: Implications For Depositional Environments And Palaeoclimate.

2021 ◽  
Author(s):  
Ekundayo Joseph Adepehin ◽  
Bamidele Samuel Oretade ◽  
Peter Sunday Ola
Keyword(s):  
Late Cretaceous ◽  
Gamma Ray ◽  
Depositional Environments ◽  
Subtropical Climate ◽  
Standard Laboratory ◽  
Palynological Analysis ◽  
Subsurface Sediments ◽  
Sandy Shale ◽  
Assemblage Zone ◽  
Laboratory Procedures

Abstract Presented in this study are the findings of a cross-examination of the subsurface stratigraphic successions (1500-4600 m) penetrated by the Gaibu-1 well, Bornu Basin, NE Nigeria to understand the palaeoenvironmental settings and the palaeoclimatic conditions of the sediments. Sedimentological/textural description, lithological identification and palynological analysis were carried out using standard laboratory procedures and wireline (gamma-ray and SP) logs. The sediments consist predominantly of sandstone, siltstone, sandy shale, and shale. The sandstones range from fine-coarse, angular to sub-rounded, moderate to poorly sorted, and are texturally immature. Five (5) stratigraphic sub-divisions; the Bima, the Yolde, the Gongila, the Fika (Upper, Middle and Lower members) and the Gombe formations were identified. The palynozonation enabled four distinctive zones: (i) A (1) Triorites africaensis Assemblage Zone, (ii) A (2) Cretacaeiporites scabratus / Odontochitina costata Assemblage Zone, (iii) A (3) Droseridites senonicus Assemblage Zone, A (4) Syncolporites/Milfordia spp. Assemblage Zone. These suggest the well penetrated Cenomanian – Maastrichtian (younger) successions, interpreted to have been deposited in a series of continental to marginal marine environments. The sediments are characterised by palynofloral assemblages that are indicative of a tropical to subtropical climate condition that is warm and humid, which correspond to the late Cretaceous Palmae Province of Africa – Southern America.

scholarly journals MAGNETIC SUSCEPTIBILITY AND GAMMA-RAY SPECTROMETRY ON DRILL CORE: LITHOTYPE CHARACTERIZATION AND 3D ORE MODELING OF THE MORRO DO PADRE NIOBIUM DEPOSIT, GOIÁS, BRAZIL

2015 ◽  
Vol 33 (2) ◽  
Author(s):  
Marta Henriques Jácomo ◽  
Tereza Cristina Junqueira Brod ◽  
Augusto Cesar Bittencourt Pires ◽  
José Affonso Brod ◽  
Matheus Palmieri ◽  
...  
Keyword(s):  
Magnetic Susceptibility ◽  
Late Cretaceous ◽  
Gamma Ray ◽  
Gamma Ray Spectrometry ◽  
Drill Core ◽  
Carbonatite Complex ◽  
Central Brazil ◽  
Rock Types ◽  
Drill Holes ◽  
Fresh Rock

ABSTRACT. The Morro do Padre niobium Deposit, in the Late-Cretaceous Catal˜ao 2 alkaline-carbonatite complex, central Brazil, consists of stockworks of nelsonite and carbonatite dykes intruded into Precambrian phyllites, quartzites, and amphibolites. A gamma-ray spectrometry and magnetic susceptibility petrophysical survey was conducted on the cores of 73 drill holes in fresh-rock, producing a total of 1295 geophysical samples. Nelsonite, the host rock of the niobium mineralization in the Morro do Padre Deposit, has a characteristic geophysical signature, with higher gamma-ray spectrometry counting rates and magnetic susceptibility values, compared to other rock types. The studied nelsonites may be divided into N1 and N2 types. N2 nelsonite is richer in K, U and Th than N1. Carbonatites are divided into magnetic (C1) and nonmagnetic (C2) varieties. The nonmagnetic carbonatites can be subdivided into C2a and C2b. The C2a carbonatite is richer in K, U and Th than C2b, which is consistent with the presence of apatite and/or monazite in the former. The geophysical 3Dmodeling has shown that the main mineralized body is elongated in the E-W direction. It is about 100 m wide and 300 m long with a maximum depth of approximately 850 m reached by drilling.Keywords: 3D ore modeling, niobium ore, applied geophysics, alkaline rocks, nelsonite. RESUMO. O depósito de nióbio do Morro do Padre no complexo carbonatítico alcalino de Catalão 2 do Cretáceo Superior, região central do Brasil, consiste em stockworks de nelsonito e diques de carbonatito intrudidos em filitos pré-cambrianos, quartzitos e anfibolitos. A pesquisa petrofísica de gamaespectrometria e de susceptibilidade magnética foi realizada em testemunhos de 73 furos de sondagem em rocha fresca, produzindo um total de 1.295 amostras. Nelsonito, a rocha hospedeira da mineralização de nióbio no depósito Morro do Padre, tem uma assinatura geofisica característica, com maiores taxas de radiação gamaespectrométrica e maiores valores de susceptibilidade magnética em comparação com outros tipos de rochas. Os nelsonitos estudados podem ser divididos em N1 e N2. O nelsonito N2 é mais rico em K, U e Th do que o N1. Carbonatitos são divididos em magnéticos (C1) e não magnéticos (C2). Os carbonatitos não magnéticos podem ser subdivididos em C2a e C2b. O carbonatito C2a é mais rico em K, U e Th do que o C2b, o que é consistente com a presença de apatita e/ou monazita na composição minerológica. O modelamento 3D revela um corpo principal de nelsonito mineralizado, alongado segundo a direção E-W. Este é cerca de 100 m de largura e 300 m de comprimento, com uma profundidade máxima de 850 m.Palavras-chave: modelamento 3D de minério, minério de nióbio, geofísica aplicada, rochas alcalinas, nelsonito.

The Late Cretaceous Niobrara Formation in the south-central South Dakota (USA): a correlation study using porosity and gamma ray logs

2017 ◽  
Author(s):  
Gregório do Patrocínio Pedro ◽  
Soraya Gardel Carelli ◽  
John Foster Sawyer ◽  
Ana Paola Martins ◽  
Thiago Moreira
Keyword(s):  
South Dakota ◽  
Late Cretaceous ◽  
Gamma Ray ◽  
Correlation Study ◽  
The South ◽  
Niobrara Formation ◽  
South Central ◽  
Central South

Tectonic controls on Late Cretaceous sediment provenance and stratigraphic architecture in the Book Cliffs, Utah

2018 ◽  
Vol 130 (11-12) ◽  
pp. 1763-1781 ◽  
Author(s):  
Nicolas C. Bartschi ◽  
Joel E. Saylor ◽  
Thomas J. Lapen ◽  
Michael D. Blum ◽  
Bridget S. Pettit ◽  
...  
Keyword(s):  
Late Cretaceous ◽  
Sediment Provenance ◽  
Book Cliffs ◽  
Stratigraphic Architecture ◽  
Cretaceous Sediment

On the possible gamma-ray source in Cygnus

1967 ◽  
Vol 31 ◽  
pp. 469-471
Author(s):  
J. G. Duthie ◽  
M. P. Savedoff ◽  
R. Cobb
Keyword(s):  
Gamma Rays ◽  
Gamma Ray ◽  
Right Ascension

A source of gamma rays has been found at right ascension 20h15m, declination +35°, with an uncertainty of 6° in each coordinate. Its flux is (1·5 ± 0·8) x 10-4photons cm-2sec-1at 100 MeV. Possible identifications are reviewed, but no conclusion is reached. The mechanism producing the radiation is also uncertain.

Sign in / Sign up

Export Citation Format

Share Document