Definition of Depositional Environment of Productive Series Based on Well Logging Data

Author(s):  
L. Shikhova
1989 ◽  
Vol 26 (10) ◽  
pp. 2092-2105 ◽  
Author(s):  
Jeffrey P. Schmok ◽  
Garry K. C. Clarke

Neoglacial Lake Alsek is an ice-dammed lake in the southwest Yukon that forms when Lowell Glacier rapidly advances from a side valley to block the Alsek River. A sedimentary record of past fillings and catastrophic drainages is preserved in small lakes lying within the Lake Alsek basin. Sediment cores from some of these small lakes were retrieved and studied. The cores were subjected to facies analysis involving description, classification, and interpretation of depositional processes, leading to assessment of depositional environment. Despite a relatively sparse set of sedimentary data, five distinctive deposits and associated environments can be recognized: (1) matrix-supported diamicton interpreted as a deposit of iceberg-rafted sediment; (2) sand and coarse silt interpreted as tractive current deposits; (3) massive silt and clay interpreted as rapidly deposited, lake margin derived sediment; (4) laminated silt and clay interpreted as glaciolacustrine deposits; and (5) carbonaceous muds interpreted as eutrophic pond deposits. Facies sequence analysis reveals that the sedimentary sequences are nonrandomly ordered, but cyclicity of the deposits was not found. Erosional unconformities reflecting gaps in the sediment record and difficulties with basin-wide stratigraphic correlations hamper further definition of the Lake Alsek filling and draining chronology. These problems could be overcome in future studies if either greater exposures could be studied or sufficient chronostratigraphic information could be obtained.


2006 ◽  
Vol 33 (1) ◽  
pp. 83 ◽  
Author(s):  
DIOGO RODRIGUES ANDRADE DA SILVA ◽  
ANA MARIA MIZUSAKI ◽  
SYLVIA MARIA COUTO DOS ANJOS ◽  
ROMMULO VIEIRA CONCEIÇÃO

The Rb-Sr method has been successfully applied to argillaceous sedimentary rocks in order to supply parameters for the definition of their depositional ages. In many studied cases, despite the geologically significant results, there are doubts concerning the interpretation of the obtained data and their limitations. This happens because sedimentary rocks are considered to be the mixture of detrital fragments of diverse sources, and therefore is the possibility of contain an isotopic record of their source rocks. The Rb-Sr method, when applied to mudrocks, allows constraining absolute depositional ages, owing to the resetting of the isotopic Rb/Sr system during deposition. This process is called isotopic homogenization in the depositional environment. Some special care must be taken with respect to sampling, sample grain size, depositional setting, and mineralogical composition. Nevertheless, questions still remain when concerning this methodology, particularly on the real occurrence and extent of the isotopic homogenization in the sedimentary environments. In the present work, the Rb-Sr method has been applied to samples of sedimentary rocks collected from different units representing several depositional settings from the Paraná Basin. The parameters responsible by the isotopic homogenization of Sr have been evaluated. The obtained results allowed the improvement of the application of the Rb-Sr method to sedimentary rocks, and significant results concerning depositional ages were obtained.


Author(s):  
Bahman Kiani Shavandi ◽  
Vahid Ahmadi

<div><p><em>Asmari formation in Maroon Oilfield is made up of fossil-bearing limestone, dolomitic limestone, argillaceous limestone, sandstone and shale. It is the main reservoir rock for multiple oil wells of Zagros. The formation in Maroon Oilfield dates back to Oligocene(Rupelian – Burdigalian). In the present study, sequence stratigraphy and depositional environment of Asmari Reservoir Formation located in Maroon Oilfield are studied through well-logging data. The lower limit of Asmari Formation in the studied area is Pabede Formation and its upper limit is Gachsaran Formation. The lower limit between Asmari and Pabede formations and upper limit between Asmari and Gachsaran formations are not continuous and signs of discontinuity are observed in them. The field, macroscopic and microscopic studied and determination of percentage and type of allochem and orthochem elements led to identification of 17 carbonate and clastic facies in Asmari Formation. In the section, 6 depositional sequences were identified and labeled as sequence 1-6. The sequence limits are all of SB2 type with exception of Sequence 6 which is SB1. </em></p></div>


1966 ◽  
Vol 24 ◽  
pp. 3-5
Author(s):  
W. W. Morgan

1. The definition of “normal” stars in spectral classification changes with time; at the time of the publication of theYerkes Spectral Atlasthe term “normal” was applied to stars whose spectra could be fitted smoothly into a two-dimensional array. Thus, at that time, weak-lined spectra (RR Lyrae and HD 140283) would have been considered peculiar. At the present time we would tend to classify such spectra as “normal”—in a more complicated classification scheme which would have a parameter varying with metallic-line intensity within a specific spectral subdivision.


1975 ◽  
Vol 26 ◽  
pp. 21-26

An ideal definition of a reference coordinate system should meet the following general requirements:1. It should be as conceptually simple as possible, so its philosophy is well understood by the users.2. It should imply as few physical assumptions as possible. Wherever they are necessary, such assumptions should be of a very general character and, in particular, they should not be dependent upon astronomical and geophysical detailed theories.3. It should suggest a materialization that is dynamically stable and is accessible to observations with the required accuracy.


1979 ◽  
Vol 46 ◽  
pp. 125-149 ◽  
Author(s):  
David A. Allen

No paper of this nature should begin without a definition of symbiotic stars. It was Paul Merrill who, borrowing on his botanical background, coined the termsymbioticto describe apparently single stellar systems which combine the TiO absorption of M giants (temperature regime ≲ 3500 K) with He II emission (temperature regime ≳ 100,000 K). He and Milton Humason had in 1932 first drawn attention to three such stars: AX Per, CI Cyg and RW Hya. At the conclusion of the Mount Wilson Ha emission survey nearly a dozen had been identified, and Z And had become their type star. The numbers slowly grew, as much because the definition widened to include lower-excitation specimens as because new examples of the original type were found. In 1970 Wackerling listed 30; this was the last compendium of symbiotic stars published.


Author(s):  
K. T. Tokuyasu

During the past investigations of immunoferritin localization of intracellular antigens in ultrathin frozen sections, we found that the degree of negative staining required to delineate u1trastructural details was often too dense for the recognition of ferritin particles. The quality of positive staining of ultrathin frozen sections, on the other hand, has generally been far inferior to that attainable in conventional plastic embedded sections, particularly in the definition of membranes. As we discussed before, a main cause of this difficulty seemed to be the vulnerability of frozen sections to the damaging effects of air-water surface tension at the time of drying of the sections.Indeed, we found that the quality of positive staining is greatly improved when positively stained frozen sections are protected against the effects of surface tension by embedding them in thin layers of mechanically stable materials at the time of drying (unpublished).


Author(s):  
W. A. Shannon ◽  
M. A. Matlib

Numerous studies have dealt with the cytochemical localization of cytochrome oxidase via cytochrome c. More recent studies have dealt with indicating initial foci of this reaction by altering incubation pH (1) or postosmication procedure (2,3). The following study is an attempt to locate such foci by altering membrane permeability. It is thought that such alterations within the limits of maintaining morphological integrity of the membranes will ease the entry of exogenous substrates resulting in a much quicker oxidation and subsequently a more precise definition of the oxidative reaction.The diaminobenzidine (DAB) method of Seligman et al. (4) was used. Minced pieces of rat liver were incubated for 1 hr following toluene treatment (5,6). Experimental variations consisted of incubating fixed or unfixed tissues treated with toluene and unfixed tissues treated with toluene and subsequently fixed.


Author(s):  
J. D. Hutchison

When the transmission electron microscope was commercially introduced a few years ago, it was heralded as one of the most significant aids to medical research of the century. It continues to occupy that niche; however, the scanning electron microscope is gaining rapidly in relative importance as it fills the gap between conventional optical microscopy and transmission electron microscopy.IBM Boulder is conducting three major programs in cooperation with the Colorado School of Medicine. These are the study of the mechanism of failure of the prosthetic heart valve, the study of the ultrastructure of lung tissue, and the definition of the function of the cilia of the ventricular ependyma of the brain.


Sign in / Sign up

Export Citation Format

Share Document