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Search Results: 1 - 10 of 118 matches for " Fossils "
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Helium and Argon Isotopic Studies of Fossil Material and the Theoretical Evolution of He and Ar in Earth’s Atmosphere through Time  [PDF]
Yuko Arakawa, Jun-Ichi Matsuda
International Journal of Geosciences (IJG) , 2012, DOI: 10.4236/ijg.2012.325091
Abstract: We analyzed the elemental concentrations and the isotopic compositions of helium and argon in Cambrian to Jurrassic aged Gastropod, Ammonite and Trilobite fossils in order to examine variation in these gases through time. Fossil samples yielded He and Ar isotopic ratios close to the present day atmospheric values, but also indicated some addition of a radiogenic component. We compared the results to theoretical values calculated from a mathematical model of Earth’s atmosphere assuming mantle degassing. Results from our mathmatical models showed that the 40Ar/36Ar ratio of Earth’s atmosphere increased rapidly after the formation of the Earth, but has been almost identical to the present day value for the last 1 Ga. For atmospheric helium, model results were consistent with present day atmospheric values, assuming complete helium degassing from the continental crust into the atmosphere. The model suggests that the atmospheric 3He/4He ratio has remained relatively constant for the last 0.1 Ga. Given the similarity between present day and ancient He and Ar isotopic ratios, we conclude that the corresponding ratios measured in ancient fossil material may partially reflect composition of the ancient atmosphere and are not necessarily due to contamination by the present day atmosphere.
Concerning the Original Viewpoint of Biogeologic Accumulation of the Old Bedded Phosphorites in the Khubsugul and Zavkhan Basins of Mongolia  [PDF]
Dorj Dorjnamjaa, Gundsambuu Altanshagai
Open Journal of Geology (OJG) , 2015, DOI: 10.4236/ojg.2015.59059
Abstract: This paper concerns deals with?biogeologic?accumulation and their peculiarities, lithological unites of the phosphorite-bearing formations of these basins and an evolution of the old biota. Old bedded phosphorites are believed to be connected with specific biogeological events happening in the Neoproterozoic glaciation, which was followed by rapid deglaciation,?Ediacaran bioradiation and the “great” postglacial transgression bearing phosphorites at its initial phase. The Mongolian phosphate basins give evidence of this phenomenon. Khubsugul basin is located in the northern Mongolia. The Neoproterozoic-Cambrian phosphorite-bearing khubsugul group is subdivided into 3 formations as ongolik, kheseen and erkhelnuur which are rich in organic fossils (a group of cyanobacterial mats, archaeocyaths, trilobites) in the ascending order. The Zavkhan basin lies in the western Mongolia. The Ediacaran-lower Cambrian sediments are divided into five formations: Maikhanuul (diamictites), Tsagaanolom (phosphorite-bearing carbonate), Bayangol, Salaanygol and Khairkhan. All the formations contain the paleontological fossils (algae, sponges, cyanobacterial mats, ichnocoenosis, soft-bodied fauna, archaeocyaths, etc.). Bedded phosphorites are the object for comprehensive research of bacterial paleontology. It is shown at example of the Mongolian Khubsugul and Zavkhan sea shelf phosphate basins. The expounded actual material clearly shows that the heterogeneous biologic activity, suitable geologic (transgressive systems tracts) and paleogeographic (glaciations, warm climate, etc.) conditions played an important role in the formation and accumulation of the biogenic bedded phosphorites.
Solar Cells: In Research and Applications—A Review  [PDF]
Shruti Sharma, Kamlesh Kumar Jain, Ashutosh Sharma
Materials Sciences and Applications (MSA) , 2015, DOI: 10.4236/msa.2015.612113
Abstract: The light from the Sun is a non-vanishing renewable source of energy which is free from environmental pollution and noise. It can easily compensate the energy drawn from the non-renewable sources of energy such as fossil fuels and petroleum deposits inside the earth. The fabrication of solar cells has passed through a large number of improvement steps from one generation to another. Silicon based solar cells were the first generation solar cells grown on Si wafers, mainly single crystals. Further development to thin films, dye sensitized solar cells and organic solar cells enhanced the cell efficiency. The development is basically hindered by the cost and efficiency. In order to choose the right solar cell for a specific geographic location, we are required to understand fundamental mechanisms and functions of several solar technologies that are widely studied. In this article, we have reviewed a progressive development in the solar cell research from one generation to other, and discussed about their future trends and aspects. The article also tries to emphasize the various practices and methods to promote the benefits of solar energy.
El desarrollo del pensamiento paleontológico
Delicio, Maria Paula;
Rem: Revista Escola de Minas , 2002, DOI: 10.1590/S0370-44672002000100014
Abstract: at paleontology, a quick analysis seems to be simply the study of the lives forms that inhabited our planet in past times. this may be true if we look only to "strict sensu" meaning of the word (latin:- palaios =old / onto =life / logy =study), that mean's the study of old seres (mendes, 1984). but, in the truth, this is one of the many facets that compose the world of the paleontology. this science doesn't only study the fossils, but also its contained vestiges in the sedimentary and metasedimentary rocks, its implications stratigraphy and geohistory. it is important to observe that, the meaning of the word "fossil" had been suffered many modifications since it's first appearance. this word comes from the latin fossilem, that means, "extracted of the earth". in the beginning, it was used to designate any object or remarkable material removed of the earth or found in its surface, what ever were it's origin. under this definition, the term included, what we call today fossils, as well as, the minerals and the stones. aristóteles was the first one to establish, the distinction between fossils and minerals, for him, the first ones were stones that could not melt, in opposition to the minerals, which were fusible. only at the beginning of the xviii century, that the fossil term began to be used with the current meaning (beviá, 1996). the understanding of the nature of the fossils as old life remains and the recognition that they have the same age and the same conditions of formation of the rocks that contains them, were progress that happened only gradually, during the development of the human knowledge.
Alexandr Pavlovich Rasnitsyn, (palaeo)entomologist extraordinaire – a personal appreciation
Denis Brothers
ZooKeys , 2011, DOI: 10.3897/zookeys.130.1890
Abstract: This note is not meant to be an exhaustive account of the many achievements of Alex Rasnitsyn over the 75 years of his life thus far. Apart from anything else, I have little knowledge of his activities outside of my professional interactions with him. Also, there will undoubtedly be several other biographical essays this year to celebrate his accomplishments in many fields. So, my intention, after providing the essential details to place him in context, mainly derived from his personal page on the Paleontological Institute’s website (Rasnitsyn 2011) and a note in the Paleontological Journal (Laboratory of Arthropods, in press), is to give my personal impressions of our interactions, his influence on my own life and work, and on hymenopterology in general.
Fósseis: Mitos e Folclore
Antonio Carlos Sequeira Fernandes
Anuário do Instituto de Geociências , 2005,
Abstract: Fossils have been familiar objects to man since the prehistoric times, with striking connotations in the folklore of several cultures. They were used as decorative elements in necklaces, regarded as heroes or giants in the classical greek and roman times, interpreted as teeth and bones of dragons, used as amulets against the bites and poisons of snakes, and as medicines to the treatment of several disorders. This article describes some of these examples.
Continental Trace Fossils in the Semnan Area (Northern Iran)  [PDF]
Mousa Bagheri, Sadat Feiznia, Mehran Arian, Rahim Shabanian, Rahim Mahari
Open Journal of Geology (OJG) , 2013, DOI: 10.4236/ojg.2013.32009
Abstract:

Continental ichnology has been taking an ever increasing importance in stratigraphy. In this paper, Continental Trace Fossils in Semnan area have been studied. Semnan Province is one of the 31 provinces which is located in the north of Iran. In the East of Semnan City, Quaternary deposits occupy about 93% of the surface area, of which the Alluvial represents one of the most important geomorphological features in the area. Nevertheless, the outspread ichnological studies in Semnan City have received lesser attention in Continental Trace Fossils. Based on the systematic ichnology, 6 trace fossils are distinguished, namely Celliforma isp, Coprinisphaera isp, Palaeophycus tubularis, planolithes isp, Tombownichnus plenus, and Skolithos isp. The existence of Rhizoliths along with the tetrapod footprints and the survey of lithofacies all indicate that the trace fossils are related to Coprinisphaera ichnofacies. Based on ichnological and sedimentary facies analysis, the Continental Trace Fossils, in the study area, are located in the flood plain, point bar, and playa environment.

Energy and Economic Growth, Is There a Connection? Energy Supply Threats Revisited  [PDF]
Paul Ojeaga, Deborah Odejimi, Emmanuel George, Dominic Azuh
Open Journal of Energy Efficiency (OJEE) , 2014, DOI: 10.4236/ojee.2014.33007
Abstract: The increased cost of accessing energy and the effects on economic growth (GDP) across regions is one of grave concern [1]. The Cost implication of energy supply often shapes regional energy policies across the globe. This paper presents an empirical investigation into the relationship between energy generation and economic growth, while also investigating probable threats to sustainable energy supply across regions. Energy generation was found to have some implications for economic growth across regions. It was found that hydro electric, renewable energy and nuclear generation sources were significantly driving growth across regions while coal and gas sources were not. This was particularly true since the cost of fossils was having strong cost implications, for overall energy generation cost in countries in regions due to overdependence on fossils. Generating sources were also found to have strong implications for sustained energy supply (energy security), renewable energy and gas generating sources that had the strongest effects on sustainable energy supply across regions. This was probably true since regions were focusing on new technologies in energy generation process, which are cheaper, cleaner and more sustaining, while still depending on gas plants due to the relative cost implications of maintaining gas plants compared to hydro and nuclear generating plants. The method of estimation used in the study is the seemingly unrelated regression estimation method.
New Fossil Reptile Records from the Siwalik of North India  [PDF]
A. C. Nanda, H. H. Schleich, B. S. Kotlia
Open Journal of Geology (OJG) , 2016, DOI: 10.4236/ojg.2016.68052
Abstract: From the Siwalik Group of Haryana and Himachal Pradesh, new fossil reptile records are described. The Siwalik fauna from Haryana and Himachal is recorded from the pre-Pinjor and Pinjor beds (Upper Siwalik Subgroup: Pliocene—Lower Pleistocene). The reptile fauna includes Crocodylus aff. palustris, Gavialis cf. gangeticus, Rhamphosuchus crassidens, Batagur sp., Geoclemys hamiltoni and Hardella thurjii. The findings are significant as fossil reptiles from the Siwalik Group are scanty as compared to the richer mammalian fauna.
Las colecciones científicas y la protección del patrimonio paleontológico
Cristín, Alejandro;Perrilliat, María del Carmen;
Boletín de la Sociedad Geológica Mexicana , 2011,
Abstract: the function and importance of scientific collections lies in the objects of unique nature that they contain, the raw material to generate and validate scientific knowledge. the paleontological collections preserve, maintain, and keep available fossils and the information they contain. in this way they protect the most valuable heritage of society: the scientific knowledge of at least a part of nature and its social benefits.
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