scholarly journals Optically stimulated luminescence techniques applied to the dating of the fall of meteorites in Morasko

2018 ◽  
Vol 45 (1) ◽  
pp. 74-81
Author(s):  
Piotr Moska ◽  
Wojciech Stankowski ◽  
Grzegorz Poręba
Keyword(s):  
Iron Meteorite ◽  
Optically Stimulated Luminescence ◽  
Luminescence Dating ◽  
Luminescence Signal ◽  
Geological Materials ◽  
The Past ◽  
The Earth ◽  
Materials Used ◽  
The Moment

Abstract Geological materials used for luminescence dating and associated with the fall of meteorites on the Earth’s surface are extremely rare. The Morasko region has gained fame over the past 100 years because of a cosmic catastrophe which took place there. After thousands of years, the remains of a large metal meteorite which fell in this area have been found. In this article, we would like to state whether it is possible, using luminescence methods, to determine the moment when the iron meteorite fell on the surface of the Earth. The material which was analysed consisted of meteorite crust layers – melt/fusion and “semi melt/fusion”, including sintered ones, along with the sediments surrounding the meteorite. The final results are connected with four objects of different sizes (large ones and small shrapnel – 261 kg, 34 kg, 970 g and 690 g). The obtained results show a large discrepancy, which is most likely associated with the problem of resetting the luminescence signal of the tested materials.

Can moisture content estimates from nuclear magnetic resonance improve optically stimulated luminescence dating - first results on Loess samples from Toshan/Iran

2020 ◽  
Author(s):  
Raphael Dlugosch ◽  
Christian Zeeden ◽  
Tobias Lauer ◽  
Sumiko Tsukamoto
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Moisture Content ◽  
Dose Rate ◽  
Optically Stimulated Luminescence ◽  
Luminescence Dating ◽  
The Past ◽  
History Of ◽  
Wilting Point ◽  
Nuclear Magnetic

<p>Dating of loess deposits using optically stimulated luminescence (OSL) enable us to extract important information about the climate during the last ~150 ka. A good estimation of the dose rate during the past is essential for OSL and depends, among others, on the history of the moisture content in the proximity of the dated sample. While the current moisture content can be measured by heating/drying, the history of the moisture variations of a sample is generally unknown. Reference values reported on similar materials and climate conditions may provide a range for the expected moisture variations in the past, but these values are generally rough guesses and not depth- and time-specific.</p><p>Nuclear magnetic resonance (NMR) relaxometry targeting the hydrogens of the pore fluid can estimate the current moisture content of a sample without heating. Additionally, the NMR relaxation time distribution yields information of the expected moisture content for a given field potential (e.g. wilting point). This can help to estimate a sample-specific range of likely moisture variation in a quick (several min) and no-invasive way.</p><p>We discuss this new approach on a loess profile from Toshan (Iran) published previously by (Lauer et al., 2017) and (Vlaminck, 2018). The later pointed out inconsistencies in the obtained age model. The estimated sample specific moisture content for the wilting point (15 to 35 wt.%) provide the low boundary for the moisture content estimate, which is higher than previously assumed (5 wt.%). The new dose rate calculated for these sample specific moisture content values lead to clearly older and more consistent ages (less age inversions).</p><p>We suggest that NMR derived moisture content data is valuable for obtaining information on the moisture content of samples. Especially the minimum moisture can be derived reliably, giving more robust water content estimates for OSL dating.</p><p><strong> </strong></p><p><strong> </strong></p><p><strong>References</strong></p><p>Lauer, T., Vlaminck, S., Frechen, M., Rolf, C., Kehl, M., Sharifi, J., Lehndorff, E., Khormali, F., 2017. The Agh Band loess-palaeosol sequence – A terrestrial archive for climatic shifts during the last and penultimate glacial–interglacial cycles in a semiarid region in northern Iran. Quaternary International, Loess, soils and climate change in Iran and vicinity 429, 13–30. https://doi.org/10.1016/j.quaint.2016.01.062</p><p>Vlaminck, S., 2018. Northeastern Iranian loess and its palaeoclimatic implications (PhD Thesis). Universität zu Köln.</p>

Conservation Guidelines for Invertebrate Paleontology Collections

2000 ◽  
Vol 10 ◽  
pp. 93-104
Author(s):  
Janet B. Waddington
Keyword(s):  
Natural History ◽  
Rock Matrix ◽  
Vast Number ◽  
Preventive Conservation ◽  
The Past ◽  
The Earth ◽  
Invertebrate Paleontology ◽  
Conservation Principles ◽  
Materials Used ◽  
Universal Treatment

THE TERM CONSERVATION refers to the whole subject of the care and treatment of valuable materials. Its definition is two-fold: (1) the control of the environment to minimize the decay of artifacts and materials; and (2) treatment of materials to arrest decay and to stabilize them against further deterioration. Restoration is the continuation of the treatment to return an object without falsification to a state in which it can be displayed (Howie, 1992; series editor's preface). The vast number of specimens in invertebrate paleontology collections makes treatment or restoration impractical or even impossible except for remarkable display specimens. It is possible, however, to control the environment, both physical and procedural, in which collections are maintained. It is easier to prevent deterioration than to fix it once it has occurred. This is the principle of preventive conservation.There is a general misconception, held by many paleontologists, that there are no conservation concerns with paleontology collections, or, if any, the concerns are minor. This unfortunately is not the case; although fossils and their rock matrix have lasted hundreds of millions of years in the earth, once excavated they are subject to many forces of destruction (Crowther and Collins, 1987). Problems in collections occur as a result of many different factors: inappropriate storage environment; inappropriate application of a “universal” treatment; or unstable materials used in preparation and treatment. Minerals such as pyrite may oxidize; shales crack and delaminate. Prepared specimens may include introduced materials such as consolidants and glues that themselves are subject to deterioration. Research into conservation of natural history materials has grown significantly over the past two decades. This paper will emphasize preventive conservation principles to address some of the conservation concerns particularly relevant to paleontological specimens and suggest some practical ways of reducing the risks to the collections.

Dynamical theory of the rotation of the Earth

1986 ◽  
Vol 408 (1835) ◽  
pp. 267-275 ◽  
Keyword(s):  
Average Rate ◽  
Liquid Core ◽  
Angular Acceleration ◽  
Dynamical Theory ◽  
Rate Of Change ◽  
Moment Of Inertia ◽  
Iron Core ◽  
The Past ◽  
The Earth ◽  
The Moment

From recent values of improved accuracy of the apparent secular accelerations v and v' of the Moon and Sun, the lunar and solar tidal couples N and N' can be found. The appropriate dynamical theory shows that the moment of inertia of the Earth, C , has been diminishing at an average rate of -1.67 x 10 27 cm 2 g s -1 during the past 3300 years, giving rise to a non-tidal angular acceleration ω ∙ i = 1.52 x 10 -22 s -2 in addition to the retardations of ω resulting from the lunar and solar couples. The intrinsic couple associated with Ċ , the time-rate of change of C , is considerably greater than the solar tidal couple on all values of v and v' so far determined. For an initially all-solid Earth, use of known seismic data shows that the moment of inertia has decreased during the past 3 Ga at an average rate of -1.72 x 10 27 cm 2 g s -1 since a liquid core first began to form, a figure in close agreement with the value based on ancienteclipse data. On the time-honoured hypothesis that the core has resulted from iron separating downwards in an originally homogeneous Earth, the rate of decrease of C is -0.873 x 10 27 cm 2 g s -1 , only about one-half of that based on ancient-eclipse data, while if applied to these data the ratio N / N' = 11.35, which is more than twice the theoretical ratio on any tidal hypothesis. These results show that the iron-core theory is physically unacceptable.

Modeling Light Exposure of Quartz Grains During Mortar Making: Consequences for Optically Stimulated Luminescence Dating

Radiocarbon ◽  
2020 ◽  
Vol 62 (3) ◽  
pp. 693-711 ◽  
Author(s):  
Pierre Guibert ◽  
Petra Urbanová ◽  
Jean-Baptiste Javel ◽  
Guillaume Guérin
Keyword(s):  
Light Exposure ◽  
Statistical Treatment ◽  
Optically Stimulated Luminescence ◽  
Osl Dating ◽  
Luminescence Dating ◽  
Basic Premise ◽  
Lime Mortar ◽  
Optically Stimulated Luminescence Dating ◽  
Exposure Distribution ◽  
The Moment

ABSTRACTDating lime mortar shows great potential for establishing the chronology of a construction. The basic premise of mortar dating by optically stimulated luminescence (OSL) is that quartz in the sand used for making mortar has been optically zeroed during the preparation process (optical bleaching). The moment to be dated is the last exposure of sand grains to light, before being embedded within the masonry and hidden from light. However, the main problem is the frequent partial and heterogeneous bleaching of grains, and this led us to use the single grain technique (SG-OSL) systematically. Some theoretical and experimental aspects of a new statistical treatment (the EED model, as exponential exposure distribution) are detailed and discussed. Our experience shows that SG-OSL dating of mortars is successful in a majority of situations. In a minority of cases (around 15%) difficulties originate when there is inappropriate OSL behavior of grains, and thus OSL dating is not possible. In the other cases, good agreement was obtained between OSL ages and the reference ones for a series of samples from a variety of ages and situations, even in the case of poorly bleached material. Anyway, the present situation of OSL dating methodology justifies the systematic use of SG-OSL in the dating of masonry today.

Optically stimulated luminescence dating of late Holocene raised strandplain sequences adjacent to Lakes Michigan and Superior, Upper Peninsula, Michigan, USA

2005 ◽  
Vol 63 (2) ◽  
pp. 122-135 ◽  
Author(s):  
Erin P. Argyilan ◽  
Steven L. Forman ◽  
John W. Johnston ◽  
Douglas A. Wilcox
Keyword(s):  
Lake Michigan ◽  
Lake Superior ◽  
Formation Rate ◽  
Optically Stimulated Luminescence ◽  
Luminescence Dating ◽  
Upper Peninsula ◽  
The Past ◽  
Optically Stimulated Luminescence Dating ◽  
High Lake Level ◽  
Eolian Sediments

This study evaluates the accuracy of optically stimulated luminescence to date well-preserved strandline sequences at Manistique/Thompson bay (Lake Michigan), and Tahquamenon and Grand Traverse Bays (Lake Superior) that span the past ∼4500 yr. The single aliquot regeneration (SAR) method is applied to produce absolute ages for littoral and eolian sediments. SAR ages are compared against AMS and conventional 14C ages on swale organics. Modern littoral and eolian sediments yield SAR ages <100 yr indicating near, if not complete, solar resetting of luminescence prior to deposition. Beach ridges that yield SAR ages <2000 yr show general agreement with corresponding 14C ages on swale organics. Significant variability in 14C ages >2000 cal yr B.P. complicates comparison to SAR ages at all sites. However, a SAR age of 4280 ± 390 yr (UIC913) on ridge77 at Tahquamenon Bay is consistent with regional regression from the high lake level of the Nipissing II phase ca. 4500 cal yr B.P. SAR ages indicate a decrease in ridge formation rate after ∼1500 yr ago, likely reflecting separation of Lake Superior from lakes Huron and Michigan. This study shows that SAR is a credible alternative to 14C methods for dating littoral and eolian landforms in Great Lakes and other coastal strandplains where 14C methods prove problematic.

The Origin of the Moon and its Relationship to the Origin of the Solar System

1962 ◽  
Vol 14 ◽  
pp. 133-148 ◽  
Author(s):  
Harold C. Urey
Keyword(s):  
Solar System ◽  
The Moon ◽  
The Past ◽  
The Earth ◽  
Short Period ◽  
Origin Of The Moon

During the last 10 years, the writer has presented evidence indicating that the Moon was captured by the Earth and that the large collisions with its surface occurred within a surprisingly short period of time. These observations have been a continuous preoccupation during the past years and some explanation that seemed physically possible and reasonably probable has been sought.

Chelovek.RU/Человек.RU

Chelovek RU ◽  
2020 ◽  
pp. 18-53
Author(s):  
Sergei Avanesov ◽  
Keyword(s):  
Family History ◽  
Great Distance ◽  
Point Of View ◽  
The Past ◽  
Russian Philosopher ◽  
True Meaning ◽  
The Future ◽  
Pavel Florensky ◽  
The Moment

Abstract. The article analyzes the autobiography of the famous Russian philosopher, theologian and scientist Pavel Florensky, as well as those of his texts that retain traces of memories. According to Florensky, the personal biography is based on family history and continues in children. He addresses his own biography to his children. Memories based on diary entries are designed as a memory diary, that is, as material for future memories. The past becomes actual in autobiography, turns into a kind of present. The past, from the point of view of its realization in the present, gains meaning and significance. The au-thor is active in relation to his own past, transforming it from a collection of disparate facts into a se-quence of events. A person can only see the true meaning of such events from a great distance. Therefore, the philosopher remembers not so much the circumstances of his life as the inner impressions of the en-counter with reality. The most powerful personality-forming experiences are associated with childhood. Even the moment of birth can decisively affect the character of a person and the range of his interests. The foundations of a person's worldview are laid precisely in childhood. Florensky not only writes mem-oirs about himself, but also tries to analyze the problems of time and memory. A person is immersed in time, but he is able to move into the past through memory and into the future through faith. An autobi-ography can never be written to the end because its author lives on. However, reaching the depths of life, he is able to build his path in such a way that at the end of this path he will unite with the fullness of time, with eternity.

Five Years and Count(er)ing: Memoir after Memoir

CounterText ◽  
2020 ◽  
Vol 6 (1) ◽  
pp. 26-32
Author(s):  
Norbert Bugeja
Keyword(s):  
Guest Editor ◽  
Arab Countries ◽  
National Museum ◽  
Terror Attack ◽  
Special Issue ◽  
The Past ◽  
Personal Perspectives ◽  
The Moment ◽  
Ongoing Project

In this retrospective piece, the Guest Editor of the first number of CounterText (a special issue titled Postcolonial Springs) looks back at the past five years from various scholarly and personal perspectives. He places particular focus on an event that took place mid-way between the 2011 uprisings across a number of Arab countries and the moment of writing: the March 2015 terror attack on the Bardo National Museum in Tunis, which killed twenty-two people and had a profound effect on Tunisian popular consciousness and that of the post-2011 Arab nations. In this context, the author argues for a renewed perspective on memoir as at once a memorial practice and a political gesture in writing, one that exceeds concerns of genre and form to encompass an ongoing project of political re-cognition following events that continue to remap the agenda for the region. The piece makes a brief final pitch for Europe's need to re-cognise, within those modes of ‘articulacy-in-difficulty’ active on its southern borders, specific answers to its own present quandaries.

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