scholarly journals Geochemistry of the cretaceous-tertiary boundary (Fish Clay) at Stevns Klint (Denmark): Ir, Ni and Zn in kerogen

2006 ◽  
Vol 71 (7) ◽  
pp. 793-806 ◽  
Author(s):  
Pavle Premovic ◽  
Milena Krsmanovic ◽  
Bratislav Todorovic ◽  
Mirjana Pavlovic ◽  
Nikola Nikolic ◽  
...  
Keyword(s):  
Trace Metals ◽  
Surface Waters ◽  
Shallow Marine ◽  
Asteroid Impact ◽  
Impact Ejecta ◽  
Previous Hypothesis ◽  
Geochemical Analyses ◽  
The Impact ◽  
Fish Clay ◽  
Marine Basin

Geochemical analyses of trace metals (Ir, Ni and Zn) in the kerogen of the black marl of the Cretaceous-Tertiary boundary succession (Fish Clay) at Stevns Klint (H?jerup Church) were undertaken. The data for this kerogen were in accordance with a previous hypothesis that this (insoluble) geoorganic polymer was derived from humic substances (mainly humic acids) of a nearshore soil. Substantial proportions of Ir, Ni and Zn within the kerogen structure were probably contained in these substances arriving at the sedimentary site. It is proposed that these humics were probably transported by acid surface waters (induced by the KT asteroid impact) into the shallow marine basin of Stevns Klint. It is also suggested that local leaching/weathering of the asteroidal impact fallout on the land near these waters played an important role in providing Ir, Ni and Zn for these substances. Apparently, Ir, Ni and Zn of the kerogen were created by the chondritic component of the impact ejecta fallout.

scholarly journals Cretaceous-Paleogene boundary Fish Clay at Højerup (Stevns Klint, Denmark): Zn, Pb and REE in kerogen

2008 ◽  
Vol 73 (4) ◽  
pp. 453-461
Author(s):  
Pavle Premovic ◽  
Maja Stankovic ◽  
Mirjana Pavlovic ◽  
Milos Djordjevic
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Humic Substances ◽  
Rare Earths ◽  
Land Surface ◽  
Coastal Areas ◽  
Previous Hypothesis ◽  
Geochemical Analyses ◽  
The Impact ◽  
Fish Clay

Geochemical analyses of Zn, Pb and rare earth elements (La, Ce, Nd, Sm, Eu, Tb, Yb and Lu) in the kerogen of the black marl at the Cretaceous - Paleogene boundary Fish Clay at H?jerup were performed. Substantial proportions of the Zn, Pb and rare earths were probably contained in terrestrial humic substances (the kerogen precursor) arriving at the marine sedimentary site. This is in accord with a previous hypothesis that kerogen is mainly derived from humic acids of an oxic soil in of the adjacent coastal areas of eastern Denmark. It is also suggested that humics enriched in Zn, Pb and rare earth elements were transported mainly through fluvial transport into the deposition site of the Fish Clay. Local weathering/leaching of the impact-eject fallout on the land surface and local terrestrial rocks by impact-induced? acid surface waters perhaps played an important role in providing Zn, Pb and rare earths to these humic substances. Apparently, chondritic and non-chondritic Zn originated from the impact fallout; Pb and rare earth elements were most likely sourced by exposed rocks in the coastal areas of eastern Denmark.

Cretaceous – Paleogene boundary Fish Clay at Højerup (Stevns Klint, Denmark): trace metals in kerogen

2007 ◽  
Vol 178 (5) ◽  
pp. 411-421 ◽  
Author(s):  
Pavle I. Premović ◽  
Bratislav Ž. Todorović ◽  
Mirjana S. Pavlović
Keyword(s):  
Rare Earth ◽  
Trace Metals ◽  
Rare Earth Elements ◽  
Humic Substances ◽  
Rare Earths ◽  
Land Surface ◽  
Coastal Areas ◽  
Geochemical Analyses ◽  
The Impact ◽  
Fish Clay

Abstract Geochemical analyses of trace metals (Ir, Ni, Co, Cr, Zn, Au and Pb) and rare earth elements (La, Ce, Nd, Sm, Eu, Tb, Yb and Lu) in kerogen of the black marl at the Cretaceous–Paleogene boundary Fish Clay at Højerup have been undertaken. Substantial proportions of the trace metals and rare earths were probably contained in terrestrial humic substances (the kerogen precursor) arriving at the marine sedimentary site. This is in accord with a previous hypothesis that kerogen is mainly derived from humic acids of an oxic soil in of the adjacent coastal areas of eastern Denmark. It is also suggested that humics were transported mainly through fluvial transport into the site of the deposition of the Fish Clay. The local weathering/leaching of the impact-ejecta fallout on the land surface or local terrestrial rocks by impact-induced? acid surface waters perhaps played an important role in providing trace metals and rare earths for these humic substances. Apparently, chondritic Ir, Au, Ni, Co, Cr and chondritic and non-chondritic Zn originated from the impact fallout; Pb and rare earth elements were most likely sourced by the rocks exposed in the coastal areas of eastern Denmark.

Identifying Sources of Sulfate Aerosols Reaching Whiteface Mountain, NY

1985 ◽  
Vol 43 ◽  
pp. 98-101
Author(s):  
James S. Webber
Keyword(s):  
Trace Metals ◽  
Acid Deposition ◽  
Surface Waters ◽  
Dry Deposition ◽  
Coal Combustion ◽  
Public Awareness ◽  
Sulfate Aerosols ◽  
Wet And Dry Deposition ◽  
Whiteface Mountain ◽  
Toxic Trace Metals

INTRODUCTION“Acid rain” and “acid deposition” are terms no longer confined to the lexicon of atmospheric scientists and 1imnologists. Public awareness of and concern over this phenomenon, particularly as it affects acid-sensitive regions of North America, have increased dramatically in the last five years. Temperate ecosystems are suffering from decreased pH caused by acid deposition. Human health may be directly affected by respirable sulfates and by the increased solubility of toxic trace metals in acidified waters. Even man's monuments are deteriorating as airborne acids etch metal and stone features.Sulfates account for about two thirds of airborne acids with wet and dry deposition contributing equally to acids reaching surface waters or ground. The industrial Midwest is widely assumed to be the source of most sulfates reaching the acid-sensitive Northeast since S02 emitted as a byproduct of coal combustion in the Midwest dwarfs S02 emitted from all sources in the Northeast.

The impact of nitrogen deposition on upland surface waters in Great Britain: A regional assessment of nitrate leaching

1995 ◽  
Vol 85 (2) ◽  
pp. 297-302 ◽  
Author(s):  
T. E. H. Allott ◽  
C. J. Curtis ◽  
J. Hall ◽  
R. Harriman ◽  
R. W. Battarbee
Keyword(s):  
Great Britain ◽  
Nitrogen Deposition ◽  
Surface Waters ◽  
Nitrate Leaching ◽  
Regional Assessment ◽  
The Impact

DART and LICIACUBE: Documenting Kinetic Impact

2021 ◽  
Author(s):  
Andrew Cheng ◽  
Elizabetta Dotto ◽  
Eugene Fahnestock ◽  
Vincenzo Della Corte ◽  
Nancy Chabot ◽  
...  
Keyword(s):  
Time Delay ◽  
Velocity Distribution ◽  
Physical Properties ◽  
Optical Depth ◽  
Depth Profiles ◽  
Full Characterization ◽  
Approach Distance ◽  
Impact Ejecta ◽  
The Impact

<p>The NASA Double Asteroid Redirection Test (DART) mission will demonstrate asteroid deflection by a kinetic impactor. DART will impact Dimorphos, the secondary member of the (65803) Didymos system, in late September to early October, 2022 in order to change the binary orbit period. DART will carry a 6U CubeSat called LICIACube, contributed by the Italian Space Agency, to document the DART impact and to observe the impact ejecta. LICIACube will be released by DART 10 days prior to Didymos encounter, and LICIACube will fly by Dimorphos at closest approach distance of about 51 km and with a closest approach time delay of about 167 s after the DART impact. LICIACube will observe the structure and evolution of the DART impact ejecta plume and will obtain images of the surfaces of both bodies at best ground sampling about 1.4 m per pixel. LICIACube imaging importantly includes the non-impact hemisphere of the target body, the side not imaged by DART.</p> <p> </p> <p>The LICIACube flyby trajectory, notably the closest approach distance and the time delay of closest approach, are designed to optimize the study of ejecta plume evolution without exposing the satellite to impact hazard. LICIACube imaging will determine the direction of the ejecta plume and the ejection angles, and will further help to determine the ejecta momentum transfer efficiency <em>β</em>. The ejecta plume structure, as it evolves over time, is determined by the amount of ejecta that has reached a given altitude at a given time. The LICIACube plume images enable characterization of the ejecta mass versus velocity distribution, which is strongly dependent on target properties like strength and porosity and is therefore a powerful diagnostic of the DART impact, complementary to measurements of the DART impact crater by the ESA Hera mission which will arrive at Didymos in 2026. Hera will measure crater radius and crater volume to determine the total volume of ejecta, which together with a ejecta mass-velocity distribution gives a full characterization of the DART impact.</p> <p> </p> <p>Models of the ejecta plume evolution as imaged by LICIACube show how LICIACube images can discriminate between different target physical properties (mainly strength and porosity), thereby allowing inferences of the magnitude of the ejecta momentum. Measured ejecta plume optical depth profiles can distinguish between gravity-controlled and strength-controlled impact cases and help determine target physical properties. LICIACube ejecta plume images further provide information on the direction of the ejecta momentum as well as the magnitude, requiring full 2-D simulations of the plume images. We will present new simulation model optical depth profiles across the plume at arbitrary positions.</p> <p><br />We thank NASA for support of the DART project at JHU/APL, under Contract # NNN06AA01C, Task Order # NNN15AA05T. The Italian LICIACube team acknowledges financial support from Agenzia Spaziale Italiana (ASI, contract No. 2019-31-HH.0 CUP<br />F84I190012600).</p>

scholarly journals The mass impacts on chemosynthetic primary producers: potential implications on anammox communities and their consequences

2018 ◽  
Vol 18 (05) ◽  
pp. 440-444
Author(s):  
Noel Pérez ◽  
Jorge Luis Velazco-Vargas ◽  
Osmel Martin ◽  
Rolando Cardenas ◽  
Jesús Martínez-Frías
Keyword(s):  
Water Column ◽  
Deposition Rate ◽  
Extreme Case ◽  
Chemical Compounds ◽  
Global Scale ◽  
Biogeochemical Cycle ◽  
Potential Influence ◽  
Asteroid Impact ◽  
Global Cooling ◽  
The Impact

AbstractThe potential of a mass asteroid impact on Earth to disturb the chemosynthetic communities at global scale is discussed. Special emphasis is made on the potential influence on anammox communities and their implications in the nitrogen biogeochemical cycle. According to our preliminary estimates, anammox communities could be seriously affected as a consequence of global cooling and the large process of acidification usually associated with the occurrence of this kind of event. The scale of affectations could vary in a scenario like the Chicxulub as a function of the amount of soot, depth of the water column and the deposition rate for sulphates assumed in each case. The most severe affectations take place where the amount of soot and sulphates produced during the event is higher and the scale of time of settlements for sulphates is short, of the order of 10 h. In this extreme case, the activity of anammox is considerably reduced, a condition that may persist for several years after the impact. Furthermore, the impact of high levels of other chemical compounds like sulphates and nitrates associated with the occurrence of this kind of event are also discussed.

scholarly journals Considerations for determining ‘optimal nutrition’ for copper, zinc, manganese and molybdenum

1999 ◽  
Vol 58 (2) ◽  
pp. 497-505 ◽  
Author(s):  
Mark L. Failla
Keyword(s):  
Trace Metals ◽  
Daily Intake ◽  
Functional Markers ◽  
Dietary Intakes ◽  
Normal Range ◽  
Copper Zinc ◽  
Daily Intakes ◽  
Zn Status ◽  
The Impact ◽  
Cu And Zn

Defining optimal dietary intakes of Cu and Zn throughout the life cycle continues to present a considerable challenge for nutrition scientists. Although the daily intake of these micronutrients is below that currently recommended for many groups, traditional biochemical indicators of nutritional status for these trace metals largely remain within the normal range. Thus, it is unclear whether the recommended daily intakes may be unnecessarily high, or if the commonly-used markers simply lack the necessary sensitivity and specificity that are required for accurately assessing Cu and Zn status. The increasing number of reports that daily supplements with these trace metals enhance the activities of selective metalloenzymes and specific cellular and organ processes further points out the need to differentiate between meeting the requirement and providing optimal nutriture. Results from recent studies suggesting that alternative molecular and functional markers possess sufficient sensitivity to better assess Cu and Zn status are discussed. Likewise, recent studies evaluating the impact of very low and excessive levels of dietary Mn and Mo on selective biochemical and metabolic indicators are reviewed.

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