scholarly journals Gypsum Precipitating From Volcanic Effluent as an Archive of Volcanic Activity

2021 ◽  
Vol 9 ◽  
Author(s):  
Vincent J. van Hinsberg ◽  
Kim Berlo ◽  
Daniele L. Pinti ◽  
Bassam Ghaleb
Keyword(s):  
Volcanic Activity ◽  
Hydrothermal System ◽  
Growth Zone ◽  
Rock Fragment ◽  
Time Period ◽  
Icp Ms ◽  
Age Model ◽  
Compositional Variability ◽  
D Values ◽  
Kawah Ijen

Records of volcanic activity are a key resource in volcano monitoring and hazard mitigation. The time period for which such records are available and the level of detail vary widely among volcanic centers and there is, therefore, a need for supplementary sources of this information. Here, we use growth-zoned gypsum as a mineral archive of the activity of Kawah Ijen volcano in East-Java, Indonesia. Gypsum precipitates where water seeps from the crater lake and hydrothermal system, and it has formed a 100 m long cascading plateau. A 19 cm plateau cross-section was analysed for minor and trace elements using laser-ablation ICP-MS. Absolute ages were assigned to this transect based on 210Pb dating. This 210Pb age model was corrected for variations in the 210Pb0 resulting from fluctuations in the volcanic radon flux by using 84Kr/36Ar and 132Xe/36Ar. The age model indicates that the transect covers a period from 1919 ± 12 to 2008 ± 0.2. Gypsum-fluid partition coefficients (D) permit the gypsum compositions to be converted to the concentrations in the fluid from which each growth zone grew. The D-values also show the compatibility of the elements in the gypsum structure, and identify the LREE, Sr, Pb, Tl, Ni, Co, Cu, Zn, Cd, Sb, Th, and Mo as least susceptible to contamination from rock fragment and mineral inclusions, and therefore as most reliable elements of the gypsum record. Compositional variability in the timeseries correlates with known element behavior in the Kawah Ijen system and shows three element groups: the LREE, Sr, and Pb that represent rock-leaching; Cu, Zn, and Cd, which have previously been linked to immiscible sulfide destabilization in a deep-seated basalt; and Sb, Tl, and As which point to a contribution from the shallow system and evolved magma. Moreover, the gypsum record shows that episodes of unrest and quiescence have a distinct compositional signature in Kawah Ijen seepage fluids, and can be distinguished. Thus, we show that gypsum is a sensitive recorder of volcanic activity and can provide detailed information on the state of the magmatic-hydrothermal system in the past.

Effects of exploitation by two co-existing fleets on the bluefish, Pomatomus saltatrix, in southern Brazil: an application of a seasonal catch-at-age model

2002 ◽  
Vol 53 (5) ◽  
pp. 835 ◽  
Author(s):  
Flávia M. Lucena ◽  
Carl M. O'Brien ◽  
Enir G. Reis
Keyword(s):  
Southern Brazil ◽  
Pomatomus Saltatrix ◽  
Management Options ◽  
Time Period ◽  
Stock Biomass ◽  
Spawning Stock ◽  
Age Model ◽  
Estimate Population Size ◽  
High Level ◽  
Seasonal Characteristic

This paper describes 20 years in the exploitation of the bluefish, Pomatomus saltatrix, in southern Brazil and investigates the effects of the commercial fleets on stock structure. Port samples were obtained from the commercial fisheries based at Rio Grande do Sul for the period 1992–1998. In addition, data derived from the exploitation during the period 1977–1983 (Krug and Haimovici 1991) were included in this analysis. A statistical catch-at-age model is proposed to estimate population size and exploitation rates for both periods of study. This model incorporates both the seasonal characteristic and multi-fleet nature of the P. saltatrix fishery. During the most recent time period, fishery mortality has increased and spawning stock biomass has reduced in comparison to the earlier period 1977–1983. Currently, the exploitation of P. saltatrix relies on fish of all age classes. Adults have been intensively exploited and juveniles may not be abundant enough to maintain the stock at the current high level of exploitation. Management options for the stock are presented based on a redistribution of effort between fleets. Simulations indicate that a ban on fishing in shallow waters for either one or both gears would restore the level of spawning stock biomass.

scholarly journals Mobility of REE from a hyperacid brine to secondary minerals precipitated in a volcanic hydrothermal system: Kawah Ijen crater lake (Java, Indonesia)

2020 ◽  
Vol 740 ◽  
pp. 140133 ◽  
Author(s):  
Claudio Inguaggiato ◽  
Sabrina Pappaterra ◽  
Loic Peiffer ◽  
Carmine Apollaro ◽  
Lorenzo Brusca ◽  
...  
Keyword(s):  
Hydrothermal System ◽  
Crater Lake ◽  
Secondary Minerals ◽  
Kawah Ijen

A warmer Mediterranean region at the Miocene to Pliocene transition

2020 ◽  
Author(s):  
Iuliana Vasiliev ◽  
Daniela Boehn ◽  
Darja Volkovskaja ◽  
Clemens Schmitt ◽  
Konstantina Agiadi ◽  
...  
Keyword(s):  
Mediterranean Sea ◽  
Mediterranean Basin ◽  
Mediterranean Region ◽  
Elevated Temperatures ◽  
Sea Water ◽  
Time Interval ◽  
Time Period ◽  
Organic Biomarkers ◽  
The Mediterranean ◽  
D Values

<p>Between 5.97-5.33 Ma several kilometre-thick evaporite units were deposited in the Mediterranean Basin during the Messinian Salinity Crisis (MSC). The MSC reflects a period featured by a negative hydrological budget, with a net evaporative loss of water exceeding precipitation and riverine runoff. The contemporary changes in continental and marine circum-Mediterranean temperature are, however, poorly constrained. Here we reconstruct continental mean annual temperatures (MAT) using branched glycerol dialkyl glycerol tetraether (GDGT) biomarkers for the time period corresponding to MSC Stage 3 (5.55-5.33 Ma). Additionally, for the same time interval, we estimate sea surface temperatures (SSTs) of the Mediterranean Sea using isoprenoidal GDGTs based TEX<sub>86</sub> proxy. The excellently preserved organic biomarkers were extracted from outcrops and DSDP cores spread over a large part of the onland (Malaga, Sicily, Cyprus) and offshore (holes 124 and 134 from the Balearic abyssal plane and hole 374 from the Ionian Basin) Mediterranean Basin domain. The calculated MATs for the 5.55 to 5.33 Ma interval show values around 16 to 18 ºC for the Malaga, Sicily and Cyprus outcrops. The MAT values calculated for DSDP Leg 13 holes 124, 134 and Leg 42A hole 374 are lower, around 11 to 13 ºC.</p><p>For samples where the branched and isoprenoid tetraether (BIT) index was lower than the 0.4 we could calculate TEX<sub>86</sub> derived SSTs averaging around 27 ºC for all sampled locations. Where available (i.e. Sicily), we compared the TEX<sub>86</sub> derived SSTs with alkenone based, U<sup>k</sup><sub>37</sub> derived SST estimates from the same samples. The TEX<sub>86</sub> derived SST values are slightly higher than the U<sup>k</sup><sub>37</sub> derived SST of 20 to 28 ºC. For the Mediterranean region, values between 19 and 27 ºC of the U<sup>k</sup><sub>37</sub> derived SSTs were calculated for the interval between the 8.0 and 6.4 Ma (Tzanova et al., 2015), close to our calculations for Sicily section (20 to 28 ºC). Independent of common pitfalls that may arise in using molecular biomarkers as temperature proxies, both SST estimates independently hint towards much warmer Mediterranean Sea water during the latest phase (Stage 3) of the MSC. These elevated temperatures coincide with higher δD values measured on alkenones and long chain n-alkanes (both records indicating for more arid and/or warmer conditions than today between 5.55 and 5.33 Ma). We therefore conclude that the climate between 5.55 to 5.33 Ma was warmer than present-day conditions, recorded both in the Mediterranean Sea and the land surrounding it.</p>

scholarly journals Chronology of Cauvery Delta Sediments from Shallow Subsurface Cores Using Elevated-Temperature Post-IR IRSL Dating of Feldspar

2010 ◽  
Vol 37 (-1) ◽  
pp. 37-47 ◽  
Author(s):  
L. Alappat ◽  
S. Tsukamoto ◽  
P. Singh ◽  
D. Srikanth ◽  
R. Ramesh ◽  
...  
Keyword(s):  
Elevated Temperature ◽  
Luminescence Dating ◽  
Natural Quartz ◽  
Shallow Subsurface ◽  
Dose Rates ◽  
Icp Ms ◽  
Minimum Age ◽  
Age Model ◽  
Cauvery Delta ◽  
Delta Sediments

Chronology of Cauvery Delta Sediments from Shallow Subsurface Cores Using Elevated-Temperature Post-IR IRSL Dating of Feldspar We present the results of luminescence dating of sediments from two cores from the Cauvery Delta in south-east India. Since all natural quartz OSL signals except one sample were in saturation, the elevated temperature post-IR IRSL protocol for K-feldspar was applied to establish a chronology. Internal dose rates of K-feldspar grains were calculated from the measured internal content of potassium, uranium, thorium and rubidium in the bulk of K-feldspar grains using solution ICP-OES and ICP-MS analysis. A substantial scatter in single-aliquot De values was observed which is most probably due to the effect of incomplete bleaching of fluvial sediments before burial. A minimum age model was applied to extract possible depositional ages. The study revealed that except an upper layer of Holocene sediments (< 5m), the majority of the upper ~50m of Cauvery delta sediments were deposited between marine isotope stage MIS-5 and MIS-10 or older. The feldspar luminescence ages also indicate the existence of a period of non deposition or erosion in the upper part of the cores.

A sequence of temporally separated element peaks; the fingerprint of a biogeochemical event initiated by sedimentary exhalative (SEDEX) brine expulsion

2021 ◽  
Author(s):  
Michiel Arts ◽  
Bradley Cramer ◽  
Mikael Calner ◽  
Christian Rasmussen ◽  
Alyssa Bancroft ◽  
...  
Keyword(s):  
High Resolution ◽  
Hydrothermal System ◽  
Type System ◽  
Ore Deposits ◽  
High Resolution Data ◽  
System A ◽  
Xrf Core Scanner ◽  
Extinction Event ◽  
Age Model ◽  
Resolution Data

&lt;p&gt;The Ireviken Biogeochemical Event (IBE) consists of the Ireviken Extinction Event (IEE) and is superseded by the Ireviken positive d13Ccarb Excursion (ICIE). During the Ireviken Extinction Event 80% of the conodont species and 50% of the trilobite species went extinct and Acritarchs, chitinozoans, graptolites, corals, and brachiopods communities were severely affected as well. Currently there are no indications that the Ireviken Biogeochemical event can be linked to a LIP or a bolide impact which are the usual triggers for most known biogeochemical events. The IBE has been tentatively linked to SEDEX brine expulsion, however convincing high-resolution data supporting the SEDEX brine expulsion theory was lacking.&lt;/p&gt;&lt;p&gt;The Altajme core from Gotland Sweden covers the entirety of the Ireviken Biogeochemical Event and using an ITRAX XRF core scanner&amp;#160; we were able to create a new dataset with a 1cm(~150-400 yr.) resolution. This dataset enables us to shed new light on the origin of the IBE and serves as a template for a cyclostratigraphic age model (using the detrital proxies of Ti and Al) which puts the IBE within a precise temporal framework.&lt;/p&gt;&lt;p&gt;The occurrence of peak values of Nb, Mn, Cu, Ba, Pb, Zn, As, Ag in the Altajme core follows the temporal sequence of element peaks which is characteristic for the cooling of a hydrothermal system. A Pb:Zn ratio of &gt;1 and low Cu/(Zn+Pb) ratio categorises the hydrothermal system as being the sedimentary exhalative (SEDEX) brine expulsion type system. Through these results we can undoubtedly link the Ireviken Biogeochemical Event to a SEDEX brine expulsion. Numerous SEDEX style ore deposits of Proterozoic to Cenozoic age are known, but it has been difficult to connect them with similarly aged biogeochemical events. &amp;#160;This study demonstrates that through extremely high resolution XRF/element data we can observe the far-field signature of a SEDEX brine expulsion and thus showing us the way to recognize more biogeochemical events triggered by SEDEX brine expulsions.&amp;#160;&lt;/p&gt;

scholarly journals A Reappraisal of Iberian Copper Age Goldwork: Craftmanship, Symbolism and Art in a Non-funerary Gold Sheet from Valencina de la Concepción

2015 ◽  
Vol 25 (3) ◽  
pp. 565-596 ◽  
Author(s):  
Mercedes Murillo-Barroso ◽  
Manuel Eleazar Costa Caramé ◽  
Marta Díaz-Guardamino Uribe ◽  
Leonardo García Sanjuán ◽  
Coronada Mora Molina
Keyword(s):  
Technology Use ◽  
Raw Material ◽  
Copper Age ◽  
Time Period ◽  
Icp Ms ◽  
The Social ◽  
Depth Analysis ◽  
Unique Item ◽  
Processing Techniques ◽  
Digital Imaging Processing

Taking as a point of departure the in-depth analysis and description of an exceptional discovery, consisting of a large hammered gold sheet decorated with embossed motifs from the well-known Chalcolithic settlement of Valencina de la Concepción (Seville, Spain), this article presents a general appraisal of the social and ideological role of gold in Copper Age Iberia. The information available for this find, including both its context and its inherent characteristics, opens up new perspectives for research into the technology, use, sociology and symbolism of gold during this time period. We describe and analyse this unique item in detail, including the characterization of the raw material used and the manufacturing process (via SEM-BSE and LA-ICP-MS), as well as an extensive reconstruction of the graphic motifs that are represented, by using digital imaging processing techniques (RTI). We compare this find with the data currently available for the (approximately) 100 Chalcolithic golden artefacts (or fragments of artefacts) found in Iberia to date. Finally, we present an appraisal of the social and ideological framework in which gold was used in Copper Age Iberia, discussing its relevance in aspects such as the dynamics of social complexity, worldviews or artistic creations.

scholarly journals The first results of tephrochronological investigations of the late pleistocene-holocene volcanic explosions in the valley of the Zhom-Bolok River (Eastern Sayan)

2019 ◽  
Vol 486 (3) ◽  
pp. 336-340
Author(s):  
A. A. Shchetnikov ◽  
E. V. Bezrukova ◽  
E. V. Kerber ◽  
O. Yu. Belozerova ◽  
M. I. Kuz'min ◽  
...  
Keyword(s):  
Lake Sediments ◽  
Volcanic Activity ◽  
Radiocarbon Dating ◽  
Volcanic Field ◽  
Second Phase ◽  
Volcanic Events ◽  
First Results ◽  
Age Model ◽  
Eastern Sayan ◽  
Volcanic Explosions

This article presents first tephrochronological data on the volcanic activity in the valley of the Jom-Bolok River (East Sayan Mountains, Siberia), which is the largest manifestation of the Holocene eruptions in Central Asia. The data results from our study of the proglacial Kaskadnoe-1 Lake situated near the Jom-Bolok basalt field. The lake sediments include a series of tephra-rich layers. Radiocarbon dating of the lake sediments provided a robust age model which allowed us to build timing of eruptions formed the Jom-Bolok volcanic field. We recognize two large phases of volcanism separated by almost 5 thousand years dormant phase. The first phase is traced back to ca. 14.3 cal ka BP and lasted until 6.3 cal  ka BP. Ten clusters of microtephra layers in the sediments of the first phase show 300-800 years recurrence of the volcanic events weakening upward. The event of 14.3-13.3 cal ka BP probably represents the strongest eruptions of the Jom-Bolok. The second phase started ca. 1.6 cal ka BP and highly likely continues in our days. Its strongest eruptions occurred between 1.6 and 0.8 cal ka BP with periodicity of 200 years. This tephrostratigraphy shows a multiplicity of the Jom-Bolok volcanic events and amplifies the earlier built scheme resulted from investigations of the stratified basalts, pyroclasts and lake damming events.

scholarly journals U–Pb zircon geochronology of volcanic deposits from the Permian basin of the Orobic Alps (Southern Alps, Lombardy): chronostratigraphic and geological implications

2014 ◽  
Vol 152 (3) ◽  
pp. 429-443 ◽  
Author(s):  
FABRIZIO BERRA ◽  
MASSIMO TIEPOLO ◽  
VALERIA CAIRONI ◽  
GIAN BARTOLOMEO SILETTO
Keyword(s):  
Volcanic Activity ◽  
Age Distribution ◽  
Volcanic Rocks ◽  
Southern Alps ◽  
Early Permian ◽  
Large Scatter ◽  
Permian Basin ◽  
Icp Ms ◽  
Eruption Age ◽  
Sedimentary Succession

AbstractU–Pb zircon ages from volcanic rocks of Early Permian age (Southern Alps, Lombardy), associated with fault-controlled transtensional continental basins, were determined with the laser ablation (LA)-ICP-MS technique. Four samples were collected at the base and at the top of the up to 1000 m thick volcaniclastic unit of the Cabianca Volcanite. This unit pre-dates the development of a sedimentary succession that still contains, at different stratigraphic levels, volcanic intercalations. Age results from a tuff in the basal part of the unit constrain the onset of the volcanic activity to 280 ± 2.5 Ma. Ignimbritic samples from the upper part of the unit show a large scatter in the age distribution. This is interpreted as the occurrence of antecrystic and autocrystic zircons. The youngest autocrystic zircons (c. 270 Ma) are thus interpreted as better constraining the eruption age, constraining the duration of the volcanic activity in the Orobic Basin to about 10 Ma. The new geochronological results compared with those of other Early Permian basins of the Southern Alps reveal important differences that may reflect (1) a real time-transgressive beginning and end of the volcanic activity or (2) the complex mixing of antecrystic and autocrystic zircon populations in the analysed samples.

A novel method for stable isotope measurement of gaseous elemental mercury

2020 ◽  
Author(s):  
Satoshi Irei
Keyword(s):  
Collection Efficiency ◽  
Stable State ◽  
Elemental Mercury ◽  
Dead Volume ◽  
Gaseous Elemental Mercury ◽  
Time Period ◽  
Free Air ◽  
Icp Ms ◽  
Novel Method ◽  
Short Time

&lt;p&gt;Here, we introduce a new methodology developed for highly precise stable mercury isotope ratio (&amp;#948;Hg) analysis: the sampling method collecting sufficient amount of gaseous elemental mercury (GEM) from air within 24 h or less and the extraction method effectively converting the collected GEM to Hg&lt;sup&gt;2+&lt;/sup&gt; in less than 10 mL of acidified solution.&lt;/p&gt;&lt;p&gt;A big gold-amalgam trap (BAuT), which has approximately 11 times larger inner diameter of the tube and more gold-amalgam granular than a conventional gold-amalgam trap, was designed for quick and effective sampling of GEM in a short time period. A 24-h sampling demonstrated that the collection efficiency was higher than 99.9% under the flow rate of 55 LPM. Prior to the extraction the collected GEM by BAuT was pre-concentrated to a conventional gold-amalgam trap to reduce the dead volume.&lt;/p&gt;&lt;p&gt;The GEM pre-concentrated was transferred into a four side sealed 2L Tedler bag with a PTFE stopcock by heating the gold-amalgam trap to 600 &amp;#186;C for ~ 4 min under the 0.5 LPM flow of Hg-free air. Prior to this transfer 5mL of 0.5~40% (v/v) reversed aqua resia or RAR (hydrochloric acid: nitric acid = 1:2) was pre-introduced into the bag. The bag with GEM and RAR was left for the conversion of GEM into the stable state in the solution (i.e., Hg&lt;sup&gt;2+&lt;/sup&gt;). The solution recovered was then analyzed by multi collector-ICP-MS for the Hg concentration and &amp;#948;Hg.&lt;/p&gt;&lt;p&gt;Results with a standard reference material showed that the recovery from the test with 10% RAR and the extraction duration of 8 days was the highest, 97%, with the 5% of recovery for the residual GEM in the gas-phase. The &amp;#948;Hg analysis for five isotope ratios exhibited that the accuracy was between 0.01 and 0.3 &amp;#8240;. Results from the analytical tests of ambient GEM using this methodology will be discussed.&lt;/p&gt;

Stability and density management in Douglas-fir plantations

2000 ◽  
Vol 30 (6) ◽  
pp. 910-920 ◽  
Author(s):  
J S Wilson ◽  
C D Oliver
Keyword(s):  
Pseudotsuga Menziesii ◽  
Size Variation ◽  
Douglas Fir ◽  
Potential Range ◽  
Stand Development ◽  
Experimental Plot ◽  
Time Period ◽  
Model Predictions ◽  
D Values ◽  
The Impact

Limited tree size variation in coastal Oregon, Washington, and British Columbia Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) plantations makes them susceptible to developing high height to diameter ratios (H/D same units) in the dominant trees. The H/D of a tree is a relative measure of stability under wind and snow loads. Experimental plot data from three large studies was used to evaluate the impact of initial planting densities and thinning on plantation H/D values. The H/D predictions from the experimental plot data match spacing trial results closely but are substantially different than distance-independent growth model predictions. The results suggest that plantation H/D values can be lowered and stability promoted through reduced planting densities or early thinning; however, later thinnings may not be effective in promoting stability, since they do not appear to lower H/D values. Higher initial planting densities shorten the time period during which thinning can be expected to effectively lower future H/D values. Time-sensitive thinning requirements in dense plantations make their management inflexible. The flexibility with which a stand can be managed describes the rigidity of intervention requirements and (or) potential range of stand development pathways.

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