Results 21 to 30 of about 1,456,955 (125)

Evaporitic Chert Provenance: Evaluating Petrographic and Geochemical Workflows for Source Discrimination

Archaeometry, EarlyView.
ABSTRACT Chert tools were widely used in prehistory by human societies due to their knapping suitability and availability, but their relatively uniform composition, especially in evaporitic cherts, complicates sourcing, requiring specialised analytical methods.
Bruno Gómez de Soler, Pablo Rodríguez‐Salgado, Maurice Brodbeck, Judit Bria, Thomas Belgrano, Julian Menuge   +5 more
wiley   +1 more source

Numerical modelling of mud volcanoes and their flows using constraints from the Gulf of Cadiz [PDF]

, 2003
It is estimated that the total number of submarine mud volcanoes is between 1000 and 100 000. Because many are associated with greenhouse gases, such as methane, it is argued that the global flux of these gases to the atmosphere from the world’s ...
Murton, B, Biggs, CJ, Biggs, J., Murton, B.J.   +3 more
core   +1 more source

Influence of Laser Repetition Rate, Fluence and Spot Size on LA‐Q‐ICP‐MS/MS 87Sr/86Sr Precision: Insights from Apatites and Silicate Glasses

Geostandards and Geoanalytical Research, EarlyView.
Key Points Higher laser repetition rate, fluence and larger spot size increase signal intensity. Higher laser repetition rate produces overlaps in aerosolised particles, improving signal stability and precision. For Sr‐rich materials, moderate spot diameter (≤ 60 μm), 3 J cm‐2 fluence and ≥ 12 Hz repetition rate are recommended.
Edafe O. Ominigbo, David T. Murphy, Kate E. Jenkins, Mitchell de Bruyn, Karine H. Moromizato   +4 more
wiley   +1 more source

Points vs. passes: A comparison between electric fishing techniques for sampling fish populations in upland headwater streams

Journal of Fish Biology, EarlyView.
Abstract Point‐abundance sampling by electric fishing (PASE) was compared with single‐pass (DF1) and triple‐pass depletion sampling (DF3) electric fishing on the same reaches of four headwater streams sampled over multiple years in the Ribble catchment, UK. Juvenile salmonids, mostly brown trout Salmo trutta with some Atlantic salmon S.
Reagan H. Pearce, Martin R. Perrow, Mark L. Tomlinson, Kirsty A. Turner   +3 more
wiley   +1 more source

Coupled plagioclase dissolution and K‐feldspar overgrowth precipitation preserve anomalously high permeability in deeply buried sandstones

Sedimentology, EarlyView.
ABSTRACT This study investigated the formation mechanism responsible for anomalously high permeability (AHP) observed in the Eocene sandstones at depths from 3824 to 3832 m in the Huizhou Sag, Pearl River Mouth Basin, China, using helium porosity and permeability measurements, thin section, scanning electron microscopy, electron probe X‐ray ...
Changgui Xu, Huan Li, Wei Wang, Yangdong Gao, Guangrong Peng, Lin Ding, Eric O. Ansah, Pei Liu, Xiaoyan Li, Saju Menacherry, Hongtao Zhu, Xianghua Yang, Zhiwei Zeng   +12 more
wiley   +1 more source

Origin and fluxes of atmospheric REE entering an ombrotrophic peat bog in Black Forest (SW Germany): Evidence from snow, lichens and mosses [PDF]

, 2006
The fate of the Rare Earth Elements (REE) were investigated in different types of archives of atmospheric deposition in the Black Forest, Southern Germany: (1) a 70 cm snow pack collected on the domed part of a raised bog and representing 2 months of ...
Le Roux, Gaël, Aubert, D., Stille, Peter, Krachler, Michael, Shotyk, William, Kober, B., Kober, Bernd, Aubert, Dominique, Krachler, M., Stille, P., Shotyk, W., Le Roux, G., Cheburkin, A., Cheburkin, Andriy   +13 more
core   +1 more source

REE geochemistry of some alkali-rich intrusive rocks in China

, 1997
Based on the REE analyses of about 300 samples from 40 alkali-rich intrusive rocks, a systematic study on the features of REE composition was made, and the major factors controlling the REE distribution are discussed.
Zhou, LD, Zhao, ZH
core   +1 more source

Conditions and timing for the precipitation of early marine diagenetic dolomite in the Triassic Dolomia Principale (northern Italy)

Sedimentology, EarlyView.
ABSTRACT Thermodynamic constraints and empirical evidence often suggest that fabric‐retentive replacement dolomites are stable carbonate minerals that preserve ancient seawater properties. This study evaluates this hypothesis by examining the Upper Triassic Dolomia Principale in Northern Italy.
Vivien Folliot, Giovanna Della Porta, Mathias Mueller, Fabrizio Berra, Benjamin F. Walter, Aratz Beranoaguirre, Sylvia Riechelmann, Oskar Schramm, Adrian Immenhauser   +8 more
wiley   +1 more source

Siliceous sponges or seawater as a silicon source? Tracing silicon burial pathways of the Upper Cretaceous opal‐CT deposits using δ30Si and δ7Li

Sedimentology, EarlyView.
ABSTRACT Classical models of formation of sedimentary siliceous rocks (flint, chert, opoka) commonly assume that the Cretaceous marine silicon (Si) cycle was primarily biologically controlled, broadly analogous to the modern ocean. In this framework, siliceous sponges are regarded as the principal source of dissolved silica (dSi) to sediment porewaters,
Agata Jurkowska, Ewa Świerczewska‐Gładysz, Marek Szczerba, Tomáš Magna, Szymon Kowalik Filipowicz   +4 more
wiley   +1 more source

Salt Range Formation of Pakistan Preserves Unique Record of Volcanic Fertilization During the Ediacaran Shuram Excursion

Terra Nova, EarlyView.
ABSTRACT Thin, discontinuous, organic‐rich oil shale beds in the siliciclastic‐evaporitic Salt Range Formation (SRF) of Pakistan are of approximate Neoproterozoic to Cambrian age based on stratigraphic constraints. The beds are enriched (26–43 wt.% total organic carbon, TOC) in aliphatic organic matter (OM) of low thermal maturity despite their ...
Paul C. Hackley, Ryan J. McAleer, Jay M. Thompson, Brett J. Valentine, Imran Khan   +4 more
wiley   +1 more source