Results 51 to 60 of about 34,086 (157)

Artifact geochemistry demonstrates long-distance voyaging in the Polynesian Outliers. [PDF]

Sci Adv, 2023
Hermann A, Gutiérrez P, Chauvel C, Maury R, Liorzou C, Willie E, Phillip I, Forkel R, Rzymski C, Bedford S.   +9 more
europepmc   +1 more source

Molecular Structure and Rotational Dynamics in the Acetonitrile:Acetylene (1:2) Plastic Co-Crystal at Titan Conditions [PDF]

arXiv
The surface of Saturn's moon Titan is coated with small molecule organic solids termed cryominerals. Cryominerals play an analogous role to minerals on Earth in Titan's surface geology and geochemistry. To develop a predictive understanding of Titan's surface geochemistry, we need to characterize the structure and dynamics of cryominerals at the ...
arxiv  

A ~60 Myr periodicity is common to marine-87Sr/86Sr, fossil biodiversity, and large-scale sedimentation: what does the periodicity reflect? [PDF]

Journal of Geology, 120, 217-226 (2012), 2012
We find that the marine 87Sr/86Sr record shows a significant periodicity of 59.3 \pm 3 Myr. The 87Sr/86Sr record is 171{\deg} \pm 12{\deg}out of phase with a 62 (\pm 3) Myr periodicity previously reported in the record of marine-animal diversity. These periodicities are close to 58 (\pm 4) Myr cycles found for the number of gap-bounded sedimentary ...
arxiv  

Multi‐Stage Growth of Kyanite in Migmatites Interpreted by Integrating Forward Thermodynamic Modelling and Trace Element Signature

Journal of Metamorphic Geology, Volume 43, Issue 4, Page 315-339, May 2025.
ABSTRACT Trace element zoning in kyanite can retain information about its growth history, particularly in anatectic metapelites. There, kyanite can grow (i) at sub‐solidus conditions through metamorphic reactions involving other aluminous phases as reactants, (ii) through muscovite dehydration melting reactions, and (iii) during cooling and melt ...
Sara Nerone, Chiara Groppo, Mónica Ágreda‐López, Maurizio Petrelli, Franco Rolfo   +4 more
wiley   +1 more source

Chemistry of the Earth's Earliest Atmosphere [PDF]

arXiv, 2012
In this chapter we describe chemistry of the early atmosphere of the Earth during and shortly after its formation where there is little if any geological record. We review the arguments for a secondary origin of the terrestrial atmosphere, that is by outgassing during and/or after accretion rather than by capture of solar nebula gas.
arxiv  

A New UHP‐HP Tectono‐Metamorphic Architecture for the Southern Dora‐Maira Massif Nappe Stack (Western Alps) Based on Petrological and Microstructural Evidence

Journal of Metamorphic Geology, Volume 43, Issue 4, Page 359-383, May 2025.
ABSTRACT The southern Dora‐Maira Massif, where coesite was first discovered 40 years ago, is among the most studied and better known example of high/ultra‐high‐pressure (HP/UHP) terranes. Previous to this study, the Polymetamorphic Basement Complex of the southern Dora‐Maira Massif has been defined as a nappe stack consisting of three juxtaposed ...
Chiara Groppo, Simona Ferrando, Fabrizio Tursi, Franco Rolfo   +3 more
wiley   +1 more source

Martian Methyl Chloride. A lesson in uncertainty [PDF]

arXiv, 2013
The MSL Lander Curiosity has recently detected methyl halides coming from heated samples of Martian soil. This is reminiscent of similar findings in the Viking Lander spacecraft. In the 1970s a consensus developed quickly explaining the methyl halides as contamination originating from the spacecraft, and ignoring lines of evidence that the two ...
arxiv  

Equilibrium Silicon Isotope Fractionation in Eclogites and Granites Constrained by Single Crystal X‐Ray Diffraction and the Force Constants Approach

Geophysical Research Letters, Volume 52, Issue 8, 28 April 2025.
Abstract Using our recently developed X‐ray diffraction based force constants approach, we have determined the equilibrium Si isotope fractionation between omphacite/garnet, quartz/kyanite, and quartz/zircon at temperatures relevant to the petrogenesis. We find that Na strongly affects the Si isotope fractionation between omphacite and garnet.
Dongzhou Zhang, Jingui Xu, Przemyslaw K. Dera, Bin Chen, Ming Chen   +4 more
wiley   +1 more source

The First Near‐Real‐Time Compatible Numerical Method for Co‐Seismic Ionospheric Disturbances Simulation

Geophysical Research Letters, Volume 52, Issue 8, 28 April 2025.
Abstract Numerous studies demonstrated a huge potential for ionospheric total electron content (TEC) measurements to be included in earthquake and tsunami risk assessments. However, up to now, only a few methodologies or tools can be used in near‐real‐time (NRT) for these purposes.
S. A. Sanchez, E. A. Kherani, E. Astafyeva, E. R. de Paula   +3 more
wiley   +1 more source

Mercury's Tidal Love Number h2 ${h}_{2}$ From Co‐Registration of MLA Profiles

Geophysical Research Letters, Volume 52, Issue 7, 16 April 2025.
Abstract Due to its eccentric orbit, Mercury experiences a varying gravitational pull from the Sun along its orbit, leading to periodic surface tidal deformation. The previous measurement of Mercury's tidal h2 ${h}_{2}$ by Bertone et al. (2021, https://doi.org/10.1029/2020je006683) is based on minimizing height differences at cross‐overs of the Mercury
Haifeng Xiao, Alexander Stark, Gregor Steinbrügge, Arthur Briaud, Luisa M. Lara, Pedro J. Gutiérrez   +5 more
wiley   +1 more source