scholarly journals Supplemental Material: Metamorphism of the Sierra de Maz and implications for the tectonic evolution of the MARA terrane

2021 ◽  
Author(s):  
A. Tholt ◽  
S.R. Mulcahy ◽  
et al.
Keyword(s):  
Analytical Methods ◽  
Tectonic Evolution ◽  
Mineral Chemistry ◽  
Isotopic Data ◽  
Back Scatter Electron

<div>Analytical methods, garnet compositional maps, a comparison of thermobarometry methods, monazite back-scatter electron images, mineral chemistry, and garnet and monazite isotopic data.<br></div><div><br></div><div><br></div><div><br></div><div><br></div><div><br></div>

Supplemental Material: Metamorphism of the Sierra de Maz and implications for the tectonic evolution of the MARA terrane

2021 ◽  
Author(s):  
A. Tholt ◽  
S.R. Mulcahy ◽  
et al.
Keyword(s):  
Analytical Methods ◽  
Tectonic Evolution ◽  
Mineral Chemistry ◽  
Isotopic Data ◽  
Back Scatter Electron

<div>Analytical methods, garnet compositional maps, a comparison of thermobarometry methods, monazite back-scatter electron images, mineral chemistry, and garnet and monazite isotopic data.<br></div><div><br></div><div><br></div><div><br></div><div><br></div><div><br></div>

scholarly journals Supplemental Material: Metamorphism of the Sierra de Maz and implications for the tectonic evolution of the MARA terrane

2021 ◽  
Author(s):  
A. Tholt ◽  
S.R. Mulcahy ◽  
et al.
Keyword(s):  
Analytical Methods ◽  
Tectonic Evolution ◽  
Mineral Chemistry ◽  
Isotopic Data ◽  
Back Scatter Electron

<div>Analytical methods, garnet compositional maps, a comparison of thermobarometry methods, monazite back-scatter electron images, mineral chemistry, and garnet and monazite isotopic data.<br></div><div><br></div><div><br></div><div><br></div><div><br></div><div><br></div>

LITHOSPHERIC ARCHITECTURE AND TECTONIC EVOLUTION OF THE SOUTHWESTERN U.S. CORDILLERA: CONSTRAINTS FROM ZIRCON HF AND O ISOTOPIC DATA

2018 ◽  
Author(s):  
James B. Chapman ◽  
◽  
Michelle Nikolay Dafov ◽  
George E. Gehrels ◽  
Mihai N. Ducea ◽  
...  
Keyword(s):  
Tectonic Evolution ◽  
Isotopic Data

scholarly journals A unique basaltic micrometeorite expands the inventory of solar system planetary crusts

2009 ◽  
Vol 106 (17) ◽  
pp. 6904-6909 ◽  
Author(s):  
Matthieu Gounelle ◽  
Marc Chaussidon ◽  
Alessandro Morbidelli ◽  
Jean-Alix Barrat ◽  
Cécile Engrand ◽  
...  
Keyword(s):  
Solar System ◽  
Mineral Chemistry ◽  
Carbonaceous Chondrites ◽  
Isotopic Data ◽  
Solar System Formation ◽  
Sample Return ◽  
Dust Transport ◽  
Element Abundances ◽  
Transport Dynamics ◽  
Sample Return Mission

Micrometeorites with diameter ≈100–200 μm dominate the flux of extraterrestrial matter on Earth. The vast majority of micrometeorites are chemically, mineralogically, and isotopically related to carbonaceous chondrites, which amount to only 2.5% of meteorite falls. Here, we report the discovery of the first basaltic micrometeorite (MM40). This micrometeorite is unlike any other basalt known in the solar system as revealed by isotopic data, mineral chemistry, and trace element abundances. The discovery of a new basaltic asteroidal surface expands the solar system inventory of planetary crusts and underlines the importance of micrometeorites for sampling the asteroids' surfaces in a way complementary to meteorites, mainly because they do not suffer dynamical biases as meteorites do. The parent asteroid of MM40 has undergone extensive metamorphism, which ended no earlier than 7.9 Myr after solar system formation. Numerical simulations of dust transport dynamics suggest that MM40 might originate from one of the recently discovered basaltic asteroids that are not members of the Vesta family. The ability to retrieve such a wealth of information from this tiny (a few micrograms) sample is auspicious some years before the launch of a Mars sample return mission.

scholarly journals Different Tectonic Evolution of Fast Cooling Ophiolite Mantles Recorded by Olivine-Spinel Geothermometry: Case Studies from Iballe (Albania) and Nea Roda (Greece)

Minerals ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 64
Author(s):  
Micol Bussolesi ◽  
Giovanni Grieco ◽  
Alessandro Cavallo ◽  
Federica Zaccarini
Keyword(s):  
Tectonic Evolution ◽  
Early Stage ◽  
Mineral Chemistry ◽  
Northern Greece ◽  
Present Contribution ◽  
Cooling Rates ◽  
History Of ◽  
Ferrian Chromite ◽  
Fast Cooling ◽  
Subduction Setting

Mg-Fe2+ diffusion patterns in olivine and chromite are useful tools for the study of the thermal history of ultramafic massifs. In the present contribution, we applied the exponential modeling of diffusion patterns to geothermometry and geospeedometry of chromitite ores from two different ophiolite contexts. The Iballe ophiolite (Northern Albania) hosts several chromitite pods within dunites. Primary and re-equilibrated Mg#, estimated by using an exponential function, provided re-equilibration and primary temperatures ranging between 677 and 996 °C for chromitites and between 527 and 806 °C for dunites. Cooling rates for chromitites are higher than for dunites, suggesting a different genesis for the two lithologies, confirmed also by spinel mineral chemistry. Chromitites with MORB affinity formed in a SSZ setting at a proto-forearc early stage, explaining the higher cooling rates, while dunites, with boninitic affinity, were formed deeper in the mantle in a more mature subduction setting. At the Nea Roda ophiolite (Northern Greece) olivine in chromitites do not show Mg-Fe variations, and transformation into ferrian chromite produced “fake” diffusion patterns within chromite. The absence of diffusion patterns and the low estimated temperatures (550–656 °C) suggest that Nea Roda chromitites were completely re-equilibrated during an amphibolite-facies metamorphic event that obliterated all primary features.

scholarly journals Supplemental Material: Forearc magmatic evolution during subduction initiation: Insights from an Early Cretaceous Tibetan ophiolite and comparison with the Izu-Bonin-Mariana forearc

2020 ◽  
Author(s):  
Jin-Gen Dai ◽  
et al.
Keyword(s):  
Trace Elements ◽  
Trace Element ◽  
Early Cretaceous ◽  
Analytical Methods ◽  
Major And Trace Elements ◽  
Magmatic Evolution ◽  
Isotopic Data ◽  
Subduction Initiation ◽  
Mariana Forearc

Detailed analytical methods in Text S1, major- and trace-element compositions of clinopyroxene, orthopyroxene, and amphibole, whole-rock major and trace elements, Sr-Nd isotopic data, and zircon U-Pb and Lu-Hf data in Tables S1–S7; Figures S1–S5.

Ordo-Silurian assemblage in the Indochina interior: Geochronological, elemental, and Sr-Nd-Pb-Hf-O isotopic constraints of early Paleozoic granitoids in South Laos

2020 ◽  
Vol 133 (1-2) ◽  
pp. 325-346 ◽  
Author(s):  
Yuejun Wang ◽  
Yuzhi Zhang ◽  
Xin Qian ◽  
Vongpaseuth Senebouttalath ◽  
Yang Wang ◽  
...  
Keyword(s):  
Tectonic Evolution ◽  
High Field ◽  
Igneous Rocks ◽  
Early Paleozoic ◽  
Isotopic Data ◽  
High Field Strength ◽  
Tectonic Zone ◽  
Type Granite ◽  
Juvenile Crust ◽  
South Tibet

Abstract In order to verify the early Paleozoic accretionary assemblage in the Indochina interior and constrain the Prototethyan tectonic evolution in Southeast Asia, this study presents a set of new U-Pb geochronological, elemental, and Sr-Nd-Pb-Hf-O isotopic data for the fifty-two representative granitoids in South Laos. The granitoids from the Kontum terrane, Tam Ky-Phuoc Son tectonic zone, and southern Truong Son igneous zone in South Laos yield the crystallization ages of 464–485 Ma, 455–471 Ma, and 427–446 Ma, respectively, with a northerly younging trend within the Indochina interior. They are mainly monzogranite with A/CNK = 0.96–1.99 and K2O &gt; Na2O, which are marked by enrichment in large-ion lithophile elements and depletion in high field strength elements with remarkable Nb-Ta, Sr-P, and Ti negative anomalies. Their initial 87Sr/86Sr ratios range from 0.70510 to 0.71559, εNd(t) from −9.5 to −3.0, (206Pb/204Pb)i from 18.65 to 19.72, (207Pb/204Pb)i from 15.66 to 15.80, and (208Pb/ 204Pb)i from 38.84 to 39.79. The corresponding zircon ɛHf(t) and δ18O values are in the range of −10.6 to +1.0 and 6.88‰ to 8.94‰, respectively. In addition, their Sr-Nd-Pb and Hf-O isotopic compositions are generally similar with those of time-equivalent granitoids in South Tibet and SW Yunnan, China, and synchronous mafic-intermediate igneous rocks in South Laos, but distinctive from those of the supracrustal sedimentary-derived South China Paleozoic granite and Lincang-Sukhothai S-type granite. The early Paleozoic granitoids in South Laos might have originated from a mixed source of the wedge-derived juvenile crust coupled with supracrustal materials. All these data synthetically suggest the southward subduction of the Tam Ky-Phuoc Son Ocean and the northerly on-growing Ordo-Silurian accretionary orogenesis within the previously defined “single-ancient” Indochina block. The assemblage of the Indochina block might initiate at ca. 430 Ma in the Silurian and terminate in the Early-Middle Devonian.

scholarly journals Supplemental Material: Cretaceous to Oligocene magmatic and tectonic evolution of the western Alaska Range: Insights from U-Pb and 40Ar/39Ar geochronology

2020 ◽  
Author(s):  
J.V. Jones III ◽  
et al.
Keyword(s):  
Analytical Methods ◽  
Tectonic Evolution ◽  
Analytical Data ◽  
Alaska Range ◽  
Ar Geochronology

<div>Complete descriptions of all U-Pb and <sup>40</sup>Ar/<sup>39</sup>Ar analytical methods together with detailed analytical data for all samples.<br></div><div><br></div><div><br></div><div><br></div>

scholarly journals Suprasubduction zone ophiolite fragments in the central Appalachian orogen: Evidence for mantle and Moho in the Baltimore Mafic Complex (Maryland, USA)

Geosphere ◽  
2021 ◽  
Author(s):  
George L. Guice ◽  
Michael R. Ackerson ◽  
Robert M. Holder ◽  
Freya R. George ◽  
Joseph F. Browning-Hanson ◽  
...  
Keyword(s):  
New York ◽  
Tectonic Evolution ◽  
Mineral Chemistry ◽  
Bulk Rock ◽  
Suprasubduction Zone ◽  
Tectonic Processes ◽  
Iapetus Ocean ◽  
Mantle Peridotites ◽  
Mafic Complex ◽  
Appalachian Orogen

Suprasubduction zone (SSZ) ophiolites of the northern Appalachians (eastern North America) have provided key constraints on the fundamental tectonic processes responsible for the evolution of the Appalachian orogen. The central and southern Appalachians, which extend from southern New York to Alabama (USA), also contain numerous ultra- mafic-mafic bodies that have been interpreted as ophiolite fragments; however, this interpretation is a matter of debate, with the origin(s) of such occurrences also attributed to layered intrusions. These disparate proposed origins, alongside the range of possible magmatic affinities, have varied potential implications for the magmatic and tectonic evolution of the central and southern Appalachian orogen and its relationship with the northern Appalachian orogen. We present the results of field observations, petrography, bulk-rock geochemistry, and spinel mineral chemistry for ultramafic portions of the Baltimore Mafic Complex, which refers to a series of ultramafic-mafic bodies that are discontinuously exposed in Maryland and southern Pennsylvania (USA). Our data indicate that the Baltimore Mafic Complex comprises SSZ ophiolite fragments. The Soldiers Delight Ultramafite displays geochemical characteristics—including highly depleted bulk-rock trace element patterns and high Cr# of spinel—characteristic of subduction-related mantle peridotites and serpentinites. The Hollofield Ultramafite likely represents the “layered ultramafics” that form the Moho. Interpretation of the Baltimore Mafic Complex as an Iapetus Ocean–derived SSZ ophiolite in the central Appalachian orogen raises the possibility that a broadly coeval suite of ophiolites is preserved along thousands of kilometers of orogenic strike.

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