MAGMATISM IN THE EOCENE EMIGRANT PASS VOLCANIC FIELD, NORTHERN NEVADA: TRACE ELEMENT AND ISOTOPIC INDICATORS OF MAGMA SOURCES AND CRUSTAL INFLUENCES

2020 ◽  
Author(s):  
Sabrina Chan ◽  
◽  
Brian Cousens ◽  
Christopher Henry
Keyword(s):  
Trace Element ◽  
Volcanic Field ◽  
Northern Nevada ◽  
Magma Sources

scholarly journals Supplemental Material: Postcaldera intrusive magmatism at the Platoro caldera complex, Southern Rocky Mountain volcanic field, Colorado, USA

2021 ◽  
Author(s):  
A.K. Gilmer ◽  
et al.
Keyword(s):  
Trace Element ◽  
Rocky Mountain ◽  
Volcanic Field ◽  
Trace Element Geochemistry ◽  
Zircon Geochronology ◽  
Element Geochemistry ◽  
Isotopic Compositions ◽  
Southern Rocky Mountain

<div>Table S1: Whole-rock compositions of analyzed samples. Table S2: Major and trace element geochemistry of feldspar. Table S3: Major and trace element geochemistry of pyroxene. Table S4: Major and trace element geochemistry of biotite. Table S5: Major and trace element geochemistry of amphibole. Table S6: Zircon geochronology and trace element geochemistry. Table S7: Lutetium and hafnium isotopic compositions of zircon. Table S8: Amphibole-plagioclase thermometry. Table S9: Sample locations and lithologies.<br></div>

Petrographic, Geochemical and Isotopic (Sr–Nd–Pb–Os) Study of Plio-Quaternary Volcanics and the Tertiary Basement in the Jorullo-Tacámbaro Area, Michoacán-Guanajuato Volcanic Field, Mexico

2019 ◽  
Vol 60 (12) ◽  
pp. 2317-2338 ◽  
Author(s):  
Marie-Noëlle Guilbaud ◽  
Claus Siebe ◽  
Christine Rasoazanamparany ◽  
Elisabeth Widom ◽  
Sergio Salinas ◽  
...  
Keyword(s):  
Trace Element ◽  
Crustal Contamination ◽  
Volcanic Belt ◽  
Volcanic Field ◽  
Calc Alkaline ◽  
Trace Element Pattern ◽  
Alkaline Rocks ◽  
Rock Types ◽  
Oceanic Sediments ◽  
Element Pattern

Abstract The origin of the large diversity of rock types erupted along the subduction-related Trans-Mexican Volcanic Belt (TMVB) remains highly debated. In particular, several hypotheses have been proposed to explain the contemporary eruption of calc-alkaline and alkaline magmas along the belt. The Michoacán-Guanajuato Volcanic Field (MGVF) is an atypical, vast region of monogenetic activity located in the western-central part of the TMVB. Here we present new petrographic, geochemical, and isotopic (Sr–Nd–Pb–Os) data on recent volcanics in the Jorullo-Tacámbaro area that is the closest to the oceanic trench. TMVB-related volcanics in this area are Plio-Quaternary (&lt;5 Ma) and mainly form a calc-alkaline series from basalts to dacites, with rare (&lt;5 vol. %) alkaline rocks that range from trachybasalts to trachydacites, and transitional samples. Crystal textures are consistent with rapid crystallization at shallow depth and processes of mixing of similar magma batches (magma recharge). All of the samples exhibit an arc-type trace element pattern. Alkaline and transitional magmas have higher Na2O and K2O, lower Al2O3, and higher concentrations in incompatible elements (e.g. Sr, K, Ba, Th, Ce, P) compared to calc-alkaline rocks. Calc-alkaline rocks are similar isotopically to transitional and alkaline samples, except for a few low 87Sr/86Sr samples. Sr, Nd and Pb isotopes do not correlate with MgO or 187Os/188Os, indicating that they were not significantly influenced by crustal contamination. Isotopic and trace-element systematics suggest that the Tacámbaro magmas are produced by melting of a mantle wedge fluxed by fluids derived from a mixture of subducted sediments and altered oceanic crust. Alkaline and transitional magmas can be derived from a lower degree of partial melting of a similar source to that of the calc-alkaline rocks, whereas the few low 87Sr/86Sr calc-alkaline rocks require a lower proportion of fluid derived from oceanic sediments and crust. Volcanism at the trenchward edge of the MGVF was thus driven purely by subduction during the last 5 Ma, hence discarding slab rollback in this sector of the TMVB.

scholarly journals Trace-Element and Pb Isotope Evidence on Extracting Sulfides from Potassic Melts beneath Longmenshan and Molabushan Volcanoes, Wudalianchi, Northeast China

Minerals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 319 ◽  
Author(s):  
Sergei Rasskazov ◽  
Yi-Min Sun ◽  
Irina Chuvashova ◽  
Tatyana Yasnygina ◽  
Chen Yang ◽  
...  
Keyword(s):  
Trace Element ◽  
Volcanic Rocks ◽  
Volcanic Field ◽  
Lava Flows ◽  
Pb Isotope ◽  
Linear Pattern ◽  
Wide Range ◽  
Mantle Sources ◽  
Isotope Evidence ◽  
Isotope Study

In the Wudalianchi volcanic field, eruptions started with low-Mg potassic lava flows 2.5–2.0 Ma ago and later changed to both low- and moderate-Mg potassic compositions. Volcanic rocks from the Molabushan and Longmenshan volcanoes record an unusually wide range of Pb abundances (from 3.7 ppm to 21 ppm relative to predominant range of 10–15 ppm). To determine the cause of these, we performed a comparative trace-element and Pb isotope study of rocks from these volcanoes and older lava flows. On a uranogenic lead diagram, older low-Mg lavas from lithospheric mantle sources plot on a secondary isochron with a slope corresponding to an age of 1.88 Ga. This contrasts with moderate-Mg volcanic rocks from the Molabushan cone, interpreted to have been derived from a recent convective mantle source, which define a flat linear pattern. Low-Mg rocks from the Molabushan flow have lead isotopic compositions that indicate mixed Gelaqiu and Molabu sources. Relative to rocks from the Molabushan cone, moderate-Mg lavas and slags from the East Longmenshan volcano have modified compositions characterized by Pb, S, and Ni abundances, Ni/Co, Ni/MgO ratios as well as 206Pb/204Pb, 207Pb/204Pb, 208Pb/204Pb, Ce/Pb, Th/Pb, and U/Pb ratios. We infer that the older Wudalianchi magmas were likely derived from a Paleoproterozoic lithospheric fragment, related to the evolved primordial mantle, and that later magmas were generated in the convecting mantle. These were influenced by segregation of small amounts of sulfides.

Origin and evolution of the lowermost lava successions at Santorini volcano (Greece): insights from major and trace element composition of rocks from the submarine caldera wall

2021 ◽  
Author(s):  
Katharina Pank ◽  
Thor H. Hansteen ◽  
Jörg Geldmacher ◽  
Dieter Garbe-Schönberg ◽  
Brian Jicha ◽  
...  
Keyword(s):  
Trace Element ◽  
Bronze Age ◽  
Magma Mixing ◽  
Volcanic Field ◽  
Trace Element Composition ◽  
Published Data ◽  
Caldera Wall ◽  
Remotely Operated Vehicle ◽  
Origin And Evolution ◽  
Santorini Volcano

&lt;p&gt;Santorini volcano in the central sector of the South Aegean volcanic arc is one of the most active and potentially dangerous magmatic systems in Europe having had twelve Plinian eruptions over the last 350&amp;#160;ka of which at least four eruptions were accompanied by caldera collapses. The well-known Late Bronze Age eruption (~3.6&amp;#160;ka&lt;sup&gt;A&lt;/sup&gt;) for example is considered to rank as one of the largest eruptions since the Late Miocene.&lt;/p&gt;&lt;p&gt;The main focus of research thus far has been on the comparatively young and subaerial deposits, whereas older stages of volcanism have been poorly studied. Our study comprises samples from the submarine caldera flanks and gives new insights into the early evolutionary stages of Santorini volcano, contributing to a better understanding of its eruptive history and potential risks. The submarine lava successions were sampled along the inner caldera wall by a remotely operated vehicle (ROV) during R/V POSEIDON cruise 511 in 2017.&lt;/p&gt;&lt;p&gt;The investigated lavas can be divided into two magmatic series: a low-K basaltic series overlain by medium- to high-K series, including basaltic andesites, andesites and occasional dacites. First results of &lt;sup&gt;40&lt;/sup&gt;Ar/&lt;sup&gt;39&lt;/sup&gt;Ar dating reveal ages of ~250&amp;#160;ka for the andesites. For the presumably older basalts, no reliable age data could be obtained.&lt;/p&gt;&lt;p&gt;Major and trace element compositions and mineral zoning patterns suggest that fractional crystallization was the dominant process controlling magma evolution. In addition, repeated magma mixing played an important role as indicated by characteristic zonation patterns within plagioclase and clinopyroxene ante- and phenocrysts. Comparison of the major and trace element compositions with published data from subaerial deposits show a strong similarity between our lavas and the ~528-308&amp;#160;ka&lt;sup&gt;A&lt;/sup&gt; old deposits of Peristeria volcano, a composite stratocone in the north of the volcanic field and whose subaerial deposits are found on northern Thera only&lt;sup&gt;B&lt;/sup&gt;. This similarity is also supported by the Sr-Nd-Pb isotopic compositions of our lavas. Our results indicate both an extended age range of Peristeria activity and a much wider geographic distribution of its lava flows than previously recognized.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;&lt;sup&gt;A&lt;/sup&gt; T.&amp;#160;H. Druitt et al. (1999), Santorini Volcano, Geological Society of London Memoir&lt;/p&gt;&lt;p&gt;&lt;sup&gt;B&lt;/sup&gt; T.&amp;#160;H. Druitt et al. (2015): Field guide to Santorini Volcano&lt;/p&gt;

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