The composition of igneous rocks in the continental crust has changed throughout Earth's history. However, the impact of these compositional variations on chemical weathering, and by extension on seawater and atmosphere evolution, is largely unknown. We use the strontium isotope ratio in seawater [(87Sr/86Sr)seawater] as a proxy for chemical weathering, and we test the sensitivity of (87Sr/86Sr...

Shea, M. and Foland, K.A., 1986. The Marysvale Natural Analog Study: Preliminary oxygen isotope relations. In: N.A. Chapman and J.A.T. Smellie (Guest-Editors), Natural Analogues to the Conditions around a Final Repository for High-level Radioactive Waste. Chem. Geol., 55: 281--295. Rocks of and around the Marysvale mining area in central Utah, U.S.A., have experienced massive, subsolidus hydrot...

Palaeoproterozoic high-K I-type granites, high-level porphyry intrusions, and felsic volcanic rocks of the Whitewater Volcanics dominate the Hooper and Lamboo Complexes in the Kimberley region of northwestern Australia. The granites, porphyries and volcanic rocks are gradational into each other in the field, and they have the same mineralogy, similar major and trace element abundances, and indi...

Article history: Received 6 October 2016 Accepted 29 January 2017 Available online 08 February 2017 Widespread Late Triassic granitoid rocks in the SouthQinling Belt (SQB) represent excellent subjects to study the geochemical and geodynamic evolution of magmatic rocks during the collision between the North China Craton and South China Block. In this study, we report new geological, geochemical,...

The Jones Mountains (lat. 73°30’ S, long. 94° W) were discovered in January, 1960. In November of the same year, a University of Minnesota party led by Cam Craddock initiated studies of the geology of this previously unknown small group of mountains. The rocks exposed in this east-west trending group consist of a Mesozoic basement complex of granites in fault contact with younger felsic rocks. ...

INTRODUCTION A variety of mantle-derived igneous rocks comprise the primary sources of diamond, with the principal hosts being kimberlite and lamproite. Primary diamonds or graphite pseudomorphs after diamond are also known to occur in some lamprophyres (Jaques, Kerr et al., 1989), alkali basalts and alpine type peridotites (Kaminskii, 1984). Significant quantities of diamond have not yet been ...

Meta-ultramafi c rocks occur as small (2 to 100 m long), podiform bodies in all three major Precambrian rock suites of the Tobacco Root Mountains of southwest Montana. Most samples consist of a randomly oriented, coarse-grained assemblage of orthopyroxene, olivine, and magnesiohornblende ± spinel, partially replaced by a fi ne-grained assemblage that may include anthophyllite, talc, cummingtoni...

Clay-rich sediments from the Kajjansi, Kitiko, Kitetika, and Ntawo valleys in central Uganda were analyzed for mineralogical and chemical composition, including the rare earth element (REE) contents. The valleys are filled with Quaternary to Recent alluvial and lacustrine sands, silt, and gravels, which formed from the bed rock metasediments of the Buganda-Toro System and from granitoid rocks t...

Sedimentary rocks have complicated permeability fluctuations arising from the geological processes that formed them. These permeability fluctuations significantly affect the flow of fluids through the rocks. We analyze data on two sandstone samples from different geological environments, and find that the permeability fluctuations display long-range power-law correlations characterized by an ex...

Citation: Lupoi JS, Fritz LP, Parris TM, Hackley PC, Solotky L, Eble CF and Schlaegle S (2017) Assessment of Thermal Maturity Trends in Devonian–Mississippian Source Rocks Using Raman Spectroscopy: Limitations of Peak-Fitting Method. Front. Energy Res. 5:24. doi: 10.3389/fenrg.2017.00024 assessment of Thermal Maturity Trends in Devonian–Mississippian source rocks Using raman spectroscopy: limit...