Introduction: Nakhlites are martian clinopyrox-enites with minor amounts of olivine and mesostasis. All the known nakhlites show similar mineralogy to each other as well as common crystallization and ejection ages and are believed to have formed in the same igneous body on Mars. The discovery of new nakhlites could offer substantial information to better understand the formation condition and g...

First posted February 19, 2021 For additional information, contact: Director, Geology, Geophysics, and Geochemistry Science CenterU.S. Geological SurveyBox 25046, MS-973Denver, CO 80225-0046 The igneous geology of the St. Francois Mountains terrane in southeast Missouri is dominated by products 1.48 to 1.45 billion year old volcanic plutonic magmatism but also includes volumetrically minor, com...

A fractal (power-law) distribution is the only statistical distribution applicable to a scale-invariant process. One of the major problems in petrology is the distribution of trace elements in the Earth’s crust. Extreme values of this distribution result in ore deposits. There is accumulating observational evidence that tonnage–grade statistics of ore deposits are often fractal (powerlaw). Rayl...

U–Pb ages of 637 new detrital zircons Triassic sandstones from the Northwestern Sichuan Basin (NWSB), together with petrology and paleocurrent data, are used to constrain sediment provenance tectonic–paleogeographic evolution western Yangtze Block. The age data for Lower generally show populations at ∼1,850 Ma, 980–705 680–510 290–230 Ma a minor cluster ∼2.4 Ga. Such spectrum features eastward ...