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Punctuated sediment discharge during early Pliocene birth of the Colorado River: Evidence from regional stratigraphy, sedimentology, and paleontology
The Colorado River in the southwestern U.S. provides an excellent natural laboratory for studying the origins of a continent-scale river system, because deposits that formed prior to and during river initiation are well exposed in the lower river valley and nearby basinal sink. This paper presents a synthesis of regional stratigraphy,...
Dorsey, Rebecca J.; O’Connell, Brennan; McDougall-Reid, Kristin; Homan, Mindy B. Ore-forming adakitic porphyry produced by fractional crystallization of oxidized basaltic magmas in a subcrustal chamber (Jiamate, East Junggar, NW China)
Adakitic intrusions are supposed to have a close genetic and spatial relationship to porphyry Cu deposits. However, the genesis of adakitic intrusions is still under dispute. Here, we describe newly discovered intrusive complex rocks, which are composed of ore-bearing, layered magnetite-bearing gabbroic and adakitic rocks in Jiamate, East Junggar...
Hong, Tao; Xu, Xing-Wang; Gao, Jun; Peters, Stephen; Zhang, Di; Jielili, Reyaniguli; Xiang, Peng; Li, Hao; Wu, Chu; You, Jun; Liu, Jie; Ke, Qiang Networking our science to characterize the state, vulnerabilities, and management opportunities of soil organic matter
Soil organic matter (SOM) supports the Earth's ability to sustain terrestrial ecosystems, provide food and fiber, and retains the largest pool of actively cycling carbon. Over 75% of the soil organic carbon (SOC) in the top meter of soil is directly affected by human land use. Large land areas have lost SOC as a result of land use practices, yet...
Harden, Jennifer W.; Hugelius, Gustaf; Ahlström, Anders; Blankinship, Joseph C.; Bond-Lamberty, Ben; Lawrence, Corey; Loisel, Julie; Malhotra, Avni; Jackson, Robert B.; Ogle, Stephen M.; Phillips, Claire; Ryals, Rebecca; Todd-Brown, Katherine; Vargas, Rodrigo; Vergara, Sintana E.; Cotrufo, M. Francesca; Keiluweit, Marco; Heckman, Katherine; Crow, Susan E.; Silver, Whendee L.; DeLonge, Marcia; Nave, Lucas E. Element migration of pyrites during ductile deformation of the Yuleken porphyry Cu deposit (NW-China)
The strongly deformed Yuleken porphyry Cu deposit (YPCD) occurs in the Kalaxiangar porphyry Cu belt (KPCB), which occupies the central area of the Central Asian Orogenic Belt (CAOB) between the Sawu’er island arc and the Altay Terrane in northern Xinjiang. The YPCD is one of several typical subduction-related deposits in the KPCB, which has...
Hong, Tao; Xu, Xing-Wang; Gao, Jun; Peters, Stephen; Li, Jilei; Cao, Mingjian; Xiang, Peng; Wu, Chu; You, Jun Control of landslide volume and hazard by glacial stratigraphic architecture, Northwest Washington state, USA
Landslide volumes span many orders of magnitude, but large-volume slides tend to travel farther and consequently can pose a greater hazard. In northwest Washington State, USA, a landscape abounding with landslides big and small, the recent occurrence of the large-volume and tragically deadly State Route 530 (Oso) landslide is a stark reminder of...
Perkins, Jonathan; Reid, Mark E.; Schmidt, Kevin M. Analysis of the age and paleomagnetic orientation of the Broadwell Mesa Basalt, Bristol Mountains, CA
To add to the regional paleomagnetic data documenting block rotation in eastern California, we determined the age and paleomagnetic rotation of the Broadwell Mesa basalt, a basalt in the Bristol Mountains, CA as part of an effort to constrain the timing and rotation of blocks adjacent to the fault. The east-striking sinistral Broadwell Mesa fault...
Phelps, Geoffrey; Hillhouse, John; Fleck, Robert J.; Miller, David M.; Buesch, David C.; Cyr, Andrew J.; Schmidt, Kevin M.
Evaluation of hypotheses for right-lateral displacement of Neogene strata along the San Andreas Fault between Parkfield and Maricopa, California
We used geological field studies and diatom biostratigraphy to test a published hypothesis that Neogene marine siliceous strata in the Maricopa and Parkfield areas, located on opposite sides of the San Andreas Fault, were formerly contiguous and then were displaced by about 80–130 kilometers (km) of right-lateral slip along the fault. In the...
Stanley, Richard G.; Barron, John A.; Powell, Charles L.
Fluorine
Fluorine compounds are essential in numerous chemical and manufacturing processes. Fluorspar is the commercial name for fluorite (isometric CaF2), which is the only fluorine mineral that is mined on a large scale. Fluorspar is used directly as a fluxing material and as an additive in different manufacturing processes. It is the source of fluorine...
Schulz, Klaus J.; DeYoung,, John H.; Seal, Robert R.; Bradley, Dwight C.; Hayes, Timothy S.; Miller, M. Michael; Orris, Greta J.; Piatak, Nadine M.
Platinum-group elements
The platinum-group elements (PGEs)—platinum, palladium, rhodium, ruthenium, iridium, and osmium—are metals that have similar physical and chemical properties and tend to occur together in nature. PGEs are indispensable to many industrial applications but are mined in only a few places. The availability and accessibility of PGEs could be disrupted...
Schulz, Klaus J.; DeYoung,, John H.; Seal, Robert R.; Bradley, Dwight C.; Zientek, Michael L.; Loferski, Patricia J.; Parks, Heather L.; Schulte, Ruth F.; Seal, Robert R.
Rhenium
Rhenium is one of the rarest elements in Earth’s continental crust; its estimated average crustal abundance is less than 1 part per billion. Rhenium is a metal that has an extremely high melting point and a heat-stable crystalline structure. More than 80 percent of the rhenium consumed in the world is used in high-temperature superalloys,...
Schulz, Klaus J.; DeYoung,, John H.; Seal, Robert R.; Bradley, Dwight C.; John, David A.; Seal, Robert R. ; Polyak, Désirée E.
Tin
Tin (Sn) is one of the first metals to be used by humans. Almost without exception, tin is used as an alloy. Because of its hardening effect on copper, tin was used in bronze implements as early as 3500 B.C. The major uses of tin today are for cans and containers, construction materials, transportation materials, and solder. The predominant ore...
Schulz, Klaus J.; DeYoung,, John H.; Seal, Robert R.; Bradley, Dwight C.; Kamilli, Robert J.; Kimball, Bryn E.; Carlin, James F. Connecting the Soda–Avawatz and Bristol–Granite Mountains faults with gravity andaeromagnetic data, Mojave Desert, California
The Soda–Avawatz and Bristol–Granite Mountains faults are considered by some to form the northeastern margin of the eastern California shear zone yet their connectivity and extents are obscured by surficial deposits and the estimates of total right-lateral offset from geologic data range from 0 to as much as 24 km. We use gravity and recently...
Langenheim, Victoria; Miller, David M.