Formerly-Aragonite Seafloor Fans from Neoproterozoic Strata, Death Valley and Southeastern Idaho, United States: Implications for “Cap Carbonate” Formation and Snowball Earth

2013 ◽  
pp. 33-44 ◽  
Author(s):  
Frank A. Corsetti ◽  
Nathaniel J. Lorentz ◽  
Sara B. Pruss
Keyword(s):  
United States ◽  
Death Valley ◽  
Snowball Earth ◽  
Carbonate Formation ◽  
Cap Carbonate

Geochronological constraints on Neoproterozoic rifting and onset of the Marinoan glaciation from the Kingston Peak Formation in Death Valley, California (USA)

Geology ◽  
2020 ◽  
Vol 48 (11) ◽  
pp. 1083-1087 ◽  
Author(s):  
Lyle L. Nelson ◽  
Emily F. Smith ◽  
Eben B. Hodgin ◽  
James L. Crowley ◽  
Mark D. Schmitz ◽  
...  
Keyword(s):  
Thermal Ionization Mass Spectrometry ◽  
Death Valley ◽  
Snowball Earth ◽  
Ionization Mass ◽  
Glacial Deposit ◽  
Cap Carbonate ◽  
Depositional Age ◽  
Geochronological Constraints ◽  
Kingston Peak Formation ◽  
Discontinuous Fault

Abstract Death Valley (California, USA) hosts iconic Cryogenian snowball Earth deposits, but the lack of direct geochronological constraints has permitted a variety of correlations and age models. Here, we report two precise zircon U-Pb isotope dilution–thermal ionization mass spectrometry dates for the Kingston Peak Formation: a volcanic eruptive age of 705.44 ± 0.28 Ma from the synglacial Limekiln Spring Member, and a maximum depositional age of 651.69 ± 0.64 Ma from the nonglacial Thorndike submember, which is below the Wildrose diamictite. These dates confirm that the Limekiln Spring and Surprise Members were deposited during the Sturtian glaciation, while the Wildrose submember is a Marinoan glacial deposit, and the overlying Sentinel Peak Member of the Noonday Formation is a Marinoan cap carbonate. Additionally, the age from the Thorndike submember supersedes existing radioisotopic ages from the Datangpo Formation in South China as the youngest constraint on the onset of the Marinoan glaciation, demonstrating that the Cryogenian nonglacial interlude lasted for at least 9 m.y. and the Marinoan glaciation was <17 m.y. long. Cryogenian glaciation in western Laurentia occurred against the backdrop of ∼85 m.y. of episodic rift-related subsidence and magmatism within laterally discontinuous, fault-bound basins.

A Remarkable Array: Species Diversity in the United States

2000 ◽  
Author(s):  
Bruce A. Stein ◽  
Larry E. Morse
Keyword(s):  
United States ◽  
North America ◽  
Sea Level ◽  
Eastern China ◽  
The United States ◽  
The Other ◽  
Death Valley ◽  
The Arctic ◽  
Blue Ridge Mountains ◽  
Little Tennessee River

The Carolina hemlock (Tsuga caroliniana) survives in just a few rocky streambeds along the lower slopes of the Blue Ridge Mountains. Other species of hemlock abound across the United States, but none bear a close resemblance to this particular tree. The closest relatives of the Carolina hemlock, in fact, survive in only one other forest on Earth, some 7,000 miles away in Hubei province of eastern China. The forests of eastern Asia and eastern North America are so similar that if you were suddenly transported from one to the other, you would be hard-pressed to tell them apart. In the swift mountain streams rushing past these seemingly displaced hemlocks live a number of small, colorful fish known as darters. Darters are found only in North America and have evolved into a prolific variety of fishes. Up to 175 species inhabit U.S. waters, including the famous snail darter (Percina tanasi), which brought endangered species issues to the fore when it held up construction of the Tellico Dam on the Little Tennessee River. How is it that these two organisms, hemlock and darter, one with its closest relatives on the other side of the globe and the other found nowhere else in the world, came to be living side by side? Just how many plants and animals share the piece of Earth that we know as the United States of America? Why these and not others? These are central questions for understanding the diversity of the nation’s living resources. The United States encompasses an enormous piece of geography. With more than 3.5 million square miles of land and 12,000 miles of coastline, it is the fourth largest country on Earth, surpassed only by Russia, Canada, and China. The nation spans nearly a third of the globe, extending more than 120 degrees of longitude from eastern Maine to the tip of the Aleutian chain, and 50 degrees in latitude from Point Barrow above the Arctic Circle to the southern tip of Hawaii below the tropic of Cancer. This expanse of terrain includes an exceptional variety of topographic features, from Death Valley at 282 feet below sea level to Mt. McKinley at 20,320 feet above sea level.

Ernest Leslie Ransome

2019 ◽  
Vol 96 (3) ◽  
pp. 77-96
Author(s):  
Stephen Mikesell
Keyword(s):  
United States ◽  
Reinforced Concrete ◽  
The United States ◽  
Art Museum ◽  
Death Valley ◽  
Secondary Sources ◽  
History Of ◽  
Culinary Institute Of America ◽  
Historical Accounts ◽  
St Helena

Ernest L. Ransome is a famous but often misunderstood 19th century California engineer and builder. Architectural historians and engineering professionals see him as a central figure in developing reinforced concrete as a usable building material decades before its use became prevalent. He is most commonly recognized as building the first reinforced concrete bridge, San Francisco's Alvord Lake Bridge, which was built in 1890 and is still in use. Historical accounts of his work, however, are based chiefly upon secondary sources and are sometimes incorrect or misleading. This article clarifies Ransome's true role in concrete building in California and debunks misinformation about the famous Alvord Lake Bridge. It traces his career in the United States (he emigrated to California in 1870 at the age of 26), first as a manufacturer of imitation stone and later as a builder of increasingly large and complex buildings and structures. It discusses his work on a series of iconic Northern California buildings and structures: the 1888 Bourn Winery (now the Culinary Institute of America school in St. Helena); the 1890 Torpedo Building, still standing on the Oakland side of Yerba Buena Island; the 1890 Alvord Lake Bridge and its near twin the Conservatory Bridge, both still in use in Golden Gate Park; the 1891 Art Museum, now being used as the Canter Center on the Stanford University campus. It also discusses Ransome's partnership with Sidney Cushing, a railroad magnate in Marin County for whom the Cushing Amphitheater on Mt. Tamalpais was named, and Francis Marion “Borax” Smith, who built the borax industry in Death Valley and who founded and owned the Key System transit in the East Bay. The article concludes with observations about Ransome's true place in the history of concrete engineering in the United States and concrete construction in California.

Ediacaran fossils from the southwestern Great Basin, United States

2000 ◽  
Vol 74 (2) ◽  
pp. 349-359 ◽  
Author(s):  
James W. Hagadorn ◽  
Ben Waggoner
Keyword(s):  
United States ◽  
Great Basin ◽  
Southern Africa ◽  
Lower Cambrian ◽  
Trace Fossils ◽  
Death Valley ◽  
Lower Member ◽  
Upper Third

Ediacaran fossils from the southwestern Great Basin may help constrain regional Vendian-Cambrian biostratigraphy and provide biogeographic links between facies in this region and elsewhere. Locally, trace fossils suggest the Vendian-Cambrian boundary occurs within or below the upper third of the lower member of the Wood Canyon Formation. Ediacaran soft-bodied and tubular fossils, including the frondlike fossil Swartpuntia and tubular, mineralized or agglutinated fossils similar to Archaeichnium Cloudina Corumbella, and Onuphionella occur in the lowermost Wood Canyon Formation. Discoidal forms referred to Nimbia occur in both the lowermost Wood Canyon Formation and the underlying strata of the Stirling Quartzite. These fossils occur directly below Lower Cambrian trace fossils, including Treptichnus pedum, and confirm the persistence of the Ediacaran biota to near the base of the Cambrian. These faunas may also help strengthen previously proposed correlation schemes between the two main facies belts of the southwestern Great Basin (the Death Valley and White-Inyo facies), because a nearly identical Vendian-lowest Cambrian succession of faunas occurs in both regions. Lastly, lack of cosmopolitan Ediacaran faunas in these strata suggests a paleobiogeographic link between the southwestern U.S. and southern Africa in Vendian time.

How tillite weathering during the snowball Earth aftermath induced cap carbonate deposition

Geology ◽  
2012 ◽  
Vol 40 (11) ◽  
pp. 1027-1030 ◽  
Author(s):  
Sébastien Fabre ◽  
Gilles Berger
Keyword(s):  
Snowball Earth ◽  
Cap Carbonate ◽  
Carbonate Deposition

scholarly journals Microbial activity records in Marinoan Snowball Earth postglacial transition layers connecting diamictite with cap carbonate (Otavi Group, NW-Namibia)

2017 ◽  
Vol 110 (1) ◽  
Author(s):  
Ildikó Gyollai ◽  
Márta Polgáry ◽  
Krisztián Fintor ◽  
Elemér Pál-Molnár ◽  
Friedrich Popp ◽  
...  
Keyword(s):  
Microbial Activity ◽  
Snowball Earth ◽  
Transition Layers ◽  
Cap Carbonate
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