Geotimes

Geotimes is a free electronic newsfeed for the geoscience community. Originally launched as GeoSpectrum, a newsletter of the American Geosciences Institute in 1995, Geotimes has been reborn as the go-to source of information on AGI's 52 Member Societies. The American Geosciences Institute coordinates and edits Geotimes, but it is the result of contributed materials from societies, geoscience organizations and others in the community.

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UMD: Jackson on core formation

2018 University of Maryland Geology Colloquium Series

Friday, January 26th 2018 at 3:00 pm
in PLS 1140

Colin Jackson
Smithsonian Institution

Early episodes of high-pressure core formation preserved in plume mantle

Dividing line: The past, present and future of the 100th Meridian

In 1878, John Wesley Powell first advanced the idea that the climatic boundary between the United States’ humid East and arid West lay along the 100th meridian, which
runs from pole to pole and, today, cuts through six U.S. states. But what does it really mean, and what is its future?

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cement [materials]

cement [materials] (ce-ment'). A manufactured gray powder which when mixed with water makes a plastic mass that will "set" or harden. It is combined with an aggregate to make concrete. Nearly all of today's production is portland cement. See also: cement rock.

woodruffite

woodruffite (wood'-ruff-ite). A sooty-black tetragonal mineral: (Zn,Mn2+)2Mn4+5O12•4H2O . It is related to todorokite .

oncolite

oncolite (on'-co-lite). A small, variously shaped, concentrically laminated, calcareous sedimentary structure, resembling an oolith, and formed by the accretion of successive layered masses of gelatinous sheaths of blue-green algae. It is smaller than a stromatolite and generally does not exceed 10 cm in diameter. Also spelled: onkolite. Cf: catagraphite.

stick-slip

stick-slip . A jerky, sliding motion associated with fault movement that may be a mechanism in shallow-focus earthquakes. A model of fault slip in which distinct slip episodes are separated by periods in which the fault is locked and stress increases.

Photo Release: North, east, south, west: The many faces of Abell 1758

Resembling a swarm of flickering fireflies, this beautiful galaxy cluster glows intensely in the dark cosmos, accompanied by the myriad bright lights of foreground stars and swirling spiral galaxies. A1758N is a sub-cluster of Abell 1758, a massive cluster containing hundreds of galaxies. Although it may appear serene in this NASA/ESA Hubble Space Telescope image, the sub-cluster actually comprises two even smaller structures currently in the turbulent process of merging.

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