NATURE
1. An Earth-sized planet
with an Earth-like density
Francesco Pepe, Andrew Collier Cameron, David W.
Latham, Emilio Molinari, Stéphane Udry, Aldo S. Bonomo, Lars A. Buchhave, David
Charbonneau, Rosario Cosentino, Courtney D. Dressing, Xavier Dumusque, Pedro
Figueira, Aldo F. M. Fiorenzano, Sara Gettel, Avet Harutyunyan, Raphaëlle D.
Haywood, Keith Horne, Mercedes Lopez-Morales, Christophe Lovis, Luca Malavolta,
Michel Mayor, Giusi Micela, Fatemeh Motalebi, Valerio Nascimbeni, David
Phillips et al.
Nature 503, 377–380 (21 November 2013) doi:10.1038/nature12768
Received
25 September 2013 Accepted 14 October 2013 Published online 30 October 2013
Orbiting
less than two stellar radii above the visible surface of a Sun-like star, the
Earth-sized exoplanet Kepler-78b is a hellish world. But its existence bodes
well for the discovery and characterization of habitable planets.
2. A rocky composition for
an Earth-sized exoplanet
Andrew W. Howard, Roberto Sanchis-Ojeda, Geoffrey W.
Marcy, John Asher Johnson, Joshua N. Winn, Howard Isaacson, Debra A. Fischer,
Benjamin J. Fulton, Evan Sinukoff & Jonathan J. Fortney
Nature 503, 381–384 (21 November 2013) doi:10.1038/nature12767
Doppler spectroscopic measurements of the mass of
the Earth-sized planet Kepler-78b reveal that its mean density is similar to
Earth’s, suggesting a composition of rock and iron.
3. Global carbon dioxide
emissions from inland waters
Peter A. Raymond, Jens Hartmann, Ronny Lauerwald,
Sebastian Sobek, Cory McDonald, Mark Hoover, David Butman, Robert Striegl,
Emilio Mayorga, Christoph Humborg, Pirkko Kortelainen, Hans Dürr, Michel
Meybeck, Philippe Ciais & Peter Guth
Nature 503, 355–359 (21 November 2013) doi:10.1038/nature12760
An
analysis of regional variations in global inland water surface area, dissolved
CO2 and gas transfer velocity yields a global CO2 evasion
rate of 2.1 × 1015 grams of carbon per year, which is higher than
previous estimates owing to a larger contribution from streams and rivers.
PNAS
4. Gas injection may have triggered earthquakes in the Cogdell oil
field, Texas
Wei
Gan and Cliff Frohlich
PNAS
2013 110 (47) 18786-18791; published ahead of print November 4, 2013,
doi:10.1073/pnas.1311316110
Between
1957 and 1982, water flooding was conducted to improve petroleum production in
the Cogdell oil field north of Snyder, TX. A contemporary analysis concluded
this induced earthquakes that occurred between 1975 and 1982. The National
Earthquake Information Center detected no further activity between 1983 and
2005, but 18 earthquakes between 2006 and 2011.
However,
since 2004 significant volumes of gases including supercritical CO2 have been
injected into the Cogdell field. The timing of gas injection suggests it may
have contributed to triggering the recent seismic activity.
GEOLOGY
5. Tectonic forcing of
Early to Middle Jurassic seawater Sr/Ca
Clemens
V. Ullmann, Stephen P. Hesselbo, and Christoph Korte
Geology,
December 2013, v. 41, p. 1211-1214
These
findings underline the strong control of global tectonic processes on the
evolution of biomineralization and downplay the role of biomineral evolution in
influencing strontium chemistry of seawater in the mid-Mesozoic.
6. What does a mean mean? The temporal evolution of detrital cosmogenic
denudation rates in a transient landscape
Geology, December 2013, v. 41, p. 1215-1218, first
published on October 30, 2013, doi:10.1130/G34746.1
We
employ a numerical landscape evolution model to explore how 10Be-derived
denudation rates vary over time and space during transient adjustment. We find
that denudation rates increase in the downstream direction from ∼0.2
mm/yr in the upper catchment to ∼0.5 mm/yr at the outlet.
This interpretation of our data has potentially far-reaching implications for
quantifying the uplift history and response time of transient landscapes using
cosmogenic nuclides
7. Altered regional sediment transport regime after a large typhoon,
southern Taiwan
Geology, December 2013, v. 41, p. 1223-1226, first
published on October 16, 2013, doi:10.1130/G34826.1
Analyses of river suspended sediment response to
record-breaking regional rainfall in southern Taiwan during typhoon Morakot,
7–9 August 2009, reveal systematic changes in the regional sediment transport
regime.
8. Late Cretaceous winter sea ice in Antarctica?
Vanessa
C. Bowman, Jane E. Francis, James B. Riding
Geology, December 2013, v. 41, p. 1227-1230, first
published on October 16, 2013, doi:10.1130/G34891.1
We present palynomorph records from Seymour Island,
Antarctica, that may suggest Maastrichtian sea ice. These data and our
interpretation support the presence of ephemeral ice sheets on Antarctica
during the latest Cretaceous, highlighting the extreme sensitivity of this
region to global climate change.
9. A re-evaluation of the
Pleistocene behavior of the Scoresby Sund sector of the Greenland Ice Sheet
Jan
Sverre Laberg, Matthias Forwick, Katrine Husum, and Tove Nielsen
Geology,
December 2013, v. 41, p. 1231-1234, first published on October 16, 2013,
doi:10.1130/G34784.1
Here
we present seismic data showing that glacigenic debris-flow deposits dominate
the younger than ca. 2.58 Ma succession of the Scoresby Sund trough mouth fan
on the East Greenland continental margin, suggesting much more frequent
expansions of the Greenland Ice Sheet to the shelf break than found previously.
10. Kimberlite (U-Th)/He
dating links surface erosion with lithospheric heating, thinning, and
metasomatism in the southern African Plateau
Jessica
R. Stanley, Rebecca M. Flowers, and David R. Bell
Geology,
December 2013, v. 41, p. 1243-1246, first published on October 16, 2013,
doi:10.1130/G34797.1
Here
we combine new apatite (U-Th)/He (AHe) data from four South Africa kimberlites
ranging in emplacement age from ca. 143 Ma to ca. 74 Ma with a wealth of other
geologic information from the pipes to resolve the timing, patterns, and causes
of erosion across ∼200 km of the southern African Plateau.
11. Volcanic ash reveals
time-transgressive abrupt climate change during the Younger Dryas
Christine
S. Lane, Achim Brauer, Simon P.E. Blockley, and Peter Dulski
Geology,
December 2013, v. 41, p. 1251-1254, first published on October 30, 2013,
doi:10.1130/G34867.1
We
show that the onset of climatic amelioration during the YD cold period was
locally abrupt, but time-transgressive across Europe. Synchronization of two
high-resolution continental records, using the Vedde Ash layer (12,140 ± 40
varve yr B.P.), allows us to trace the shifting of the polar front as a major
control of regional climate amelioration during the YD in the North Atlantic
realm.
SCIENCE
12.Constraints on the Late Holocene Anthropogenic Contribution to the
Atmospheric Methane Budget
Logan Mitchell, Ed Brook, James E. Lee,
Christo Buizert, Todd Sowers
doi: 10.1126/science.1238920
Two ice core methane concentration records from
Greenland and Antarctica were used to construct a high-resolution record of the
methane inter-polar difference (IPD). This constrains the latitudinal
distribution of emissions and shows late preindustrial Holocene (LPIH)
emissions increased primarily in the tropics with secondary increases in the
subtropical Northern Hemisphere. Differences in anthropogenic and natural
latitudinal characteristics were exploited to demonstrate both sources were
required to explain LPIH changes in methane concentration.
13.
Drilling Plans Endanger Yasuni’s Biodiversity
Juan Jose Alava, Nastenka Calle
doi: 10.1126/science.342.6161.931-a
Ecuador’s Yasuni National Park has always faced
threats of oil exploitation despite being one of the most megadiverse forests
and a sanctuary for ancestral indigenous people. In 2007, President Rafael
Correa accepted monetary compensation from the international community towards
Ecuador’s economy in return for preventing oil exploitation; however, he has
now abandoned the moratorium and justifies it by citing inadequate donations to
protect the park.
NATURE COMMUNICATIONS
14.
Pink marine sediments reveal rapid ice melt and Arctic meltwater discharge
during Dansgaard–Oeschger warmings
Tine L. Rasmussen, Erik Thomsen
doi: 10.1038/ncomms3849
During warmings, pink clay from Devonian Red
Beds is transported in suspension by meltwater from the surrounding ice sheet
and replaces the greenish silt normally deposited on the northwestern slope of
Svalbard during interstadials. Decreasing concentrations of ice-rafted debris
during the interstadials signify that the ice sheet retreats as meltwater
production increases.
15.
Discovery of the action of a geophysical synchrotron in the Earth’s Van Allen
radiation belts
Ian R. Mann, E. A. Lee, S. G. Claudepierre, J.
F. Fennell, A. Degeling, I. J. Rae, D. N. Baker, G. D. Reeves, H. E. Spence, L.
G. Ozeke, R. Rankin, D. K. Milling, A. Kale, R. H. W. Friedel, F. Honary
doi: 10.1038/ncomms3795
Evidence from the Combined Release and Radiation
Effects Satellite (CRRES) probe and recently launched multi-satellite NASA Van
Allen Probes mission, with supporting modelling, shows coherent ultra-low
frequency interactions in the Van Allen belts. The observed modulations and
energy-dependent spatial structure indicate a mode of action analogous to a
geophysical synchrotron.
