## Wednesday, July 31, 2013

Cthulhu vs cat!

### Venus Was Catastrophically Resurfaced by Volcanoes

Monte Carlo models of the interaction between impact cratering and volcanic resurfacing on Venus: The effect of the Beta-Atla-Themis anomaly

Authors:

1. I. Romeo (a)

Affiliation:

Abstract:

Detailed Monte Carlo models of the interaction of impact cratering and volcanic resurfacing, which included the Beta-Atla-Themis (BAT) volcanic concentration, were used to test different planetary resurfacing histories. The results were compared with: 1) the randomness of the spatial distribution of craters, 2) the number of modified craters, 3) the number of dark-floored craters due to volcanic flooding, 4) the frequency-area distribution of volcanic units, 5) the frequency-size distribution of craters and modified craters, and (6) the spatial distribution of craters and modified craters with respect to the BAT anomaly. Two catastrophic and two equilibrium resurfacing models were tested. The two catastrophic models consisted of one with a drastic decay and the other with a moderate decay of volcanic activity following the catastrophic event. The two equilibrium models consisted of one with a gradual decay of volcanic activity at the end of the model and the other with a magmatic event followed by a gradual decay of volcanic activity. Both equilibrium models and catastrophic model with moderate decay fail to reproduce the small reduction of the crater density in the BAT area. The model that best fits all the observations is a global catastrophic resurfacing event followed by a drastic decay of volcanic activity. Thus, a Venus global catastrophic resurfacing event erasing all previous craters with little post-resurfacing volcanism is supported by this study.

### Hey, Science Fiction Writers: You Can Impress More With Reality

A valid N body simulation solution.  Now, your uber advanced race which can do anything can at least do something like this...science has moved on since the 1970s.

wow.

### Two 6,000 Year Old Neolithic Barrows Excavated in UK

The remains of two large 6000-year-old halls, each buried within a prehistoric burial mound, have been discovered by archaeologists from The University of Manchester and Herefordshire Council -- in a UK first.

The sensational finds on Dorstone Hill, near Peterchurch in Herefordshire, were thought to be constructed between 4000 and 3600 BC.

Some of the burnt wood discovered at the site shows the character of the building's structure above ground level -- in another UK first.

The buildings, probably used by entire communities, are of unknown size, but may have been of similar length to the Neolithic long barrows beneath which they were found – 70metres and 30m long.

They were, say the team, deliberately burnt down after they were constructed and their remains incorporated into the two burial mounds.

However -- much detail has been preserved in the larger barrow: structural timbers in carbonized form, postholes showing the positions of uprights, and the burnt remains of stakes forming internal partitions.

Most importantly, the core of each mound is composed of intensely burnt clay, representing the daub from the walls of the buildings.

The buildings were likely to have been long structures with aisles, framed by upright posts, and with internal partitions.

The smaller barrow contains a 7m by 2.5m mortuary chamber, with huge sockets which would have held upright tree trunks at each end.

These massive posts bracketed a linear 'trough' lined with planks, which would have held the remains of the dead.

### Descent of the Orangutan

Orangutans might be the king of the swingers, but primatologists in Borneo have found that the great apes spend a surprising amount of time walking on the ground. The research, published in the American Journal of Primatology found that it is common for orangutans to come down from the trees to forage or to travel, a discovery which may have implications for conservation efforts.

An expedition led by Brent Loken from Simon Fraser University and Dr. Stephanie Spehar from the University of Wisconsin Oshkosh, travelled to the East Kalimantan region of Borneo. The region's Wehea Forest is a known biodiversity hotspot for primates, including the Bornean orangutan subspecies, Pongo pygmaeus morio, the least studied of orangutan subspecies.

"Orangutans are elusive and one reason why recorded evidence of orangutans on the ground is so rare is that the presence of observers inhibits this behaviour," said Loken. "However, with camera traps we are offered a behind the scenes glimpse at orangutan behaviour."

The team positioned ground-based cameras across a 38-square-kilometre region of the forest and succeeded in capturing the first evidence of orangutans regularly coming down from the trees.

The amount of time orangutans spent on the forest floor was found to be comparable to the ground-dwelling pig-tailed macaque, Macaca nemestrina, which is equally abundant in Wehea Forest. Over 8-months orangutans were photographed 110 times, while the macaques were photographed 113 times.

The reason orangutans come down from the trees remains a mystery. However, while the absence of large predators may make it safer to walk on the forest floor, a more pressing influence is the rapid and unprecedented loss of Borneo's orangutan habitat.

### Is Mercury a Signal for Mass Vulcanism Across the KT/K=Pg Boundary?

Mercury as a proxy for volcanic activity during extreme environmental turnover: The Cretaceous-Paleogene transition

Authors:

1. A.N. Sial (a)
2. L.D. Lacerda (b)
3. V.P. Ferreira (a)
4. R. Frei (c)
5. R.A. Marquillas (d)
6. J.A. Barbosa (e)
7. C. Gaucher (f)
8, C.C. Windmöller (g)
9, N.S. Pereira (a)

Affiliations:

a. NEG-LABISE, Department of Geology, Federal University of Pernambuco, Recife, PE, 50740-530, Brazil

b. LABOMAR, Institute of Marine Sciences, Federal University of Ceará, Fortaleza, 60165-081, Brazil

c. Institute of Geography and Geology, University of Copenhagen, Oster Volgade 10, Copenhagen, Denmark, 1350

d. Universidad de Salta, Salta, Argentina CONICET, Buenos Aires 177, 4400 Salta, Argentina

e. LAGESE, Department Geology, Federal University of Pernambuco, Recife, 50740-530, Brazil

g. Department of Chemistry, Federal University of Minas Gerais, Av. Antônio Carlos 6627, Belo Horizonte, Minas Gerais, 31270-901, Brazil

Abstract:

The usually low geological background concentrations of Hg makes this trace element suitable for identifying accumulation pulses in sediments that can be tentatively related to weathering processes and thus to climatic changes. Intense volcanism has witnessed the Cretaceous‒Paleogene transition (KTB) and was, perhaps, responsible for dramatic climatic changes and decrease in biodiversity and mass extinction. We have used Hg concentrations as a proxy for volcanic activity and atmospheric Hg and CO2 buildup across the KTB at three localities. In the Salta Basin, Argentina, Hg contents display several spikes across the KTB, with a maximum value of 250 ng.g− 1. In three drill cores across the KTB in the Paraíba Basin, northeastern Brazil, Hg contents increase from the late Maastrichtian to early Danian and Hg spikes predate the KTB, perhaps, as a record of volcanic activity before (but very close to) this transition. At Stevns Klint, Denmark, Hg contents reached almost 250 ng.g− 1 within a 5 cm thick-clay layer, the Fiskeler Member (‘Fish Clay’) that comprises the KTB. Some co-variation between Hg and Al2O3 contents has been observed in all of the studied sections across the KTB, suggesting that Hg is probably adsorbed onto clays. Thermo-desorption experiments in selected samples from the Yacoraite Formation showed Hg+ 2 as the major species present, which is in agreement with a volcanic origin. Combined Hg and C-isotope chemostratigraphy may become a powerful tool for the eventual assessment of the role of volcanic activity during extreme climatic and biotic events, such as those during the KTB.

### Carbon Dioxide Depleted in Late Archean Sea Water

Decrease of seawater CO2 concentration in the Late Archean: An implication from 2.6 Ga seafloor hydrothermal alteration

Authors:

1. Takazo Shibuya (a, b, c)
2. Miyuki Tahata (d)
3. Yuichiro Ueno (d)
4. Tsuyoshi Komiya (e)
5. Ken Takai (a, b, f)
6. Naohiro Yoshida (g, h)
7. Shigenori Maruyama (e)
8. Michael J. Russell (c)

Affiliations:

a. Precambrian Ecosystem Laboratory (PEL), Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2-15 Natsushima-cho, Yokosuka 237-0061, Japan

b. Submarine Hydrothermal System Research Group, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2-15 Natsushima-cho, Yokosuka 237-0061, Japan

c. Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109, USA

d. Department of Earth and Planetary Sciences, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8551, Japan

e. Department of Earth Science and Astronomy, The University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo 153-8902, Japan

f. Subsurface Geobiology Advanced Research (SUGAR) project, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2-15 Natsushima-cho, Yokosuka 237-0061, Japan

g. Department of Environmental Science and Technology, Tokyo Institute of Technology, G1-25, 4259 Nagatsuta, Yokohama, 226-8502, Japan

h. Department of Environmental Chemistry and Engineering, Tokyo Institute of Technology, G1-25, 4259 Nagatsuta, Yokohama, 226-8502, Japan

Abstract:

Before continents attained a critical aerial dimension on the early Earth, hydrothermal carbonation of subseafloor crust is considered to have played the dominant role in fixing CO2 from the CO2-rich ocean. However, it is uncertain how and when the seawater CO2 level decreased and the strong carbonation of oceanic crust ceased. Here we report the depth profiles of the volume concentration and the carbon isotopes of calcites in the Late Archean/Paleoproterozoic volcanic rocks (Fortescue and Hamersley groups), exposed in the southwestern Pilbara Craton, Western Australia. The depth profiles indicate that 2.6 Ga seafloor hydrothermal carbonation is well preserved in the study area and that the CO2 content of subseafloor crust per seafloor unit area is estimated to be clearly lower than those in the Early and Middle Archean and similar to the Phanerozoic equivalents. This suggests that the CO2 concentration in seawater decreased from the Middle Archean to the Late Archean. This period broadly corresponds to the time of the first appearance of supercontinent on Earth. The amalgamation of continents has the potential to decrease seawater CO2 concentration due to the removal of platform carbonate to continental interior. Subsequent fragmentation of supercontinent likely cause the carbonate deposition around newly created continental shelves. It is therefore implied that seawater CO2 concentration in the early Earth was lowered by not only the hydrothermal carbonation of subseafloor crust but also through the formation and breakup of supercontinent in the Late Archean.

## Tuesday, July 30, 2013

By 2011, however, the program had seen almost a decade of cost overruns and schedule delays. Under pressure from lawmakers, NASA rebaselined the program with a revised cost estimate of $8.8 billion, a new launch date of October 2018, and a healthy amount of schedule margin to maintain both. At nearly nine times the original cost, and more than a decade behind schedule, JWST was finally on track. Since then, the program has entered a critical phase; myriad technical concerns have emerged, including mass issues on the spacecraft, delayed delivery of two instruments and technical problems with key subsystems, one of which required the addition of a third round of lengthy cryo-vacuum testing to the Integrated Science Instrument Module (ISIM). Combined, these issues have cost 18 of 26 months of schedule reserve on the ISIM, the heart of the telescope that houses JWST's four instruments, designed to detect light from distant stars and galaxies. One of the late instruments is the Near-infrared Spectrograph (NIRSpec), a 200-kg spectrometer designed to observe up to 100 celestial bodies simultaneously at various spectral resolutions being supplied by the European Space Agency (ESA) and built by Astrium GmbH of Ottobrun, Germany. According to ESA, in July 2011 three cracks were found in the part that holds the optics components for NIRSpec. After a failure review board in January 2012, ESA had to reassemble the instrument using a flight spare optical bench. During the rebuild and test, however, ESA encountered additional problems with NIRSpec, including failure of the NASA-supplied microshutter arrays to close. The project also suffered from slower-than-planned progress on the reintegration on the part of Astrium, according to the Government Accountability Office (GAO), which conducted an in-depth review of JWST in 2012. ### New Observations of Quaoar THE SIZE, SHAPE, ALBEDO, DENSITY, AND ATMOSPHERIC LIMIT OF TRANSNEPTUNIAN OBJECT (50000) QUAOAR FROM MULTI-CHORD STELLAR OCCULTATIONS Authors: 1. F. Braga-Ribas (a,b,bb) 2. B. Sicardy (b,c) 3. J. L. Ortiz (d) 4. E. Lellouch (b) 5. G. Tancredi (e) 6. J. Lecacheux (b) 7. R. Vieira-Martins (a,f,g) 8. J. I. B. Camargo (a) 9. M. Assafin (g) 10. R. Behrend (h) 11. F. Vachier (f) 12. F. Colas (f) 13. N. Morales (d) 14. A. Maury (i) 15. M. Emilio (j) 16. A. Amorim (k) 17. E. Unda-Sanzana (l) 18. S. Roland (e) 19. S. Bruzzone (e) 20. L. A. Almeida (m) 21. C. V. Rodrigues (m) 22. C. Jacques (n) 23. R. Gil-Hutton (o) 24. L. Vanzi (p) 25. A. C. Milone (m) 26. W. Schoenell (d,k) 27. R. Salvo (e) 28. L. Almenares (e) 29. E. Jehin1 (g) 30. J. Manfroid (q) 31. S. Sposetti (r) 32. P. Tanga1 (i) 33. A. Klotz (t) 34. E. Frappa (u) 35. P. Cacella (u) 36. J. P. Colque (l) 37. C. Neves (j) 38. E. M. Alvarez (v) 39. M. Gillon (q) 40. E. Pimentel (n) 41. B. Giacchini (n) 42. F. Roques (b) 43. T. Widemann (b) 44. V. S. Magalhães (m) 45. A. Thirouin (d) 46. R. Duffard (d) 47. R. Leiva1 (f) 48. I. Toledo (x) 49. J. Capeche (e) 50. W. Beisker (y) 51. J. Pollock (z) 52. C. E. Cedeño Montaña (m) 53. K. Ivarsen (aa) 54. D. Reichart (aa) 55. J. Haislip (aa) 56. A. Lacluyze (aa) Affiliations: a. Observatório Nacional, Rio de Janeiro, Brazil b. Observatoire de Paris, LESIA, F-92195 Meudon, France c. Université Pierre et Marie Curie, F-75252 Paris, France d. Instituto de Astrofísica de Andalucía-CSIC, E-18080 Granada, Spain e. Observatorio Astronomico Los Molinos, Montevideo U-12400, Uruguay f. Observatoire de Paris, IMCCE, F-75014 Paris, France g. Observatório do Valongo/UFRJ, Rio de Janeiro, Brazil h. Observatoire de Genève, Sauverny, Switzerland i. San Pedro de Atacama Celestial Explorations, San Pedro de Atacama, Chile j. Universidade Estadual de Ponta Grossa, Ponta Grossa, Brazil k. Universidade Federal de Santa Catarina, Florianópolis, Brazil l. Unidad de Astronomía, Universidad de Antofagasta, Antofagasta, Chile m. Instituto Nacional de Pesquisas Espaciais, DAS, São José dos Campos, Brazil n. Centro de Estudos Astronômicos de Minas Gerais (CEAMIG), Belo Horizonte, Brazil o. Complejo Astronómico El Leoncito and San Juan National University, San Juan, Argentina p. Department of Electrical Engineering and Center of Astro-Engineering, Pontificia Universidad Católica de Chile, Av. Vicuña Mackenna 4860, Santiago, Chile q. Institut d'Astrophysique de l'Université de Liége, B-4000 Liège, Belgium r. Gnosca Observatory, Gnosca, Switzerland s. Laboratoire Lagrange, Université de Sophia Antipolis, Observatoire de la Côte d'Azur, CNRS UMS7293, F-06304 NICE Cedex 4, France t. Université de Toulouse, UPS-OMP, IRAP, F-31000 Toulouse, France u. Euraster, 1B cours J. Bouchard, F-42000 St-Etienne, France v. Rede de Astronomia Observacional, Brasilia, Brazil w. Observatorio Los Algarrobos, Salto, Uruguay x. Joint ALMA Observatory, Alonso de Córdova 3107, Vitacura, Santiago, Chile y. International Occultation Timing Association-European Section, D-30459 Hannover, Germany z. Department of Physics and Astronomy, Appalachian State University, Boone, NC 28608, USA aa. Physics and Astronomy Department, University of North Carolina, Chapel Hill, NC, USA bb. Current address: Rua General José Cristino, 77, CEP 20921-400, Rio de Janeiro, RJ, Brazil. Abstract: We present results derived from the first multi-chord stellar occultations by the transneptunian object (50000) Quaoar, observed on 2011 May 4 and 2012 February 17, and from a single-chord occultation observed on 2012 October 15. If the timing of the five chords obtained in 2011 were correct, then Quaoar would possess topographic features (crater or mountain) that would be too large for a body of this mass. An alternative model consists in applying time shifts to some chords to account for possible timing errors. Satisfactory elliptical fits to the chords are then possible, yielding an equivalent radius R equiv = 555 ± 2.5 km and geometric visual albedo pV = 0.109 ± 0.007. Assuming that Quaoar is a Maclaurin spheroid with an indeterminate polar aspect angle, we derive a true oblateness of$\epsilon = 0.087^{+0.0268}_{-0.0175}$, an equatorial radius of$569^{+24}_{-17}\$ km, and a density of 1.99 ± 0.46 g cm–3. The orientation of our preferred solution in the plane of the sky implies that Quaoar's satellite Weywot cannot have an equatorial orbit. Finally, we detect no global atmosphere around Quaoar, considering a pressure upper limit of about 20 nbar for a pure methane atmosphere.

In the future, with this many authors, I am not going to reformat.  Good grief.