Origin and evolution of the atmospheres of early Venus,Earth and Mars     

Helmut Lammer  Aubrey L. Zerkle  Stefanie Gebauer  Nicola Tosi  Lena Noack  Manuel Scherf  Elke Pilat-Lohinger  Manuel Güdel  John Lee Grenfell  Mareike Godolt  Athanasia Nikolaou 《Astronomy and Astrophysics Review》2018,26(1):2

We review the origin and evolution of the atmospheres of Earth, Venus and Mars from the time when their accreting bodies were released from the protoplanetary disk a few million years after the origin of the Sun. If the accreting planetary cores reached masses \(\ge 0.5 M_\mathrm{Earth}\) before the gas in the disk disappeared, primordial atmospheres consisting mainly of H\(_2\) form around the young planetary body, contrary to late-stage planet formation, where terrestrial planets accrete material after the nebula phase of the disk. The differences between these two scenarios are explored by investigating non-radiogenic atmospheric noble gas isotope anomalies observed on the three terrestrial planets. The role of the young Sun’s more efficient EUV radiation and of the plasma environment into the escape of early atmospheres is also addressed. We discuss the catastrophic outgassing of volatiles and the formation and cooling of steam atmospheres after the solidification of magma oceans and we describe the geochemical evidence for additional delivery of volatile-rich chondritic materials during the main stages of terrestrial planet formation. The evolution scenario of early Earth is then compared with the atmospheric evolution of planets where no active plate tectonics emerged like on Venus and Mars. We look at the diversity between early Earth, Venus and Mars, which is found to be related to their differing geochemical, geodynamical and geophysical conditions, including plate tectonics, crust and mantle oxidation processes and their involvement in degassing processes of secondary \(\hbox {N}_2\) atmospheres. The buildup of atmospheric \(\hbox {N}_2\), \(\hbox {O}_2\), and the role of greenhouse gases such as \(\hbox {CO}_2\) and \(\hbox {CH}_4\) to counter the Faint Young Sun Paradox (FYSP), when the earliest life forms on Earth originated until the Great Oxidation Event \(\approx \) 2.3 Gyr ago, are addressed. This review concludes with a discussion on the implications of understanding Earth’s geophysical and related atmospheric evolution in relation to the discovery of potential habitable terrestrial exoplanets.  相似文献   

Remote Sensing of Biologically Reworked Sediments: A Laboratory Experiment     

Annelies De Backer  Stefanie Adam  Jaak Monbaliu  Erik Toorman  Magda Vincx  Steven Degraer 《Estuaries and Coasts》2009,32(6):1121-1129

The present study aims to test the application of remote sensing to address the impact of bioturbation on physical sediment properties. Therefore, a laboratory experiment was developed, using microcosms mimicking a marine intertidal water–sediment interface to test the influence of Corophium volutator densities on sediment properties. Three main variables (water content, clay content, and mean grain size) were measured in three treatments (no Corophium, 5,000 Corophium per square meter, and 20,000 Corophium per square meter) after 16 days of bioturbation. Results obtained with conventional—destructive—techniques showed a significant increase of water content and a significant, but small decrease of clay content in the presence of Corophium. The remote sensing technique detected the impact of Corophium on water content as an increase in absorption at 1,450 nm, but was not able to detect the animal impact on clay content. This study demonstrates that remote sensing data could be significantly modified by bioturbation activities and that remote sensing can be applied in the laboratory to address the impact of bioturbation on sediment properties. This possibly opens new perspectives for long-term experiments concerning the role of bioturbation on sedimentary processes.  相似文献   

Erratum to: Variations of sulphur isotope signatures in sulphides from the metamorphosed Ming Cu(−Au) volcanogenic massive sulphide deposit,Newfoundland Appalachians,Canada     

Stefanie M. Brueckner  Stephen J. Piercey  Graham D. Layne  Glenn Piercey  Paul J. Sylvester 《Mineralium Deposita》2015,50(5):641-642

  相似文献   

Discussion of "Comparison of Conductivity Values Obtained from Aquifer Pumping Tests and Conservative Tracer Tests," by William L. Niemann and Charles W. Rovey II, Ground Water Monitoring & Remediation, v. 20, no. 3, pages 122–128.     

Fred J. Molz III  Stefanie A. Crisman 《Ground Water Monitoring & Remediation》2001,21(3):32-33

  相似文献   

Application Procedures for the Electromagnetic Borehole Flowmeter in Shallow Unconfined Aquifers     

Stefanie A. Crisman  Fred. J. Molz  David L. Dunn  Frank C. Sappington 《Ground Water Monitoring & Remediation》2001,21(4):96-100

It is increasingly common for the electromagnetic borehole flowmeter (EBF) to he used to measure hydraulic conductivity (K) distributions in subsurface flow systems. Past applications involving the EBF have been made mostly in confined aquifers (Kabala 1994; Boman et al. 1997; Podgorney and Ritzi 1997; Ruud and Kabala 1997a, 1997b; Flach et al. 2000), and it has been common to set up a flow field around a test well using a small pump that is located near the top of the well screen (Mob, and Young 1993). In thin, unconfined aquifers that exhibit ground water tables near the ground surface and that undergo drawdown during pumping, such a configuration can be problematical because pumping and associated drawdown may effectively isolate the upper portion of the aquifer from the flowmeter. In these instances, a steady-state flow field in the vicinity of the test well may be created using injection rather than pumping, allowing for testing in the otherwise isolated upper portion of the aquifer located near the initial water table position. Using procedures developed by Molz and Young (1993), which were modified for an injection mode application, testing was conducted to determine whether or not the injection mode would provide useful information in a shallow, unconfined aquifer that required the collection of data near the initial water table position. Results indicated that the injection mode for the EBF was well suited for this objective.  相似文献   

Glacial morphology and post-glacial contourites in northern Prince Gustav Channel (NW Weddell Sea,Antarctica)     

Camerlenghi  Angelo  Domack  Eugene  Rebesco  Michele  Gilbert  Robert  Ishman  Scott  Leventer  Amy  Brachfeld  Stefanie  Drake  Allison 《Marine Geophysical Researches》2001,22(5-6):417-443

We present the results of a marine geophysical investigation of the northern Prince Gustav Channel. By comparative analysis of multibeam bathymetric data, single channel seismic reflection profiles, underway chirp sonar data, ADCP current data and sediment coring, we define the main morphological elements of the area. In particular we define the glacial morphogenesis in relation to the excavation of inner shelf basins and troughs along structural discontinuities and lithologic boundaries. We identify streamlined surfaces that testify to the grounding of ice and past ice flow directions. These glacial forms are found only on glacial tills preserved in the deepest part of the basins, while net erosion to bedrock has occurred elsewhere. Since the Last Glacial Maximum (LGM), the relict glacial morphology has been draped by hemipelagic and diatomaceous mud, and bottom currents have played a major role in focusing sedimentation within small depocentres, that we define as contouritic drifts. Based on shallow sediment architecture and supported by direct measurements, we propose that the direction of bottom water flow is from the outer shelf into the Prince Gustav channel as a result of a combination of tidal currents and ice shelf-related thermohaline circulation.  相似文献   

Geostandards and Geoanalytical Research Bibliographic Review 2007     

Klaus Peter Jochum  Stefanie M. Brueckner  Uwe Nohl  Brigitte Stoll  Ulrike Weis 《Geostandards and Geoanalytical Research》2008,32(4):509-514

  相似文献   

Differences between Paleozoic Asia and Paleozoic North America as shown by the distribution of ultrahigh-pressure (UHP) terranes   总被引：2，自引：2，他引：0  

John J.W. Rogers  Stefanie L.D. Bernosky 《Gondwana Research》2008,13(3):428-433

Numerous UHP suites developed in East Asia during the Paleozoic because subduction occurred in an area of low thermal gradients. By contrast, no Paleozoic UHP suites formed in North America or in terranes accreted to it because all subduction under accreting terranes occurred in an area of high thermal gradients centered in North America. High thermal gradients beneath North America are also demonstrated by an abundance of intracratonic rifts and basins. These differences in thermal gradients between North America and East Asia may have been caused by a very large mantle convection cell, with a rising limb under North America and a descending limb in an oceanic area where East Asia was assembled.  相似文献   

Structure and evolution of the volcanic rift zone at Ponta de São Lourenço,eastern Madeira     

Andreas Klügel  Stefanie Schwarz  Paul van den Bogaard  Kaj A. Hoernle  Cora C. Wohlgemuth-Ueberwasser  Jana J. Köster 《Bulletin of Volcanology》2009,71(6):671-685

Ponta de São Lourenço is the deeply eroded eastern end of Madeira’s east–west trending rift zone, located near the geometric intersection of the Madeira rift axis with that of the Desertas Islands to the southeast. It dominantly consists of basaltic pyroclastic deposits from Strombolian and phreatomagmatic eruptions, lava flows, and a dike swarm. Main differences compared to highly productive rift zones such as in Hawai’i are a lower dike intensity (50–60 dikes/km) and the lack of a shallow magma reservoir or summit caldera. ⁴⁰Ar/³⁹Ar age determinations show that volcanic activity at Ponta de São Lourenço lasted from >5.2 to 4 Ma (early Madeira rift phase) and from 2.4 to 0.9 Ma (late Madeira rift phase), with a hiatus dividing the stratigraphy into lower and upper units. Toward the east, the distribution of eruptive centers becomes diffuse, and the rift axis bends to parallel the Desertas ridge. The bending may have resulted from mutual gravitational influence of the Madeira and Desertas volcanic edifices. We propose that Ponta de São Lourenço represents a type example for the interior of a fading rift arm on oceanic volcanoes, with modern analogues being the terminations of the rift zones at La Palma and El Hierro (Canary Islands). There is no evidence for Ponta de São Lourenço representing a former central volcano that interconnected and fed the Madeira and Desertas rifts. Our results suggest a subdivision of volcanic rift zones into (1) a highly productive endmember characterized by a central volcano with a shallow magma chamber feeding one or more rift arms, and (2) a less productive endmember characterized by rifts fed from deep-seated magma reservoirs rather than from a central volcano, as is the case for Ponta de São Lourenço.  相似文献   

Palaeogeographic Changes at Lake Chokrak on the Kerch Peninsula,Ukraine, during the Mid‐ and Late‐Holocene     

Daniel Kelterbaum  Helmut Brückner  Vasiliy Dikarev  Stefanie Gerhard  Anna Pint  Alexey Porotov  Victor Zin'ko 《Geoarchaeology》2012,27(3):206-219

This project has reconstructed the palaeogeographic and environmental evolution of Lake Chokrak on the Kerch Peninsula, Ukraine, during the mid‐ and late‐Holocene. This record has been evaluated in association with a regional archaeological data set to explore human–environment interactions over this period. The results show major changes in the palaeogeographic setting of Lake Chokrak since the 3rd millennium B.C., when the postglacial marine transgression had started to fill the study area. Microfaunal analyses reveal the long persistence of an open marine embayment that only became separated from the Sea of Azov when a sand barrier developed during the late 2nd millennium B.C. When colonizing the Black Sea region after the 8th century B.C., the Greek settlers erected a fortification with a small settlement on a promontory that was by then a peninsula‐like headland extending into the lake. The colonists abandoned their settlement at the end of the 1st millennium B.C. when the depth of the surrounding lake decreased from 1.5 m to less than 1 m. Today, Lake Chokrak dries up completely during summer. A detailed relative sea level (RSL) curve for the northern coast of Kerch has been established. Sea level reached its highest position at the present day. Since the 3rd millennium B.C., sea level continuously rose, without any of the previously postulated regression/transgression cycles. The RSL curve indicates differential subsidence rates within short distances in relatively stable areas, exceeding 40 cm per 1000 years. © 2012 Wiley Periodicals, Inc.  相似文献