Mineralogy and petrography of C asteroid regolith: The Sutter's Mill CM meteorite     

Michael Zolensky  Takashi Mikouchi  Marc Fries  Robert Bodnar  Peter Jenniskens  Qing‐zhu Yin  Kenji Hagiya  Kazumasa Ohsumi  Mutsumi Komatsu  Matthew Colbert  Romy Hanna  Jessie Maisano  Richard Ketcham  Yoko Kebukawa  Tomoki Nakamura  Moe Matsuoka  Sho Sasaki  Akira Tsuchiyama  Matthieu Gounelle  Loan Le  James Martinez  Kent Ross  Zia Rahman 《Meteoritics & planetary science》2014,49(11):1997-2016

Based upon our characterization of three separate stones by electron and X‐ray beam analyses, computed X‐ray microtomography, Raman microspectrometry, and visible‐IR spectrometry, Sutter's Mill is a unique regolith breccia consisting mainly of various CM lithologies. Most samples resemble existing available CM2 chondrites, consisting of chondrules and calcium‐aluminum‐rich inclusion (CAI) set within phyllosilicate‐dominated matrix (mainly serpentine), pyrrhotite, pentlandite, tochilinite, and variable amounts of Ca‐Mg‐Fe carbonates. Some lithologies have witnessed sufficient thermal metamorphism to transform phyllosilicates into fine‐grained olivine, tochilinite into troilite, and destroy carbonates. One finely comminuted lithology contains xenolithic materials (enstatite, Fe‐Cr phosphides) suggesting impact of a reduced asteroid (E or M class) onto the main Sutter's Mill parent asteroid, which was probably a C class asteroid. One can use Sutter's Mill to help predict what will be found on the surfaces of C class asteroids such as Ceres and the target asteroids of the OSIRIS‐REx and Hayabusa 2 sample return missions (which will visit predominantly primitive asteroids). C class asteroid regolith may well contain a mixture of hydrated and thermally dehydrated indigenous materials as well as a significant admixture of exogenous material would be essential to the successful interpretation of mineralogical and bulk compositional data.  相似文献   

Glaciotectonised Quaternary sediments at Cape Shpindler,Yugorski Peninsula,Arctic Russia: implications for glacial history,ice movements and Kara Sea Ice Sheet configuration     

Hanna Lokrantz   lafur Inglfsson  Steven L. Forman 《第四纪科学杂志》2003,18(6):527-543

The coastal cliffs of Cape Shpindler, Yugorski Peninsula, Arctic Russia, occupy a key position for recording overriding ice sheets during past glaciations in the Kara Sea area, either from the Kara Sea shelf or the uplands of Yugorski Peninsula/Polar Urals. This study on Late Quaternary glacial stratigraphy and glaciotectonic structures of the Cape Shpindler coastal cliffs records two glacier advances and two ice‐free periods older than the Holocene. During interglacial conditions, a sequence of marine to fluvial sediments was deposited. This was followed by a glacial event when ice moved southwards from an ice‐divide over Novaya Zemlya and overrode and disturbed the interglacial sediments. After a second period of fluvial deposition, under interstadial or interglacial conditions, the area was again subject to glacial overriding, with the ice moving northwards from an inland ice divide. The age‐control suggests that the older glacial event could possibly belong to marine oxygen isotope stage (MOIS) 8, Drenthe (300–250 ka), and that the underlying interglacial sediments might be Holsteinian (>300 ka). One implication of this is that relict glacier ice, buried in sediments and incorporated into the permafrost, may survive several interglacial and interstadial events. The younger glacial event recognised in the Cape Shpindler sequence is interpreted to be of Early‐to‐Middle Weichselian age. It is suggested to correlate to a regional glaciation around 90 or 60 ka. The Cape Shpindler record suggests more complex glacial dynamics during that glaciation than can be explained by a concentric ice sheet located in the Kara Sea, as suggested by recent geological and model studies. Copyright © 2003 John Wiley & Sons, Ltd.  相似文献   

New mineralogical and chemical data on the Machinga (L6) chondrite,Malawi     

Christian Koeberl  Wolf Uwe Reimold  Hanna E. Horsch  Roland K. W. Merkle 《Meteoritics & planetary science》1990,25(1):23-26

Abstract— The Machinga, southern Malawi, Africa, L6 chondrite (observed fall, 22 January 1981) contains accessory phases of metal, troilite, chromite, and native Cu (which is associated with limonite and found in zones of aqueous alteration). Rare accessory phases are apatite and pentlandite, which are uncommon in L6 chondrites. Major mineral constituents (olivine, orthopyroxene, and plagioclase) indicate shock effects at a level of about 15–20 GPa shock pressure. The meteorite is thus classified to be of L6d type. Melt pockets of widely variable composition are abundant.  相似文献   

Study of photoelectric observations of the eclipsing binary system FZ-Delphinus     

M.A. Hanna  N.S. Awadalla 《Astrophysics and Space Science》2004,291(1):85-96

Photoelectric observations in B and V for the FZ Del system are presented and its light curves are analyzed. Absolute parameters are obtained. The system shows a near contact subgaint secondary component with a likely K1 spectral type. The O-C curve is presented and probably a secular orbital period variations is detected on a timescale of about 6.9×10⁶ yrs, suggesting thermal timescale mass transfer. A new light elements for the system have been obtained. The system can be considered as an early stage of conservative case of mass transfer. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

NUMERICAL INVESTIGATION INTO THE INFLUENCE OF GEOMETRY AND CONSTRUCTION MATERIALS ON URBAN STREET CLIMATE     

Hanna Swaid 《自然地理学》2013,34(4):342-358

A numerical model is developed for simulating the nocturnal cooling of the ground and walls in typical urban canyons. The model is capable of dealing with homogeneous as well as inhomogeneous (layered) soil and wall substrates. Experiments carried out with the model show that the difference in the thermal properties of urban asphalt and concrete pavements and the rural dry soil substrate could create urban/rural surface temperature differences of up to 4–5K. In narrow cross-section canyons, the influence of geometry on the street microclimate increases and becomes dominant for aspect ratios exceeding 2. The external surfaces of insulated canyon walls cool drastically overnight and therefore induce lower heat island intensities than conventional wall constructions. Some findings of the numerical investigations are corroborated with available nocturnal cooling field observations.  相似文献   

The new equine sector and its influence on multifunctional land use in peri-urban areas     

Hanna Elisabeth Elg?ker 《GeoJournal》2012,77(5):591-613

The equine sector is increasingly influencing land use, especially in peri-urban areas where the demand for land is already high. The sector not only influences traditional farming and land use, but also social, legal and economic development, and thus demands new interpretations of rural and urban. However, there is currently a lack of information on the consequences of this sector at landscape, social and economic level. This study examines the influence of the equine sector on the development of multifunctional land use in peri-urban areas, using data and examples from Sweden. It also examines specific features of the associated growing area of research and the positioning of the issue within the broader context of land use and planning. The methods used were a case study of a municipality, together with interviews and analyses of statistical material at regional level in the context of multifunctional land use, planning and sustainable development. It was found that the structure of the equine sector varies at both national and local level due to local conditions, but that there are also common features that need to be further studied using a broad interdisciplinary starting point.  相似文献   

Spatial disaster vulnerability and risk assessments: challenges in their quality and acceptance   总被引：5，自引：4，他引：1  

Alexander Fekete 《Natural Hazards》2012,61(3):1161-1178

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Late Quaternary marine-based Kara Sea ice sheets: a review of terrestrial stratigraphic data highlighting their formation     

Ólafur Ingólfsson  Per Möller  & Hanna Lokrantz 《Polar research》2008,27(2):152-161

Reconstructions of the Late Quaternary glacial history of the Kara Sea area show repeated build-up of ice-sheet domes over the shallow epicontinental Kara Sea. Inferred ice divides were situated over the central Kara Sea, and the ice sheet repeatedly inundated the surrounding coastal areas of western Siberia. Geological fingerprinting of the Kara Sea ice sheet include end moraine zones, raised beaches, tills, glaciotectonic deformations and coarsening-upward sediment sequences, reflecting isostatic rebound cycles. This paper reviews evidence from several areas along the perimeter of the Kara Sea, suggesting that peripheral sites were critical for the initiation of the large Kara Sea ice sheet. Ice-sheet inception progressed with the formation of local ice caps that later coalesced on the adjacent shelf with globally falling sea levels, eventually merging and growing into a large ice dome.  相似文献   

Laboratory characterization of the structural properties controlling dynamical gas transport in Mars-analog soils     

Hanna G. Sizemore  Michael T. Mellon 《Icarus》2008,197(2):606-620

Dynamical transport of gases within the martian regolith controls many climatic processes, and is particularly important in the deposition and/or mobilization of shallow ground ice, as well as exchange of other volatiles between the martian regolith and atmosphere. A variety of theoretical studies have addressed issues related to ground ice dynamics on Mars and in the terrestrial analog environment of the Antarctic Dry Valleys. These theoretical studies have drawn on a limited set of empirical measurements to constrain the structural parameters controlling gas diffusion and flow in soils. Here, we investigate five groups of Mars-analog soils: glass spheres, JSC Mars-1, aeolian dune sand, Antarctic Dry Valley soils, and arctic loess. We present laboratory measurements of the structural properties most relevant to gas transport in these soils: porosity, tortuosity, permeability, bulk and intrinsic densities, grain-size distribution, pore-size distribution and BET surface area. Our results bear directly both on the appropriateness of assumptions made in theoretical studies and on current outstanding issues in the study of shallow ground ice on Mars and in the Dry Valleys. Specifically, we find that (1) measured values of tortuosity are lower than values commonly assumed for Mars by a factor of two to three; (2) diffusive loss of ground ice on Mars can likely proceed up to four times faster than predicted by theoretical studies; (3) soil permeabilities are sufficiently high that flushing of the soil column by bulk flow of atmospheric gases may further speed loss or deposition of shallow ground ice; (4) the pore volume in some Mars-analog soils is sufficiently high to explain high volumetric ice abundances inferred from Mars Odyssey Gamma Ray Spectrometer data as simple pore ice; and (5) measured properties of soils collected in Beacon Valley, Antarctica agree well with assumptions made in theoretical studies and are consistent with rapid loss of ground ice in the current climate.  相似文献   

Can crystallization of olivine tholeiite give rise to potassic rhyolites?—an experimental investigation   总被引：6，自引：0，他引：6  

Matthew L. Whitaker  Hanna Nekvasil  Donald H. Lindsley  Michael McCurry 《Bulletin of Volcanology》2008,70(3):417-434

Experiments were conducted to determine whether the rhyolites and basalts of the intraplate silica-saturated potassic suites could be genetically related through crystallization. Extreme crystallization (96–97%) of a high-MgO (10.62 wt%) olivine tholeiite from the Snake River Plain with an initial bulk water content of 0.4 wt% at a mid-crustal pressure of 4.3 kbar generated potassic rhyolitic liquids similar in major element chemistry to those found in the Quaternary rhyolite domes of the Snake River Plain and their plutonic equivalents in the Proterozoic Laramie Anorthosite Complex. Residual liquids comparable in composition to the bulk rock compositions of intermediate rocks found at the Craters of the Moon and Cedar Butte eruptive centers in the Snake River Plain are also generated along this crystallization path. This paper constitutes part of a special issue dedicated to Bill Bonnichsen on the petrogenesis and volcanology of anorogenic rhyolites.  相似文献