Topography of a composite relict rock glacier, Ślęża Massif, SW Poland     

Dorota Borowicz  Roman &#;urawek 《Geografiska Annaler: Series A, Physical Geography》2003,85(1):31-41

A detailed geodetic survey and, additionally, a map of slope covers have been carried out for a composite relict rock glacier on the slopes of Mt ?l??a (718 m a.s.l.), Sudetic Foreland, SW Poland. The survey allows one to distinguish the mobilisation, transition and accumulation zones and to define geomorphic features diagnostic for relict rock glaciers such as lateral ridges standing above a central depression, steep margins of the landforms in the transition and accumulation zones, as well as absence of distinct head scarps above. Furthermore, it indicates that the present‐day hydrographic pattern on the surface of relict rock glaciers has been superimposed on the relief inherited from the active landforms. The topography indicates that tension prevailed rather than compression during the development of the rock glaciers. Some of the features, such as small lateral lobes, developed probably as a result of the compressive flow, however. The pattern of the slope cover shows that it developed during activity of the rock glaciers and been modified afterwards due to solifluction.  相似文献   

Concepts and controversies in tidal marsh ecology     

Charles T. Roman 《Estuaries and Coasts》2002,25(1):148-148

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Book reviews     

Robert L. Shipp  Charles T. Roman  G. Fister  Michael M. Mullin  John G. Williams  Joel Wagner 《Estuaries and Coasts》1996,19(3):751-754

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Experimental insight into spalling behavior of concrete tunnel linings under fire loading     

Matthias Zeiml  Roman Lackner  Herbert A. Mang 《Acta Geotechnica》2008,3(4):295-308

New experimental insight into the spalling behavior of concrete in fire conditions is presented in this paper. Spalling was recorded by a high-speed camera. The slow-motion sequences allow us to determine the size, shape, and velocity of the spalled-off pieces. With this information at hand, the released energy associated with every spalling event is computed and compared to the energies associated with pore-pressure and thermal-stress spalling. This comparison provides new insight into the impact of the various thermal, mechanical, and hydral processes controlling concrete spalling.  相似文献   

Plastic deformation of orthoenstatite and the ortho- to high-pressure clinoenstatite transition: a metadynamics simulation study     

Sandro Jahn  Roman Martoňák 《Physics and Chemistry of Minerals》2008,35(1):17-23

Atomic-scale mechanisms of plastic deformation in orthoenstatite, MgSiO₃ are studied by computer simulation methods. The combined use of metadynamics and molecular dynamics allows a direct observation of the structural changes during the creation of stacking faults in the (100) plane. A sequence of slip deformations in two different (100) planes at P = 15 GPa and T = 1,000 K reveals a probable transformation mechanism for the ortho- to high-pressure clinopyroxene transition. Each of the observed slips consists of at least four partial deformations crossing high-energy intermediate structures. In agreement with experimental studies, both (100)[010] and (100)[001] slip systems are activated in the deformation process. The observation of a dominant (100)[001] single slip system in pyroxenes may be related to the fact that high-energy intermediate dislocations with (100)[010] component are not stable on geological or experimental timescales.  相似文献   

Integrating Geospatial Technologies in Fifth-Grade Curriculum: Impact on Spatial Ability and Map-Analysis Skills     

May Jadallah  Alycia M. Hund  Jonathan Thayn  Joel Garth Studebaker  Zachary J. Roman  Elizabeth Kirby 《The Journal of geography》2017,116(4):139-151

This study explores the effects of geographic information systems (GIS) curriculum on fifth-grade students' spatial ability and map-analysis skills. A total of 174 students from an urban public school district and their teachers participated in a quasi-experimental design study. Four teachers implemented a GIS curriculum in experimental classes over six weeks while three teachers continued with regular teaching in control classes. Both groups completed pre- and post-tests measuring spatial ability and map-analysis skills. Students in the GIS classes demonstrated more growth over time in spatial ability and map-analysis skills than did their peers in the control classes.  相似文献   

Crustal analysis of the Ulleung Basin in the East Sea (Japan Sea) from enhanced gravity mapping     

Chan Hong Park  Jeong Woo Kim  Nobuhiro Isezaki  Daniel R. Roman  Ralph R. B. von Frese 《Marine Geophysical Researches》2006,27(4):253-266

To facilitate geological analyses of the Ulleung Basin in the East Sea (Japan Sea) between Korea and Japan, shipborne and satellite altimetry-derived gravity data are combined to derive a regionally coherent anomaly field. The 2-min gridded satellite altimetry-based gravity predicted by Sandwell and Smith [Sandwell DT, Smith WHF (1997) J Geophys Res 102(B5):10,039–10,054] are used for making cross-over adjustments that reduce the errors between track segments and at the cross-over points of shipborne gravity profiles. Relative to the regionally more homogeneous satellite gravity anomalies, the longer wavelength components of the shipborne anomalies are significantly improved with minimal distortion of their shorter wavelength components. The resulting free-air gravity anomaly map yields a more coherent integration of short and long wavelength anomalies compared to that obtained from either the shipborne or satellite data sets separately. The derived free-air anomalies range over about 140 mGals or more in amplitude and regionally correspond with bathymetric undulations in the Ulleung Basin. The gravity lows and highs along the basin’s margin indicate the transition from continental to oceanic crust. However, in the northeastern and central Ulleung Basin, the negative regional correlation between the central gravity high and bathymetric low suggests the presence of shallow denser mantle beneath thinned oceanic crust. A series of gravity highs mark seamounts or volcanic terranes from the Korean Plateau to Oki Island. Gravity modeling suggests underplating by mafic igneous rocks of the northwestern margin of the Ulleung Basin and the transition between continental and oceanic crust. The crust of the central Ulleung Basin is about a 14–15 km thick with a 4–5 km thick sediment cover. It may also include a relatively weakly developed buried fossil spreading ridge with approximately 2 km of relief.  相似文献   

Coal taxes as supply-side climate policy: a rationale for major exporters?     

Philipp M. Richter  Roman Mendelevitch  Frank Jotzo 《Climatic change》2018,150(1-2):43-56

The shift away from coal is at the heart of the global low-carbon transition. Can governments of coal-producing countries help facilitate this transition and benefit from it? This paper analyses the case for coal taxes as supply-side climate policy implemented by large coal exporting countries. Coal taxes can reduce global carbon dioxide emissions and benefit coal-rich countries through improved terms-of-trade and tax revenue. We employ a multi-period equilibrium model of the international steam coal market to study a tax on steam coal levied by Australia alone, by a coalition of major exporting countries, by all exporters, and by all producers. A unilateral export tax has little impact on global emissions and global coal prices as other countries compensate for reduced export volumes from the taxing country. By contrast, a tax jointly levied by a coalition of major coal exporters would significantly reduce global emissions from steam coal and leave them with a net sector level welfare gain, approximated by the sum of producer surplus, consumer surplus, and tax revenue. Production taxes consistently yield higher tax revenues and have greater effects on global coal consumption with smaller rates of carbon leakages. Questions remain whether coal taxes by major suppliers would be politically feasible, even if they could yield economic benefits.  相似文献   

Evidence of high sea level during isotope stage 5c in Queensland,Australia     

J.W. Pickett  C.H. Thompson  R.A. Kelley  D. Roman 《Quaternary Research》1985,24(1):103-114

Thirty-nine species of scleractinian corals have been recovered from under a high dune on the western (mainland) side of North Stradbroke Island, eastern Australia. The corals are associated with thin intertidal sediments and their good condition implies burial in situ and preservation in a saturated zone. Most likely this occurred as the coast prograded and a large dune advanced into the littoral zone, burying intertidal sediments and coral. The species assemblage indicates a sheltered environment but one open to the ocean without wide fluctuations in salinity. Three species yielded a mean ${}^{230}\text{Th}{}^{234}\text{U}$ age of 105,000 yr B.P. which is significantly younger than the nearest Pleistocene corals at Evans Head, New South Wales. The corals provide evidence of a sea stand near present sea level during isotope Stage 5c, which is considerably higher than previously suggested for this period. Their good condition implies that the overlying parabolic dune is of comparable age and formed during that high stand of sea level. Also, the isotope age provides a maximum period for the development of giant podzols in the podzol chronosequences on coastal dunes in southern Queensland.  相似文献   

Fishes and decapod crustaceans of Cape Cod eelgrass meadows: Species composition,seasonal abundance patterns and comparison with unvegetated substrates     

K. L. Heck  K. W. Able  M. P. Fahay  C. T. Roman 《Estuaries and Coasts》1989,12(2):59-65

Bimonthly trawl samples from eelgrass and nearby unvegetated areas on Cape Cod, Massachusetts, showed greater species richness in eelgrass meadows relative to unvegetated areas, and greater summer abundance in vegetation for decapod crustaceans and fishes. The composition of eelgrass-associated decapods and fishes was dominated by cold-water taxa and was strikingly different from that of the better studied eelgrass meadows of the mid-Atlantic coast. Four of the eight decapod species collected, including the second and third most abundant taxa, do not even appear in collections reported from Chesapeake Bay eelgrass meadows. Similarly, 10 of the 22 fish species taken, including the first and sixth most abundant species, are not reported from Chesapeake Bay eelgrass samples. Cape Cod eelgrass beds seem to play a nursery role for several commercially important fish species, although the nursery function is less obvious than in previously studied mid-Atlantic eelgrass meadows.  相似文献