United States international policies and military strategies in the era of defunct aggressor

In the post-Soviet era, the United States (US) is expected to contribute its military forces and defense resources in the event of need for Regional Conflicts and Operations Other Than War (OOTW). Such contributions may not be forthcoming. The principal reasons for the possible absence to the US contributions to maintain the New World Order is the paucity in the articulation of the US foreign and defense policies. The US public's well known preference for domestic policies, rather than foreign military and related operations, has been reinforced by the absence of the comprehensive explanation by the US political leaders of the US foreign and defense policies to the American people. The US military are preparing military doctrine for the possible engagements in the Regional Conflicts and OOTW, but these efforts are affected by the US well established past military doctrine to fight wars to a clear victory on the battlefield as well as by the absence of clear national military policy. American particulation in the future military operations — Regional Conflicts or OOTW — remains very much in doubt.     

Garnet-cordierite-biotite equilibria in the Steinach aureole,Bavaria

Three garnet-biotite pairs and eleven garnet-cordierite-biotite triplets from the Steinach aureole (Oberpfalz, North-East Bavaria) were analyzed using an electron probe microanalyzer.The regional metamorphic muscovite-biotite schists contain garnets strongly zoned with Mn-Ca-rich centers and Fe-rich edges, the average composition being almandine 67 — spessartine 4 — pyrope 4 — grossular (+andradite) 25.The first contact garnet that is formed in mica schists of the outermost part of the aureole is small, virtually unzoned, and has an average composition of almandine 52 — spessartine 37 — pyrope 8 — grossular (+andradite) 3. With increasing metamorphic grade, there is a consistent trend to form garnets richer in Fe ending up with a composition almandine 84.5 — spessartine 5.5 — pyrope 7.5 — grossular (+andradite) 2.5. This trend is accompanied by a general increase in grain size and modal amount of garnet. Associated cordierites and biotites also become richer in Fe with increasing grade. While the garnets in the highest grade sillimanite hornfelses are poorly zoned, the transitional andalusite-sillimanite hornfelses contain garnets with distinct but variable zonation profiles.These facts can possibly be explained by the time-temperature relationships in the thermal aureole. In a phase diagram such as the Al-Fe-Mg-Mn tetrahedron, the limiting mineral compositions of a four-phase volume or a three-phase triangle are fixed by T and P (the latter remaining effectively constant within a thermal aureole). Thus, in garnet-cordierite-biotite assemblages, garnet zonation should be controlled by temperature variation rather than by a non-equilibrium depletion process. Taking into account the experimental data of Dahl (1968), a zoned garnet from a transitional andalusite-sillimanite hornfels would reflect a temperature increase of about 40° C during its growth. A hypothetical P-X diagram is proposed to show semi-quantitatively the compositional variation of garnet-cordierite pairs with varying pressures (T constant).     

Observations of the electrical asthenosphere beneath Scandinavia

The recent recognition that long period (i.e., of the order of hours) electromagnetic induction studies could play a major role in the detection of the asthenosphere has led to much interest amongst the geophysical and geological communities of the geomagnetic response functions derived for differing tectonic environments. Experiments carried out on the ocean bottom have met with considerable success in delineating the “electrical asthenosphere”, i.e., a local maximum in electrical conductivity (minimum in electrical resistivity) in the upper mantle.In this paper, observations of the time-varying magnetic field recorded in three regions of Scandinavia, northern Sweden (Kiruna—KIR), northern Finland/northeastern Norway (Kevo—KEV) and southern Finland (Sauvamaki—SAU), are analysed in order to obtain estimates of the inductive response function, C(ω), for each region. The estimated response functions are compared with one from the centre of the East European Platform (EEP), and it is shown that the induced eddy currents, at periods of the order of 10³–10⁴ s, in the three regions flow much closer to the surface than under the platform centre. Specifically, at a period of ~3000 s, these currents are flowing at depths of the order of: KEV—120 km; KIR—180 km; SAU—210 km; EEP—280 km; implying that the transition to a conducting zone, of σ -0.2 S/m, occurs at around these depths. One-dimensional inversion of and shows that there must exist a good conducting zone, of σ = 0.1–1.0 S/m, under each of the two regions, of 40 km minimum thickness, at depths of: KEV 105–115 km; KIR 160–185 km. This is to be contrasted with EEP, where the ρ-d profile displays a monotonically decreasing resistivity with depth, reaching σ~0.1 S/m at > 300 km.Finally, a possible temperature range for the asthenosphere, consistent with the deduced conducvitity, is discussed. It is shown that, at present, there is insufficient knowledge of the conditions (water content, melt fraction, etc.) likely to prevail in the asthenosphere to narrow down the probable range of 900°–1500°C.     

Delineation of active faulting and some tectonic interpretations in the Munich-Milan section of the eastern Alps — use of LANDSAT-1 and 2 imagery

Based on studies of images obtained from LANDSAT-1 and 2, several seemingly active movement zones have been delineated in a section of the eastern Alps and are being reported in the present paper for the first time. These zones, trending W—E to NW—SE, cut across all earlier Alpine boundaries and contacts and on either side along their length, are marked with drag effects, indicating their post-Alpine neotectonic nature. Their relation with the present-day central European stress field, as determined from fault-plane studies and in-situ stress measurements, has been sought. In conjunction with the evidence from neighbouring areas, a dextral shear tendency of the present-day Mediterranean is indicated. Further, a number of extensive lineaments have been observed in the Alpine section. Statistically, there are three major lineation sets trending N45°, N15°, N345°. They appear to have developed cogenetically as a result of shear and tensile failures due to a stress field with maximum principal stress oriented averagely at N15°. This direction of the maximum principal stress, deduced from the above lineation analysis of the eastern Alps, is in striking conformity with the one believed to have been in existence for the development of the Rhinegraben (N20°). It appears that the Rhinegraben and the Alpide belt have evolved cogenetically and concurrently under the same dominant stress field (P₁ = N—NNE, P₂ = vertical and P₃ = E—ESE) and hence the two geotectonic features are really not antagonistic and mutually incompatible as usually believed on the grounds that one involves tension (taphrogenesis — Rhinegraben) and the other compression (orogenesis — Alpide belt) but are different manifestations of the same stress field. Besides, some additional light has been thrown on the possible controls of development of the Giudicaria Line and cause of predominance of NE—SW trending sinistral faults.     

Effect of grossular-content in garnet on the partitioning of Fe and Mg between garnet and biotite

In contrast to Ferry (1980) (X _Ca)-values in garnet even lower than 0.1 have a significant effect on the calculated equilibrium temperature using the experimental calibration of the Fe and Mg paritioning between garnet and biotite. Garnet compositions and Mg/Fe — distribution coefficients from samples of the Eoalpine staurolite — in zone in the southern Ötztal are related by the quadratic regression equation: InK _D= -1.7500 (±0.0226) + 2.978 (±0.5317)X _Ca ^Gt -5.906(±2.359)(X _Ca ^Gt )² Temperatures derived by the Ferry and Spear (1978) calibration using chemistry — correctedK _D values are petrologically realistic.Analysis of our data supports non ideal mixing of grossular with almandine — pyrope solid solution. The derived excess mixing energies are quite small for the almandine — pyrope solution (W _FeMg= –133 cal/mole) and about +2775 cal/mole for the difference between pyrope-grossular and almandine-grossular solutions (W _MgCa —W _FeCa) at metamorphic conditions of 570° C and 5,000 bar. The mixing parameters proposed by Ganguly and Saxena (1984) are not confirmed by our data as they would result in significantly lower temperatures.     

Maritime impacts on the littoral organization — The case of the Western Mediterranean

Littoral life in the W Mediterranean is undergoing relevant changes. There are about 40 seaports in thh are, making up a sort of Southern Range (from Algesiras to Leghorn), and besides that a South-Western Area (Italian Mezzogiorno), and a Developing Area (African coast). A new spatial model of oil transport — the third one sinnce the Sixties — is emerging, having a high degree of freedom. Growing consumption of steam coal brings about the construction of deep-sea terminals generating feeder effects within the Mediterranean. In unitized transport the Mediterranean has weaker relations with Europe than with non-European areas, and brings about the construction of platforms for the distribution of containers. NW industrial areas are being transformed and concentrations of new tertiary activities are emerging, relations between littoral cities and inland cities are changing, medium ports are coming to the fore. Relations between W and E Mediterranean shores are changing.     

Stratigraphic-structural-paleoclimatic controls of the newly discovered iron ore deposits of Western Australia

Until a few years ago the Australian iron-ore reserves were estimated to about 300 million t. The recent discoveries of extensive stratified iron deposits in the Hamersley Range, West Australia, raised this estimate to 15–20,000 million t. — The mineralization was controlled in a threefold manner, i.e., stratigraphical (the productive horizon forms the base of the Brockman formation), structural (the iron enrichment took place in synclinal structures) and paleoclimatic (the iron deposits are related to an old land surface of probable Miocene age). — The absence of any metamorphism, granitisation or plutonic action supports the hypothesis of a residual origin of the deposit.P.S. Together with the proofs of this paper the article on the Iron ores of the Ophthalmia Region, Western Australia by J. M. Neilson was received (Trans. Soc. Min. Eng., AIME, New York, 232, Dec. 1965, p. 327 to 338). Neilson reaches in part similar conclusions as here proposed. The differences will be discussed in a future issue of Mineralium Deposita.     

Marine C reservoir ages for 19th century whales and molluscs from the North Atlantic

In order to compare radiocarbon dates on marine and terrestrial samples the former have to be corrected for a reservoir age. We present reservoir ages from dating 21 whales collected 1860–1901 and recalculating dates of 23 molluscs collected 1857–1926. Most of the whales were caught along the coast of Norway, but one is from France and one from Iceland. We assume the former mainly lived in the North and equatorial Atlantic and in the Norwegian Sea. Whales feed only on pelagic organisms and will provide the reservoir age for the open ocean surface water. However, they travel long distances and will integrate the reservoir ages of the different water masses along their way. Molluscs (dated from Norway, Spitsbergen and Arctic Canada) are stationary and monitor the sea water passing their dwelling site, but some also take up carbon from particulate food or sediment pore water. Coastal water also often contains some continental carbon. We present two different views on how to analyze and interpret the data. Mangerud recommends to use reservoir ages based on a combination of the whale and mollusc dates, i.e. 380±30 and 360±30 yr relative to Intcal04 and British oak, respectively, and a ΔR value of 20±30 for the surface water in the N-Atlantic and Norwegian Sea. Bondevik and Gulliksen maintain that the reservoir age—and ΔR—along the Norwegian coast is latitude dependant, with ΔR-values increasing from −3±22 in the South to 105±24 at Spitsbergen. Whales, reflecting North Atlantic open ocean surface water have lower ΔR (7±11) than most molluscs.     

Stress and viscosity in the asthenosphere

Stresses and effective viscosities in the asthenosphere to a depth of 400 km are calculated on the basis of Weertmans “temperature method” i.e., on relating viscosity to the ratio of the temperature to the melting point (=homologous temperature). Some oceanic and continental geotherms and two melting point—depth curves, the dry pyrolite solidus and the forsterite₉₀ melting curve are used for the conversion of the homologous temperature to the effective viscosity. Two creep laws are considered, the linear, grain-size-dependent Nabarro—Herring (NH) creep law, and a power creep law, in which the creep rate is proportional to the third power of the stress. A plate tectonic model yields creep rates of 2 · 10⁻¹⁴ s⁻¹ for the oceanic and 3 · 10⁻¹⁵ s⁻¹ for the continental asthenosphere. These values are held constant for the calculations and may be valid for regions inside plates.The dry pyrolite mantle model results in high homologous temperatures in the asthenosphere below oceans (0.9), very low stresses (a few bars and lower) and shows a low viscosity “layer” of about 200-km thickness. Below continental shields the homologous temperature has a maximum value of 0.73, stresses are around 5–20 bar and the low-viscosity region is thicker and less pronounced than in the oceanic case. The Fo₉₀ mantle model generally gives lower homologous temperatures (maximum value below oceans beside active ridges 0.75). The stresses in the asthenosphere beneath oceans vary from a few bars to about 50 bar and below continents to about 100 bar. The low-viscosity region seems to reach great depths without forming a “channel”. The Figs. 1 and 2 show the approximate viscosity—depth distribution for the two mantle models under study.Assuming a completely dry mantle and a mean grain size of 5 mm, power law creep will be the dominating creep process in the asthenosphere. However, grains may grow in a high-temperature—low-stress regime (i.e., below younger oceans), an effect which will further diminish the influence of NH creep. In the upper 100–150 km of the earth some fluid phases may affect considerably creep processes.     

Petrochemical and thermodynamic evidence on the origin of kimberlites

The petrochemistry of kimberlites from Yakutia and Lesotho has been studied using a silicate melt model with the SiO₂, CO₂ and H₂O derivatives as the main anions.A model has been developed, according to which the dissolution of H₂O in an ultramafic melt results in orthosilicates (H₂SiC ₄ ^-2 , H₃SiO ₄ ^– , H₄SiO₄ etc.) rather than metasilicates, while the dissolution of CO₂ produces additional hydrocarbonate complexes. It suggests that at high PCO ₂ ¹ , and where the orthosilicic calcium salt clusters are likely to be present in the magma, the kimberlite melt can break down into carbonate and silicate liquids. Therefore, the composition of kimberlite magma will be determined by the H₂O/CO₂ ratio under the relatively constant fluid pressure. This can be seen from the distinct fluidrs trend in the H₂O-CO₂-SiO₂ diagram for the Yakutia and Lesotho diamond-bearing kimberlites. The H₂O/CO₂ ratio changes with the liquidus temperature along this trend (Perchuk and Vaganov 1977) which suggests that liquid immiscibility predominates over the simple CO₂ solubility in the melts of kimberlite composition. The well-known Boyd's diagrams for the equilibrium PT-conditions in peridotites have been applied along with new experimental data to natural Cpx and Opx, and the PT-parameters were correlated for peridotite inclusions in kimberlite pipes in Yakutia and Lesotho. The liquidus temperatures for the extrapolated area of these correlations gave depths (pressures) at which kimberlite magmas are formed (200–250 km).The hypothesis on SiO₂ partitioning between the melt and the fluid was used to calculate the composition of dry initial kimberlite which characterised the average mantle composition: SiO₂ — 45.12; TiO₂ — 2.49; Al₂O₃ — 3.58; Cr₂O₃ — 0.12; FeO — 9.32; MnO — 0.16; CoO — 0.11; MgO — 23.47; CaO — 13.44; Na₂O — 0.20; K₂O — 1.12; P₂O₅ — 0.69; S — 0.18; sum — 100 wt.%. This kimberlite is close to wehrlite in composition.     

Paragenetic relations in gedrite — cordierite — staurolite — biotite sillimanite — kyanite gneisses at Ajitpura,Rajasthan, India

Aluminous parageneses containing gedrite, cordierite, garnet, staurolite, biotite, sillimanite, kyanite, quartz or spinel plus corundum are found as dark colored lenses in the polymetamorphic, multideformed Archean complex at Ajitpura in northwest peninsular India. Staurolite, like kyanite, is a relict phase of earlier metamorphism and is excluded as a paragenetic mineral in view of its incompatibility with quartz and gedrite and its lower X _Mg values than for garnet of the assemblage. Its stability here is attributed to zinc content of up to 3 wt%. The XMg in other ferromagnesian minerals decreases in the order: cordierite, biotite, gedrite, garnet, as found elsewhere in high grade rocks.The textural criteria and systematic partitioning of Fe and Mg in the ferromagnesian phases, excluding staurolite, indicate attainment of equilibrium during the second metamorphism. From tie line configurations in the phase diagrams, X _Mg ratios in the constituent minerals, and other petrographic criteria, it is suggested that gedrite — cordierite-garnet — sillimanite — biotite assemblage has been produced by the reactions: Biotite+Sillimanite+Quartz = Cordierite+Garnet+K-feldspar+Vapor (1) and Biotite+Sillimanite+Quartz = Cordierite +Gedrite+K-feldspar+Vapor (2) which occurred during partial melting of the rocks at fixed P and T conditions.By isothermal P-X(Fe-Mg) sections it has been demonstrated that release of FeO, SiO₂ and other components modified the composition of the reactant biotite presumably by the substitution FeSi2 Al, whereby reaction 1 was replaced by reaction 2. Cordierite with higher X _Mg was produced with gedrite instead of with garnet, whose X _Mg is less than X _Mg of gedrite. Reaction 2 has been tentatively located in T-P space from the intersection of some continuous loops in the P-X(Fe-Mg) diagram at 700°C and also by other constraints. The discontinuous reaction 2 is located about 1–2 kilobars higher than reaction 1, which implies that it is difficult to distinguish between effects of pressure and those of melting on the X _Mg ratios of the reaction phases.The P-T calibrations of garnet — cordierite, garnet — biotite and garnet — plagioclase equilibria and the calibrations from other dehydration curves give temperatures near 700°C and pressure (assuming ) about 6 kilobars.     

Geomagnetic induction anomalies along the hyderabad—kalingapatnam profile

Observations of H- and Z-variations made at ten temporary field stations along the Hyderabad—Bhadrachalam—Kalingapatnam (east coast) profile during February–March, 1973, are analyzed and discussed. The results are also compared with those of the Alibag (west coast)—Hyderabad profile, completed in May–July, 1970.It is found that the Z-ranges of quiet daily variations are enhanced one and a half times the Hyderabad value, and the H-ranges only very slightly reduced at the coastal station of Kalingapatnam. This coastal effect of 6γ in Z_r at Kalingapatnam gradually decreases inland and probably exists upto Salur (70 km inland from the coast). At Bhadrachalam, both H- and Z-ranges of quiet daily variations are found to be enhanced, possibly due to induction effects from deep-seated conductors in the Godavari rift valley. The enhancement of both H and Z daily ranges at Jeypore in the eastern “ghats” (hills) is attributed to induced electric currents in conductors arising from the orogeny well below the “ghats”.It is difficult to separate the coastal effect from the orogenic effect, both of which seem to taper off and merge at Salur.     

Urban ecology and location theory: Dominance and territory

Woods left on good farmland in Ohio and neighboring states are likely to be beech-maple woods. There may well be a dozen or more tree species present, but the most obvious, because the most common, will be beeches and sugar maples … these trees exhibit the phenomenon of ecological dominance. There can be little doubt that the other plants of the wood are adapted to the presence of the abundant beeches and maples so that to describe them as dominants in this way is good use of language. The beeches and maples determine the micro climate, and even the soil, to which all the other living things must adapt - PAUL COLINVAUX.In the social reality, despite all change, the domination of man by man is still the historical continuum that links pre-technological and technological reason. However, the society which projects and undertakes the technological transformation of nature alters the base of domination by gradually replacing personal dependence … with dependence on the “objective order of things” (on economic laws, the market, etc…) … domination now generates a higher rationality — that of a society which sustains its hierarchic structure while exploiting ever more efficiently the natural and mental resources… - HERBERT MARCUSE     

Further Comment: Spatial Continuity Measures

Conclusion In closing, I think it not inappropriate to make clear—both toReply's authors and to the geostatistical community at large—that my purpose in pressing these issues is not mere whimsical or frivolous harassment.My purpose is to urge the mining industry, as I have done before (1984), to insist upon reserve estimation methods that are soundly based onall applicable mathematical principles undistorted by speculative interpretation, selection, or practice. My criticism of geostatistics is not so much of what its practitioners do — and of what I first did long ago (1959)—but of the undisciplined and misleading things its pundits say about what they do.     

Effects of human population growth on the Fraser and Okanagan River systems,Canada: a comparative inquiry

Perhaps nowhere in Canada, if indeed in North America, could two adjacent watershed basins be selected which show such remarkable differences in their historical and recent response to human population growth effects. One — the Fraser — covers some 234,000 km² (about one quarter of the province of British Columbia) and houses nearly two-thirds of its total population. The other — the Okanagan — forms a small part (some 14,000 km²) of the upper Columbia River drainage in Canada. Native Indian populations at maximum before European contact in the late 1700s were about 50,000 in the Fraser basin and probably less than a fifth of that in the Okanagan. Present total resident populations of the Fraser and Okanagan basins, about 2 million and 1\4 million respectively, have greatly different distributions and thereby effects within the watersheds they occupy. In addition seasonal tourist populations have important and differential impacts within the two watersheds. Expression of these effects on water, fisheries and other aquatic resources of the two basins are explored along with possibilities and suggestions for their sustainable development. The latter, despite some glimmers of hope, will not be tenable without major changes in public attitude, in government policy at all levels, and in other measures which to many may seem impossible.     

Kinetics of high-pressure phase transformations: Implications to the evolution of the olivine → spinel transition in the downgoing lithosphere and its consequences on the dynamics of the mantle

The rate of a high-pressure phase transition increases exponentially with temperature (T) and overpressure or pressure beyond equilibrium (ΔP). It is also greatly promoted by introducing shear stress, diminishing grain size, and adding water or other catalysts to the reactants. For an isothermal and isobaric transition with no compositional change, if steady state of nucleation on grain surfaces is attained, the rate equation can be expressed: (1) before site saturation by: X = 1 − exp(−Kt⁴), where

Full-size image (2K)

and (2) after site saturation by: X = 1 − exp(−K′T), where

Full-size image (1K)

, where X is volume fraction of completion of transformation, t is time, and the C's are characteristic constants. C₁ and C₉ are functions of grain size, C₃ and C₆ are functions of shear stress. All the C's are almost independent of temperature and pressure. Thus, if X as a function of T, ΔP, and t over a narrow P-T range can be experimentally determined, the C's can be calculated and the effect of grain size and shear stress on the rate of transformation can be evaluated. The isothermal and isobaric rate equations for a given composition, shear stress, and grain size are then experimentally determinable. The non-isothermal and non-isobaric rate equation can be calculated from the isothermal and isobaric ones if the rate of penetration into the metastability field is known. The important feature of the kinetics of high-pressure phase transitions predicted by these rate equations is that for a given rate of penetration into the metastability field, there can be defined a characteristic temperature, T_ch, below which the rate of the transition is virtually zero no matter how metastable the material is. For the olivine → spinel transition in the mantle, this characteristic temperature may be as high as 700° C. Thus, in a fast moving downgoing slab, the temperature at its cold center may remain below T_ch even down to depths in excess of 600 km, thereby greatly depressing the olivine—spinel phase boundary.At an early stage in the development of a downgoing slab, the plunging speed is slow. This allows the interior of the slab to heat up and the olivine → spinel transition to proceed rapidly and near equilibrium. As a result, the olivine—spinel phase boundary in the slab will be distorted upwards. The rising of the denser spinel phase then provides an additional driving force which accelerates the plate. Since the upper portion of the slab is pulled from below and the lower portion pushed from above, earthquakes of down-dip extension will occur in the upper mantle while those of down-dip compression will originate in the transition zone. Because the transformation occurs close to equilibrium, there will be an aseismic region separating the two seismic zones. When the plate velocity exceeds a certain limit, the temperature in the cold interior becomes low enough to depress the olivine → spinel transition. The phase boundary is then distorted downwards. The buoyant force thereby created will reduce the driving force, and the plunging speed of the plate will approach a steady state. In addition, the buoyant force will compress the slab from below and result in earthquakes of down-dip compression throughout the length of the slab. Now the olivine → spinel transition is so far from equilibrium that the reaction becomes implosive. A rise in frequency of deep earthquakes towards the implosion region in the lower transition zone is thus predicted. Therefore, as well as stabilizing the plate velocity, the olivine → spinel transition may also control earthquake distributions throughout the downgoing slab.     

Phase equilibria and elastic properties of a pyrolite model for the oceanic upper mantle

The upper-mantle source regions of basaltic magmas in oceanic regions contain both H₂O and CO₂. If the water content of the upper-mantle peridotite is (<0.4%) approx., then its solidus has a distinctive P,T character such that the geotherm for older oceanic regions will enter a zone of incipient (<2%) melting — the low-velocity zone (LVZ) — at depths of 85–95 km. This LVZ is overlain by a lithosphere of subsolidus amphibole-bearing peridotite in which there is a density increase at ~55 km due to the first appearance of garnet. An alternative model in which the LVZ is attributed to the presence of CO₂ fluid phase bubbles is incompatible with experimental data showing high solubility of CO₂ in basaltic magmas at the P,T conditions of the LVZ. The LVZ contains a small melt fraction as an intergranular film (aspect ratio <10⁻²); this melt is of olivine melilitite (CO₂, H₂O present) or olivine nephelinite (H₂O only present) character and is interstitial to olivine > orthopyroxene > garnet > clinopyroxene mineralogy. Temperatures at the top of the LVZ are in the range 1000–1150°C. The lithosphere thickens with age and distance from the mid-oceanic ridges, reaching a stable configuration at a thickness of 85–95 km for t > 80 m.y. With increasing age of the oceanic crust, the velocities in the lithosphere increase, the LVZ becomes thinner, and the velocity contrast between the lithosphere and the LVZ decreases. The pyrolite petrological model and its velocity profile satisfactorily account for most of the geophysical data for various age provinces in oceanic regions.     

Invented tradition and Academic convention in geographical thought about New England

In the histories of colonial (pre-revolutionary) New England environment and landscape a three-stage process is recapitulated. An image of the past was formed which was factitious, but for reasons largely of self-glorification of the settlers the image was raised to the level of myth, memory of the actuality completely erased in one generation. Finally the myth became universally accepted by the populace — an invented tradition — the academy eventually giving it the stamp of (uncritical) approval and making it an established convention. Seven invented traditions/conventions are described: 1) The native American as Ignoble Savage living off the land but with no right to it, 2) the environment as a Desart Wildernesse, later transposed in the nineteenth century to an image of 3) the impenetrable primeval forest, 4) the culture shock of this primordial world stripping the settlers of English regional/cultural differences and making them instant Americans, or generalized (Puritan) New Englanders, 5) the colonial agricultural village as universal settlement pattern for colonists of this wilderness, 6) the fabled colonial green as characteristic of these villages, defensive base for conquest of the surrounding dark forest, and 7) the colonial New Englander as prosperous yeoman in a Jeffersonian garden. The reality and actuality that can be reconstructed belies the invention and convention on every count. In the cases of all seven invented traditions one can discern a period of image formation of variable length, a period of myth creation of about 25 years in which memory of the actual past was erased — usually periods of stress and self-doubt — and then a period when one invented a better and simpler past.     

Experimental deformation of diopside and websterite

Diopside single-crystals, oriented favorably for twin gliding on both systems: (001) [100] and (100)[001] have been deformed in a Griggs apparatus using talc as pressure medium. The latter mechanism is dominant at temperatures (T) below 1050° C at strain rates () of 10⁻³ sec⁻¹, and below 800° C at ; at higher temperatures translation gliding on (100)[001] accompanied by syntectonic recrystallization is dominant but other glide systems also operate. Tests at a single set of conditions, T- and -incremental tests and stress-relaxation experiments have been carried out on websterite (68% CPX, 32% OPX), both in talc (“wet”) and talc-AlSiMag (“dry”) assemblies. Most tests were performed in the high-T regime, where syntectonic recrystallization and “relatively nonselective” glide are dominant. The mean size of recrystallized clinopyroxenes (D, μm) appears to be related to stress (σ, kb) as D = 60σ^−0.9. The mechanical data fit the power law exp(-Q/RT)σⁿ, where for the “wet” experiments A = 10^5.9kb⁻ⁿsec⁻¹, Q = 91.2 kcal/mole, n = 5.3; for σ < 3.5 kb n appears to decrease to 3.3. For the “dry” experiments A = 10^2.2, Q = 77.9, and n = 4.3 for σ < 7.0 kb. Clinopyroxene in the upper mantle occurs as ca. 0–15% mixed phase in peridotites and websterites occur as thin layers. Stresses in these materials will then be near those in the olivine-rich matrix. At , the equivalent viscosity of dry websterite is less than that of dry dunite at depths to 60 km but it increases rapidly at higher pressures; at 240 km it is 10⁶ greater than that of dunite. This may account for the low strains and passive behavior observed for clinopyroxene crystals in most peridotites and websterites, that presumably have formed at great depth. Attenuated folds of websterite in peridotite—evidence of more ductile behavior—may then have formed at shallower levels; alternatively they may have formed under “wet” conditions.     

Lithosphere structure of the Ukrainian Shield and Pripyat Trough in the region of EUROBRIDGE-97 (Ukraine and Belarus) from gravity modelling

The southern segment of the seismic profile EUROBRIDGE—EUROBRIDGE-97 (EB'97)—located in Belarus and Ukraine, crosses the suture zone between two main segments of the East European Craton—Fennoscandia and Sarmatia—as well as Sarmatia itself. At the initial stage of our study, a 3-D density model has been constructed for the crust of the study region, including the major part of the Osnitsa–Mikashevichi Igneous Belt (OMIB) superimposed by sediments of the Pripyat Trough (PT), and three domains in the Ukrainian Shield—the Volhyn Domain (VD) with the anorthosite–rapakivi Korosten Pluton (KP), the Podolian Domain (PD), and the Ros–Tikich Domain (RTD). The model comprises three layers—sediments with maximum thickness (6 km) in the PT and two heterogeneous layers in the crystalline crust separated at a depth of 15 km. 3-D calculations show the main features of the observed gravity field are caused by density heterogeneities in the upper crust. Allocation of density domains deeper than 15 km is influenced by Moho topography. Fitting the densities here reveals an increase (up to 2960 kg m⁻³) in the modelled bodies accompanied by a Moho deepening to 50 km. In contrast, a Moho uplift to a level of 35–37 km below the KP and major part of the PT is associated with domains of reduced densities. An important role for the deep Odessa–Gomel tectonic zone, dividing the crust into two regions one of basically Archean consolidation in the west (PD and RTD) and one of Proterozoic crust in the east (Kirovograd Domain)—was confirmed.2-D density modelling on the EB'97 profile shows that in the upper crust three main domains of different Precambrian evolution—the OMIB (with the superimposed PT), the VD with the KP, and the PD—can be distinguished. Deeper, in the middle and lower crust, layered structures having no connection to the surface geology are dominant features of the models. Least thickness of the crust was obtained below the KP. Greatest crustal thickness (more than 50 km) was found below the PD, characterised also by maximum deviation of velocity/density relation in the rocks from a standard one. The velocity and density models along the EB'97 profile have been interpreted together with inferred V_p/V_s ratios to estimate crustal composition in terms of SiO₂ content. In the course of the modelling, the status of the PD as a centre of Archean granulitic consolidation has been confirmed. The crustal structure of the anorthosite–rapakivi KP is complex. For the first time, a complicated structure for the lower crust and lower crust–upper mantle transition zone beneath the KP has been determined. The peculiarities of the crustal structure of the KP are quite well explained in terms of formation of rapakivi–anorthosite massifs as originating from melt chambers in the upper mantle and lower crust. An important role for the South Pripyat Fault (SPF), repeatedly activated during Proterozoic–Palaeozoic times, has been ascertained. At the subplatform stage of crustal evolution the SPF was, probably, a magma channel facilitating the granitic intrusions of the KP. In the Palaeozoic the fault was reactivated during rifting in the PT.