An Integrated Moral Obligation Model for Landowner Conservation Norms

This study applies an integrated moral obligation model to examine the role of environmental and cultural values, and beliefs in the activation of landowner conservation norms. Data for this study were collected through a self-administered survey of riparian landowners in two Minnesota watersheds: Sand Creek and Vermillion River watersheds. Study findings suggest that collectivistic and biospheric–altruistic values form the bases for the activation of personal norms. Further, beliefs about local responsibility and ability to act influence personal norms to protect water resources. Findings suggest that landowners’ personal norms of water conservation are more likely to be activated by conservation strategies that appeal to biospheric–altruistic and collectivistic values, emphasize adverse consequences of water pollution, highlight water resource protection as a local responsibility, and provide the resources needed to protect water resources.     

Experimental study on the deterioration and natural remediation of the Ariake Sea tidal mud caused by the sea laver treatment acid practice and the upward seepage of pore water liquid

This study presents a laboratory study of the following two aspects: (1) the influence of sea laver treatment acid on the geoenvironmental properties of Ariake Sea tidal mud, and (2) the natural remediation effect on the sea laver treatment acid contaminated Ariake Sea tidal mud caused by the upward seepage of pore water liquid in the mud. Firstly, the mechanisms of the transport of sea laver treatment acid in the Ariake Sea tidal mud and the generation mechanisms of the upward seepage flow in the Ariake Sea tidal mud are discussed. Secondly, a series of one-dimensional laboratory infiltration tests were carried out to investigate the deterioration of the Ariake Sea tidal mud caused by the sea laver acid treatment practice. Test results reveal that the acid treatment practice caused considerable change in the geochemical properties of the mud in terms of increase in sulfide content and decrease in pH value. After the treatment by the sea laver treatment acid, the sulfide content of the mud even exceeded the safe limit value for the benthos, which represents undesirable living condition for benthos. Thirdly, series of laboratory fresh seawater infiltration tests for the deteriorated Iida site mud were conducted to illustrate this natural remediation efficiency. It is found that with the infiltration of the fresh seawater, the sulfide content of the Iida site mud was considerably reduced and pH value increased to an acceptable range for benthos living in the tidal flat mud. With the increase in the infiltration time and the hydraulic gradient, the remediation efficiency could be increased.     

http://dx.doi.org/10.1016/j.gsf.2016.11.007

Lunar anorthosite is a major rock of the lunar highlands,which formed as a result of plagioclasefloatation in the lunar magma ocean(LMO).Constraints on the sufficient conditions that resulted in the formation of a thick pure anorthosite(mode of plagioclase 95 vol.%) is a key to reveal the early magmatic evolution of the terrestrial planets.To form the pure lunar anorthosite,plagioclase should have separated from the magma ocean with low crystal fraction.Crystal networks of plagioclase and mafic minerals develop when the crystal fraction in the magma(φ) is higher than ca.40-60 vol.%,which inhibit the formation of pure anorthosite.In contrast,when φ is small,the magma ocean is highly turbulent,and plagioclase is likely to become entrained in the turbulent magma rather than separated from the melt.To determine the necessary conditions in which anorthosite forms from the LMO,this study adopted the energy criterion formulated by Solomatov.The composition of melt,temperature,and pressure when plagioclase crystallizes are constrained by using MELTS/pMELTS to calculate the density and viscosity of the melt.When plagioclase starts to crystallize,the Mg~# of melt becomes 0.59 at 1291 C.The density of the melt is smaller than that of plagioclase for P 2.1 kbar(ca.50 km deep),and the critical diameter of plagioclase to separate from the melt becomes larger than the typical crystal diameter of plagioclase(1.8-3 cm).This suggests that plagioclase is likely entrained in the LMO just after the plagioclase starts to crystallize.When the Mg~# of melt becomes 0.54 at 1263 C,the density of melt becomes larger than that of plagioclase even for 0 kbar.When the Mg~# of melt decreases down to 0.46 at 1218 C,the critical diameter of plagioclase to separate from the melt becomes 1.5-2.5 cm,which is nearly equal to the typical plagioclase of the lunar anorthosite.This suggests that plagioclase could separate from the melt.One of the differences between the Earth and the Moon is the presence of water.If the terrestrial magma ocean was saturated with H_2O,plagioclase could not crystallize,and anorthosite could not form.     

Tectonic implications of damage zone-related fault-fracture networks revealed in drill core through the Nojima fault, Japan

1800 m of drill core through the Nojima fault zone, Japan, reveals subsidiary fault and fracture networks that developed in the fault zone that triggered the 1995 Ms 7.2 Kobe earthquake. The subsidiary fault zones contain a fault gouge of < 1 cm bounded by thin zones of foliated cataclasite or breccia. Fractures are filled with calcite veins, calcite-cemented breccias, clay, and iron-oxide and carbonate alternation of the granitic host rock. These features are typical of extensional fractures that form the conduit network for fluid flux close to a major fault zone. The zone of distributed deformation surrounding the main fault is 50 m in width, and the dip of the Nojima fault at > 1 km depth is 75°. The fault-fracture networks associated with the Nojima fault zone are coseismic and were filled with carbonate and fine-grained material during repeated seismic-related infiltration of the fault zone by carbonate-bearing subsurface water. This study shows that fault-related fracture networks plays an important role as fluid flow conduits within seismically active faults, and can change in character from zones of high permeability to low permeability due to cementation and/or pore collapse.     

Experimental and theoretical study of stability of dense hydrous magnesium silicates in the deep upper mantle

Fluid-undersaturated experiments were conducted to determine the phase relations in the simplified peridotite system MgO-SiO₂-H₂O (MSH) at 11.0-14.5 GPa and 800-1400 °C. Stability relations of dense hydrous magnesium silicates (DHMSs) under fluid-undersaturated conditions were experimentally examined. From the fluid-absent experimental results, we retrieved thermodynamic data for clinohumite, phase A, phase E, and hydrous wadsleyite, consistent with the published data set for dry mantle minerals. With this new data set, we have calculated phase equilibria in the MSH system including dehydration reactions. The dehydration reactions calculated with lower water activities of 0.68-0.60 match the fluid-present experiments of this study above 11.0 GPa and 1000 °C, indicating that considerable amounts of silicate component were dissolved into the fluid phase. The calculated phase equilibria illustrate the stability of the post-antigorite phase A-bearing assemblages. In the cold subducting slab peridotite, phase A + enstatite assemblage survives into the transition zone, whereas phase A + forsterite + enstatite assemblage forms hydrous wadsleyite at a much shallower depth of about 360-km. The slab is subducted with no dehydration reactions occurring when entering the transition zone. The phase equilibria also show the high temperature stability of phase E. Phase E is stable up to 1200 °C at 13.5 GPa, a plausible condition in the mantle of relatively low temperature, i.e., beneath subduction zones. Phase E is a possible water reservoir in the mantle as well as wadsleyite and ringwoodite.     

Occurrence of phosphatic microfossils in an Ediacaran–Cambrian mid-oceanic paleo-atoll limestone of southern Siberia

New phosphatic microfossils were recently discovered in an Ediacaran–Cambrian mid-oceanic paleo-atoll limestone in the southern Gorny Altai Mountains in southern Siberia. Microfossils with calcium phosphate shells are abundant in the limestone that occurs as an exotic block within a Cambrian accretionary complex in the Kurai area. SEM observations confirm that the calcium phosphatic shells are ellipsoidal and equal-sized, about 200–300 μm in diameter. Shell walls are about 1 μm thick. As the absence of external and internal structures hinders a detailed comparison/identification, these microfossils are tentatively treated here as paleontological problematica. EPMA-analysis confirmed the concentration of elements P and Ca in microfossil shells and the absence in the matrix, suggesting the primary phosphatic composition of the shells. Because phosphatic microfossils are generally scarce in the Ediacaran but abundant from the Lower Cambrian, in particular within pre-trilobitic SSF assemblages, the phosphatic fossil-bearing limestone in the Kurai area possibly belongs to the Lower Cambrian. The present find proves that mid-oceanic paleo-seamounts as well as continental shelf domains had already been inhabited by diverse metazoans in the Ediacaran–Cambrian transitional interval.     

http://dx.doi.org/10.1016/j.gsf.2016.08.001

Geological observations indicate that there are only a few rocks of Archean Earth and no Hadean rocks on the surface of the present-day Earth. From these facts, many scientists believe that the primordial continents never existed during Hadean Earth, and the continental volume has kept increasing. On the other hand, recent studies reported the importance of the primordial continents on the origin of life, implying their existence. In this paper, we discussed the possible process that could explain the loss of the primordial continents with the assumption that they existed in the Hadean. Although depending on the timing of the initiation of plate tectonics and its convection style, subduction erosion, which is observed on the present-day Earth, might have carried the primordial continents into the deep mantle.     

Frontiers in early Earth history and primordial life——Part Ⅱ

正Following the publication of Part Ⅰ of the series on"Frontiers in early Earth history and primordial life"(Maruyama and Santosh,2017),we present the second part in this volume compiling state-of-the-art research focusing on issues related to the early evolutionary history of the Earth and life.The first paper by Imaeda and Ebisuzaki(2018)on"Single planet formation regime in the high-ionization environment:     

Pacific-type orogeny revisited: Miyashiro-type orogeny proposed

Abstract The concept of Pacific-type orogeny is revised, based on an assessment of geologic data collected from the Japanese Islands during the past 25 years. The formation of a passive continental margin after the birth of the Pacific Ocean at 600 Ma was followed by the initiation of oceanic plate subduction at 450 Ma. Since then, four episodes of Pacific-type orogeny have occurred to create an orogenic belt 400 km wide that gradually grew both oceanward and downward. The orogenic belt consists mainly of an accretionary complex tectonically interlayered with thin (<2 km thick), subhorizontal, high-P/T regional metamorphic belts. Both the accretionary complex and the high-P/T rocks were intruded by granitoids ～100 million years after the formation of the accretionary complex. The intrusion of calc-alkaline (CA) plutons was synchronous with the exhumation of high-P/T schist belts. Ages from microfossils and K-Ar analysis suggest that the orogenic climax happened at a time of mid-oceanic ridge subduction. The orogenic climax was characterized by the formation of major subhorizontal orogenic structures, the exhumation of high-P/T schist belts by wedge extrusion and subsequent domed uplift, and the intrusion-extrusion of CA magma dominantly produced by slab melting. The orogenic climax ended soon after ridge subduction, and thereafter a new Pacific-type orogeny began. A single Pacific-type orogenic cycle may correspond to the interaction of the Asian continental margin with one major Pacific oceanic plate. Ophiolites in Japan occur as accreted material and are not of island-arc but of plume origin. They presumably formed after the birth of the southern Pacific superplume at 600 Ma, and did not modify the cordilleran-type orogeny in a major way. Microplates, fore-arc slivers, intra-oceanic arc collisions and the opening of back-arc basins clearly contributed to cordilleran orogenesis. However, they were of secondary importance and served only to modify pre-existing major orogenic components. The most important cause of cordilleran-type orogeny is the subduction of a mid-oceanic ridge, by which the volume of continental crust increases through the transfer of granitic melt from the subducting oceanic crust to an orogenic welt. Accretionary complexes are composed mainly of recycled granitic sediments with minor amounts of oceanic material, which indicate that the accretion of oceanic material, including huge oceanic plateaus, was not significant for orogenic growth. Instead, the formation and intrusion of granitoids are the keys to continental growth, which is the most important process in Pacific-type orogeny. Collision-type orogeny does not increase the volume of continental crust. The name ‘Miyashiro-type orogeny’ is proposed for this revised concept of Pacific-type or cordilleran-type orogeny, in order to commemorate Professor A. Miyashiro's many contributions to a better understanding of orogenesis.     

Geologic evidence for late Quaternary repetitive surface faulting on the Isurugi fault along the northwestern margin of the Tonami Plain,north‐central Japan

Our detailed field investigation, paleoseismic trenching, and airborne light detection and ranging (LiDAR)‐derived topographic data provides the first direct evidence for late Quaternary repetitive surface faulting on the northeast‐striking Isurugi fault along the northwestern margin of the Tonami Plain in the Hokuriku region of north‐central Japan. This fault has been interpreted previously by different researchers as both inactive and active, owing to a lack of geologic evidence and a failure to identify fault‐related geomorphic features. Our mapping of LiDAR topography revealed a series of northeast‐trending warped fluvial terraces, about 1.5 km long and 170 m wide, with an age of ≤ 29 ka. We interpreted these geomorphologic features to represent an active pop‐up structure bounded to the southeast by the northwest‐dipping main thrust of the Isurugi fault and to the northwest by a southeast‐dipping backthrust that splays off the main thrust in the shallow subsurface. Paleoseismic trenching across the northwestern part of an elongate terrace exposed a series of southeast‐dipping backthrusts and associated northwest‐verging monoclines. The deformation and depositional age of the strata provide evidence for repetitive surface rupturing on the backthrusts since the latest Pleistocene; the latest of these events occurred in the Holocene between about 4.0 and 0.9 ka. Despite the poor preservation of the surface expression of the Isurugi fault, repetitive scarp‐forming faulting in the late Quaternary and the proximity of the Oyabe River and its tributaries to the fault trace suggest that there may be an extension of the Isurugi fault to the northeast and southwest beneath the Tonami Plain that makes the fault long enough to generate a large earthquake (Mw ≥ 6.8) accompanied by surface rupture.