GeoResJ Pub Date : 2015-03-01 DOI: 10.1016/j.grj.2014.11.003

A. Poortinga , J.G.S. Keijsers , S.M. Visser , M.J.P.M. Riksen , A.C.W. Baas

{"title":"Temporal and spatial variability in event scale aeolian transport on Ameland, The Netherlands","authors":"A. Poortinga , J.G.S. Keijsers , S.M. Visser , M.J.P.M. Riksen , A.C.W. Baas","doi":"10.1016/j.grj.2014.11.003","DOIUrl":"10.1016/j.grj.2014.11.003","url":null,"abstract":"<div><p>Coastal dunes are the primary defence protecting the coastline from the destructive forces of the sea in The Netherlands. Aeolian processes are important in this context as they contribute to dune accretion and thus the safety of the coastal hinterland. In this study, we analyze horizontal and vertical variability of event scale aeolian sand transport on a wide beach on the island of Ameland, The Netherlands. Data were obtained from a meteorological station, groundwater monitoring wells and a camera installed on the beach. Fifteen aeolian transport events (two involving onshore winds, seven longshore and six offshore) were measured using a comprehensive grid of 37 customized MWAC traps. The highest sand transport rates and largest variability was found for alongshore events. Surface moisture, governed by groundwater, was found to be an important controlling parameter for aeolian transport rates and vertical flux profiles. Groundwater levels were largely dominated by beach inundation, influencing the groundwater table for a two week period. Variations in vertical flux profiles between traps were larger for wet sand transport events than dry ones. In general, sand transport rates were highest at the foreshore and lowest at the dune toe. Sand transport dynamics are dependent on local conditions such as beach dimensions, beach orientation and also meteorological and surface characteristics. Moderate (high frequency, low magnitude) events are also capable of transporting large amounts of sand. Future studies should include spatially explicit measurements of elevation and surface moisture to obtain a more complete understanding of the complex sand transport dynamics.</p></div>","PeriodicalId":93099,"journal":{"name":"GeoResJ","volume":"5 ","pages":"Pages 23-35"},"PeriodicalIF":0.0,"publicationDate":"2015-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.grj.2014.11.003","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"54365231","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 14

Holocene record of Tuggerah Lake estuary development on the Australian east coast: Sedimentary responses to sea-level fluctuations and climate variability 澳大利亚东海岸Tuggerah湖河口发展的全新世记录:沉积对海平面波动和气候变率的响应

GeoResJ Pub Date : 2015-03-01 DOI: 10.1016/j.grj.2015.01.002

Peter I. Macreadie , Timothy C. Rolph , Claudia Schröder-Adams , Ron Boyd , Charles G. Skilbeck

{"title":"Holocene record of Tuggerah Lake estuary development on the Australian east coast: Sedimentary responses to sea-level fluctuations and climate variability","authors":"Peter I. Macreadie , Timothy C. Rolph , Claudia Schröder-Adams , Ron Boyd , Charles G. Skilbeck","doi":"10.1016/j.grj.2015.01.002","DOIUrl":"10.1016/j.grj.2015.01.002","url":null,"abstract":"<div><p>We investigated the Holocene palaeo-environmental record of the Tuggerah Lake barrier estuary on the south-east coast of Australia to determine the influence of local, regional and global environmental changes on estuary development. Using multi-proxy approaches, we identified significant down-core variation in sediment cores relating to sea-level rise and regional climate change. Following erosion of the antecedent land surface during the post-glacial marine transgression, sediment began to accumulate at the more seaward location at ∼8500years before present, some 1500years prior to barrier emplacement and ∼4000years earlier than at the landward site. The delay in sediment accumulation at the landward site was a consequence of exposure to wave action prior to barrier emplacement, and due to high river flows of the mid-Holocene post-barrier emplacement. As a consequence of the mid-Holocene reduction in river flows, coupled with a moderate decline in sea-level, the lake experienced major changes in conditions at ∼4000years before present. The entrance channel connecting the lake with the ocean became periodically constricted, producing cyclic alternation between intervals of fluvial- and marine-dominated conditions. Overall, this study provides a detailed, multi-proxy investigation of the physical evolution of Tuggerah Lake with causative environmental processes that have influenced development of the estuary.</p></div>","PeriodicalId":93099,"journal":{"name":"GeoResJ","volume":"5 ","pages":"Pages 57-73"},"PeriodicalIF":0.0,"publicationDate":"2015-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.grj.2015.01.002","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"54365252","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 6

Subducted, detached, and torn slabs beneath the Greater Caucasus 大高加索地下俯冲、分离和撕裂的板块

GeoResJ Pub Date : 2015-03-01 DOI: 10.1016/j.grj.2014.09.004

Tea Mumladze , Adam M. Forte , Eric S. Cowgill , Charles C. Trexler , Nathan A. Niemi , M. Burak Yıkılmaz , Louise H. Kellogg

{"title":"Subducted, detached, and torn slabs beneath the Greater Caucasus","authors":"Tea Mumladze , Adam M. Forte , Eric S. Cowgill , Charles C. Trexler , Nathan A. Niemi , M. Burak Yıkılmaz , Louise H. Kellogg","doi":"10.1016/j.grj.2014.09.004","DOIUrl":"10.1016/j.grj.2014.09.004","url":null,"abstract":"<div><p>The Greater Caucasus Mountains contain the highest peaks in Europe and define, for over 850km along strike, the leading edge of the second-largest active collisional orogen on Earth. However, the mechanisms by which this range is being constructed remain disputed. Using a new database of earthquake records from local networks in Georgia, Russia, and Azerbaijan, together with previously published hypocenter locations, we show that the central and eastern Greater Caucasus Mountains are underlain by a northeast-dipping zone of mantle seismicity that we interpret as a subducted slab. Beneath the central Greater Caucasus (east of 45°E), the zone of seismicity extends to a depth of at least 158km with a dip of ∼40°NE and a slab length of ∼130–280km. In contrast, beneath the western GC (west of 45°E) there is a pronounced lack of events below ∼50km, which we infer to reflect slab breakoff and detachment. We also observe a gap in intermediate-depth seismicity (45–75km) at the western end of the subducted slab beneath the central Greater Caucasus, which we interpret as an eastward-propagating tear. This tear coincides with a region of minimum horizontal convergence rates between the Lesser and Greater Caucasus, as expected in a region of active slab breakoff. Active subduction beneath the eastern Greater Caucasus presents a potentially larger seismic hazard than previously recognized and may explain historical records of large magnitude (M 8) seismicity in this region.</p></div>","PeriodicalId":93099,"journal":{"name":"GeoResJ","volume":"5 ","pages":"Pages 36-46"},"PeriodicalIF":0.0,"publicationDate":"2015-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.grj.2014.09.004","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"54365191","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 54

Dust devils and dustless vortices on a desert playa observed with surface pressure and solar flux logging 用地表压力和太阳通量测井观察沙漠上的尘卷风和无尘漩涡

GeoResJ Pub Date : 2015-03-01 DOI: 10.1016/j.grj.2014.11.002

Ralph D. Lorenz , Brian K. Jackson

{"title":"Dust devils and dustless vortices on a desert playa observed with surface pressure and solar flux logging","authors":"Ralph D. Lorenz , Brian K. Jackson","doi":"10.1016/j.grj.2014.11.002","DOIUrl":"10.1016/j.grj.2014.11.002","url":null,"abstract":"<div><p>Dust devils are convective vortices rendered visible by lofted dust, and may be a significant means of injecting dust into the atmosphere, on both Earth and Mars. The fraction of vortices that are dust-laden is not well-understood, however. Here we report a May/June 2013 survey on a Nevada desert playa using small stations that record pressure and solar flux with high time resolution (2Hz): these data allow detection of vortices and an estimate of the dust opacity of the subset of vortices that geometrically occult the sun. The encounter rate of vortex pressure drops of 0.3hPa or larger is 50–80 per 100days, with 0.6hPa or larger drops occurring about 3times less often. Obscuration events associated with pressure drops occur less frequently, in part because near-misses must be in the sunward direction to cause attenuation of the solar beam and in part because some vortices are not dust-laden. 40% of vortex events had no detectable attenuation, and only 20% of events caused dimming greater than about 2% (a maximum of ∼35%), with stronger dimming tending to occur with larger pressure drops. The distribution suggests dust lifting may be dominated by a few intense devils, complicating estimation of the total flux into the atmosphere.</p></div>","PeriodicalId":93099,"journal":{"name":"GeoResJ","volume":"5 ","pages":"Pages 1-11"},"PeriodicalIF":0.0,"publicationDate":"2015-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.grj.2014.11.002","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"54365212","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 32

The nature of the Moho in Australia from reflection profiling: A review 从反思剖析看澳大利亚莫霍人的性质

GeoResJ Pub Date : 2015-03-01 DOI: 10.1016/j.grj.2015.02.001

B.L.N. Kennett, E. Saygin

引用次数: 34

Temperatures, thermal structure, and behavior of eruptions at Kilauea and Erta Ale volcanoes using a consumer digital camcorder 温度，热结构，并在基拉韦厄火山和埃尔塔阿尔火山喷发行为使用消费数码摄像机

GeoResJ Pub Date : 2015-03-01 DOI: 10.1016/j.grj.2015.01.001

Gregory T. Carling , Jani Radebaugh , Takeshi Saito , Ralph D. Lorenz , Anne Dangerfield , David G. Tingey , Jeffrey D. Keith , John V. South , Rosaly M. Lopes , Serina Diniega

{"title":"Temperatures, thermal structure, and behavior of eruptions at Kilauea and Erta Ale volcanoes using a consumer digital camcorder","authors":"Gregory T. Carling , Jani Radebaugh , Takeshi Saito , Ralph D. Lorenz , Anne Dangerfield , David G. Tingey , Jeffrey D. Keith , John V. South , Rosaly M. Lopes , Serina Diniega","doi":"10.1016/j.grj.2015.01.001","DOIUrl":"10.1016/j.grj.2015.01.001","url":null,"abstract":"<div><p>Remote thermal monitoring of active volcanoes has many important applications for terrestrial and planetary volcanic systems. In this study, we describe observations of active eruptions on Kilauea and Erta Ale volcanoes using a short-wavelength, high-resolution, consumer digital camcorder and other non-imaging thermal detectors. These systems revealed brightness temperatures close to the eruption temperatures and temperature distributions, morphologies and thermal structures of flow features, tube systems and lava fountains. Lava flows observed by the camcorder through a skylight on Kilauea had a peak in maximum brightness temperatures at 1230°C and showed brightness temperature distributions consistent with most rapid flow at the center. Surface brightness temperatures of cooling lava flows on Kilauea were close to 850°C. Centimeter-scale thermal features are evident around pahoehoe ropes and inflated flows and stalactites in lava tubes. Observations of the fountaining Erta Ale lava lake in February 2011 extend the baseline of observations of the eruptive episode begun in late 2010. We observed a fountain using the camcorder and found a peak in maximum brightness temperatures at 1164°C, consistent with previous studies. Steep temperature gradients were observed across centimeter-scale distances between the highly exposed fountain and cracks and the much cooler lava lake surface and crater walls. The instrument and methods described here lead to robust pictures of the temperatures and temperature distributions at these volcanoes and reveal desired characteristics of planetary remote sensing platforms for the study of volcanically active bodies such as Io.</p></div>","PeriodicalId":93099,"journal":{"name":"GeoResJ","volume":"5 ","pages":"Pages 47-56"},"PeriodicalIF":0.0,"publicationDate":"2015-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.grj.2015.01.001","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"54365245","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 13

Effect of particle mixing morphology on aerosol scattering and absorption: A discrete dipole modeling study 粒子混合形态对气溶胶散射和吸收的影响:一个离散偶极子模型研究

GeoResJ Pub Date : 2014-09-01 DOI: 10.1016/j.grj.2014.07.001

Qing Zhang, J.E. Thompson

{"title":"Effect of particle mixing morphology on aerosol scattering and absorption: A discrete dipole modeling study","authors":"Qing Zhang, J.E. Thompson","doi":"10.1016/j.grj.2014.07.001","DOIUrl":"10.1016/j.grj.2014.07.001","url":null,"abstract":"<div><p>Atmospheric aerosol particles may undergo phase separation due to differences in miscibility. This alters the morphology of particles such that they are no longer well-mixed, simple spheres. As a result, scattering and absorption of sunlight in Earth’s atmosphere could be affected. In turn, this may alter direct climate forcing by aerosols. In this work we examine the impact of phase separation on aerosol optics for the bi-sphere, core–shell, and engulfed morphologies. We find bi-spherical particles often exhibit very different scattering and absorption cross-sections for a mid-visible wavelength (0.53μm) relative to an equivalent, volume-weighted spherical case. Optical differences are largely driven by the particle shape, rather than differences in refractive index between phases. However, when averaged across a typical urban particle size distribution, the differences in light scattering largely vanish and bi-sphere and volume equivalent models generally agreed to within 10% for dielectric particles. For particles that are light absorbing, the bi-sphere and volume averaged cases often yielded dissimilar results with the volume-averaged case reflecting absorption >10% more than the phase separated particles. This was particularly true for bi-spheres in which one component particle is strongly light absorbing. Core–shell and engulfed morphologies yield volume scattering efficiencies within a few percent of volume-weighted spheres. However, modeled light absorption between the phase separated and volume averaged models frequently differ by >20% when inclusions absorb light strongly. Therefore, modeling light absorption of mixed-phase particles through the volume-mixing rule cannot be recommended.</p></div>","PeriodicalId":93099,"journal":{"name":"GeoResJ","volume":"3 ","pages":"Pages 9-18"},"PeriodicalIF":0.0,"publicationDate":"2014-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.grj.2014.07.001","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"54365150","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 9

Combined sulfur, carbon and redox budget constraints on genetic models for the Here’s Your Chance Pb–Zn deposit, Australia 澳大利亚铅锌矿综合硫、碳和氧化还原预算约束的遗传模型

GeoResJ Pub Date : 2014-09-01 DOI: 10.1016/j.grj.2014.09.001

Jeffrey M. Dick , Katy A. Evans , Alex I. Holman , David Leach , Kliti Grice

{"title":"Combined sulfur, carbon and redox budget constraints on genetic models for the Here’s Your Chance Pb–Zn deposit, Australia","authors":"Jeffrey M. Dick , Katy A. Evans , Alex I. Holman , David Leach , Kliti Grice","doi":"10.1016/j.grj.2014.09.001","DOIUrl":"10.1016/j.grj.2014.09.001","url":null,"abstract":"<div><p>The formation of base metal sulfide deposits requires not only a source of metals but also reduced sulfur. If incoming sulfur is present in ore fluids as sulfate, then a source of electrons is needed to drive the reduction of sulfate to sulfide. The oxidation of organic matter can release electrons that provide the reducing capacity, whether it be in low- or high-temperature settings that are conducive to biological or thermochemical sulfate reduction (BSR or TSR). The amounts of organic matter reacted and sulfide minerals formed can be estimated by mass balance calculations. In this study, an integrated mass balance expression is formulated that takes into account the sulfide mineral content and organic carbon content and H/C ratios of mineralised and non-mineralised rocks. Model calculations based on carbon, sulfur and redox budget balances suggest that the extent of oxidation of the organic matter present at the Here’s Your Chance (HYC) Pb–Zn deposit is insufficient for reduction of the required quantity of sulfate. The results imply that externally derived reducing capacity and/or reduced sulfur is required to form the metal resource. Possible sources include hydrocarbon-rich fluids from deeper parts of the sedimentary sequence or formation of sulfide and organic matter as products of BSR during sedimentation/early diagenesis. However, the observed oxidation of organic matter associated with the deposit suggests that at least some reducing capacity is locally derived. Therefore, our calculations are consistent with genetic models for HYC that have multiple sources of redox budget for sulfate reduction.</p></div>","PeriodicalId":93099,"journal":{"name":"GeoResJ","volume":"3 ","pages":"Pages 19-26"},"PeriodicalIF":0.0,"publicationDate":"2014-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.grj.2014.09.001","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"54365161","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 3

Compact and inexpensive kite apparatus for geomorphological field aerial photography, with some remarks on operations 紧凑和廉价的风筝装置，用于地貌学领域的航空摄影，有一些操作说明

GeoResJ Pub Date : 2014-09-01 DOI: 10.1016/j.grj.2014.06.001

Ralph D. Lorenz , Stephen P. Scheidt

引用次数: 12

Chloride partitioning and solubility in hydrous phonolites from Erebus volcano: A contribution towards a multi-component degassing model 埃里伯斯火山含水空纹岩中氯化物的分配和溶解度:对多组分脱气模型的贡献

GeoResJ Pub Date : 2014-09-01 DOI: 10.1016/j.grj.2014.09.003

Marina Alletti , Alain Burgisser , Bruno Scaillet , Clive Oppenheimer

{"title":"Chloride partitioning and solubility in hydrous phonolites from Erebus volcano: A contribution towards a multi-component degassing model","authors":"Marina Alletti , Alain Burgisser , Bruno Scaillet , Clive Oppenheimer","doi":"10.1016/j.grj.2014.09.003","DOIUrl":"10.1016/j.grj.2014.09.003","url":null,"abstract":"<div><p>We present results from a series of experiments on the partitioning of chlorine between a hydrous fluid phase and a phonolitic melt that we then use to model specific aspects of volcanic degassing. Experiments were performed from 250 to 10MPa on a phonolite from Erebus lava lake, Antarctica, at 1000°C near the QFM solid buffer. Only one of 48 experimental samples shows coexistence of low-density vapour and high-density brine in the fluid phase while 35 samples are unambiguously in the vapour field. Large uncertainties in the H<sub>2</sub>O–NaCl phase diagram at the <em>P</em>–<em>T</em> considered do not allow us to assign reliable phase behaviour to the remaining samples. We select a vapour-dominated subset of our dataset to establish an empirical HCl solubility law valid at low pressures and salinities. This law is incorporated into a thermodynamical model of degassing, which we use to compute equilibrium temperatures from gas measurements made at Erebus in 2010. The quiescent lake activity features cyclic temperature variations between 1000 and 1050°C, which is consistent with thermal convection within the shallow plumbing system. Backward tracking of representative gas compositions and temperatures shows the evolution with pressure of the molar ratio of SO<sub>2</sub>/HCl in the gas, a quantity that is often measured in volcanic plumes. Model outputs suggest that this ratio can vary by up to an order of magnitude when the pressure changes from atmospheric to 100MPa, depending on degassing style (coupled vs. decoupled ascent of gas and melt).</p></div>","PeriodicalId":93099,"journal":{"name":"GeoResJ","volume":"3 ","pages":"Pages 27-45"},"PeriodicalIF":0.0,"publicationDate":"2014-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.grj.2014.09.003","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"54365184","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 15

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