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1.
Geologic carbon capture and storage (CCS) is an option for reducing CO2 emissions, but leakage to the surface is a risk factor. Natural CO2 reservoirs that erupt from abandoned oil and gas holes leak to the surface as spectacular cold geysers in the Colorado Plateau, United States. A better understanding of the mechanisms of CO2‐driven cold‐water geysers will provide valuable insight about the potential modes of leakage from engineered CCS sites. A notable example of a CO2‐driven cold‐water geyser is Crystal Geyser in central Utah. We investigated the fluid mechanics of this regularly erupting geyser by instrumenting its conduit with sensors and measuring pressure and temperature every 20 sec over a period of 17 days. Analyses of these measurements suggest that the timescale of a single‐eruption cycle is composed of four successive eruption types with two recharge periods ranging from 30 to 40 h. Current eruption patterns exhibit a bimodal distribution, but these patterns evolved during past 80 years. The field observation suggests that the geyser's eruptions are regular and predictable and reflect pressure and temperature changes resulting from Joule–Thomson cooling and endothermic CO2 exsolution. The eruption interval between multiple small‐scale eruptions is a direct indicator of the subsequent large‐scale eruption.  相似文献   

2.
This paper documents the deposition of large boulders on the Beecroft Peninsula, New South Wales, during a one in four‐year swell event in October 1999. The size of the boulders in relation to the magnitude of the swell suggests that the boulder field at Whale Point on the Beecroft Peninsula is explicable in terms of storm swells alone.  相似文献   

3.
A method is presented for quantifying the degree of edge roundness of large crystalline boulders using a simple instrument. The method utilises the transition due to granular disintegration from sharp to rounded boulder edges, so that the degree of edge roundness is a function of time and can be used as a relative dating tool. Edge roundness can be precisely measured in the field if strict morphological criteria are adhered to when selecting boulders to measure. Roundness can be expressed as a length measurement between fixed points on adjacent facets, as a normalised index, or as a radius of curvature. Boulder edge‐roundness was employed to resolve uncertainty over the extent of the ‘Loch Lomond Stadial’ (LLS) glacier in the North‐east Corrie of Lochnagar. Small but significant differences in edge roundness between two sets of moraine ridges indicate that the LLS glacier was smaller than that mapped by Sissons & Grant (1972). The moraine they ascribed to the LLS relates to an earlier advance within Late Devensian time.  相似文献   

4.
An unusual coarse, shelly sedimentary unit is found elevated above present mean sea level in a sheltered pocket embayment at Old Punt Bay in south‐eastern Australia. The coarse sediments, diverse microfauna, and large shelly macrofauna of mixed affinity suggest that the deposit is the result of high‐energy deposition. The deposit was previously thought to have been deposited 1000–1300 cal bp based on one shell dated using 14C and amino acid racemisation. However, additional 14C dating indicates a likely age of ~2500 cal bp . Regardless of age constraints, the presence of rock‐encrusting oyster shells and large articulated bivalves, suggests that the depositional event must have been capable of removing and transporting coarse sediments (rock clasts), bivalves, and oysters shells from a variety of seaward environments and depositing them with little abrasion, something storm waves are unlikely to do. The deposit may be tsunamigenic. If a tsunami origin is accepted, the new dating results indicate that it is possibly coeval with a tsunami event previously reported to have affected several other sites along the coast of New South Wales at c. 2900 cal bp . Consequently, this deposit provides evidence for the event at a new site and importantly, a tighter constraint on the likely date of the events occurrence. It further adds weight to the developing catalogue of palaeotsunamis that may have affected the south‐eastern coast of Australia. Regardless of the deposit's origins, if viewed from a coastal planning perspective, this deposit indicates that this part of the coast has experienced large‐scale overwash events in the past that if repeated, would be catastrophic. There are serious implications for risk management.  相似文献   

5.
The Straits of Gibraltar have been historically an important maritime axis of connection between the Mediterranean and Atlantic areas of the Iberian Peninsula. For this reason, most of the archaeological research has focused on the coastal settlements, but its broader archaeological landscape remains mostly unknown. In this paper, we present recent intensive surveys in which a wide range of sites was detected, dating from the eighth century BC to the fourteenth AD. The ancient landscape is thus reconstructed over a long‐term perspective. Prior to the Roman expansion, the earlier Bailo‐La Silla del Papa was an urban central place that supported a dense network of subordinate settlements. Later on, the central settlement was transported from inland to the coastal town of Baelo Claudia, but the territorial structure remained based on a similar pattern.  相似文献   

6.
ABSTRACT In the 1970s the Motu‐Koita, traditional inhabitants of what is now the National Capital District of Papua New Guinea, inaugurated a yearly cultural festival thematically based on traditional coastal trading voyages known as hiri. Contestation over the location and commercialization of the festival in the capital city developed in the new century as one distant village claimed to ‘own’ the hiri. The Motu‐Koita view of their past and their identity has been affected by their encounter with Christianity, colonialism and its aftermath, and the rhetoric of the villagers’ claims drew on criteria of authenticity, cultural purity, and exclusiveness which are arguably contemporary rather than ‘traditional’. This article reviews Motu‐Koita history, the story of the origin of the hiri, and the local politics of the cultural festival. It attempts to understand the way the past, which was formerly mythopoeically invoked, is being historicized and thereby fixed in new local discourses of cultural and heritage rights and ownership, as Melanesians come to terms with the effects of global processes on their traditions and other resources.  相似文献   

7.
The city of Brisbane, capital of the Australian state of Queensland, sits on a floodplain and has been struck by two devastating flood disasters in the last 50 years. This article contributes to the growing literature on disaster memory by tracing memories of a flood in 1974 as they were constructed and re‐enacted in a more recent disaster in 2011. The article examines how disaster memories shape local identities and considers how such memories influence policy and local knowledge, doing so by reference to an analysis of three forms of memory media—personal narratives, news media reporting, and built memorials. At times, memories of 1974 enabled Brisbane residents to prepare for an oncoming flood and to understand the scope of the 2011 event. Yet other memories produced a form of forgetting by positioning the earlier flood as a successfully navigated event now safely contained in the past. Findings from the analysis thus point to the importance of understanding memories of past disasters as a critical element of disaster planning and management.  相似文献   

8.
Brazilian coastal pre‐colonial skeletal series were examined for accidental fractures, which were grouped according to biomechanical interpretation of the causative events, and results were interpreted based on cultural and environmental aspects. More than 19% of the shell mound builders and 27% of the fisher–hunter–gatherers presented healed fractures. Both series presented balanced values between male and female (18.7 and 20%, respectively, for shell mound builders; 28.1 and 25.6%, respectively, for fisher‐hunter‐gatherers), and more than the double that proportion of the individuals (69.6% for shell mound builder and 88.5% for fisher–hunter–gatherers) had localised lesions, associated with only one traumatic event. The most common type of fractures were those caused by falls blocked by lower limbs (47.8% for shell mound builders and 46.1% for fisher–hunter–gatherers), interpreted as a result of moving along the rocky coastal cliffs. Despite these similarities, both series presented particular aspects which were related mainly to differences in subsistence strategies. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   

9.
In the source areas of some large shallow earthquakes, we have found many dislodged boulders struck by severe ground shaking. Some boulders were located at quite distances from the former sockets, which remained undisturbed with surrounding clear edges. This fact indicates the possibility that vertically upward seismic acceleration exceeded the earth's gravity (1g). This phenomenon of upthrown boulders is investigated herein by examining the effects of waves, which emanate deep in the ground due to an earthquake, propagate through the ground and boulder, and reflect back to the ground, involving a variety of their interaction. An elastic dynamic analysis is carried out on the basis of a one-dimensional continuum model consisting of the ground and boulder. It is subjected to the input of the Ricker wave, which is intended to simulate an earthquake-generated wave, emanating from the bottom of the model ground. The upthrow of a boulder is taken to occur when the dynamic response at the bottom of the boulder satisfies certain conditions. It turns out that the possibility of upthrow occurrence is high when the period of the Ricker wave coincides with the fundamental period of the ground vibration. It leads to the conclusion that the upthrow takes place due to resonance in the response of the system of the ground and boulder to the external wave input. The upthrow possibility increases as the input acceleration increases. Trial is made of predicting the maximum acceleration and velocity of an earthquake, based on this consideration of the up throw phenomenon.  相似文献   

10.
Investigation of shallow‐marine environments for submerged prehistoric archaeology can be hampered in many localities by extensive bedrock exposure and thus limited preservation potential. Using the concept of ‘seamless archaeology’ where land‐based archaeology is integrated across the intertidal zone through to the offshore, a multi‐disciplinary approach is essential. This approach taken in the Bay of Firth, Orkney uses geophysics, historical archive and ethno‐archaeology, coastal geomorphology, palaeo‐environmental analyses and sea‐level science, and allows a clearer understanding of the landscape in which prehistoric settlers lived. While acknowledging the limitations of the preserved environment, we are successful in identifying areas of archaeological potential on the sea‐bed for both upstanding structural elements as well as sediment preservation that contains evidence for human occupation. This has wider implications beyond Orkney's World Heritage sites to provide a blueprint for similar studies elsewhere in the coastal zone. © 2012 The Authors  相似文献   

11.
Following the exceptional discovery of Neolithic engravings on a boulder at Vallée aux Noirs in the Fontainebleau forest, south of Paris, an excavation trench was opened in order to access the buried part of the decorated rock panel and explore the stratigraphic context of the artwork. A palaeosol was found two metres below the modern ground level, underneath multiple layers of sterile sandy soil forming a very compact sequence from which only one archaeological artefact was recovered – an Iron Age fibula (c.200–300 BC). Dating of the palaeosol was attempted through two different methods: AMS dates from charcoal suggest a significant span from the Early Bronze Age to the Iron Age, while two more consistent OSL dates point to formation of the palaeosol during the Late Neolithic (3500–3000 cal BC). The entire engraved rock surface (16 m2), including its buried part, was fully recorded. Four main semiotic groups were identified: a typical fifth‐millennium crook‐hafted axe with a ring, two boats with steering oars, and a central, very tall human figure dominating the composition from its 3.5‐metre height.  相似文献   

12.
Globally, sea‐level rise is expected to impact on many coastal regions and settlements. While mitigation of global greenhouse gas emissions remains an important task, adaptation is now seen as a critical component of the policy equation. Local government is a key player in adaptation planning and managing risk through their mandated role in land use planning and development control. Yet, managing the predicted impacts of climate change is proving to be a complex and difficult task for planners and policy makers. This paper reports on a case of local government deliberation on possible planning responses to address future sea‐level rise impacts in New South Wales, Australia. Using structured, expert opinion of planners and other technical experts engaged in a collaborative network in the Sydney region, we explore the feasibility of implementing planning and policy measures at the local and regional scales to respond to inundation risk as a result of sea‐level rise and storm surge events. Our research shows how local governments employ specific scale‐oriented strategies to engage private and public actors at different scales to manage legal, financial, and technical risks in coastal adaptation.  相似文献   

13.
Ancient Roman populations are expected to exhibit considerable biological variation because of extensive trade networks and migration patterns throughout Europe and the circum‐Mediterranean. The purpose of this research is to examine regional biological variation in Italy during imperial Roman times (1st to 3rd centuries ad ) using three samples exhibiting distinctive class and economic systems. The individuals buried at Isola Sacra and Velia represent middle‐class tradesmen and merchants from coastal port populations from Central and Southern Italy, respectively, while the individuals from Castel Malnome represent an inland population near Rome of freed slaves and other lower‐class individuals involved in heavy labour associated with salt production. Data were recorded from 25 three‐dimensional cranial coordinate landmarks and analysed using Procrustes superimposition and associated multivariate statistics in MorphoJ. Procrustes analysis of variance statistics were unable to detect any significant group differences for centroid size (p  = 0.595), but did detect differences in shape (p  = 0.0154), suggesting some variation between the three samples. Canonical variates analyses based on Procrustes distance values suitable for small sample sizes indicated that while Castel Malnome was not significantly different from either of the coastal sites (Isola Sacra, p  = 0.2071 and Velia, p  = 0.8015), Isola Sacra and Velia were significantly different (p  = 0.0119). The similarity of Castel Malnome to the other sites may reflect inherent heterogeneity in the sample, as it represents a group of freed slaves likely originating from various geographic locations. The separation of the two coastal sites is not unexpected, as Velia's location was influenced by an influx of Greek populations in the southern Italian Peninsula. This work supports previous studies using traditional craniometrics and dental metrics showing group similarity across the Italian Peninsula and a separation between more northern and southern groups. Copyright © 2017 John Wiley & Sons, Ltd.  相似文献   

14.
Melissa W. Wright 《对极》2012,44(3):564-580
Abstract: Since 2006, when Mexico's President declared war against the drug trade, the people of the northern Mexican border city, Ciudad Juárez, have been living through a record‐breaking escalation of violence, the occupation of their city by federal troops and police forces, unprecedented human and civil rights violations, and a pervasive experience of fear in public space. These events have occurred simultaneous to a devastating economic crisis. This paper asks the question, how can a feminist and Marxist geographer contribute to an analysis of what is happening in Ciudad Juárez? To address this question, I create a dialogue among activists in northern Mexico and post‐structuralist feminist and Marxist positions regarding the meaning of public fear in this city for the city's residents, for Mexico's democracy and for the making of public knowledge about the Mexico–US border.  相似文献   

15.
Urban water was supplied to the Roman city of Forum Julii (Fréjus, southeastern France) for at least 200 years by a 39.4 km long aqueduct, operating in ad 50. Two perennial springs were successively collected, the Foux and the Siagnole, located at the outlet of Triassic and Jurassic karstic reservoirs, respectively. In this study, we performed high‐resolution PIXE (Particle‐Induced X‐ray Emission) measurements of Ca, Si, Fe and Sr concentrations on selected cross‐sections of laminated carbonate sampled along the sidewalls, before and after the connection of the two collection channels. Seasonal variations of water composition, suspended sediment load and discharge are recorded by alternating clear and dark layers, and can be traced by their Sr and Fe contents. On the basis of an annual bimodal high‐discharge regime for the two karstic reservoirs, the concentration measurements allow the derivation of a chronological record (117.5 years) of water supply and maintenance activities for a part of the operational period of the aqueduct. The water level in the channel was mainly controlled by the extent of carbonate deposition and by dredging, repair and maintenance operations rather than by the past hydrological regime of the two springs.  相似文献   

16.
The use of red iron‐based earth pigments, or ochre, is a key component of early symbolic behaviours for anatomically modern humans and possibly Neanderthals. We present the first ochre provenance study in Central Europe showing long‐term selection strategies by inhabitants of cave sites in south‐western Germany during the Upper Palaeolithic (43–14.5 ka). Ochre artefacts from Hohle Fels, Geißenklösterle and Vogelherd, and local and extra‐local sources, were investigated using neutron activation analysis (NAA), X‐ray diffraction (XRD) and scanning electron microscopy (SEM). The results show that local ochre sources were continuously and systematically accessed for c.29 500 years, with periodic events of long‐distance (about > 300 km) ochre acquisition during the Aurignacian (c.35–43 ka), suggesting higher mobility than previously suspected. The results reveal previously unknown long‐term, complex spatio‐temporal behavioural patterns during the earliest presence of Homo sapiens in Europe.  相似文献   

17.
Whereas most theoretical and historiographical accounts of the event have focused on its present and past dimensions, this article addresses the relatively underexplored phenomenon of the future event. As temporal junctures, events often already elicit effects before they come to pass, and even if they never do. Building on foundational work on the relation between experience and expectation by Hans‐Georg Gadamer and Reinhart Koselleck as well as on current historiographical debates on “past futures,” I develop a threefold typology of the future event, distinguishing between the assumption of the routine event, the expectation of the relative event, and the adumbration of the radical event. Engaging with case studies like the year 2000, the ambivalent character of so‐called media events, and ongoing debates about a possible climate collapse and the COVID‐19 pandemic, I show how reconsidering the complex temporalities of the future event can shed new light on the ways in which past societies made their futures present.  相似文献   

18.
A survey of soil erosion was conducted in Australia using the fallout radioisotope caesium‐137 as an indicator of topsoil redistribution. Two hundred and six sites were sampled, 100 within rotational cropping and horticultural use, 52 within uncultivated permanent pasture and forest, and 54 in rangelands. Average net soil losses were approximately equal for cultivated cropping lands and rangelands (ca. 5.5 t ha?1 yr?1), and just over 1 t ha?1 yr?1 for pasture and forest. The Mann Whitney U Test revealed that losses under cropping and rangeland conditions were significantly higher (p < 0.05) than under uncultivated pasture and forest. Soil loss was negatively correlated with mean annual rainfall and slope gradient, and positively correlated with slope length (Spearman's rank correlation). There was no correlation between rates of soil loss and a rainfall erosi‐vity index. An assessment of erosional events was provided by landholders for 104 sites, with their ranking being weakly but significantly correlated with soil loss estimates (r =+0.35). Sixty percent of sites had net soil losses greater than 1 t ha?1 yr?1, and 74% of sites had losses of more than 0.5 t ha?1 yr?1. This latter rate may be regarded as a limit for a tolerable level of soil loss. These high rates of soil loss have occurred since the mid‐1950s despite there being significant landholder awareness of the soil erosion hazard.  相似文献   

19.
The method for deriving a stage‐discharge relationship has a significant impact on the shape of the river's rating curve. We compare rating curves for a single gauging station on a mutiple‐channelled river in Australia compiled using three different methods – the Urban Runoff and Basin Systems (URBS) rainfall‐runoff model, an empirically‐based velocity‐area method, and the predictive Hydrologic Engineering Centre‐River Analysis System (HEC‐RAS) computer model. The rainfall‐runoff model was found to predict lower discharges for stage heights over 3.5 m than both the empirically‐based velocity‐area method and the HEC‐RAS model. The empirically‐based velocity‐area model predicts similar discharges to the rainfall‐runoff model for stage heights less than 3 m but much higher discharges for larger flood events. The HEC‐RAS model predicts higher discharges than both other rating curves at all stage heights probably due to under‐estimation of the impact of surface roughness on flow velocity. The three models are discussed with particular reference to their use on multiple‐channelled rivers.  相似文献   

20.
This article discusses youth out‐migration on the non‐metropolitan New South Wales Eastern Seaboard. High levels of in‐migration and counter‐urbanisation, typical of many coastal non‐metropolitan towns in NSW, mask the out‐migration of youth. There are relatively few 15–24 year olds in the coastal communities of non‐metropolitan New South Wales, because many youths out‐migrate to larger centres, for a range of reasons. Out‐migration also demarcates a life transition away from school life, adolescence and the parental home. This paper draws from research with senior high school students in one coastal town – Coffs Harbour – where such trends have been particularly apparent. It examines the propensity for youth out‐migration and discusses how young people articulate their migration intentions. Young people's perceptions of their current and future prospects feature prominently in their discourses about intended migration, although this research also demonstrates that the life courses of regional youth are unorthodox and diverse in nature.  相似文献   

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