Surface controls on the characteristics of natural CO2 seeps: implications for engineered CO2 stores

CO₂ injected into rock formations for deep geological storage must not leak to surface, since this would be economically and environmentally unfavourable, and could present a human health hazard. In Italy natural CO₂ degassing to the surface via seeps is widespread, providing an insight into the various styles of subsurface ‘plumbing’ as well as surface expression of CO₂ fluids. Here we investigate surface controls on the distribution of CO₂ seep characteristics (type, flux and temperature) using a large geographical and historical data set. When the locations of documented seeps are compared to a synthetic statistically random data set, we find that the nature of the CO₂ seeps is most strongly governed by the flow properties of the outcropping rocks, and local topography. Where low‐permeability rocks outcrop, numerous dry seeps occur and have a range of fluxes. Aqueous fluid flow will be limited in these low‐permeability rocks, and so relative permeability effects may enable preferential CO₂ flow. CO₂ vents typically occur along faults in rocks that are located above the water table or are low permeability. Diffuse seeps develop where CO₂ (laterally supplied by these faults) emerges from the vadose zone and where CO₂ degassing from groundwater follows a different flow path due to flow differences for water and CO₂ gas. Bubbling water seeps (characterized by water bubbling with CO₂) arise where CO₂ supply enters the phreatic zone or an aquifer. CO₂‐rich springs often emerge where valleys erode into CO₂ aquifers, and these are typically high flux seeps. Seep type is known to influence human health risk at CO₂ seeps in Italy, as well as the topography surrounding the seep which affects the rate of gas dispersion by wind. Identifying the physical controls on potential seep locations and seep type above engineered CO₂ storage operations is therefore crucial to targeted site monitoring strategy and risk assessment. The surface geology and topography above a CO₂ store must therefore be characterized in order to design the most effective monitoring strategy.     

The emergence of agropastoralism: Accelerated ecocultural change on the Andean altiplano, ∼3540–3120 cal BP

In the fourth millennium BP, there were major environmental and cultural changes on the Andean altiplano of South America, but the chronology remains vague. A recent synthesis describes a slow, gradual transition from hunting and gathering to agropastoralism. This proposal is tested by refining the date of the onset of more humid and stable conditions, around 3550 cal BP, based on a Bayesian model of 26 dates from Lake Wiñaymarka and an updated calculation of the lacustrine offset. This is compared to Bayesian models of 191 dates from 20 archaeological sites, which incorporate a number of recently processed radiocarbon dates. A synthesis is presented of 15 full coverage surveys, a summed probability distribution, and a Bayesian model of the transition to ceramics, which together support a scenario of a very rapid demographic increase. Fourteen models from archaeological sites are cross-referenced in a composite model, which identifies a brief, altiplano-wide emergence of agropastoralism with starting and ending boundaries of 3540 and 3120 cal BP, respectively. This starting boundary correlates strongly with the onset of improving environmental conditions, indicating synchronous cultural and environmental change. The suite of accelerating cultural changes included a marked reduction in mobility, a demographic surge, increased subsistence diversity, the adoption of ceramics, farming and the integration of camelid herding into a remarkably resilient economic strategy still in use today. This is a highly relevant but yet to be used comparative case study for the variable tempos of ‘big histories’, and ecocultural interactions that generate rapid, emergent episodes of wide-spread and enduring cultural change.     

闽台财政改革与各方权力纠葛--雍正朝台湾县知县周钟蠧案解析

雍正三年,台湾县知县周钟蠧被控贪污,由于牵涉到闽台财政改革的大背景,此案引起了雍正皇帝的高度关注,并演变为震动闽台官场的一桩大案,涉案人等都被卷入了皇权与地方官员博弈的大漩涡。案件的审理过程,伴随着闽台财政改革的全过程,从清查仓谷亏空,到耗羡归公和养廉银制度化的最终完成。透过考察周钟蠧案,闽台地区财政改革的过程得以完整呈现。在皇权的强势施压下,闽省官员提出的耗羡归公方案显得仓促而草率。     

考释胡适的两封书信

本文考证了胡适致任鸿隽、胡近仁两封信的写作时间,纠正了以往的误判。将信件的内容置于广阔的历史背景下加以考察,并与相关史料参考互证,不仅有助于考察信件的写作时间,且有助于理解信函的真实含义。     

不伦之伦:越继与降继——从族谱资料看明清徽州宗族承继的变体

宗祧承继是宗族研究的一个重要内容,学界对明清宗族继承问题研究已久,也取得了丰硕的成果,对于越继和降继,则甚少涉及。先贤们对徽州宗族社会有诸多理想性的描述,然而这些描述在很大程度上只是一种表象,现实的徽州社会要复杂得多,越继和降继就是其表现之一。探讨这两种承继方式,对于更好地解读宗祧承继和剖析明清时期徽州宗族社会的发展脉络,都有一定的积极意义。     

Children of Dutch Nazi collaborators

This article looks into what happened to the children of Dutch Nazi collaborators after the liberation of the Netherlands in May 1945. The author first outlines the historical context in which these children lived and the manner in which they recounted and recorded their memories much later. In combination with new archival research on social-welfare policy and ‘re-education’ of former National Socialist youth, this puts the discourse that dominated the Dutch debate, that is, the discourse of the ‘innocent child’ harshly punished by society, in a different light. The framework of the innocent child being punished by a cruel society obscured our view of experiences that did not fit this mould. Furthermore, it made the values and norms that were current during the reconstruction period disappear from the picture: the bad memories of children of collaborators partly originate in policy that was considered normal in those days. This, however, should not obscure the impact of the vulnerable social position which these children experienced after the war.     

Community Engagement in Historical Site Protection: Lessons from the Elmina Castle Project in Ghana

Abstract

Engaging communities in the protection of heritage means that the communities living around the heritage sites are involved in the process of identifying issues that affect the conservation of these sites and can propose ways by which they can be addressed. In Ghana, the Elmina Castle project shows close collaboration between the communities living around these slave forts and castles, the legal custodians, and other stakeholders. This case study unpicks the process to show how the existing traditional systems were approached and involved. The result of this participatory collaboration is a strategic document which will be implemented to ensure proper protection of these sites in the wake of development and modernization.     

The Architectural Reuse of Roman Marble and Stone Spolia in the Early Medieval Monte Sorbo Church (Sarsina,Central Italy)

We present the results of a multi‐method archaeometric study concerning the architectural elements reused in Monte Sorbo church (Sarsina, central Italy) between the eighth and ninth centuries AD . The provenance study has focused on classical marbles and stones, which clearly do not originate from the local Apennine geological formations and are thought to come from extra‐regional sources. A large fraction of the tested marbles is from Asia Minor, coming from both the Proconnesian district on Marmara Island and, probably, the Hasançavuslar site near Ephesus (Greco scritto). Of the four remaining marbles investigated, one is from the Carrara district and three are from different Greek quarrying areas, such as Mount Pentelikon (Athens) and the Thasos and Paros islands. The data also highlight the reuse of decorated gravestones made of Pietra di Aurisina as architectonic elements. This limestone is a fossiliferous carbonate stone outcropping in the Trieste Karst region (north‐eastern Italy), which was exploited by both the Romans and the Byzantines. The assignment of all of the columns of the central nave to the same source area provides an argument in favour of their provenance from a single monument, which was probably located in Sarsina or Ravenna, with the ‘colourful taste’ that is typical of the late Antonine and Severian periods.