Proceedings of the Geologists Association最新文献

Climate change is allowing fire to expand into previously unburnt ecosystems and regions. While management policies such as fire suppression have significantly altered their frequency and intensity. To prevent future biodiversity/ecosystem services loss, and the large financial burden of wildfires, management plans will be required to adapt to future climate and land use changes. Long-term ecological data offer a unique perspective to assess fire variability under different climate and land-use conditions. In this study, we focus on Killarney National Park, Ireland. An area which today is under threat from an increase in fire activity. Comparing palaeoecological and archaeological records, we reconstruct the past fire dynamic and its impact on the landscape, and evaluate the role of climate vs humans in influencing the natural fire regime over the millennial time-scale. Our results indicate that fire has been present in the landscape since the beginning of the Holocene, with fire in the early Holocene being largely controlled by climate and microsite conditions, and in the late Holocene being increasingly influenced by human activity. The knowledge of past fire regimes can help inform future management in order to protect the semi-natural native woodland. The park's present landscape mosaic, could be preserved by limiting forest encroachment through moderate grazing and burning, while also protecting any fragmented forest from excessive grazing and large/intense fires, via traditional fire management strategies such as fuel load management. However, a fire management strategy should only be implemented following careful consideration of all ecosystem factors and controls.

This paper introduces the Special Issue of the Proceedings of the Geologists' Association on ‘Valuing the Quaternary – Nature Conservation and Geoheritage’, arising from the International Union for Quaternary Research (INQUA) Congress in Dublin, in July 2019. It presents an overview of the values of Quaternary geoheritage, which merit recognition as an integral part of nature conservation, to protect priority sites and features for scientific research and education, and to deliver wider ecological, cultural and aesthetic benefits. The paper highlights the benefits of incorporating knowledge and understanding of Quaternary geoheritage for nature conservation and society. Palaeoenvironmental, palaeoecological and palaeobiological archives are a key source of ecological and environmental data that allow learning from the past to help address contemporary conservation challenges such as biodiversity loss, anthropogenic pressures and climate change. Quaternary science plays a vital part in supporting the wider nature conservation agenda, including strengthening the role of protected and conserved areas in the sustainable management of natural capital and ecosystem services, climate change adaptation, marine conservation, nature restoration and recovery, connecting people and nature and informing nature-based solutions to threats faced by society. However, challenges remain to achieve protection of key geoheritage sites and landscapes globally, and to integrate better understanding of geodiversity in nature conservation research, policy development and practice to help address the twin crises facing nature conservation – biodiversity loss and climate change. Quaternary studies provide temporal and spatial perspectives to inform forward-looking nature conservation that is dynamic rather than static in outlook.

Geoconservation measures in the River Tejo, the Portuguese reach of the Tagus, are compared with those in the Thames downstream of London (UK). Both are fluvio-estuarine reaches with staircases of Pleistocene depositional terraces, each with important sedimentary, palaeontological and archaeological records. In both rivers, conservation measures are in place that aim to protect these records, promote research and inform the public. Inevitably there are differences in approach. Whereas Thames Quaternary interests are protected by a network of British statutory site designations, outreach is to the fore in the Tejo. Contrasting examples are highlighted here. The Tejo has interpretative materials in local museums and detailed explanatory displays at the low-terrace archaeo-geological site of Foz do Enxarrique, near the border with Spain, and at other sites. The Thames, in contrast, has few examples of physical outreach provision and limited formal protection for Pleistocene archaeological material outside the geological network, although extensive informal protection is provided by interaction between local geological groups and county and local-authority administrations. There is also a considerable difference in the degree of threat, with the Tejo above Lisbon being a relatively undeveloped valley, albeit with sporadic quarrying for aggregate, whereas the Lower Thames is an established area for infrastructure development, lying to the east of London, close to the river crossing of the orbital motorway. The different climate in the two regions profoundly influences the longevity of exposures in Quaternary deposits, with significant implications for management strategies. The comparison exercise reveals that each region would benefit from greater development of approaches used more prominently in the other; outreach measures in the Portuguese style would greatly enhance some of the Thames sites, but formal designation of Tejo exposures could prevent damaging operations being undertaken by owners who lack knowledge of their value, as exemplified by a case study of sites at Alpiarça, ~ 130 km upstream from Lisbon.

In Morocco, the most important placers of ferrotitanium minerals are found along the Laâouina–Cape Juby Atlantic coastline, where they accumulate in the upper parts of the foreshores. The heavy minerals would come from the dismantling of the acidic to intermediate magmatic rocks of the Precambrian Anti-Atlasic buttonholes and from the Meseta basement where crystallophyllous rocks predominate. The sands emanating from this erosion, once ejected by the rivers in the Atlantic, are transported by the littoral drift in the direction of the south before being trapped at the level of the great virgation of the shoreline of Laâouina–Cape Juby. The wind deflation, in its turn, reinforces this sorting by carrying away the white sands towards the continent and also the black sands sometimes. The cliffs along the coast of Laâouina–Sidi Akhfenir are, however, barriers against wind loss unlike the sector of Sidi-Akhfenir–Cape Juby where the continuous migration of sands to the hinterland is facilitated by the absence of cliffs. The conjunction of these factors has the consequence of weakening the retention of sands' ferrotitanium in the sector Sidi Akhfenir–Cape Juby compared with its counterpart of Laâouina–Sidi Akhfenir. In general, the Laâouina–Cape Juby coastline can be considered a morphological and hydrodynamic trap whose concentrations in ferrotitanium minerals are likely to earn the quality of a mining district despite its seasonal instability and the difficulty of estimating reserves. Indeed, in this supposed district, heavy minerals total about 95 % of the raw sediments and ilmenite predominates and its alteration state is only superficial.

In May 1871, models and skeleton casts of dinosaurs and other ancient vertebrates destined for a new Paleozoic Museum in Central Park, New York were smashed and destroyed. This greatest act of vandalism in the history of dinosaur study and museum development was attributed to the infamous William ‘Boss’ Tweed, leader of a notorious group of rogue politicians who at the time held the reins of power in the booming city. Our research on primary sources shows that Tweed was not involved, and the real villain was Henry Hilton, a powerful lawyer and businessman. Benjamin Waterhouse Hawkins had been employed to do the work and yet he was dismissed and not compensated, creating a scandal. Contrary to the generally accepted narrative of these events, we find no religious motive for the destruction, only potential conflict with the developing American Museum of Natural History. Further, based on well-reported evidence, we find that Hilton exhibited an eccentric and destructive approach to cultural artefacts, and a remarkable ability to destroy everything he touched, including the huge fortune of the department store tycoon Alexander Stewart. Evidently the destruction of Hawkins' New York City dinosaurs was one of many such crazy actions through his life; Hilton was not only bad, but also mad.

The Isle of Wedmore covers an area of ~ 19 km², rises up to ~ 65 m above the surrounding lowlands of the Somerset Levels, and was an island until the Middle Ages. The topography is interpreted as having been formed by a relay ramp between two right-stepping faults (the Weare Fault to the west and the Mudgley Fault to the east) which have tens of metres of downthrow to the south, and which are probably normal faults. The relay ramp has a dip of about 3° to the SW and is breached by the NW-striking Wedmore Fault, which has up to ~ 23 m downthrow to the NE. Several NE-trending faults occur in the relay ramp, which are interpreted as having formed when the relay ramp became a contractional step when the Weare and Mudgley faults underwent sinistral reactivation, or as N–S contraction occurred during the Cenozoic. Analogues for this behaviour are presented from the Liassic rocks on the coast between Lilstock and East Quantoxhead.