Land, sea and human effort: technical achievement and territorial engagement

Land, Sea and Human Effort was the central theme of the 28th IGU Congress in The Hague, The Netherlands. This volume contains the key-note addresses highlighting this central theme. Three major issues regarding low-land coasts came to the fore: land-use, environmental quality and safeguarding of the land. An interesting question is whether the concentration of human activities in large urban nodes will continue, or that such nodes and hierarchies will no longer structure our world, because of the ever-increasing importance of all means of communication and transport, as indicated by Johnston. Functions may disperse to specialised environments. A similar specialisation may be encountered in e.g. the development of tourism in the coastal zone. As Gormsen has elucidated, tourism has over time extended in a sequence of spatial peripheries. Consequently, phases in development may be identified with a growing impact and participation of local tourism interwoven with international growth. The environmental quality of coastal zones is seriously under threat, due to ever-increasing population pressure and human exploitation. The major problems are pollution and the availability of good quality water. Oudshoorn explored the worlds resources of drinking water, indicating the great need for political awareness of this huge problem. Cross-sectoral planning is advocated by Oudshoorn, even if water management often trespasses international boundaries and the harmonisation of the planning strategies is mostly difficult. The environmental quality of the coastal zone is also affected by the exploitation of oil and gas resources. Odell demonstrates that the conditions for this exploitation in the North Sea are unique, especially because of the great impact of an international agreement on offshore exploitation. Planning in sea areas is becoming an issue of increasing importance as it has to cope with the many, often conflicting interests, such as shipping, fishery, mining, waste disposal in relation to environmental and ecological constraints. The safeguarding of the land against river floods and sea side storm surges under the threat of a rising sea level is another important issue in coastal low-lands. Callander reviews the present state of human influence on climatic change and the associated sea level change. As indicated by Hesselman et al. new remote sensing and associated GIS techniques have recently been developed which are a great contribution in determining the fate of the coastal zones with respect to the threats induced by natural and human activities.     

Archaeomagnetic dating of seven archaeological fireplaces in the Netherlands

The palaeomagnetic directions of seven Dutch fireplaces are compared with the archaeological age estimates which range from the first to the 17^th century AD. A comparison with the British master curve of secular variation for archaeomagnetic dating results in a refinement of the archaeological age estimates in two cases, while four other archaeological age estimates can be confirmed. For one fireplace only one sample is reliable, resulting in a very poorly defined archaeomagnetic age of 2 to 3 centuries younger than the expected age (i.e. late Middle Ages). On the other hand, accepting the archaeological age estimates, the palaeomagnetic directions can contribute to the database that is used to construct the British secular-variation master curve. We applied the classification grades proposed by Tarling & Dobson (1995) which range from unreliable (grade 1) to reliable (grade 5). Three fireplaces have grades 5, one has grade 4, one grade 3, one grade 1 and for one case no grade was assigned.