Hypogene Calcitization: Evaporite Diagenesis in the Western Delaware Basin

Evaporite calcitization within the Castile Formation of the Delaware Basin is more widespread and diverse than originally recognized. Coupled field and GIS studies have identified more than 1000 individual occurrences of calcitization within the Castile Formation outcrop area, which includes both calcitized masses (limestone buttes) and laterally extensive calcitized horizons (limestone sheets). Both limestone buttes and sheets commonly contain a central brecciated zone that we attribute to hypogene dissolution. Lithologic fabric of calcitized zones ranges from little alteration of original varved laminae to fabrics showing extensive laminae distortion as well as extensive vuggy and open cavernous porosity. Calcitization is most abundant in the western portion of the Castile outcrop region where surface denudation has been greatest. Calcitization often forms linear trends, indicating fluid migration along fractures, but also occurs as dense clusters indicating focused, ascending, hydrocarbon-rich fluids. Native sulfur, secondary tabular gypsum (i.e. selenite) and hypogene caves are commonly associated with clusters of calcitization. This assemblage suggests that calcium sulfate diagenesis within the Castile Formation is dominated by hypogene speleogemesis

Computing and statistics in archaeology Danebury Hillfort, a case study

2 volsAvailable from British Library Lending Division - LD:D53204/85 / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo

Bridging archaeology and GIS: influencing factors for a 4D archaeological GIS

In archaeology, the intensive application of Geographical Information Systems (GIS) with their specialized capabilities in analysing spatial objects and relations, is hampered by the data particularities. Consequently, the idea arises to develop a comprehensive four-dimensional (4D, i.e. 3D and time) GIS tailored to archaeology, which would facilitate simultaneously handling the spatial and temporal dimensions. This paper endeavours to propose a methodological framework for the development of such a 4D archaeological GIS. This methodology is centred on the usability of the system and therefore integrates a methodology based on human cognition and the approach of the user-centred design cycle. The proposed framework consists of three pillars: (i) the user-oriented, (ii) data-oriented and (iii) analysis-oriented pillar