Preface

• Main Author: Nielsen, Troels F.D
• Format: Article in Journal/Newspaper
• Language: English
• Published: Geological Survey of Denmark and Greenland (GEUS) 2023
• Subjects: cryptic variation; cumulates; layered intrusion; gabbros; mineral chemistry; phase layering; Earth Science; Greenland; East Greenland
• Online Access: https://geusbulletin.org/index.php/geusb/article/view/8356; https://doi.org/10.34194/geusb.v56.8356

The Palaeogene Skaergaard intrusion, East Greenland, has since its first description by Wager & Deer (1939) been a foremost natural laboratory for the study of low-pressure fractionation of basaltic melt. Ocean floors are composed of basalt and the processes that control compositions of basaltic melts are fundamental to the dynamics of the Earth. This special issue of GEUS Bulletin by Peter Thy, Christian Tegner and Charles E. Lesher is the most recent in a more than eighty year succession of trendsetting works on the evolution of the Skaergaard intrusion and evolution of basaltic melt. The early sample collections, housed in the universities of Oxford and Cambridge, were used for the development of fractionation models, mapping of the distribution as well as the partition of major and trace elements between melts and liquidus phases in basaltic melts. These and many other studies resulted in the monumental “Layered Igneous Rocks”, edited by L.R. Wager and G.M. Brown (Wager & Brown 1968). By the 1970s, the original collection in the Oxford University Museum of Natural History and the Sedgwick Museum of Earth Sciences, University of Cambridge had seen extensive use. The science developed and new and more detailed sampling was now required. Fieldwork and sampling in the later part of the 20th century led to a flurry of new studies by more research groups, including Neil Irvine of Carnegie’s Geophysical Laboratory and the University of Oregon group lead by Alex McBirney. Despite all the efforts, no consensus was reached on the many fundamental chemical and physical processes in basaltic magma chambers. The available collections did not provide sufficiently systematic and detailed information for the modelling of the evolution of the basaltic melt and the genesis of the precious metal deposit that had been discovered in the intrusion. Exploration drill cores offered the possibility for tight stratigraphic sampling through >1000 m of gabbro. In combination with surface sampling, a new standard profile with ...