caa a22 4500 46579128X CHVBK 20180323112025.0 cr unu---uuuuu 170327e19900201xx s 000 0 eng 10.1007/BF00306449 doi (NATIONALLICENCE)springer-10.1007/BF00306449 The differentiation of the Skaergaard intrusion [Elektronische Daten] Reply to A.R. McBirney and H.R. Naslund [R. Hunter, R. Sparks] Conclusions: McBirney and Naslund have missed the two central points that we reiterate for clarity. First the composition of the cotectic cumulate extract for the LZc, best estimated from the average composition of adcumulate rocks, had a substantially lower silica content than any conceivable basaltic liquid, so silica enrichment is unavoidable. This is true of all the dyke compositions reported by Brooks and Nielsen, even the anomalous rock E with SiO2=46%. Second it is the normal behaviour of tholeiite basaltic magma to produce increasingly iron-rich cumulate extracts with little change in silica until FeTi oxide precipitation occurs when silica-enrichment and compositional divergence begins. Such divergence between equivalent cumulate plutonic and fractionated volcanic rocks hads been widely documented. Skaergaard magmas do have some uncommon features. However, similar assemblages exist in volcanic rocks as in the andesitic to rhyolitic glasses of the Loch Ba ring dyke, Mull (Sparks 1988). It is also a basic principle that elements enriched in cumulate rocks often become depleted in the corresponding liquids. Iron enrichment in the Skaergaard cumulates is complementary to iron depletion in liquids. Springer-Verlag, 1990 Hunter R. Department of Geology, University of Liverpool, L69 3BX, Liverpool, United Kingdom aut Sparks R. Department of Geology, University of Bristol, BS81RJ, Bristol, United Kingdom aut Contributions to Mineralogy and Petrology Springer-Verlag 104/2(1990-02-01), 248-251 0010-7999 104:2<248 1990 104 410 https://doi.org/10.1007/BF00306449 text/html Onlinezugriff via DOI 1 review-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00306449 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Hunter R. Department of Geology, University of Liverpool, L69 3BX, Liverpool, United Kingdom aut NATIONALLICENCE 700 1- Sparks R. Department of Geology, University of Bristol, BS81RJ, Bristol, United Kingdom aut NATIONALLICENCE 773 0- Contributions to Mineralogy and Petrology Springer-Verlag 104/2(1990-02-01), 248-251 0010-7999 104:2<248 1990 104 410 Metadata rights reserved Springer special CC-BY-NC licence nationallicence SWISSBIB 463994124 BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer