Abstracts of Acta Geologica Sinica (Chinese Edition): Vol. 73, No. 4, 1999

The Reservior Characteristics of Lower Ordovician Dolomites Below Pre-Mesozoic Unconformity in Yakela Fault-convex, Tarim Basin The Blueschist Belt in the Shuanghu Region, Central-Northern Tibet and Its Tectonic Implications Reef Palaeopool and Prediction of Buried Reefs in the Lower Permian Series from Shiwandashan Basin of Guangri Province Geochemistry of Rare Earth Elements in Late Paleozoic Coals in the North China Phase Transition and Composition Change of Minerals from Melting Experiment of Two Kinds of Metamorphics in Fuping Group, Pingshan, Hebei Province, China Palaeoecology and Palaeoenvironment of the Jehol Biota — A Palaeoecological and Palaeoenvironmental Reconstruction of Conchostracan Palaeocommunities in the Northern Hebei-Western Liaoning Area Research on Micro-FT.IR of Macerals of C-P Coals in the Bohal Bay Basin Self-similar Texture of the Mid—Longling—Ruili Strike-Slip System and the Location of Hydrothermal Deposits Metamorphism of the Eclogites from the ZK703 drillhole in Donghai, South Sulu (Jiangsu-Shandong) Ultrahigh-pressure Metamorphic Belt, Eastern China     

Evaluating geological heritage: correspondence on Ruban, D.A. ‘Quantification of geodiversity and its loss’ (PGA, 2010, 121(3): 326-333)

This article comments on the recent paper in this journal by Ruban (2010) which presented a simple quantitative scheme for the calculation of landscape geodiversity and its application to evaluating geodiversity between different locations. This comment article highlights some conceptual and methodological issues in the set-up and application of Ruban's scheme, and suggests that geodiversity as a measure can only be meaningful if it is set within a wider context of landscape and geological conservation and management. Some examples of conservation strategies in Great Britain are described in order to illustrate this wider context.     

Petrogenesis of monzonoritic dykes in the Egersund-Ogna anorthosite (Rogaland,S.W. Norway): trace elements and isotopic (Sr,Pb) constraints

Two major monzonoritic dykes occur in the Egersund-Ogna anorthositic massif (S.W. Norway): the Lomland dyke, which varies from norite to monzonite, and the Vettaland ferronoritic dyke. They are characterized by high Fe, Ti and P contents, low SiO₂, variable K₂O (0.5%–4.5%) and high Fe/Mg ratios. Small variations in REE distribution are observed inside the Lomland dyke [La/Yb=12; LREE ca. 150–180 (chondrite-normalized values), neutral to slightly positive Eu anomaly]. Part of the Vettaland dyke is severely depleted in Zr, Rb and REE and shows a positive Eu anomaly. All rocks are depleted in U and Th, and show very low Cr and Ni contents, as well as high Sr contents (400–600 ppm). Variation within the Lomland dyke is satisfactorily ex-plained through subtraction of an apatite-bearing noritic cumulate. The role of apatite is predominant in controlling the REE behaviour. Eutectic partial melting of a Fe-rich noritic cumulate (containing apatite) under low pH₂O conditions is suggested for the Vettaland dyke by REE modelling. Sr isotopic initial ratios are different in Lomland (ca. 0.708) and Vettaland (ca. 0.706) dykes. These values preclude direct derivation from the mantle as well as comagmatic relationship with anorthosite. Contamination of a mantle derived magma by deep crustal material or anatexis of the LIL depleted lower crust is compatible with the low U and Th contents, and with the Pb isotopic ratios. The Vettaland partial melting process is extended to all monzonoritic types, the necessary heat being provided by the high temperature anorthositic crystal mush. Chargé de Recherches du F.N.R.S (Belgium)