In England, in the sphere of Jurassic geology, we are wardens of a classic area, for our cliffs and quarries are the standards of comparison for the whole world. A German authority, Dr. Hans Salfeld, remarked after a brief study in 1914: ‘Research on the faunas and their succession shows that the English Upper Jurassic can be taken as the type of that of North-West Europe, in the most complete development anywhere yet known.’ He had studied only the Upper Jurassic, but the same could with equal truth be said of the Lower.

We began considering development of this book in 2010 while we were preparing a guidebook for a karst geology field trip. Our discussions resulted in realization that there are few, if any, karst areas in the world where so much research and investigation existed, especially when one considers that Florida’s near-surface carbonate rocks are eogenetic. That is, they have never been deeply buried or subjected to heat and pressure or had sufficient time to substantially alter their original textures and mineral contents.

The Khetri, Alwar and Lalsot-Khankhera Copper Belts contain widespread Cii±Au±Ag±Co±Fe±REE±U mineralisation over a 150x 150 km area of Rajasthan and Haryana, NW India. Mineralisation is hosted by the mid-Proterozoic Delhi Supergroup, which comprises shallow-water, locally evaporitic, sedimentary rocks, with lesser mafic and felsic volcanic rocks. These rocks have been metamorphosed to the low- to mid-amphibolite facies, defonned into NE-SW striking, doubly-plunging folds, and intruded by numerous 1.5-1.7 Ga syntectonic granitoids and 0.75-0.85 Ga post-tectonic granitoids. Post-tectonic granitoids range from tonalite to syenite, contain hornblende and biotite as the dominant mafic minerals and magnetite, titanite, allanite, apatite, fluorite as accessory phases, and are geochemically characterised by A/CNK ratios <1.1, low Al and Ca, high Th and HFSE, and enrichment in LREE, indicating A-type affinities.