From: Dolomitization of the Upper Jurassic carbonate rocks in the Geneva Basin, Switzerland and France
Authors | Geological age | Locality | Formation | Type(s) and characteristics of dolomite(s) | Model(s)/origin(s) of dolomitization |
---|---|---|---|---|---|
Brigaud et al. (2009a) | Middle Jurassic | Paris Basin, France | Oolite miliaire inférieure, Calcaires à Polypiers | 1. Medium—euhedral—cloudy cores and clear rims 2. Coarse—anhedral | 1. Dewatering during compaction of clay-rich formations and expulsion of Mg2. Hydrothermal dolomitization by per-ascensum fluids from Triassic formations |
Railsback and Hood (2001) | Early-Middle Jurassic | Atlas Mountains, Morocco | Ziz Valley | 1. Clear or cloudy rhombs—void filling cement 2. Sub-euhedral to euhedral—cloudy cores—replacive—calcitized 3. Anhedral—clear cores replacive calcitized | Marine-meteoric mixing zone Influx of Mg-poor meteoric waters causing calcitization of dolomite |
Qing et al. (2001) | Early Jurassic | Gibraltar | Gibraltar Limestone Formation | 1. Fine (~ 50 µm)—subhedral to anhedral 2. Medium (~ 150 µm)—subhedral—cloudy cores and clear rims | Replacement dolomitization induced by penesaline seawater that refluxed during high- and low-frequency sea-level changes |
Haas et al. (2014) | Late Triassic | Hungary | Transdanubian Range | 1. Fine to medium—porphyrotopic—cloudy cores and clear rims 2. Fine—anhedral to subhedral—cloudy cores 3. Medium—euhedral to subhedral—cloudy cores and clear rims 4. Coarse—xenotopic—void filling | 1. Synsedimentary microbial dolomitization 2. Early shallow burial dolomitization 3. Burial pervasive dolomitization 4. Saddle dolomite precipitation in fractures 5. dedolomitization after uplift and near-surface exposition |
Beckert et al. (2015) | Early Permian | Central Oman | Saiq | 1. Fine—subhedral 2. Fine to medium—subhedral—idiotopic to hypidiotopic—replacive 3. Medium to coarse—xenotopic—void filling | 1. Seepage reflux of hypersaline fluids near surface to shallow burial dolomitization 2. Burial dolomitization with or without hydrothermal fluids 3. Dedolomitization by meteoric fluids |
Gasparrini et al. (2006) | Late Carboniferous | Variscan Cantabrian, Spain | Bodon Unit | 1. Medium—anhedral—replacive—fabric destructive 2. Coarse—xenotopic—void filling | Burial, convective flow dolomitization by hydrothermal and hypersaline brines, possibly marine-derived |
Gawthorpe (1987) | Early Carboniferous | Bowland Basin, N. England | Pendleside Limestone | 1. Medium—anhedral to subhedral—cloudy cores and clear rims—replacive 2. Medium to coarse—subhedral, euhedral to anhedral—idiotopic to xenotopic—replacive 3. Fine—anhedral to subhedral—replacive—pore filling 4. Medium to coarse—subhedral to euhedral—cloudy cores and clear rims 5. Coarse—anhedral—replacive 6. Coarse—anhedral hypidiotopic to xenotopic—replacive and pore filling | Fault-related fracturing dolomitization from fluids saturated in Fe and Mg as a results of clay minerals transformations together with maturation of organic matter |
Guo et al. (2016) | Early Ordovician–Late Cambrian | Tarim Basin, China | Lower Qiulit, Penglaiba, Yingshan | 1. Fine—anhedral to subhedral 2. Fine to medium—euhedral to subhedral—cloudy cores and clear rim 3. Fine to coarse—anhedral—poikilotopic—fabric destructive—cloudy with rare clear rims 4. Fine to medium—euhedral to subhedral—cloudy core and clear rim 5. Coarse—xenotopic | 1. Penecontemporaneous to near-surface dolomitization at low temperatures mediated by microbes, precipitated from slightly modified brines 2. Shallow burial dolomitization by seawater in association with burial dissolution 3. Recrystallization or neomorphism upon previous dolomite 4. and 5. Hydrothermal dolomitization from per-ascencum migrating fluids along fracture/fault conduits |