Community news

Speleology in Kazakhstan

Shakalov on 04 Jul, 2018
Hello everyone!   I pleased to invite you to the official site of Central Asian Karstic-Speleological commission ("Kaspeko")   There, we regularly publish reports about our expeditions, articles and reports on speleotopics, lecture course for instructors, photos etc. ...

New publications on hypogene speleogenesis

Klimchouk on 26 Mar, 2012
Dear Colleagues, This is to draw your attention to several recent publications added to KarstBase, relevant to hypogenic karst/speleogenesis: Corrosion of limestone tablets in sulfidic ground-water: measurements and speleogenetic implications Galdenzi,

The deepest terrestrial animal

Klimchouk on 23 Feb, 2012
A recent publication of Spanish researchers describes the biology of Krubera Cave, including the deepest terrestrial animal ever found: Jordana, Rafael; Baquero, Enrique; Reboleira, Sofía and Sendra, Alberto. ...

Caves - landscapes without light

akop on 05 Feb, 2012
Exhibition dedicated to caves is taking place in the Vienna Natural History Museum   The exhibition at the Natural History Museum presents the surprising variety of caves and cave formations such as stalactites and various crystals. ...

Did you know?

That Pleistocene is an epoch of the quaternary period, after the pliocene of the tertiary and before the holocene; also the corresponding worldwide series of rocks. it began two million years ago and lasted until the start of the holocene some 8,000 years ago [1].?

Checkout all 2699 terms in the KarstBase Glossary of Karst and Cave Terms

What is Karstbase?

Search KARSTBASE:

keyword
author

Browse Speleogenesis Issues:

KarstBase a bibliography database in karst and cave science.

Featured articles from Cave & Karst Science Journals
Chemistry and Karst, White, William B.
See all featured articles
Featured articles from other Geoscience Journals
Karst environment, Culver D.C.
Mushroom Speleothems: Stromatolites That Formed in the Absence of Phototrophs, Bontognali, Tomaso R.R.; D’Angeli Ilenia M.; Tisato, Nicola; Vasconcelos, Crisogono; Bernasconi, Stefano M.; Gonzales, Esteban R. G.; De Waele, Jo
Calculating flux to predict future cave radon concentrations, Rowberry, Matt; Marti, Xavi; Frontera, Carlos; Van De Wiel, Marco; Briestensky, Milos
Microbial mediation of complex subterranean mineral structures, Tirato, Nicola; Torriano, Stefano F.F;, Monteux, Sylvain; Sauro, Francesco; De Waele, Jo; Lavagna, Maria Luisa; D’Angeli, Ilenia Maria; Chailloux, Daniel; Renda, Michel; Eglinton, Timothy I.; Bontognali, Tomaso Renzo Rezio
Evidence of a plate-wide tectonic pressure pulse provided by extensometric monitoring in the Balkan Mountains (Bulgaria), Briestensky, Milos; Rowberry, Matt; Stemberk, Josef; Stefanov, Petar; Vozar, Jozef; Sebela, Stanka; Petro, Lubomir; Bella, Pavel; Gaal, Ludovit; Ormukov, Cholponbek;
See all featured articles from other geoscience journals

Economic Geology, 2005, Vol 100, Issue 5, p. 905-934
Magmatic and Hydrothermal Chronology of the Giant Rio Blanco Porphyry Copper Deposit, Central Chile: Implications of an Integrated U-Pb and 40Ar/39Ar Database
Abstract:
The history of hypabyssal intrusion and hydrothermal activity in the northeastern and central parts of the be-hemothian (sensu Clark, 1993) Rio Blanco-Los Bronces porphyry copper-molybdenum deposit is clarified on the basis of integrated U-Pb and 40Ar/39Ar geochronology. Isotope dilution thermal ion mass spectrometry (ID-TIMS) U-Pb dates for zircon separates and ID-TIMS and sensitive high resolution ion microprobe (SHRIMP) dates for single zircon grains in pre-, syn- and late-mineralization volcanic and intrusive host rocks in the Rio Blanco, Don Luis, and Sur-Sur mining sectors provide a temporal framework for interpretation of incremental-heating and spot-fusion 40Ar/39Ar dates for, respectively, magmatic biotite and hydrothermal biotite, muscovite, and orthoclase. The ore deposit is hosted in part by 16.77 {} 0.25 to 17.20 {} 0.05 (2{sigma}) Ma andesitic volcanic strata of the Farellones Formation, but the major host rocks are units of the San Francisco batholith, including the 11.96 {} 0.40 Ma Rio Blanco granodiorite (mine terminology), the 8.40 {} 0.23 Ma Cascada granodiorite, and the 8.16 {} 0.45 Ma diorite. Hypabyssal dacitic intrusions (late porphyries) emplaced into the batholith yield 206Pb/238U ID-TIMS dates ranging from 6.32 {} 0.09 Ma (quartz monzonite porphyry), through 5.84 {} 0.03 Ma (feldspar porphyry) to 5.23 {} 0.07 Ma (Don Luis porphyry). The late-mineralization Rio Blanco dacite plug yields a SHRIMP zircon age of 4.92 {} 0.09 Ma. The 40Ar/39Ar plateau ages for phenocrystic biotites in quartz monzonite porphyry, feldspar porphyry, and Don Luis porphyry, as well as the preore diorite, range only from 5.12 {} 0.07 to 4.57 {} 0.06 Ma. All are significantly younger than the corresponding zircons and exhibit no correlation with intrusive sequence. The 40Ar/39Ar ages for hydrothermal biotite and orthoclase veins within the San Francisco batholith units fall in a narrow interval from 5.32 {} 0.27 to 4.59 {} 0.11 Ma. Hydrothermal sericites (muscovite), one associated with chalcopyrite, yielded spot-fusion ages of 4.40 {} 0.15 Ma (Rio Blanco granodiorite hosted) and 4.37 {} 0.06 Ma (Don Luis porphyry hosted). Comparison with the ID-TIMS and SHRIMP zircon ages indicates that most of the 40Ar/39Ar ages, even 95 percent plateaus, do not record initial magmatic cooling or hydrothermal alteration-mineralization events, evidence for quasipervasive reheating to at least 300{degrees}C by successive intrusions. Published Re-Os ages for two molybdenite samples range from 5.4 to 6.3 Ma and overlap extensively with the zircon U-Pb ages for the late porphyries. They imply that Cu-Mo mineralization overlapped temporally with the emplacement of, at least, quartz monzonite porphyry and feldspar porphyry units of the late porphyry suite and was, therefore, contemporaneous with the rise of dacitic melts to subvolcanic levels. Hydrothermal activity is inferred to have continued until 4.37 {} 0.06 Ma, following intrusion of the Don Luis porphyry and the early stages of emplacement of the Rio Blanco dacite plug complex. Hypogene Cu-Mo mineralization therefore probably persisted for 2 m.y. The geochronologic data do not resolve whether ore formation was continuous or episodic, but the observed crosscutting relationships between intensely altered and mineralized country rocks and less altered and mineralized late porphyry bodies support a model in which the ascent of metal-rich brines from an unexposed zone of the parental magma chamber was periodically stimulated by magma perturbation and hypabyssal intrusion