Model ages of fracture fillings and mineralogical and geochemical evidence for water-rock interaction in fractures in granite: The Melechov Massif, Czech Republic

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216208%3A11310%2F18%3A10376686" target="_blank" >RIV/00216208:11310/18:10376686 - isvavai.cz</a>

Výsledek na webu

<a href="https://doi.org/10.1016/j.apgeochem.2018.05.016" target="_blank" >https://doi.org/10.1016/j.apgeochem.2018.05.016</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.apgeochem.2018.05.016" target="_blank" >10.1016/j.apgeochem.2018.05.016</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Model ages of fracture fillings and mineralogical and geochemical evidence for water-rock interaction in fractures in granite: The Melechov Massif, Czech Republic

Popis výsledku v původním jazyce

The mineral, chemical and Pb-isotope composition were investigated in the host granite and low-temperature open-fracture fillings from the 100 m deep borehole PDM-1 located in the Melechov Massif of the Moldanubian Batholith. The fillings are dominated by limonite and clay-mineral (illite, kaolinite, montmorillonite, nontronite, chlorite) mixtures, accompanied by minor amounts of residual minerals from the parent rock (quartz, feldspars, zircon, monazite). Chemically contrasting fracture assemblages occur mainly at lesser depths ( &lt; 55 m), where a high content of Fe-oxides and hydroxides locally with Mn-oxides is common. High Fe is correlated with a very high content of U, P, and V, whereas Mn is accompanied by Li, Co, Ni, Zn and Ba. Enrichment in mechanically transported primary accessory minerals and their gravity sorting in the flow of paleogroundwater is the most probable explanation for high REE, Y, Zr, Hf and Th in some samples. The fracture fillings mostly have higher U/Pb and Pb-206/Pb-207 ratios than the parent rock, which enables them to be dated by a one-stage model. The model ages indicate major U-Pb redistribution event around 130 Ma which is assumed to represent the main episode of formation of clay-rich fillings, and minor events at 280 Ma and in the Tertiary, whereas the Quaternary processes were of minimal importance. Formation of fractures in the fresh granite, however, occurred shortly after its solidification (ca. 300-320 Ma).

Název v anglickém jazyce

Model ages of fracture fillings and mineralogical and geochemical evidence for water-rock interaction in fractures in granite: The Melechov Massif, Czech Republic

Popis výsledku anglicky

The mineral, chemical and Pb-isotope composition were investigated in the host granite and low-temperature open-fracture fillings from the 100 m deep borehole PDM-1 located in the Melechov Massif of the Moldanubian Batholith. The fillings are dominated by limonite and clay-mineral (illite, kaolinite, montmorillonite, nontronite, chlorite) mixtures, accompanied by minor amounts of residual minerals from the parent rock (quartz, feldspars, zircon, monazite). Chemically contrasting fracture assemblages occur mainly at lesser depths ( &lt; 55 m), where a high content of Fe-oxides and hydroxides locally with Mn-oxides is common. High Fe is correlated with a very high content of U, P, and V, whereas Mn is accompanied by Li, Co, Ni, Zn and Ba. Enrichment in mechanically transported primary accessory minerals and their gravity sorting in the flow of paleogroundwater is the most probable explanation for high REE, Y, Zr, Hf and Th in some samples. The fracture fillings mostly have higher U/Pb and Pb-206/Pb-207 ratios than the parent rock, which enables them to be dated by a one-stage model. The model ages indicate major U-Pb redistribution event around 130 Ma which is assumed to represent the main episode of formation of clay-rich fillings, and minor events at 280 Ma and in the Tertiary, whereas the Quaternary processes were of minimal importance. Formation of fractures in the fresh granite, however, occurred shortly after its solidification (ca. 300-320 Ma).

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10505 - Geology

Projekt

<a href="/cs/project/GA17-05935S" target="_blank" >GA17-05935S: Vliv změn environmentální chemie na jezerní ekosystémy na počátku mladšího dryasu</a><br>

Návaznosti

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Rok uplatnění

2018

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Applied Geochemistry

ISSN

0883-2927

e-ISSN

—

Svazek periodika

95

Číslo periodika v rámci svazku

AUGUST

Stát vydavatele periodika

GB - Spojené království Velké Británie a Severního Irska

Počet stran výsledku

15

Strana od-do

124-138

Kód UT WoS článku

000437294900011

EID výsledku v databázi Scopus

2-s2.0-85047927726