Abstract
Berthierine occurs as pore-linings of well crystallized laths of variable thickness in oil-sands of the Clearwater Formation, Alberta, Canada. Berthierine crystallized early in diagenesis within portions of a deltaic/estuarine complex dominated by brackish to fresh water.
Separates prepared using high gradient magnetic separation contain approximately equal amounts of monoclinic and orthohexagonal berthierine. Minor, but variable, quantities of inseparable, iron-rich impurities mainly consist of chamosite Ib and IIb, and Fe-rich smectitic clays.
Clearwater Formation berthierine has a range of chemical compositions that differ from those reported for most other berthierines. The SiO2 (27-35 wt%), Fe2O3 (5-8 wt%) and Al2O3 (16-18 wt%) contents for Clearwater Formation berthierine fall between values normally reported for berthierine and odinite. The average structural formula of five samples studied in detail is (Fe1.012+Al0.82Mg0.46Fe0.283+ Mn(
| Translated title of the contribution | Berthierine from the Lower Cretaceous Clearwater Formation, Alberta, Canada |
|---|---|
| Original language | English |
| Pages (from-to) | 1 - 21 |
| Number of pages | 22 |
| Journal | Clays & Clay Minerals |
| Volume | 44(1) |
| Publication status | Published - 1996 |