ThomasEdwardLane.pdf

stages along frastum zones es fracturing, faulting and diaaah~tion
continued. (5) mat-ore hydmthernal dolomites (v, VI), dminnted by
replacive and pore-filling saddle Bolmites with depleted "'0, crystsl-
lized around widespread, dilatant fractures forming spar hreccian,
ps8udobrecci.s and ooarse sparry dolastones. Faults associated with
regional uplift displaced the D/s cnpleiles end formed fluid conduits
creating a fourth end final environment for late fault-dated, turbid
doltmites (V11) which replaced limestones.
The genesis of epigenetis dolosto- and sulphiaes is Interpreted
to be the result of regional fracturing during the initial stager of the
Siluro-Devonian Acadian Orogeny. Rising geotheml gradients generated
by structural thi&ening of the must probably caused warning of basinal
fluids, the release of mtsls and sviphvr from minerals in the eedhnents
end baement and the formation of hydrothermal convection in the
ssdhntary pile. Steep fcsct,xss pemtrntea the base of ths aedimn-
tary pile and enabled fluids to rise directly €ran basement depth oC 4
to 6 h. At the deposit site the warn, Woyant fluids rose to the top
of fracture aquifer8 where they displaced cwler fornetion waters.
Couling, loss of co,, hulphate reduction andlox incree~ed pH probably
accounted for rvlphide precipitation.