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"Country Rock" - ?

Strider		Posted : Wednesday, 5 September 2012 8:49:32 PM(UTC)
Rank: Gold Dust Groups: Registered Joined: 10/02/2012(UTC) Posts: 5 Thanks: 3 times Was thanked: 2 time(s) in 2 post(s)		Hey Guys, I've got a couple questions, What exactly is "country rock" and how do you identify it on geological maps? What is it meant when one refers to a beach being "cut"? Cheers

simon		Posted : Wednesday, 5 September 2012 8:58:54 PM(UTC)
Rank: Gold Ingot Groups: Registered Joined: 7/01/2011(UTC) Posts: 789 Location: Central Otago Thanks: 33 times Was thanked: 239 time(s) in 150 post(s)		a cut beach is where the tide erodes into the beach. the term cut refers to the cut that is made into the slope of the beach. evidence of cutting is easily found on sand beaches on the east coast of the south island. usually a spring or king tide will produce a cut on beaches like st kilda, dunedin. country rock may be a bit of an old geology term i think. i've seen it in a couple of books but i think they are referring to the bedrock, i.e. the schist belt in otago. the common rock of the area. in the alps it would be graywacke. fiordland granite. etc.
		WWW

1864hatter		Posted : Wednesday, 5 September 2012 9:02:48 PM(UTC)
Rank: Gold Ingot Groups: Registered Joined: 4/08/2010(UTC) Posts: 1,007 Location: Auckland.... Thanks: 49 times Was thanked: 566 time(s) in 269 post(s)		Country rock is basically what is below all the gravels and young sedimentary rock. For most of Otago the country rock is Schist. Other names for country rock are Basement rock or bedrock. On a Geoloagical map you will have to have a look at the key/rock types to get an idea of what country rock is where. A beach cut is when you get a step in what is normally a smooth sloping beach. Cuts form during times when ocean currents are a bit different to normal and transport sand away. Usually this happens during storms etc. cuts can be from centimetres to metres in size. Hope that helps
		And now....On sandy beaches and muddy soil, rings and coins await my coil!

1864hatter		Posted : Wednesday, 5 September 2012 9:04:05 PM(UTC)
Rank: Gold Ingot Groups: Registered Joined: 4/08/2010(UTC) Posts: 1,007 Location: Auckland.... Thanks: 49 times Was thanked: 566 time(s) in 269 post(s)		Would you look at that while I was writing Simon jumped in and answered the question. At least we agree!
		And now....On sandy beaches and muddy soil, rings and coins await my coil!

Strider		Posted : Wednesday, 5 September 2012 9:23:27 PM(UTC)
Rank: Gold Dust Groups: Registered Joined: 10/02/2012(UTC) Posts: 5 Thanks: 3 times Was thanked: 2 time(s) in 2 post(s)		Cheers guys, In some books you read that the gold forms in quartz veins in "country rock". Is their a particular type of rock that contains quartz veins in which gold commonly forms?

1864hatter		Posted : Wednesday, 5 September 2012 10:44:53 PM(UTC)
Rank: Gold Ingot Groups: Registered Joined: 4/08/2010(UTC) Posts: 1,007 Location: Auckland.... Thanks: 49 times Was thanked: 566 time(s) in 269 post(s)		I'd say the most common rock associated with large scale gold deposits would be a low to medium grade schist. Having said that however gold can be deposited in almost any rock. The most important thing is that you have a heat source and water to act as a fluid for the deoposition of quartz. In schist the heat source is basically the Earths inner heat and the fluid is often from metamorpic reactions within the rock that release water. An alternative to this is where a volcanic heat source heats water and drives the gold deposition system. The hot springs in the taupo region carry gold.
		And now....On sandy beaches and muddy soil, rings and coins await my coil!