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Home , Diabase, Igneous rock

Map Matching Cards 4th Grade, Lesson 7, 2014 NCSTA-PDI; Updated by R. Bechtel adapted from C. Alligood (NCDPI)

1. Alaskite - Mitchell County, NC 2. - Chatham County  This is an extremely light colored variety of the  It is made of fragments and ash that , composed primarily of three exploded from volcanoes; they accumulated on – white , light gray , silvery the ground and hardened into the volcanic muscovite , dark red dots are . (extrusive igneous) rock known as tuff.  It occurs as very coarse (large) veins called  These volcanoes were active about 540-600 . These pegmatites are 320-390 million ago and they were similar to the million years old and occur along the edge of the modern volcanoes of Japan and the Aleutians. Blue Ridge. 3. – Nash County, NC 4. - Anson County, NC  It formed as molten rock intruded the surrounding  This sample consists of quartz grains deposited rock. This intermediate intrusive igneous rock is about 65 million years ago. part of the Rocky Mount intrusive suite (270-320  It was carried by an ancient river and deposited million years old) and includes the prominent where the river emptied into the Atlantic Ocean minerals and . (the coastline was much farther to the west than  This intermediate rock is chemically between light it is now). colored granite and dark colored . 5. - Granville County 6. - Henderson County, NC  It is a type of – the fine-grained, dark  Gneiss (pronounced “nice”) is a colored igneous rock that makes up the sea floor. consisting of bands and streaks of alternating  It is magnetic – test it with a small magnet on a darker and lighter color minerals. string.  This rock was originally granite that crystallized  This diabase formed about 200 million years ago from molten about 490 million years ago, as the Pangea split apart and the and was then metamorphosed (heated and Atlantic Ocean began to form. squeezed) into gneiss about 350 million years ago.  Eye-shaped white , normally rectangular, were squished during metamorphosis and are called augen (German for “eye”). 7. Granite - Surry County, NC 8. Argillite & Tuff - Cabarrus County, NC  Mount Airy Granite is a medium-grained igneous  The argillite & tuff formed about the same time rock composed of quartz, white feldspar and and same way as the Andesite Tuff. biotite mica.  The tuff came from an explosive volcanic  It formed about 350 million years ago as magma (extrusive igneous) eruption and the argillite came cooled deep inside the ’s . from and silt (sedimentary) laid down during gradually removed the overlying layers of rock quiet periods. exposing the granite on the Earth’s surface.  The rocks were originally deposited around 550  Granite is North Carolina’s state rock. million years ago, later everything was then slightly metamorphosed.

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Map Matching Cards 4th Grade, Lesson 7, 2014 NCSTA-PDI; Updated by R. Bechtel adapted from C. Alligood (NCDPI)

9. - Pender County, NC 10. Murphy Marble - Swain County  Limestone is a made of the  Marble is metamorphosed limestone mineral (and sometimes fossils).  Limestone is a sedimentary rock made mostly of  Calcite fizzes in acid, put a drop of vinegar or a the mineral calcite weak solution of HCL on the specimen.  Limestone usually forms in marine environments  This limestone formed more than 40 million years  Because marble also has calcite, it fizzes in acid; ago when layers of seashells and mud put a drop of vinegar or a weak solution of HCL on accumulated in a tropical ocean. the specimen.

11. - Durham /Orange Counties 12. Phosphate “rejects” Beaufort Cnty, NC  Dacite is an extrusive igneous rock.  Phosphate (black pellets) is associated with the  It is relatively high in quartz which makes this marine (ocean) sedimentary rock, limestone. very sticky (viscous) which can lead to very  It was deposited on the ocean floor about 15 explosive eruptions (Mt. St. Helens 1980) million years ago. It is accompanied by fossils of  This dacite was part of an active volcanic island many marine animals including sharks and whales. chain 500-570 million years ago  The fossilized teeth of the Megalodon Shark is our  It was metamorphosed 400 million years ago State Fossil. when the islands collided & stuck (accreted) onto ancient North America

13. Granite Richmond Cnty, NC 14. Pyrophyllite - Moore County, NC  Lilesville Granite is a coarse-grained igneous rock  This soft mineral is found in metamorphic rock. composed of quartz, white and pink feldspar and  It can grow in radiating like the spokes of biotite mica. a bicycle tire.  It formed at about the same time and way as the  Similar in appearance to , it was named for the Mount Airy granite, but the larger grain-size and, Greek words for fire and rock since its early use especially the large pink crystals, indicate that it was for hearthstones around fireplaces. cooled much slower.

15. Quartz Gravel - Anson County  This gravel is made mostly of rounded pieces of quartz and was deposited about the same time as the Cretaceous Sand sample. INTENTIONALLY LEFT BLANK  It was carried by an ancient river, possibly during a flooding event.  The gravel is rounded by the abrasive action of the river in the same way a rock tumbler rounds pieces of rock.