First described in 1853 by August Breithaupt, Jarocite (also Jarosite) is a complex mineral with the chemical formula KFe3+3(OH)6(SO4)2.
Category Archives: Geological Periods and Formations
February 2010 – Evaporites
Evaporites are non-clastic, or chemical sediments, created through the precipitation of dissolved salts from water. They most frequently occur at the site of a former large water body such as a lake or landlocked sea, on coastal plains (sabkha zones), or where rivers feed very arid desert areas. As the water involved slowly evaporates the [...]
on February 1, 2010 Leave a comment
January 2010 – Siderite
Iron carbonate (FeCO3), or siderite from the Greek sideros meaning iron, is a major source of ore for steel-making being usually low in sulphur and phosphorous, and high in manganese and/or magnesium.
This mineral is able to assume almost any colour but commonly brown, yellowish-brown, or grey specimens can be found. It occurs in Britain’s [...]
on January 6, 2010 Leave a comment
September – Whinstone
Whinstone is a quarryman’s term for a variety of hard, dark-coloured, rocks including basalt and chert. Here, in the Tees Valley and Cleveland, the name refers to a hard rock that is very different from the soft sedimentary strata which make up the majority of the area’s underlying geology.
Around 58 million years ago, as [...]
on September 10, 2009 Leave a comment
June – Alum Shale
Alum Shale occurs within the upper 35 metres or so of the Whitby Mudstone Formation. A suite of rocks that originated as soft sediment accumulating on the floor of an ancient sea (the Tethys) which occupied this area between c.188 million and c.182 million years ago during the late Lower Jurassic phase of Earth’s geological [...]
on June 1, 2009 2 Comments
March – Ironstone
Iron makes up a full 35% of the whole Earth, though most is sequestered within the metallic core, with the crust containing around 6%. It is an important rock commercially, being smelted to make iron and steel. High grade deposits, often comprising more than 70% iron, were laid down in the Precambrian, around 2 billion [...]
on March 8, 2009 Leave a comment
February – Woolly Mammoth Tooth.
Mammoth lived on most of the continents in the Northern Hemisphere during the last big ice age 70-10,000 years ago. Woolly Mammoths were about the same size as Indian elephants are today and covered in a layer of coarse hair. They are a good indicator of a cold climate and tundra or Steppe [...]
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January – Flint
Flint is the dark grey to black nodular material commonly found in chalk. It is Cretaceous in age (146-65 million years old). Flint breaks with a pronounced conchoidal (curved) fracture creating sharp edges. This feature was exploited by early man to create edged tools.
It is made up of a mineral called Chalcedony, [...]
on January 7, 2009 2 Comments
November – Ammonite
Ammonites are coiled relatives of the octopus (Cephalopods) and became extinct at the end of the Cretaceous Period around 65 million years ago.
Below is an image of a Harpoceras, which lived during the Jurassic Period. These fossils can be found in the Upper Liassic shale (Whitby Mudstone Formation) which crops-out widely across Cleveland and the [...]
on November 1, 2008 Leave a comment
Slapewath
Grid Reference NZ 643 158
BGS Sheet 34
OS Sheet 94
Forwarded as RIGS 30/09/2003
Site Description
Site Status
Description of Geodiversity Exposures of Main Seam Cleveland Ironstone Formation (bottom block) beside bridge footings below Fox & Hounds public house. A small waterfall immediately upstream may exist due to presence of the Pecten Seam. The area has [...]
on September 24, 2003 Leave a comment