Aggressive waters, saturated waters

Water that comes into contact with rocks initially is undersaturated, i.e. it can dissolve the minerals of the rock and progressively be enriched with the ions freed in the dissolving reaction, till it reaches a point of saturation, i.e. the water solution contains the maximum quantity possible of a particular ion in certain temperature conditions, atmospheric pressure or content of other acids. When this condition of saturation is reached, water no longer has a chemical effect on rock, and therefore it can only affect rock with mechanical erosion processes (as in the case of surface free flowing water). If variations in temperature, in CO2 content or in concentration of the solution (e.g. in the case of evaporation) occur, saturated water becomes oversaturated, i.e. it contains an excessive quantity of dissolved calcium carbonate that should therefore be deposited in the form of calcite crystals, forming speleothemes, among which stalactites and stalagmites are the better known forms; however speleothemes may exhibit a vast range of forms and colours, at times bizarre and curious (when drops of water that carelessly drip on the sink evaporate, these form the detested calcareous deposits, which are a form of concretion).

Special reports

  • 11 June 2012

    Bats, facts and fiction

    In ancient Rome, bats were nailed to the door of the house as a protection from witches...

    16 April 2012

    Bats, The Lords of Darkness

    The UNEP Convention on Migratory Species and The Agreement on the Conservation of...

    7 January 2010

    Alps and Appennines

    The term orogeny was born from the Greek words...

  • 13 May 2013

    Small steps, great footprints

    Have you ever wondered how much space is taken up by an apple or a steak?...

    18 May 2009

    Sauropods

    40 meters long and 17 high, huge...

    10 November 2011

    Landslides

    When studying landslide phenomena, it is opportune to distinguish...

  • 28 August 2020

    The Earth seen from above: signs of fires

    This image was taken by the ASTER sensor installed on the NASA TERRA satellite platform. The image was taken on…

    15 July 2020

    Earth viewed from above

    Remote satellite sensing: what it is and what it is used for In the scientific field, the images produced by…

    30 April 2019

    Urban woods

    When walking along a tree-lined avenue in a crowded and traffic-congested city, wrapped up in our daily commitments, we do…

  • 11 June 2012

    Bats, facts and fiction

    In ancient Rome, bats were nailed to the door of the house as a protection from witches...

    16 April 2012

    Bats, The Lords of Darkness

    The UNEP Convention on Migratory Species and The Agreement on the Conservation of...

  • 7 January 2010

    Alps and Appennines

    The term orogeny was born from the Greek words...

    13 May 2013

    Small steps, great footprints

    Have you ever wondered how much space is taken up by an apple or a steak?...

  • 18 May 2009

    Sauropods

    40 meters long and 17 high, huge...

    10 November 2011

    Landslides

    When studying landslide phenomena, it is opportune to distinguish...

From the Multimedia section

Facts

  • 13 May 2011

    A walk underground

    The longest caves in the world are in Kentucky, the caves of Mammoth...

    24 February 2011

    And in underground tunnels?

    There are groups of terrestrial animals that eat insects, worms and other invertebrates...

  • 13 May 2011

    The climate underground

    Going down deep in the Earth’s crust, the temperatures increase gradually...

    Amphibians in a cave

    Proteus is an amphibian of white-yellowish or light pink colour...

  • Can you breathe in a cave?

    One of the most common beliefs is that in caves the air is often stuffy...

    Ice in caves

    In high mountain or high latitude environments, many caves can contain ice deposits...

  • A walk underground

    The longest caves in the world are in Kentucky, the caves of Mammoth...

  • 24 February 2011

    And in underground tunnels?

    There are groups of terrestrial animals that eat insects, worms and other invertebrates...

  • 13 May 2011

    The climate underground

    Going down deep in the Earth’s crust, the temperatures increase gradually...