Southwestern coast of Croatia

Jayne Munger

Legends Golf & Safari Resort Xtreme 19th HoleJoe Tagliente

SOIL STRUCTURE

WEATHERING and the BREAKDOWN of ROCKS

Surface of soil experiences greatest weathering.Exposed to weathering environment.

Weathering zones develop below the surface as waterleaches (dissolves) substances from upper layersand are then transported downwards.

Typically deposited or precipitated in lower soil layers.Upper parts lose materials while lower parts gain.Each distinct weathering zone represents a

SOIL HORIZON.The vertical succession of SOIL HORIZONS is called a SOIL PROFILE.

SOIL STRUCTURE

WEATHERING and the BREAKDOWN of ROCKS

Temperate Zone Soil Profile

Generally 5 soil horizonsO

A

B

C

E

Parent Material

SOIL STRUCTURE

WEATHERING and the BREAKDOWN of ROCKS

O HORIZON

O Horizon is the “organic”horizon.

Consists of organic matter.Contains abundant life.

Adds CO2 and organicacids to soil.

SOIL STRUCTURE

WEATHERING and the BREAKDOWN of ROCKS

A HORIZONA HORIZON is composed of

organic matter mixed with HUMUS.

HUMUS is a dark-colored,carbon-rich materialmade of decomposedorganics from O Horizon.

Thickness depends on amountof organic matter in soil.

Tropical regions have thicker A horizons.

SOIL STRUCTURE

WEATHERING and the BREAKDOWN of ROCKS

E HORIZON

E HORIZON is a light-coloredzone below the A horizon.

E stands for ELUVIATION, aprocess by which water removes material from soil.

Little or no organic matter.Iron and aluminum compounds

are removed.Water transports them downward

to lower horizons.

SOIL STRUCTURE

WEATHERING and the BREAKDOWN of ROCKS

B HORIZONB HORIZON is the zone of

ILLUVIATION.B HORIZON is the zone where

most transportedmaterials accumulate.

SOIL STRUCTURE

WEATHERING and the BREAKDOWN of ROCKS

CALICHE

CALICHE occurs in or nearthe B horizon in arid tosemi-arid regions.

Represents the depth to whichrainfall penetrates.

Brings CaCO3 downward.When water evaporates, CaCO3

is deposited.

SOIL STRUCTURE

WEATHERING and the BREAKDOWN of ROCKS

C HORIZONC HORIZON is the lowest zone

of significant weathering.Composed of partially weathered

parent material.May have evidence of oxidation

from O2-rich ground-water.

Very thin where there is littlechemical weathering (deserts).

Up to 100m in warm, wet tropical climates.

SOIL STRUCTURE

WEATHERING and the BREAKDOWN of ROCKS

PARENT MATERIAL

Below the C horizon is unaltered parent material from which theoverlying REGOLITHand SOIL have beenderived.

PALEOSOLS

WEATHERING and the BREAKDOWN of ROCKS

PALEOSOLS are buried soils that predate modernsoil development.

They presumably formed under conditions different than today.

Paleosols can be used to interpret ancient climates.

SEDIMENTATION AND SEDIMENTARY ROCKS

SEDIMENTRock fragments that settle down and accumulate,

typically in layers, after being transported bywater, wind, ice, or precipitating out of solutionin water.

SEDIMENT is the product of weathering and erosion.

SEDIMENT is converted to SEDIMENTARY ROCK.

SEDIMENTATION AND SEDIMENTARY ROCKS

SEDIMENTARY ROCK

Makes up only the top thin layer of the Earth’s crust.By volume, sedimentary rocks are only 5% of the

Earth’s outer 15 km.Sedimentary rocks constitute 75% of the rocks

EXPOSED at the Earth’s land surface.Sedimentary rocks are the principal source of

Coal, oil and natural gasIron and aluminum oreBuilding materialUnderground freshwater

Provide a record of past geologic environments and life.

SEDIMENTATION AND SEDIMENTARY ROCKS

ORIGINS OF SEDIMENTARY ROCKS

Mechanical weathering degrades rock into smallerfragments.

Chemical weathering degrades unstable rocks andminerals into stable byproducts via chemicalreactions.

Study of SEDIMENTARY ROCKS considers whathappens to these newly created particles.

SEDIMENTATION AND SEDIMENTARY ROCKSSEDIMENTATION AND SEDIMENTARY ROCKS

ORIGINS OF SEDIMENTARY ROCKS

Sediments are classified according to the source of theparticles.

Clastic or Detrital sediment is composed of transportedsolid particles.

Chemical sediment occurs when dissolved minerals areprecipitated from solution.

Organic sediments are fragments of skeletal material.Organisms extract minerals from seawater for skeletons.