Dear Dr. Vlad,

I have given  this general definition already in a different Q&A exchange in RG. Perhaps it is also an answer to your question:

The terms is not widely used anymore and mostly in papers on sedimentary geology described in a more detailed way from creep to slide.

In general it is a mass of loose material derived from the soil and the rocks immediately underneath. The processes include creeping, washing and sliding triggered by precipitation, swelling and contracting of mineral matter etc.  The mass wasting processes lead to a dumping of the material at the foot of the hill slopes, the  inclination of which can change from gentle to steep. Neither the length of transport nor the angle of the hill slopes are used as discriminators. I suggest to be more specific and perform a more subtle distinction of the processes and jump this general terms and make use of a wide range of terms used to describe mass wasting processes in geomorphology and sedimentology.

Best regards

H.G.Dill

Dear DR. Vlad

Is the Romanian system of soil taxonomy English version (SRTS, 2003, 2012) available somewhere?

You can find the question on Colluvium there:

https://www.researchgate.net/post/How_do_you_define_colluvium

Dear Dr. Virgil Vlad

The meaning is very clear as described by Dr. Harald G. Dill. 

I write here more specifically on its driving force, how the term changes due to its driving force. 

Two terms- one is 'Alluvium' and the other is 'Colluvium', Alluvium is caused by water/ streams, and the Colluvium is due to gravitational force. 

Complete meaning of Colluvium is: Deposition of rocks and its fragments, soil materials at the base of a steep slope of any land i.e., hill slopes by GRAVITATIONAL ACTION and of course accumulation.

On the contrary, 'Alluvium' is the term used to indicate all deposited soil materials- gravel, sand, silt, clay, or in transit by STREAMS/ WATER.

I'm sorry that I don't know the Romanian  system of soil classification.

Best regards,

K.G. Mandal

Dear K.G Mandal,

are definition that you quote use in India?

Because in France, colluvium can be also produce by runoff , implying water but not perenial. So it is not exclusively gravitational action.

Dear Dr. Jérôme Juilleret 

The term 'Colluvium' is not used commonly; whereas 'alluvium' is used in the literature mostly by scientists/ researchers. 

I have written the meaning of both the terms according to the literature and knowledge gained on the subject.

Regards,

KG Mandal

It is the materials that affected mainly by gravity (creeping deposits).

Yes i agree with the answer given by Dr K G Mandal

Hello there.

I agree with guys above.

When I took Soil Genesis and classification course, I learned the difference between Alluvium and Colluvium by the transport agent or conditions who affected materials transport.

Alluvium: deposit of materials (rocks, fragments or soils), those were transported by water bodies like rivers.

In Costa Rica we have many rivers, so many soils have been formed from those materials and we consider those soils as alluvial.

Colluvium: deposit of materials (rocks, fragments or soils), those were moved or transported by gravity action.

We can find soils in Costa Rica derived from colluvial materials, specially in steep lands, very common in our country.

Best regards from Costa Rica

soil deposit at bottom of hill slopes

Thanks for generating good discussion on Colluvium soils

Thanks all for very valuable contribution to the discussion on Colluvium.

As I said when I introduced this question, in fact, I repeated from memory a question that was asked me and which I lost. It referred to what is specific in the Romanian soil classification system regarding the colluvium. In my answer I only specified the particularities in the Romanian system: "colluvic soil", which refers to not-humified colluvic material (humus < 0.5%) and "cumulic soil", which refers to humified (mollic/umbric) colluvic material. In my answer I assumed that colluvium is a term known from soil manuals.

However, I add a comment: Colluvium is related to gravity and, also, to erosion of rocks/materials (including water erosion /precipitations). It accumulates to foot slopes. Of course, the alluvium is related to the main streams connected to rivers.

All the best,

Virgil Vlad