23 Topics for Loess Research [in 21st Century]
In 1900, at the International Conference of Mathematicians in Berlin, the famous mathematician David Hilbert offered a list of problems and topics to be considered in the 20th Century. This list became very famous and to some extent influenced the direction of mathematical research and scholarship; it set out directions and targets. Now, in a scaled-down, much more modest version of the target setting exercise we offer some target topics for loess research in the 21st Century. Hilbert offered 23 topics/problems and therefore we shall do the same: the 23 Topics for Loess Research:
1. Words. Words have always been a problem; the word Loess requires lengthy explanations when introduced into conversations. Remarkably few people know what loess is- we need an educational programme. There may be a way forward in the use of loess as an adjective; loess ground has some virtues- we speak of loess deposits, loess soils, loess material.. Ground studies are beset by imprecision, we talk of clay when it is unclear whether we mean clay size or clay mineral. Requirement: more precision with words; a more perceptive use of words.
2. Particles. Loess is one of the classic particulate sediments. There are particulate generalizations that can be made; Loess is described as a silty sediment, and the mode mineralogy appears to be quartz. The mode particle might be considered as a 30um diameter quartz particle. The on-going problems relate to the factors constraining the particle size range, and the mode of formation of the particles.
3. Structures. A defining factor for a loess deposit is the open structure, caused by the airfall mode of formation of the deposit. Loess deposit as particle packing; the packing structure of a loess deposit cannot be defined, although it can be modelled in various ways, which can give interesting and useful results. How to describe a packing; the one truly unanswerable question on the list.
4. Bonds. Bonding between particles. The open structure is maintained by a set of interparticle bonds. In the loess system there is a complex interaction between short range and long range bonds. The basic system of primary mineral particles will be bonded by short range contact bonds but the interesting behaviour is mediated by long range, clay-mineral type bonds.
5. Collapse. Initial collapse depends on clay mineral material which is concentrated at the major contact points in the metastable structure. The hydroconsolidation process becomes clearer and better understood, but further investigations are definitely needed.
6. Mineralogy. Quartz is seen to dominate, but other minerals will become more important as they are used as indicators of provenance and age. Sophisticated mineralogy will continue to impress.
7. Dust/Loess relationships. If loess is large dust with a mode size around 30um and small dust(travelling high in suspension dust) has a mode size of say around 3um.. are there other modes in this general size range or are there really basically two types of dust? Confusion has arisen because of a failure to identify the nature of dust material in many studies.
8. Places. Where is the loess? do we know? How well is the world's loess mapped? Is there widespread loess in Pakistan and N.W.India? How about Africa? the Kriger 1965 map showed no loess in Africa but there could be modest deposits. Loess is Siberia deserves to be better known. For various reasons various loess places have not been recognized and explored and investigated; some geographical action is required.
9. pL Loessification. Loessification has been sub-divided into small scale loessification (pL) and large scale loessification (gL). There is some interest in pL processes because they are seen as operating after Aeolian deposition. They serve to make the ground more loessic. The gL processes have been dismissed as too extreme, but pL processes, in particular the development of collapsibility, appear to merit further study.
10. PTDC systems. P provenence, the formation of loess material; T transportation, the moving of loess material; D deposition, the deposition of loess material, the formation of loess deposits; C change in the deposit. The C process has recently been added to the PTDC system- it may be here that attention is focussed, although the recognition of river action in the T stage is developing. In the C stage we find chernozemisation; C might stand for chernozemisation- it actually stands for change. The P and T processes fit securely in the world of sedimentology, the C processes are probably in the world of pedology. The D processes are transition processes. This transition has caused problems in earlier loess discussions.
11. Dating. Central to the study of loess. New techniques will be developed; greater reliability and precision will be achieved. The last 2 million+ years will be dated via the loess.
12. Climates The alternation of loess and palaeosol gives a clear indication of climate change; precision can be improved. The Hardcastle observation(the loess/climate link) turns out to be one of the most fundamental and important in loess research.
13. Rivers. We see the Danube as a loess river, but what about the Niger, Indus, Dnepr, Ob. Rivers may have a key role to play in the T stage of the loess deposit formation process.
14. Other Planets. Mars maybe? Titan maybe? We need to be aware that the idea of loess on other planets may present interesting scientific challenges. The PTDC criteria will need to be applied; will they work on other planets?
15. Erosion. Wind and water. Tensile failure; a disruption of the soil structure, a dispersion of the components, the breaking of the bonds which keep the structure intact. Loess ground may be the most erodible ground; counter erosion activities may need to be focussed on loess.
16. Deformation. This could be mostly problems with slope stability, which still pose a large problem, particularly in China. Or it could deal with what has been called the 'Teton Dam' problem- the difficult properties displayed by remoulded loess. The great geotechnical problem related to loess arises from the collapse of the open structure and this has garnered most of the attention, but there are problems with remoulded loess.
17. Cyclicity. Milankovitch gave cyclicity to the Quaternary. The cyclicity of the Quaternary is also manifested in the alternation of loess and palaeosol. There are views through other windows showing cyclicity; all shall be reconciled.
18. Larger Animals. Mammoths for example. Mammoth remains are found in loess deposits. It may be that mammoths had a special relationship to loess terrain; the Mammoth Steppe could have been a particularly loessic zone. More studies of the Mammoth/loess relationship are required. And studies of other large animals in the loess.
19. Smaller Animals. Cyanobacteria down at the very small level; here is a promising region of study and research. Snails- the classic small animals in loess; Lyell was impressed by the snails in the loess and modern malacologists maintain a high level of interest.
20. Agriculture. Ward Chesworth said that loess soils are the best soils. Loess brings good soil structure and good nutrient status; given enough water this is the ideal soil. The addition of loess material to a soil which is not obviously a loess soil gives added virtue. The soils of southern England are better soils for a sprinkling of loess. These loess-augmented soils need to be further investigated.
21. Civilization. The Chinese civilization, founded in the loess, is the oldest civilization. Loess promotes civilization. The early Europeans advanced up the Danube valley from loess deposit to loess deposit, and invented European art on the way (mostly at Willendorf).
22. Language. Varieties of English seem to have taken over the role of communication within the world of science. We need to be a little cautious in the world of loess, for good historical reasons. Loess study begins in 1824 and most of the early work was in German. Loess study is in many ways a regional study and we need to be aware of regional material written in regional languages. This is particularly true of Russian; there is a vast literature in Russian which will continue to have relevance for many years.
23. eWorld. Suddenly the whole world is the computer world. All science occurs within computer world, and loess scientists and scholars, like all scientists and scholars have to adapt. Is there are sort of loess/computer connection that needs to be recognised/exploited? Has the incorporation of loess science into eWorld forced any changes or adjustments? This might be a really fundamental question, or it might be that the changes only occur at a second order level and affect the way we store our data and publish our results.
23 entries- and this is just a trial list. Please make suggestions for additions and alterations. Like the various loess historical lists which have appeared lately this list has a large subjective content. It is open to modification.
.
In 1900, at the International Conference of Mathematicians in Berlin, the famous mathematician David Hilbert offered a list of problems and topics to be considered in the 20th Century. This list became very famous and to some extent influenced the direction of mathematical research and scholarship; it set out directions and targets. Now, in a scaled-down, much more modest version of the target setting exercise we offer some target topics for loess research in the 21st Century. Hilbert offered 23 topics/problems and therefore we shall do the same: the 23 Topics for Loess Research:
1. Words. Words have always been a problem; the word Loess requires lengthy explanations when introduced into conversations. Remarkably few people know what loess is- we need an educational programme. There may be a way forward in the use of loess as an adjective; loess ground has some virtues- we speak of loess deposits, loess soils, loess material.. Ground studies are beset by imprecision, we talk of clay when it is unclear whether we mean clay size or clay mineral. Requirement: more precision with words; a more perceptive use of words.
2. Particles. Loess is one of the classic particulate sediments. There are particulate generalizations that can be made; Loess is described as a silty sediment, and the mode mineralogy appears to be quartz. The mode particle might be considered as a 30um diameter quartz particle. The on-going problems relate to the factors constraining the particle size range, and the mode of formation of the particles.
3. Structures. A defining factor for a loess deposit is the open structure, caused by the airfall mode of formation of the deposit. Loess deposit as particle packing; the packing structure of a loess deposit cannot be defined, although it can be modelled in various ways, which can give interesting and useful results. How to describe a packing; the one truly unanswerable question on the list.
4. Bonds. Bonding between particles. The open structure is maintained by a set of interparticle bonds. In the loess system there is a complex interaction between short range and long range bonds. The basic system of primary mineral particles will be bonded by short range contact bonds but the interesting behaviour is mediated by long range, clay-mineral type bonds.
5. Collapse. Initial collapse depends on clay mineral material which is concentrated at the major contact points in the metastable structure. The hydroconsolidation process becomes clearer and better understood, but further investigations are definitely needed.
6. Mineralogy. Quartz is seen to dominate, but other minerals will become more important as they are used as indicators of provenance and age. Sophisticated mineralogy will continue to impress.
7. Dust/Loess relationships. If loess is large dust with a mode size around 30um and small dust(travelling high in suspension dust) has a mode size of say around 3um.. are there other modes in this general size range or are there really basically two types of dust? Confusion has arisen because of a failure to identify the nature of dust material in many studies.
8. Places. Where is the loess? do we know? How well is the world's loess mapped? Is there widespread loess in Pakistan and N.W.India? How about Africa? the Kriger 1965 map showed no loess in Africa but there could be modest deposits. Loess is Siberia deserves to be better known. For various reasons various loess places have not been recognized and explored and investigated; some geographical action is required.
9. pL Loessification. Loessification has been sub-divided into small scale loessification (pL) and large scale loessification (gL). There is some interest in pL processes because they are seen as operating after Aeolian deposition. They serve to make the ground more loessic. The gL processes have been dismissed as too extreme, but pL processes, in particular the development of collapsibility, appear to merit further study.
10. PTDC systems. P provenence, the formation of loess material; T transportation, the moving of loess material; D deposition, the deposition of loess material, the formation of loess deposits; C change in the deposit. The C process has recently been added to the PTDC system- it may be here that attention is focussed, although the recognition of river action in the T stage is developing. In the C stage we find chernozemisation; C might stand for chernozemisation- it actually stands for change. The P and T processes fit securely in the world of sedimentology, the C processes are probably in the world of pedology. The D processes are transition processes. This transition has caused problems in earlier loess discussions.
11. Dating. Central to the study of loess. New techniques will be developed; greater reliability and precision will be achieved. The last 2 million+ years will be dated via the loess.
12. Climates The alternation of loess and palaeosol gives a clear indication of climate change; precision can be improved. The Hardcastle observation(the loess/climate link) turns out to be one of the most fundamental and important in loess research.
13. Rivers. We see the Danube as a loess river, but what about the Niger, Indus, Dnepr, Ob. Rivers may have a key role to play in the T stage of the loess deposit formation process.
14. Other Planets. Mars maybe? Titan maybe? We need to be aware that the idea of loess on other planets may present interesting scientific challenges. The PTDC criteria will need to be applied; will they work on other planets?
15. Erosion. Wind and water. Tensile failure; a disruption of the soil structure, a dispersion of the components, the breaking of the bonds which keep the structure intact. Loess ground may be the most erodible ground; counter erosion activities may need to be focussed on loess.
16. Deformation. This could be mostly problems with slope stability, which still pose a large problem, particularly in China. Or it could deal with what has been called the 'Teton Dam' problem- the difficult properties displayed by remoulded loess. The great geotechnical problem related to loess arises from the collapse of the open structure and this has garnered most of the attention, but there are problems with remoulded loess.
17. Cyclicity. Milankovitch gave cyclicity to the Quaternary. The cyclicity of the Quaternary is also manifested in the alternation of loess and palaeosol. There are views through other windows showing cyclicity; all shall be reconciled.
18. Larger Animals. Mammoths for example. Mammoth remains are found in loess deposits. It may be that mammoths had a special relationship to loess terrain; the Mammoth Steppe could have been a particularly loessic zone. More studies of the Mammoth/loess relationship are required. And studies of other large animals in the loess.
19. Smaller Animals. Cyanobacteria down at the very small level; here is a promising region of study and research. Snails- the classic small animals in loess; Lyell was impressed by the snails in the loess and modern malacologists maintain a high level of interest.
20. Agriculture. Ward Chesworth said that loess soils are the best soils. Loess brings good soil structure and good nutrient status; given enough water this is the ideal soil. The addition of loess material to a soil which is not obviously a loess soil gives added virtue. The soils of southern England are better soils for a sprinkling of loess. These loess-augmented soils need to be further investigated.
21. Civilization. The Chinese civilization, founded in the loess, is the oldest civilization. Loess promotes civilization. The early Europeans advanced up the Danube valley from loess deposit to loess deposit, and invented European art on the way (mostly at Willendorf).
22. Language. Varieties of English seem to have taken over the role of communication within the world of science. We need to be a little cautious in the world of loess, for good historical reasons. Loess study begins in 1824 and most of the early work was in German. Loess study is in many ways a regional study and we need to be aware of regional material written in regional languages. This is particularly true of Russian; there is a vast literature in Russian which will continue to have relevance for many years.
23. eWorld. Suddenly the whole world is the computer world. All science occurs within computer world, and loess scientists and scholars, like all scientists and scholars have to adapt. Is there are sort of loess/computer connection that needs to be recognised/exploited? Has the incorporation of loess science into eWorld forced any changes or adjustments? This might be a really fundamental question, or it might be that the changes only occur at a second order level and affect the way we store our data and publish our results.
23 entries- and this is just a trial list. Please make suggestions for additions and alterations. Like the various loess historical lists which have appeared lately this list has a large subjective content. It is open to modification.
.
