Contorted stratification with clay lobes in volcanic ash beds, Raglan-Hamilton region, New Zealand

Contorted stratification in basal volcanic ash beds of the Pleistocene Hamilton Ash Formation incorporates halloysitic clay lobes which project upward into a bed of predominantly allophanic material. The forms produced are similar to convolute laminations described in other marine and non-marine sedimentary sequences. The halloysitic clay lobes have been described previously as concretions and as the products of differential weathering processes. A third hypothesis is proposed to explain the formation of the clay lobes and associated contorted stratification of these basal ash beds, namely, that the beds were deformed by plastic flowage of halloysitic clay into a sensitive allophanic bed. This deformation was possibly a result of water-saturated beds rapidly losing strength as a result of cyclic reversals of stress and strain produced by earthquake shock waves

The soils of the southeastern sector of Egmont National Park

The soils of the southeastern slopes of Egmont National Park, Taranaki, are youthful in absolute age and also in soil development. They are classed as recent soils on a parent material basis: andesitic tephras, alluvium, and peat with interbedded tephra. Of these groups the former covers the greatest part of the surveyed area and was studied in the most detail. The recent soils from andesitic tephra have a profile form dominated by buried soil horizons and little weathered tephra layers, the youngest of which was erupted 210 years ago. Characteristic features are the very weak weathering of minerals in the upper soil layers, the variable depth of melanisation, the extremely leached state of the soil profile and lastly the marked similarity of the soil chemical parameters despite appreciably different biotic regimes and a range in slope and altitude. It is concluded that the extremely high rainfall, in excess of 150 inches per annum, so controls soil processes that the variables of site and vegetation are not expressed in the measured soil parameters

Annotated bibliography of central North Island volcanic ash stratigraphy

Prior to 1929 many observations had been published giving brief accounts of the volcanic ash deposits in various parts of the North Island but no detailed investigations were undertaken. With the incidence of Bush Sickness in the Central North Island mapping of the "ash soils" was undertaken as part of the investigations into the cause of this disease. The work done at this time was the beginning of our present understanding of ash stratigraphy. In this bibliography only papers relevant to the Central North Island ash-showers have been mentioned

Unravelling upbuilding pedogenesis in tephra and loess sequences in New Zealand using tephrochronology

The genesis of soils developed in either tephra or loess on stable sites differs markedly from that of soils developed on rock because classical topdown processes operate in conjuction with geological processes whereby material is added to the land surface so that the soils form by upbuilding pedogenesis. Understanding the genesis of such soils (typically Andisols and Alfisols, respectively) often requires a stratigraphic approach combined with an appreciation of buried soil horizons and polygenesis. In New Zealand, calendrically-dated tephras provide an advantage for assessing rates of upbuilding through chronostratigraphy. Many Andisol profiles form by upbuilding pedogenesis as younger tephra materials are deposited on top of older ones. The resultant profile character reflects interplay between the rate at which tephras are added to the land surface and topdown processes that produce andic materials and horizons. In loess terrains, upbuilding pedogenesis since c. 25,000 years ago is associated with maximum rates of loess accumulation c. 3 10 mm per century, sufficiently slow for soil-forming processes to continue to operate as the land surface gradually rises. Thus, Alfisol subsoil features are only weakly developed and Bw or B(x) horizons typically are formed. In contrast, topdown pedogenesis is associated with minimal or zero loess accumulation, the land surface elevation remains essentially constant, and subsoil features become more strongly developed and Bg, Bt, or Bx horizons typically are formed

Note on the occurrence of Taupo pumice in the Hamilton basin

The presence of a thin layer of pumice lapilli and ash close to the surface of the Rukuhia and Moanatuatua peat bogs was recorded by Grange and Taylor (1939). Since this time a similar band of pumice has been noted in many of the other peat areas in the Hamilton basin. In the undeveloped fibrous peats of the Woodlands bog a layer of pumice lapilli 2 to 3 inches thick occurs at a depth of 18 to 20 inches from the surface. This is similar to the observations of Grange and Taylor. In the more loamy peats the pumice layer is predominantly fine ash and any lapilli present are extremely weathered and crush easily. In the fibrous peats it is thought that the fine ash that fell on the bog surface soon dispersed in the loose network of dead material, whereas the lapilli were of sufficient size to be trapped. In the loamy peats more active weathering took place in an acid environment as the organic matter was breaking down. This made the lapilli very fragile, so with drainage and compaction of the peat the lapilli were very soon crushed to fine ash size

Obituary − Emeritus Professor Dr John Davidson McCraw (1925−2014) MBE, MSc NZ, DSc Well, CRSNZ, FNZSSS.

John McCraw was an Earth scientist who began working as a pedologist with Soil Bureau, DSIR, then became the Foundation Professor of Earth Sciences at the University of Waikato in Hamilton, inspiring a new generation to study and work in Earth sciences . In retirement, John McCraw was an author and historian with a special emphasis on Central Otago as well as the Waikato region. Throughout his career, marked especially by exemplary leadership, accomplished administration, and commitment to his staff and students at the University of Waikato, John McCraw also contributed to the communities in which he lived through public service organizations and as a public speaker. He received a number of awards including an MBE, fellowship, and companionship, and, uniquely, is commemorated also with a glacier, a fossil, and a museum-based research room named for him. Emeritus Professor John McCraw passed away on the 14th of December, 2014. An obituary, entitled “Dedicated to earth science and his students”, was published in the Waikato Times on the 10th of January, 2015

The working life of John McCraw (1925-2014): a remarkable New Zealand pedologist and Earth scientist

John McCraw was an Earth scientist who began working as a pedologist with Soil Bureau, DSIR, then became the Foundation Professor of Earth Sciences at the University of Waikato in Hamilton, inspiring a new generation to study and work in Earth sciences, a discipline he introduced into the tertiary education system in New Zealand. In retirement, he was an author and historian with a special emphasis on Central Otago as well as the Waikato region. Throughout his career, marked especially by meritorious leadership, accomplished administration, and commitment to his staff and students at the University of Waikato, John McCraw also contributed widely to the communities in which he lived through public service organizations and as a public speaker. He received a number of awards including an MBE, fellowship, and companionship, and, uniquely, is commemorated also with a glacier, a fossil, and a museum-based research room named for him. The Earth sciences programme today as an integral part of the School of Science at the University of Waikato is stronger than ever. In the past few years several new staff have been appointed, both academic and technical, giving the largest-ever Earth sciences team of about 30 staff. As well as research-led teaching, Earth sciences has strong research groups, at the cores of which are doctoral and masterate students, and postdoctoral fellows, to carry on the work envisaged by John McCraw all those years ago. This thriving continuation of our discipline, which has always had strong multidisciplinary linkages with other sciences, is − alongside the countless students he has taught and inspired − surely his greatest legacy