Abstract
network with small pores and predominantly point contacts between clay particles; (ii) low plasticity, high natural water contents, low cohesion, low CPT tip resistance, and low permeability are attributable to the dominance of halloysite; (iii) boundary effects between pyroclastic units amplify Earth tide effects; and (iv) large spikes in pore water pressures follow rainfall events. The regular deposition since c. 0.93 Ma of siliceous pyroclastic deposits from ongoing explosive rhyolitic volcanism in TVZ, together with high natural water content and low permeability, have created a locally wet environment in the stratigraphic sequences that generates Si-enriched pore water from the weathering mainly of rhyolitic volcanic glass shards and plagioclase, providing conditions suitable for halloysite formation. Initial hydrolysis of glass shards also releases cations that promote cohesion between clay minerals. Eventual enleaching of these cations reduces cohesion between clay minerals, resulting in sensitive behavior.
| Original language | English |
|---|---|
| Title of host publication | Volcanic rocks and soils |
| Subtitle of host publication | proceedings of the International Workshop on Volcanic Rocks and Soils Lacco Ameno, Ischia Island, Italy, 24-25 September 2016 |
| Editors | Tatiana Rotonda, Manuela Cecconi, Francesco Silvestri, Paolo Tommasi |
| Place of Publication | London |
| Publisher | CRC Press |
| Pages | 3-22 |
| Number of pages | 20 |
| Edition | 1 |
| ISBN (Electronic) | 9781315647913 |
| ISBN (Print) | 9781138028869 |
| Publication status | Published - 15 Sep 2015 |
| Externally published | Yes |
| Event | International Workshop on Volcanic Rocks and Soils - Ischia Island, Lacco Ameno, Italy Duration: 24 Sep 2016 → 25 Sep 2016 Conference number: 4 |
Workshop
| Workshop | International Workshop on Volcanic Rocks and Soils |
|---|---|
| Country | Italy |
| City | Lacco Ameno |
| Period | 24/09/16 → 25/09/16 |
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Sensitive pyroclastic-derived halloysitic soils in northern New Zealand : interplay of microstructure, minerals, and geomechanics. / Moon, Vicki G.; Lowe, David J.; Cunningham, Michael J.; Wyatt, Justin B.; de Lange, Willem; Churchman, G. J.; Mörz, Tobias; Kreiter, Stefan; Kluger, Max O.; Jorat, M. Ehsan.
Volcanic rocks and soils: proceedings of the International Workshop on Volcanic Rocks and Soils Lacco Ameno, Ischia Island, Italy, 24-25 September 2016. ed. / Tatiana Rotonda; Manuela Cecconi; Francesco Silvestri; Paolo Tommasi. 1. ed. London : CRC Press, 2015. p. 3-22.Research output: Chapter in Book/Report/Conference proceeding › Conference contribution
TY - GEN
T1 - Sensitive pyroclastic-derived halloysitic soils in northern New Zealand
T2 - interplay of microstructure, minerals, and geomechanics
AU - Moon, Vicki G.
AU - Lowe, David J.
AU - Cunningham, Michael J.
AU - Wyatt, Justin B.
AU - de Lange, Willem
AU - Churchman, G. J.
AU - Mörz, Tobias
AU - Kreiter, Stefan
AU - Kluger, Max O.
AU - Jorat, M. Ehsan
PY - 2015/9/15
Y1 - 2015/9/15
N2 - Sensitive soils in the Bay of Plenty in North Island occur within weathered, rhyolitic pyroclastic and volcaniclastic deposits, with hydrated halloysite (not allophane) as the principal clay mineral. We evaluate the development of sensitivity and characteristic geomechnical behaviours for sequences of the silt-rich, halloysitic soils. Morphologically the halloysite comprises short tubes, spheroids, plates, and, uniquely, books. Key findings include (i) the varied morphologies of halloysite minerals within the microstructure create an opennetwork with small pores and predominantly point contacts between clay particles; (ii) low plasticity, high natural water contents, low cohesion, low CPT tip resistance, and low permeability are attributable to the dominance of halloysite; (iii) boundary effects between pyroclastic units amplify Earth tide effects; and (iv) large spikes in pore water pressures follow rainfall events. The regular deposition since c. 0.93 Ma of siliceous pyroclastic deposits from ongoing explosive rhyolitic volcanism in TVZ, together with high natural water content and low permeability, have created a locally wet environment in the stratigraphic sequences that generates Si-enriched pore water from the weathering mainly of rhyolitic volcanic glass shards and plagioclase, providing conditions suitable for halloysite formation. Initial hydrolysis of glass shards also releases cations that promote cohesion between clay minerals. Eventual enleaching of these cations reduces cohesion between clay minerals, resulting in sensitive behavior.
AB - Sensitive soils in the Bay of Plenty in North Island occur within weathered, rhyolitic pyroclastic and volcaniclastic deposits, with hydrated halloysite (not allophane) as the principal clay mineral. We evaluate the development of sensitivity and characteristic geomechnical behaviours for sequences of the silt-rich, halloysitic soils. Morphologically the halloysite comprises short tubes, spheroids, plates, and, uniquely, books. Key findings include (i) the varied morphologies of halloysite minerals within the microstructure create an opennetwork with small pores and predominantly point contacts between clay particles; (ii) low plasticity, high natural water contents, low cohesion, low CPT tip resistance, and low permeability are attributable to the dominance of halloysite; (iii) boundary effects between pyroclastic units amplify Earth tide effects; and (iv) large spikes in pore water pressures follow rainfall events. The regular deposition since c. 0.93 Ma of siliceous pyroclastic deposits from ongoing explosive rhyolitic volcanism in TVZ, together with high natural water content and low permeability, have created a locally wet environment in the stratigraphic sequences that generates Si-enriched pore water from the weathering mainly of rhyolitic volcanic glass shards and plagioclase, providing conditions suitable for halloysite formation. Initial hydrolysis of glass shards also releases cations that promote cohesion between clay minerals. Eventual enleaching of these cations reduces cohesion between clay minerals, resulting in sensitive behavior.
M3 - Conference contribution
SN - 9781138028869
SP - 3
EP - 22
BT - Volcanic rocks and soils
A2 - Rotonda, Tatiana
A2 - Cecconi, Manuela
A2 - Silvestri, Francesco
A2 - Tommasi, Paolo
PB - CRC Press
CY - London
ER -