Grain shape and mineralogy of loess on New Zealands South Island ...

• Main Author: Harris, Stuart A
• Format: Article in Journal/Newspaper
• Language: English
• Published: PANGAEA 1983
• Subjects: Sampling by hand; Ice; permafrost; wedge*
• Online Access: https://dx.doi.org/10.1594/pangaea.753942; https://doi.pangaea.de/10.1594/PANGAEA.753942

Infilled fissures are described from the interface between two loess deposits on Banks Peninsula, South Island, New Zealand. Both loesses differ from the other loesses by having a solifluction deposit at their base consisting of angular basalt fragments of the same angularity as fresh frost shattered basalt mixed with the loess. Typically, the fissures are narrow and up to 160 cm deep while the infilling of the overlying loess shows no obvious structure. They occur mainly at higher elevations on south (poleward) facing slopes, and the host loess forms a fragipan of high density. They are most readily explained as being seasonal frost fissures or more probably ice-wedge casts, which would have required either permafrost or deep seasonal frost for their formation. If permafrost had existed, this would imply a cooling of the mean annual temperatures by at least 16 to 18°C. ... : Supplement to: Harris, Stuart A (1983): Infilled fissures in loess, Banks Peninsula, New Zealand. Polarforschung, 53(2), 49-58 ...