The geology of Palmerston North city is dominated by Late Quaternary (approximately 0.5 to 1 million years ago) non-marine alluvial sediments. These overlie older Quaternary alluvial and marine sediments that are exposed in lower hills. The ANZAC Cliffs, along with the adjacent Waicola and Strand Cliffs, were formed around 100,000 years ago as a result of down cutting of the Manawatū River into a coastal terrace during the last interglacial period. These sand, silt, and interbedded sandy gravel horizons were visible in the cliff face and capped by loess, a windbourne accretion of fine particles of clay (20% or less by volume), and approximately equal parts of sand and silt.
ANZAC Cliffs, circa 2008
As with most young (in geological terms) sedimentary ground, it is highly susceptible to erosion through weathering, both from rain action from above and the undercutting of the cliffs by river action. As a direct result of this, it was believed that an estimated 20,000 m3 of sediment was deposited annually as silt into the Manawatū River.
Studies commenced in 2007 to investigate ways to stabilise the cliffs. At the base of the cliff an erosion-resistant rock platform was exposed. The sandstone horizon is very weak in engineering terms, but is considered more erosion-resistant than the cliff materials above. This led to the concept of realignment of the river channel back to its course circa 1992 and construction of rock protection for the toe of the slope followed by buttressing and stabilisation of the cliff above. Stabilisation works included lowering the cliff crest by some 11m and construction of an approximately 38m high fill buttress along the north-eastern edge of the site.
Geological Cross Section of cliffs
Foundation improvement works for the buttress fill included the installation of extensive stone columns and heavy compaction of the overlying ground. Earthworks consisted of cut-to-fill of approximately 300,000m⊃3; over an area of 4.6ha. Fill material for the buttress was obtained from the excavation necessary to create the realigned river channel, and excavation of the Loess material from the top of the cliff.
Between January 2008 and August 2012, exploratory holes were drilled in order to identify any constraints with respect to foundations of the proposed large fill buttress supporting the reshaped cliff. At the base of the cliff an erosion-resistant rock platform, interpreted to be of Pliocene Age (approximately 2.6 to 5.3 million years ago), was exposed. This sandstone horizon is very weak in engineering terms, but is considered more erosion-resistant than the cliff materials above.
Work commenced in late 2014 to re-align the river, and by Jan 2015 work had started on the buttress. This was completed in May 2017.
ANZAC Cliffs, circa 2017
Since then, much time and effort has been spent in regenerating vegetation on the new slopes, as well as the construction of 2 pedestrian stairways to allow the public access to the riverside from the upper level of the cliffs. These are known locally by a number of names, Te Arapiki a Tāne (the Stairway of Tāne), The Proverb Pathway, or The Steps of Lindos.
Your calves may not appreciate the 200+ steps descent to find this cache, but if you are clever and do this one in conjunction with the nearby Trad caches GC8TDKH and GC8TDKM then at least you’ll only have to do it once and have 3 caches to show for your efforts 
Logging requirements for this Earthcache (4 tasks):
Please send your answers to tasks 2,3 and 4 to me using the "Message this owner" link at the top of this cache page. You do not need to wait for my reply before logging, but if I feel you have not made the appropriate effort to answer the questions etc then I reserve the right to delete logs (although I will message you first).
1) Photo requirement. You will need to walk all the way down the Stairway of Tane to get to WP1, where you must take a photo facing aproximately S.S.E clearly showing the current state of the exposed cliff face. This will be in stark contrast to the sloped buttress of the former cliffs to your right.
You do not need to be in the photo if you prefer not to be, but if not then please include your GPSr, or some form of caching name identifier. Post your photo as part of your log entry.
Then make your way to the posted co-ordinates, which will take you to the base of a portion of the remaining exposed cliff from which you can see some of the different Sedimentary layers.
There you will need to gather the answers to the following questions;
2) When looking directly at the exposed cliff face, look up about 4m from where you are standing and you will see several different coloured stata (of several inches of thickness each), distinctive due to the appearance of insect holes bored into the face of the cliff. From what you can see, and with the information on the cache page, would you say these layers are composed of Sand, Clay, or Gravels? Please detail your observations.
3) From your observation of the visible makeup of the exposed cliff from where you are standing up to the bored holes, can you see any evidence of Marine deposits such as Shells or fossilised sea creatures?
4) Based on your observations of the presence (or otherwise) of Marine deposits, and the information in the cache description above, what geological period would you say these deposits are from? Explain briefly why you draw that conclusion.
Please take care not to include any of your answers in your log entry as spoilers for others.
Be aware that the approach to GZ is constantly regenerating, and you may encounter cutty grass, blackberry and gorse. I do visit GZ time to time to slash new growth back to make access easy, but the growth cycles are seasonal and not always timed to match my visits. I would advise NOT wearing clothes that you care too much about.
During wet seasons such as Winter or Spring, it would be advisable to have appropriate footware such as gumboots, or sturdy tramping boots.