The Geophysical significance of calc-alkaline andesites in New Zealand

Hatherton, T.

doi:10.1080/00288306.1969.10420292

Cited by 53 publications

(40 citation statements)

References 26 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Potash-silica values for Taupo Volcanic Zone (Cole, 1979) and for the Egmont area (Hatherton, 1969;Crawford, 1983) identify sites for magma generation at depths of 124-134 km and 206-220 km respectively (Fig. 5), and these are compatible with the profile of the present NE-SW plate boundary (Adams and Ware, 1977;Neall et al, 1986).…”

Section: Calc-alkaline Potash -Silica Indicessupporting

confidence: 69%

“…Subsequent K-Ar dating of the calc-alkaline volcanics (Stipp, 1968; this paper) and data from more numerous chemical analyses (Fig. 4) support the general conclusions given by Hatherton (1969), but allow more accurate estimation of magma source locations ( (Peccerillo and Taylor, 1975) so that comparison could be made with the diagrams of Hatherton (1969). The potash-silica relationship for SiOz = 55 % (K55) and SiOz = 60 % (K60), and depth to the centre of the Benioff zone (Table 1), were measured from the data of Hatherton and Dickinson (1969, fig.…”

Section: Calc-alkaline Potash -Silica Indicessupporting

confidence: 60%

“…1, indicated a pattern of Upper Tertiary and Quaternary calc-alkaline volcanism, which commenced in the Early Miocene in Northland and migrated southeast to the area of youngest activity along the line of Taupo Volcanic Zone and Egmont. A southeastward progression in volcanicity was also suggested by Kear (1959) and Hatherton (1969). Additional K-Ar dates (Fig.…”

Section: Introductionmentioning

confidence: 96%

“…5 summarise the estimated depths of the calc-alkaline magma sources which are inferred to have been located close to a continuously retreating Benioff zone at the interface of the convergent system between the Pacific and Indian plates. While maintaining a N;E-SW trend and NW dip, the Benioff surface appears to have retreated over a period of 21 myr from a position below the Whangarei-Tokatoka volcanic arc to its present location beneath the Taupo Volcanic Zone and Egmont eruptive districts, following a pattern of migration suggested by Kear (1959), Stipp (1968) and Hatherton (1969). …”

Section: Calc-alkaline Potash -Silica Indicesmentioning

confidence: 99%

“…At all stages during this southeastward migration of igneous activity, contemporaneous initial eruptions occurred at sites lying along volcanic arcs trending NE-SW and thus parallel to the Holocene Taupo Volcanic Zone-Egmont line, indicating that the whole sequence in this calc-alkaline province can be viewed as belonging to a unified, evolving tectonicmagmatic system (Brothers, 1984(Brothers, , 1985. Hatherton (1969) reviewed potash-silica indices in andesites of the North Island, and estimated depths to a Benioff source zone for the magmas. The potassium-argon dates from Stipp (1968) were not available, but Hatherton (1969:453) summarised two possible models, and the first of these has since been elaborated by other writers (e.g.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Upper Tertiary and Quaternary volcanism and subduction zone regression, North Island, New Zealand

Brothers¹

1986

Journal of the Royal Society of New Zealand

View full text Add to dashboard Cite

Upper Tertiary and Quaternary volcanism and subduction zone regression, North Island, New Zealand R. N. Brothers" Radiometric ages for Cenozoic calc-alkaline igneous rocks in the North Island indicate the presence of two contrasted areas of eruption. An older group of volcanics (27-23 Ma) is spread NW-SE along the east coast of Northland between North Cape and Whangarei; these lavas, including garnet andesites, were generated during an isolated igneous event accompanying obduction of ophiolite massifs during the Late Oligocene. A younger group of Miocene to Holocene age (21-0 Ma) is distributed between Tokatoka-Whangarei and Egmont-Taupo Volcanic Zone across a series of NE-SW time-lines (volcanic arcs) which record a southeasterly younging direction for sequential initiation of volcanism; the erupted rocks lie along two major belts trending NW-SE (East Belt and West Belt) parallel to old basement fractures. Depths to magma sources are estimated from KzO-SiOz indices, with deeper levels indicated for the Tokatoka-Egmont West Belt (114-220 km) than for the East Belt (72-148 km) between Whangarei and Taupo Volcanic Zone. The shallow-sourced magmas of the East Belt have higher 87Sr/86Sr isotope ratios than those of the West Belt, and have developed a metallogenic province with andesitic epithermal gold-silver and porphyry-copper stocks.A subduction system responsible for the Miocene and later volcanism appears to have had the same trend and polarity as the modern Benioff zone beneath the North Island, with NE-SW strike and NW dip. The first stage of this convergence system, preceding the Miocene igneous activity, was a shallow, non-volcanic underplating of the North Island originating from the Hikurangi Trench. By the Early Miocene this lower lithospheric plate had reached as far north as the latitude of Whangarei-Tokatok a where it descended steeply, perhaps due to decrease in velocity. At this stage the mode of convergence for the lower plate changed from progressive underflow to subduction regression, and volcanism commenced along the 21 Ma time-line; this volcanic front subsequently migrated southeastward at rates controlled by oceanward retreat of the subduction zone. In regions traversed by rapid subduction regression (23-27.5 km/myr) the Mesozoic greywacke basement foundered and was extensively depressed by tensional collapse, but in areas of slower migration rates ("" 10 km/myr) the basement has remained high-standing.

show abstract

Section: Calc-alkaline Potash -Silica Indicessupporting

confidence: 69%