Philippa Black - Academia.edu (original) (raw)

Papers by Philippa Black

静岡大学地球科学研究報告, 1994

ABSTRACT textversion:publisher Waipapa terrane is the exposed basement of much of the central and... more ABSTRACT textversion:publisher Waipapa terrane is the exposed basement of much of the central and northern North Island; it has in the past not been readily correlated with any of the terranes recognised in the South Island and southern North Island. Available information about the lithologies and age relations of rocks in the Waipapa terrane are summarised and three -possibly four - different geographically discrete tectonostratigraphic units, correlated with South Island terranes, are recognised : Omahuta-Puketi area ( = Caples terrane) containing volcanogenic greywackes and laminated argillites, cherts, basaltic tuffs and volcanics of Late Paleozoic age, metamorphosed to prehnite-pumpellite and pumpellite-actinolite facies and uplifted before Mid Jurassic. Bay of Islands - northern Waipapa area ( = Older Torlesse/Rakaia subterrane) of feldspathic sandstones exposed in western Bay of Islands and interleaved with argillites and lithic sandstones in the eastern Bay of Islands. Permian microfossils occur in some terrigenous argillites and in tectonically interleaved oceanic limestones and cherts. Compared with the extent of the South Island Rakaia subterrane the northern Torlesse is a very thin sequence; it is believed that the Torlesse has been tectonically thinned out by a series of imbrication zones parallel to Northland Peninsula and does not extend further to the north of New Zealand. Helena Bay-Hunuas and Moehau-Morrinsville areas which both contain sediments of Upper Jurassic to ? Cretaceous in age, although precise ages and hence stratigraphic relationships are unknown; they are correlated with the Younger Torlesse or Pahau subterrane. However, there are significant differences between the areas : Helena Bay-Hunua rocks are a turbidite sequence containing volcaniclastic sandstones and interleaved basaltic and associated oceanic sedimentary material of Triassic-Jurassic age. Moehau-Morrinsville rocks are dominated by coarser sandstones and argillite conglomerates and lack oceanic material; they are tentatively interpreted as a terrane collision facies blanketing zones of imbrication and younger than the Helena Bay-Hunuas facies. Use of the term Waipapa terrane should be discontinued and Caples, Older Torlesse ( Rakaia subterrane) and Younger Torlesse ( Pahau subterrane) used instead.

Miner Mag, 1969

Two polymorphs of tricalcium disilicate, rankinite and kilchoanite, have been discovered near Tok... more Two polymorphs of tricalcium disilicate, rankinite and kilchoanite, have been discovered near Tokatoka, New Zealand.

Geoscience Reports of Shizuoka University, Mar 1, 1994

Geology of Coal Fires: Case Studies from Around the World, 2007

... Mineralogy and petrography of iron-rich slags and paralavas 129 Figure 16. ... It is suggeste... more ... Mineralogy and petrography of iron-rich slags and paralavas 129 Figure 16. ... It is suggested that as a result of the early high-temperature crystal-lization of high-Al ... surface through open fissures also may have leached out elements from the enclosing sediments and transported ...

New Zealand Journal of Geology and Geophysics, 2001

Understanding the temporal and spatial development of the early Miocene Northland Volcanic Arc is... more Understanding the temporal and spatial development of the early Miocene Northland Volcanic Arc is critical to interpreting the patterns of volcanic activity in northern New Zealand through the late Cenozoic. The northwesterly trending arc is considered to have developed above a southwest-dipping subduction system. The distribution of its constituent eruptive centres is described in terms of an eastern belt that extends along the eastern side of Northland and a complementary broad western belt which includes subaerial and submarine volcanic edifices. Critical examination of all 216 K-Ar ages available, including 180 previously unpublished ages, and their G00012 assessment against tectonic, lithostratigraphic, seismic stratigraphic, and biostratigraphic constraints, leads us to deduce a detailed chronology of periods of activity for the various early (and middle) Miocene arc-type volcanic complexes and centres of northern New Zealand: Waipoua Shield Volcano Complex (19-18 Ma, Altonian); Kaipara Volcanic Complex (23-16 Ma, Waitakian-Altonian); Manukau Volcanic Complex (c. 23-15.5 Ma, Waitakian-Clifdenian); North Cape Volcanic Centre (23-18 Ma, Waitakian-Altonian); Whangaroa Volcanic Complex (22.5-17.5 Ma, Waitakian-Altonian); Taurikura Volcanic Complex (22-15.5 Ma, Otaian-Clifdenian); Parahaki Dacites (22.5-18 Ma, Waitakian-Altonian); Kuaotunu Volcanic Complex (18.5-11 Ma, Altonian-Waiauan). In general, volcanic activity does not show geographic migration with time, and the western (25-15.5 Ma) and eastern (23-11 Ma) belts appear to have developed concurrently.

Journal of Volcanology and Geothermal Research, 2012

Cenozoic subduction-related volcanism in northern New Zealand developed from mainly basaltic and ... more Cenozoic subduction-related volcanism in northern New Zealand developed from mainly basaltic and andesitic volcanisms in the Early Miocene to mainly silicic volcanism in the present Taupo Volcanic Zone. The first explosive silicic eruptions occurred at 12 Ma and large silicic calderas formed from 8 Ma. This transition is recorded by the 18-1.9 Ma Coromandel Volcanic Zone (CVZ) succession, which provides an outstanding opportunity to investigate the origins of the modern North Island volcanism. New major and trace element data on a rock suite representing CVZ andesites, rhyolites and basalts indicate a consistent subduction-related origin for the entire succession. The CVZ andesites generally define a consistent medium-potassic differentiation trend, however, distinct andesites with relatively sodic compositions occur at the bases of two consecutive eruptive series at~18 and~10 Ma. The distinct andesites are geochemically similar to basalts that erupted sporadically near the oceanic margin of the CVZ. CVZ rhyolites are medium-to high-potassic, peraluminous rocks with initial 87 Sr/ 86 Sr values comparable to or somewhat more radiogenic than coeval andesites (≥ 0.7049). Their bulk rock composition suggests derivation from sources comparable to leastdifferentiated andesites or basalts. We interpret the consecutive andesitic successions to represent stages in CVZ development during which distinct arc segments developed consecutively. The early stage in each segment yielded mainly intermediate volcanism whereas in the later stage volcanism locally proceeded rapidly (within~1 Myr of initial andesitic activity) to silicic activity. Taken together, the succession records the rapid development and migration of arc system in a dynamic plate boundary setting.

Journal of Volcanology and Geothermal Research, 2011

Latest Oligocene and Early Miocene volcanic rocks occur on the Northland Peninsula, New Zealand, ... more Latest Oligocene and Early Miocene volcanic rocks occur on the Northland Peninsula, New Zealand, and record the inception of Cenozoic subduction-related volcanism in the North Island that eventually evolved to its present manifestation in the Taupo Volcanic Zone. This NW-striking Northland Arc is continuous with the Reinga Ridge and comprises two parallel belts of volcanic centres ca. 60 km apart. A plethora of tectonic models have been proposed for its origins. We acquired new trace element and Sr-Nd isotope data to better constrain such models. All Northland Arc rocks carry an arc-type trace element signature, however distinct differences exist between rocks of the eastern and western belt. Eastern belt rocks are typically andesites and dacites and have relatively evolved isotope ratios indicating assimilated crustal material, and commonly contain hornblende. Additionally some eastern belt rocks with highly evolved isotope compositions show fractionated REE compositions consistent with residual garnet, and some contain garnetiferous inclusions in addition to schistose crustal fragments. In contrast, western belt rocks are mostly basalts or basaltic andesites with relatively primitive Sr-Nd isotope compositions, do not contain hornblende and show no rare earth element evidence for cryptic amphibole fractionation. Eastern and western belt rocks contain comparable slab-derived fractions of fluid-mobile trace elements and invariably possess an arc signature. Therefore the difference between the belts may be best explained as due to variation in crustal thickness across the Northland Peninsula, where western belt centres erupted onto a thinner crustal section than eastern belt rocks. The consistent arc signature throughout the Northland arc favours an origin in response to an actual, if shortlived subduction event, rather than slab detachment as proposed in some models. No Northland Arc rocks possess a convincing adakite-like composition that might reflect the subduction of very young oceanic lithosphere such as that of the Oligocene South Fiji Basin. Therefore we favour a model in which subduction of old (Cretaceous) lithosphere drove subduction.

A NNW-striking string of isolated volcanic centers, the Kiwitahi chain, erupted between 15 and 5.... more A NNW-striking string of isolated volcanic centers, the Kiwitahi chain, erupted between 15 and 5.5 Ma in northern New Zealand. Prior to 6.2 Ma, the erupted rocks were plagioclase-and hornblende-dominated andesites, which are geochemically comparable to coeval andesites erupted in the nearby, much larger Coromandel Volcanic Zone (CVZ). Compared to CVZ andesites, however, the Kiwitahi andesites show more subdued incompatible element enrichments, and they generally have relatively unradiogenic Sr isotope compositions. These features, and the small eruption volumes involved, suggest that the Kiwitahi centers formed over the edge of a magmatic system that was centered on the CVZ. The Kiwitahi centers progressively become younger towards the SSE representing the migration over the time of the edge of this magmatic system. Between 6.2 and 5.5 Ma, four centers at the southern end of the chain erupted pyroxene-dominated, high-magnesium andesites that are geochemically unlike coeval andesites in the CVZ, but similar to Quaternary high-Mg andesites erupted along the western edge of the Taupo Volcanic Zone. These are the earliest known high-Mg andesites in northern New Zealand; their appearance may mark the inception of the current configuration where high-Mg andesite eruptions precede regular andesitic volcanism at the leading edge of the arc.

Strong population growth in Auckland combined with the city's location on a constrained isthmus a... more Strong population growth in Auckland combined with the city's location on a constrained isthmus and local government plans to minimise urban sprawl is placing increasing demand on existing infrastructure. The construction of tunnels and underground infrastructure is being used to meet the demand for new infrastructure in some built up areas. As tunnelling works have expanded across the region new geotechnical problems are being encountered and known problems are becoming better understood. This paper discusses specific examples encountered by the authors relating to the East Coast Bays Formation during the construction of tunnelling, pipe-jacking and horizontal directional drilling projects. Specific issues described include conglomerate lenses such as the Albany Conglomerate and the Parnell Volcaniclastic Conglomerate, and marked strength contrasts within the East Coast Bays Formation including strongly cemented bands and uncemented sand pockets. These variable conditions present challenges for certain tunnelling methodologies. This paper describes the issues encountered, discusses the extent of knowledge to date, and makes recommendations for future projects to help avoid problems during construction.

静岡大学地球科学研究報告, 1994

ABSTRACT textversion:publisher Waipapa terrane is the exposed basement of much of the central and... more ABSTRACT textversion:publisher Waipapa terrane is the exposed basement of much of the central and northern North Island; it has in the past not been readily correlated with any of the terranes recognised in the South Island and southern North Island. Available information about the lithologies and age relations of rocks in the Waipapa terrane are summarised and three -possibly four - different geographically discrete tectonostratigraphic units, correlated with South Island terranes, are recognised : Omahuta-Puketi area ( = Caples terrane) containing volcanogenic greywackes and laminated argillites, cherts, basaltic tuffs and volcanics of Late Paleozoic age, metamorphosed to prehnite-pumpellite and pumpellite-actinolite facies and uplifted before Mid Jurassic. Bay of Islands - northern Waipapa area ( = Older Torlesse/Rakaia subterrane) of feldspathic sandstones exposed in western Bay of Islands and interleaved with argillites and lithic sandstones in the eastern Bay of Islands. Permian microfossils occur in some terrigenous argillites and in tectonically interleaved oceanic limestones and cherts. Compared with the extent of the South Island Rakaia subterrane the northern Torlesse is a very thin sequence; it is believed that the Torlesse has been tectonically thinned out by a series of imbrication zones parallel to Northland Peninsula and does not extend further to the north of New Zealand. Helena Bay-Hunuas and Moehau-Morrinsville areas which both contain sediments of Upper Jurassic to ? Cretaceous in age, although precise ages and hence stratigraphic relationships are unknown; they are correlated with the Younger Torlesse or Pahau subterrane. However, there are significant differences between the areas : Helena Bay-Hunua rocks are a turbidite sequence containing volcaniclastic sandstones and interleaved basaltic and associated oceanic sedimentary material of Triassic-Jurassic age. Moehau-Morrinsville rocks are dominated by coarser sandstones and argillite conglomerates and lack oceanic material; they are tentatively interpreted as a terrane collision facies blanketing zones of imbrication and younger than the Helena Bay-Hunuas facies. Use of the term Waipapa terrane should be discontinued and Caples, Older Torlesse ( Rakaia subterrane) and Younger Torlesse ( Pahau subterrane) used instead.

Miner Mag, 1969

Two polymorphs of tricalcium disilicate, rankinite and kilchoanite, have been discovered near Tok... more Two polymorphs of tricalcium disilicate, rankinite and kilchoanite, have been discovered near Tokatoka, New Zealand.

Geoscience Reports of Shizuoka University, Mar 1, 1994

Geology of Coal Fires: Case Studies from Around the World, 2007

... Mineralogy and petrography of iron-rich slags and paralavas 129 Figure 16. ... It is suggeste... more ... Mineralogy and petrography of iron-rich slags and paralavas 129 Figure 16. ... It is suggested that as a result of the early high-temperature crystal-lization of high-Al ... surface through open fissures also may have leached out elements from the enclosing sediments and transported ...

New Zealand Journal of Geology and Geophysics, 2001

Understanding the temporal and spatial development of the early Miocene Northland Volcanic Arc is... more Understanding the temporal and spatial development of the early Miocene Northland Volcanic Arc is critical to interpreting the patterns of volcanic activity in northern New Zealand through the late Cenozoic. The northwesterly trending arc is considered to have developed above a southwest-dipping subduction system. The distribution of its constituent eruptive centres is described in terms of an eastern belt that extends along the eastern side of Northland and a complementary broad western belt which includes subaerial and submarine volcanic edifices. Critical examination of all 216 K-Ar ages available, including 180 previously unpublished ages, and their G00012 assessment against tectonic, lithostratigraphic, seismic stratigraphic, and biostratigraphic constraints, leads us to deduce a detailed chronology of periods of activity for the various early (and middle) Miocene arc-type volcanic complexes and centres of northern New Zealand: Waipoua Shield Volcano Complex (19-18 Ma, Altonian); Kaipara Volcanic Complex (23-16 Ma, Waitakian-Altonian); Manukau Volcanic Complex (c. 23-15.5 Ma, Waitakian-Clifdenian); North Cape Volcanic Centre (23-18 Ma, Waitakian-Altonian); Whangaroa Volcanic Complex (22.5-17.5 Ma, Waitakian-Altonian); Taurikura Volcanic Complex (22-15.5 Ma, Otaian-Clifdenian); Parahaki Dacites (22.5-18 Ma, Waitakian-Altonian); Kuaotunu Volcanic Complex (18.5-11 Ma, Altonian-Waiauan). In general, volcanic activity does not show geographic migration with time, and the western (25-15.5 Ma) and eastern (23-11 Ma) belts appear to have developed concurrently.

Journal of Volcanology and Geothermal Research, 2012

Cenozoic subduction-related volcanism in northern New Zealand developed from mainly basaltic and ... more Cenozoic subduction-related volcanism in northern New Zealand developed from mainly basaltic and andesitic volcanisms in the Early Miocene to mainly silicic volcanism in the present Taupo Volcanic Zone. The first explosive silicic eruptions occurred at 12 Ma and large silicic calderas formed from 8 Ma. This transition is recorded by the 18-1.9 Ma Coromandel Volcanic Zone (CVZ) succession, which provides an outstanding opportunity to investigate the origins of the modern North Island volcanism. New major and trace element data on a rock suite representing CVZ andesites, rhyolites and basalts indicate a consistent subduction-related origin for the entire succession. The CVZ andesites generally define a consistent medium-potassic differentiation trend, however, distinct andesites with relatively sodic compositions occur at the bases of two consecutive eruptive series at~18 and~10 Ma. The distinct andesites are geochemically similar to basalts that erupted sporadically near the oceanic margin of the CVZ. CVZ rhyolites are medium-to high-potassic, peraluminous rocks with initial 87 Sr/ 86 Sr values comparable to or somewhat more radiogenic than coeval andesites (≥ 0.7049). Their bulk rock composition suggests derivation from sources comparable to leastdifferentiated andesites or basalts. We interpret the consecutive andesitic successions to represent stages in CVZ development during which distinct arc segments developed consecutively. The early stage in each segment yielded mainly intermediate volcanism whereas in the later stage volcanism locally proceeded rapidly (within~1 Myr of initial andesitic activity) to silicic activity. Taken together, the succession records the rapid development and migration of arc system in a dynamic plate boundary setting.

Journal of Volcanology and Geothermal Research, 2011

Latest Oligocene and Early Miocene volcanic rocks occur on the Northland Peninsula, New Zealand, ... more Latest Oligocene and Early Miocene volcanic rocks occur on the Northland Peninsula, New Zealand, and record the inception of Cenozoic subduction-related volcanism in the North Island that eventually evolved to its present manifestation in the Taupo Volcanic Zone. This NW-striking Northland Arc is continuous with the Reinga Ridge and comprises two parallel belts of volcanic centres ca. 60 km apart. A plethora of tectonic models have been proposed for its origins. We acquired new trace element and Sr-Nd isotope data to better constrain such models. All Northland Arc rocks carry an arc-type trace element signature, however distinct differences exist between rocks of the eastern and western belt. Eastern belt rocks are typically andesites and dacites and have relatively evolved isotope ratios indicating assimilated crustal material, and commonly contain hornblende. Additionally some eastern belt rocks with highly evolved isotope compositions show fractionated REE compositions consistent with residual garnet, and some contain garnetiferous inclusions in addition to schistose crustal fragments. In contrast, western belt rocks are mostly basalts or basaltic andesites with relatively primitive Sr-Nd isotope compositions, do not contain hornblende and show no rare earth element evidence for cryptic amphibole fractionation. Eastern and western belt rocks contain comparable slab-derived fractions of fluid-mobile trace elements and invariably possess an arc signature. Therefore the difference between the belts may be best explained as due to variation in crustal thickness across the Northland Peninsula, where western belt centres erupted onto a thinner crustal section than eastern belt rocks. The consistent arc signature throughout the Northland arc favours an origin in response to an actual, if shortlived subduction event, rather than slab detachment as proposed in some models. No Northland Arc rocks possess a convincing adakite-like composition that might reflect the subduction of very young oceanic lithosphere such as that of the Oligocene South Fiji Basin. Therefore we favour a model in which subduction of old (Cretaceous) lithosphere drove subduction.

A NNW-striking string of isolated volcanic centers, the Kiwitahi chain, erupted between 15 and 5.... more A NNW-striking string of isolated volcanic centers, the Kiwitahi chain, erupted between 15 and 5.5 Ma in northern New Zealand. Prior to 6.2 Ma, the erupted rocks were plagioclase-and hornblende-dominated andesites, which are geochemically comparable to coeval andesites erupted in the nearby, much larger Coromandel Volcanic Zone (CVZ). Compared to CVZ andesites, however, the Kiwitahi andesites show more subdued incompatible element enrichments, and they generally have relatively unradiogenic Sr isotope compositions. These features, and the small eruption volumes involved, suggest that the Kiwitahi centers formed over the edge of a magmatic system that was centered on the CVZ. The Kiwitahi centers progressively become younger towards the SSE representing the migration over the time of the edge of this magmatic system. Between 6.2 and 5.5 Ma, four centers at the southern end of the chain erupted pyroxene-dominated, high-magnesium andesites that are geochemically unlike coeval andesites in the CVZ, but similar to Quaternary high-Mg andesites erupted along the western edge of the Taupo Volcanic Zone. These are the earliest known high-Mg andesites in northern New Zealand; their appearance may mark the inception of the current configuration where high-Mg andesite eruptions precede regular andesitic volcanism at the leading edge of the arc.

Strong population growth in Auckland combined with the city's location on a constrained isthmus a... more Strong population growth in Auckland combined with the city's location on a constrained isthmus and local government plans to minimise urban sprawl is placing increasing demand on existing infrastructure. The construction of tunnels and underground infrastructure is being used to meet the demand for new infrastructure in some built up areas. As tunnelling works have expanded across the region new geotechnical problems are being encountered and known problems are becoming better understood. This paper discusses specific examples encountered by the authors relating to the East Coast Bays Formation during the construction of tunnelling, pipe-jacking and horizontal directional drilling projects. Specific issues described include conglomerate lenses such as the Albany Conglomerate and the Parnell Volcaniclastic Conglomerate, and marked strength contrasts within the East Coast Bays Formation including strongly cemented bands and uncemented sand pockets. These variable conditions present challenges for certain tunnelling methodologies. This paper describes the issues encountered, discusses the extent of knowledge to date, and makes recommendations for future projects to help avoid problems during construction.