title: Stratigraphy and sedimentology of Pliocene limestones in northern Hawke's Bay: The Opoiti, Whakapunake and Tahaenui Limestones

authors: Drinnan, Michele Maree

subjects: limestone

abstract: The Opoiti, Whakapunake and Tahaenui Limestone formations (Opoitian to Waipipian; Pliocene) crop out extensively in northern Hawke’s Bay between Wairoa and Mahia Peninsula where they are encased within mudstone dominated Wairoa Formation. The limestones are shallow cool-water carbonates that formed about tectonically active antiform structures inboard from the convergent subduction plate margin along eastern North Island. Their coarse skeletal fraction is dominated by barnacle plates with common brachiopod, pectinid and oyster remains. The carbonate factory for prolific skeletal production was likely sited in shoal water (30-60 m deep), high energy conditions atop the antiforms, with deposition from carbonate shedding down the flanks of the antiforms and even into the bounding synforms.

The individual limestone units are laterally discontinuous and perceived as large lenses (up to c.3-4 km long by c.2 km wide). The enclosing thick mud-rich (M1-M4) to locally sandy (S1-S4) lithofacies, along with occasional volcaniclastic beds (V1), are here informally recorded as Wairoa Formation A, B, C or D, depending on their stratigraphic position with respect to the three limestone units.

Stratigraphic logging of sections at Nuhaka (Tahaenui/Clonkeen), Mt Moumoukai and on Mahia Peninsula established 12 sedimentary lithofacies based on field texture and composition, namely limestones (L1-L3), sandstones (S1-S4), mudstones (M1-M4), and a volcaniclastite (V1). The lithofacies discriminate well on triangular plots involving carbonate content and insoluble sand, silt and clay grain sizes and typically show vertical similarities between field sites for each limestone, suggestive of similar depositional patterns and controls operating at the different localities.

Opoiti Limestone occurs on Mahia Peninsula and Mt Moumoukai as a bedded, c.30 m thick, moderately dipping (25° W), siliciclastic sand-rich unit with common brachiopods and mudstone clasts (L1, L2, L3) that unconformably overlies late Miocene mudstone (M1). Petrography ranges from a sandy biomicrite to a variably sandy, poorly washed rounded biosparite or bioclastic arenite in which interskeletal space is occupied mainly by microbioclastic micrite with some isopachous sparite. Carbonate content is up to c.75%; siliciclastic grains range from very fine to fine sand size. The Opoiti Limestone is likely a transgressive event deposit (TST), fining upwards into sandstone and mudstone (HST) of Wairoa Formation B, and largely under tectonic control.

Whakapunake Limestone within the field area is restricted to the west coast of Mahia Peninsula where it is c.40 m thick and comprises limestone (L3) units (10- 100 cm thick) interbedded with unique mudclast-bearing shelly sandstone (S4) units (20-100 cm thick). These couplets may be related to storm emplacements although their origin, and that of the mudclasts, remains problematic. The elongated mudclasts possibly mark the positions of original Skolithos/Ophiomorpha-like burrows that have been later modified by seismic shaking. No lower contact was observed. Upwards, the limestone grades via interbeds into shelly sandstone (S2) and mudstone (M1). Petrography ranges from packed biomicrites to poorly washed biosparites, while the sandstone interbeds are typically muddy bioclastic arenites. Cements are isopachous sparite rims and microbioclastic micrite with common siliciclasts. Carbonate contents range up to c.70% with the siliciclastic grains being of medium silt and fine sand size. The Whakapunake Limestone is likely a transgressive deposit (TST) fining upwards into shelly sandstone (TST/HST) of Wairoa Formation C, again overall tectonically driven but with possible superimposed eustatic sea level changes.

Tahaenui Limestone (L1, L3) occurs in discrete outcrops (10-30 m thick) across the full area. At Nuhaka, it unconformably overlies late Miocene mudstone (M1), while the upper contact grades into shelly sandstone (S2). At Moumoukai, it unconformably onlaps the Opoiti Limestone. It is dominated by coarse barnacle plates with interparticle isopachous sparite rims and microbioclastic micrite. Petrographically the limestone ranges from rounded biosparite to packed biomicrite. Carbonate content is up to 90%, with the siliciclastic grains being of fine-medium silt and fine sand size. The Tahaenui Limestone is overall a transgressive deposit (TST) fining upwards into shelly sandstone and mudstone (HST) of Wairoa Formation D, largely under tectonic control.

The Pliocene limestones are economically important as potential subsurface petroleum reservoirs, as a lime resource for agricultural use and as a hard stone source for aggregate. Recommendations of the immediate economic potential for development include local aggregate and fertiliser sources from the Tahaenui Limestone at Nuhaka and Mahia.

text: Stratigraphy and sedimentology of Pliocene limestones in northern Hawke's Bay: The Opoiti, Whakapunake and Tahaenui Limestones The Opoiti, Whakapunake and Tahaenui Limestone formations (Opoitian to Waipipian; Pliocene) crop out extensively in northern Hawke’s Bay between Wairoa and Mahia Peninsula where they are encased within mudstone dominated Wairoa Formation. The limestones are shallow cool-water carbonates that formed about tectonically active antiform structures inboard from the convergent subduction plate margin along eastern North Island. Their coarse skeletal fraction is dominated by barnacle plates with common brachiopod, pectinid and oyster remains. The carbonate factory for prolific skeletal production was likely sited in shoal water (30-60 m deep), high energy conditions atop the antiforms, with deposition from carbonate shedding down the flanks of the antiforms and even into the bounding synforms.

The individual limestone units are laterally discontinuous and perceived as large lenses (up to c.3-4 km long by c.2 km wide). The enclosing thick mud-rich (M1-M4) to locally sandy (S1-S4) lithofacies, along with occasional volcaniclastic beds (V1), are here informally recorded as Wairoa Formation A, B, C or D, depending on their stratigraphic position with respect to the three limestone units.

Stratigraphic logging of sections at Nuhaka (Tahaenui/Clonkeen), Mt Moumoukai and on Mahia Peninsula established 12 sedimentary lithofacies based on field texture and composition, namely limestones (L1-L3), sandstones (S1-S4), mudstones (M1-M4), and a volcaniclastite (V1). The lithofacies discriminate well on triangular plots involving carbonate content and insoluble sand, silt and clay grain sizes and typically show vertical similarities between field sites for each limestone, suggestive of similar depositional patterns and controls operating at the different localities.

Opoiti Limestone occurs on Mahia Peninsula and Mt Moumoukai as a bedded, c.30 m thick, moderately dipping (25° W), siliciclastic sand-rich unit with common brachiopods and mudstone clasts (L1, L2, L3) that unconformably overlies late Miocene mudstone (M1). Petrography ranges from a sandy biomicrite to a variably sandy, poorly washed rounded biosparite or bioclastic arenite in which interskeletal space is occupied mainly by microbioclastic micrite with some isopachous sparite. Carbonate content is up to c.75%; siliciclastic grains range from very fine to fine sand size. The Opoiti Limestone is likely a transgressive event deposit (TST), fining upwards into sandstone and mudstone (HST) of Wairoa Formation B, and largely under tectonic control.

Whakapunake Limestone within the field area is restricted to the west coast of Mahia Peninsula where it is c.40 m thick and comprises limestone (L3) units (10- 100 cm thick) interbedded with unique mudclast-bearing shelly sandstone (S4) units (20-100 cm thick). These couplets may be related to storm emplacements although their origin, and that of the mudclasts, remains problematic. The elongated mudclasts possibly mark the positions of original Skolithos/Ophiomorpha-like burrows that have been later modified by seismic shaking. No lower contact was observed. Upwards, the limestone grades via interbeds into shelly sandstone (S2) and mudstone (M1). Petrography ranges from packed biomicrites to poorly washed biosparites, while the sandstone interbeds are typically muddy bioclastic arenites. Cements are isopachous sparite rims and microbioclastic micrite with common siliciclasts. Carbonate contents range up to c.70% with the siliciclastic grains being of medium silt and fine sand size. The Whakapunake Limestone is likely a transgressive deposit (TST) fining upwards into shelly sandstone (TST/HST) of Wairoa Formation C, again overall tectonically driven but with possible superimposed eustatic sea level changes.

Tahaenui Limestone (L1, L3) occurs in discrete outcrops (10-30 m thick) across the full area. At Nuhaka, it unconformably overlies late Miocene mudstone (M1), while the upper contact grades into shelly sandstone (S2). At Moumoukai, it unconformably onlaps the Opoiti Limestone. It is dominated by coarse barnacle plates with interparticle isopachous sparite rims and microbioclastic micrite. Petrographically the limestone ranges from rounded biosparite to packed biomicrite. Carbonate content is up to 90%, with the siliciclastic grains being of fine-medium silt and fine sand size. The Tahaenui Limestone is overall a transgressive deposit (TST) fining upwards into shelly sandstone and mudstone (HST) of Wairoa Formation D, largely under tectonic control.

The Pliocene limestones are economically important as potential subsurface petroleum reservoirs, as a lime resource for agricultural use and as a hard stone source for aggregate. Recommendations of the immediate economic potential for development include local aggregate and fertiliser sources from the Tahaenui Limestone at Nuhaka and Mahia.

year: 2011

title: The Role of Amino Acids and the Threonine-SAM Pathway in the Development of Bovine Inner Cell Mass and Pluripotency

authors: Najafzadeh, Vahid

subjects: amino acid

abstract: Pluripotent stem cells (PSCs) are the foundation of all cell types in the body including functional gametes. They are derived either from the inner cell mass (ICM) of preimplantation mouse and rat embryos, known as embryonic pluripotent stem cells (ePSCs) or embryonic stem cells (ESCs) or via reprogramming of somatic cells to their pluripotent state, known as induced pluripotent stem cells (iPSCs). PSCs are excellent tools for gene editing and accelerated breeding in livestock animals. So far, germline-competent PSCs have only been isolated in mice and rats. Bovine ESCs are yet to be isolated due to the inadequate understanding of the mechanisms involved in bovine pluripotency. This study aimed to investigate the metabolic aspects of bovine ICM development and pluripotency. 
In this study, amino acids were screened via a targeted depletion approach to determine if any amino acid was critical for bovine ICM development and pluripotency. Experiments were conducted on in vitro fertilised day (D) 5 preimplantation bovine embryos, individually cultured in chemically-defined, protein- and glutamine-free synthetic oviduct fluid with variations of essential (E) and non-essential (NE) amino acids (AAs) until D8. Depleting (Δ) one (threonine, methionine), two (threonine_methionine, cysteine_methionine, cysteine_threonine, isoleucine_leucine, isoleucine_lysine, leucine_lysine), three (cysteine_methionine_threonine, isoleucine_leucine_lysine) or six (histidine_phenylalanine_arginine_valine_tryptophan_tyrosine) EAAs did not affect ICM formation, even when NEAAs were also removed from Δthreonine and Δmethionine groups. However, depleting another six (cysteine_isoleucine_lysine_leucine_methionine_threonine), nine (+cysteine_methionine_threonine, +isoleucine_leucine_lysine), eleven EAAs (+threonine, +methionine) or all twelve EAAs impaired blastocyst development. In vitro fertilised D1 preimplantation mouse embryos cultured from D1-4 were also not affected by a Δthreonine culture condition.
The role of the threonine dehydrogenase (TDH)-mediated threonine-s-adenosylmethionine (SAM) pathway in bovine ICM development and pluripotency in bovine embryos and cells was also investigated. This metabolic pathway has been shown to play a critical role in sustaining mouse pluripotency. TDH expression was probed at mRNA and protein levels, and its activity was knocked down using chemical inhibitors quinazolinecarboxamide (Qc1) and 3-hydroxynorvaline (3-HNV). The effect of TDH inhibition on embryo development, cell numbers, lineage-specific marker gene expression, histone trimethylation and autophagy was studied. 
TDH was present in trophectoderm (TE), ICM and 6 day old (D6) ICM outgrowths but absent in D6 TE primary cultures. In bovine embryos, Qc1 reduced blastocyst grade 1-3 (B¹⁻³) and 
B¹⁻² embryo development 1.5- and 2-fold, respectively, compared to the dimethyl sulfoxide (DMSO) controls. Qc1 also reduced ICM and TE cell numbers ~2-fold. This cell loss was due to increased autophagy. Qc1-treated ICM and TE nuclei were explicitly hypermethylated at histone (H)3 lysine (K)4 trimethylation (me3), while H3K9me3 and H3K27me3 were not affected. Hypoblast (PDGRFα), pluripotency-associated epiblast (NANOG, FGF4, and SOX2) and TE (CDX2) markers were not altered in the Qc1 group compared to DMSO controls. Qc1 also severely compromised mouse embryos cultured from day 1-4. In bovine cells, Qc1 compromised fresh ICM, D6 ICM outgrowths and fresh TE cells but failed to impair D6 TE primary cultures. 3-HNV severely compromised bovine embryo development, D1 ICM outgrowths, D6 TE primary cultures and bovine embryonic fibroblast (BEF) cells. However, it unexpectedly severely impaired TDH-free skin fibroblasts in a Δthreonine culture condition. 
The results indicate that the effect of amino acid starvation on embryos is different from that on individual cells. The findings also suggest that TDH is vital for bovine embryonic development via regulating H3K4me3 levels. Moreover, the results denote that TDH becomes restricted to cultured ICM cells and disappears from TE primary cultures. This may indicate that TDH is essential for maintaining bovine pluripotency. 3-HNV was claimed to be a specific TDH enzyme inhibitor; However, this study showed that it compromises TDH-free cells in a Δthreonine culture condition, suggesting that it does not specifically impair cells and embryos via the TDH-mediated threonine-SAM pathway.

text: The Role of Amino Acids and the Threonine-SAM Pathway in the Development of Bovine Inner Cell Mass and Pluripotency Pluripotent stem cells (PSCs) are the foundation of all cell types in the body including functional gametes. They are derived either from the inner cell mass (ICM) of preimplantation mouse and rat embryos, known as embryonic pluripotent stem cells (ePSCs) or embryonic stem cells (ESCs) or via reprogramming of somatic cells to their pluripotent state, known as induced pluripotent stem cells (iPSCs). PSCs are excellent tools for gene editing and accelerated breeding in livestock animals. So far, germline-competent PSCs have only been isolated in mice and rats. Bovine ESCs are yet to be isolated due to the inadequate understanding of the mechanisms involved in bovine pluripotency. This study aimed to investigate the metabolic aspects of bovine ICM development and pluripotency. 
In this study, amino acids were screened via a targeted depletion approach to determine if any amino acid was critical for bovine ICM development and pluripotency. Experiments were conducted on in vitro fertilised day (D) 5 preimplantation bovine embryos, individually cultured in chemically-defined, protein- and glutamine-free synthetic oviduct fluid with variations of essential (E) and non-essential (NE) amino acids (AAs) until D8. Depleting (Δ) one (threonine, methionine), two (threonine_methionine, cysteine_methionine, cysteine_threonine, isoleucine_leucine, isoleucine_lysine, leucine_lysine), three (cysteine_methionine_threonine, isoleucine_leucine_lysine) or six (histidine_phenylalanine_arginine_valine_tryptophan_tyrosine) EAAs did not affect ICM formation, even when NEAAs were also removed from Δthreonine and Δmethionine groups. However, depleting another six (cysteine_isoleucine_lysine_leucine_methionine_threonine), nine (+cysteine_methionine_threonine, +isoleucine_leucine_lysine), eleven EAAs (+threonine, +methionine) or all twelve EAAs impaired blastocyst development. In vitro fertilised D1 preimplantation mouse embryos cultured from D1-4 were also not affected by a Δthreonine culture condition.
The role of the threonine dehydrogenase (TDH)-mediated threonine-s-adenosylmethionine (SAM) pathway in bovine ICM development and pluripotency in bovine embryos and cells was also investigated. This metabolic pathway has been shown to play a critical role in sustaining mouse pluripotency. TDH expression was probed at mRNA and protein levels, and its activity was knocked down using chemical inhibitors quinazolinecarboxamide (Qc1) and 3-hydroxynorvaline (3-HNV). The effect of TDH inhibition on embryo development, cell numbers, lineage-specific marker gene expression, histone trimethylation and autophagy was studied. 
TDH was present in trophectoderm (TE), ICM and 6 day old (D6) ICM outgrowths but absent in D6 TE primary cultures. In bovine embryos, Qc1 reduced blastocyst grade 1-3 (B¹⁻³) and 
B¹⁻² embryo development 1.5- and 2-fold, respectively, compared to the dimethyl sulfoxide (DMSO) controls. Qc1 also reduced ICM and TE cell numbers ~2-fold. This cell loss was due to increased autophagy. Qc1-treated ICM and TE nuclei were explicitly hypermethylated at histone (H)3 lysine (K)4 trimethylation (me3), while H3K9me3 and H3K27me3 were not affected. Hypoblast (PDGRFα), pluripotency-associated epiblast (NANOG, FGF4, and SOX2) and TE (CDX2) markers were not altered in the Qc1 group compared to DMSO controls. Qc1 also severely compromised mouse embryos cultured from day 1-4. In bovine cells, Qc1 compromised fresh ICM, D6 ICM outgrowths and fresh TE cells but failed to impair D6 TE primary cultures. 3-HNV severely compromised bovine embryo development, D1 ICM outgrowths, D6 TE primary cultures and bovine embryonic fibroblast (BEF) cells. However, it unexpectedly severely impaired TDH-free skin fibroblasts in a Δthreonine culture condition. 
The results indicate that the effect of amino acid starvation on embryos is different from that on individual cells. The findings also suggest that TDH is vital for bovine embryonic development via regulating H3K4me3 levels. Moreover, the results denote that TDH becomes restricted to cultured ICM cells and disappears from TE primary cultures. This may indicate that TDH is essential for maintaining bovine pluripotency. 3-HNV was claimed to be a specific TDH enzyme inhibitor; However, this study showed that it compromises TDH-free cells in a Δthreonine culture condition, suggesting that it does not specifically impair cells and embryos via the TDH-mediated threonine-SAM pathway.

year: 2018

title: Māori education and principles of self-determination in the twenty-first century.

authors: O’Sullivan, Dominic

subjects: Maori

abstract: This paper argues that self-determination to the greatest extent possible is a legitimate aspiration for Maori people. It is argued that in education this requires a philosophical and policy response more focused on Maori autonomy than can be provided within the bicultural framework that has lately informed Maori relationships with other actors in the education arena. The paper considers the place of kohanga reo, kura kaupapa Maori and wananga in relation to broader Maori aspirations for self-determination and discusses proposals that these aspirations be furthered through the establishment of a Maori Education Authority. It is also argued that opportunities for self-determination in New Zealand are compromised by the government's unwillingness to alter a tightly controlled centralised education market to provide genuine Māori autonomy over what type of education might be available and to what end.

text: Māori education and principles of self-determination in the twenty-first century. This paper argues that self-determination to the greatest extent possible is a legitimate aspiration for Maori people. It is argued that in education this requires a philosophical and policy response more focused on Maori autonomy than can be provided within the bicultural framework that has lately informed Maori relationships with other actors in the education arena. The paper considers the place of kohanga reo, kura kaupapa Maori and wananga in relation to broader Maori aspirations for self-determination and discusses proposals that these aspirations be furthered through the establishment of a Maori Education Authority. It is also argued that opportunities for self-determination in New Zealand are compromised by the government's unwillingness to alter a tightly controlled centralised education market to provide genuine Māori autonomy over what type of education might be available and to what end.

year: 2001