scholarly journals Early Eocene Palynology from Mead Stream, New Zealand

2021 ◽  
Author(s):  
◽  
Thomas Foster Cooper
Keyword(s):  
Organic Matter ◽  
New Zealand ◽  
Energy Transport ◽  
Limited Range ◽  
Early Eocene ◽  
High Resolution Data ◽  
Early Eocene Climatic Optimum ◽  
Carbon Isotope Excursion ◽  
Extreme Salinity ◽  
First Time

<p>This study documents the first detailed palynological analysis of early Eocene strata from the Lower Marl unit at Mead Stream, southern Marlborough, New Zealand. Examination of marine palynomorph assemblages and palynofacies analysis were used to improve biostratigraphic resolution and investigate paleoclimate across the Early Eocene Climatic Optimum (EECO; ~53–49 Ma)—a period characterised by the highest temperatures of the Paleogene. Early Eocene New Zealand dinocyst zones from NZE2–NZE4, and the Charlesdowniea coleothrypta zone are established across the Lower Marl for the first time in this study. Marine palynomorph assemblages originating in outer-neritic conditions and deposited on the upper slope represent low energy transport along the margin of a terrestrial discharge plume. Palynomorph assemblages do not provide insight into sea surface temperature (SST) trends. Palynomorph assemblages may reflect extremely low surface productivity. Cycles in organic matter between marine-dominant limestones to terrestrial-dominant marls, controlled by changes in temperature and seasonal precipitation, may represent orbital forcing by way of precession cycles; however the limited range of high resolution data from this study cannot statistically confirm this. An overall increase of allochthonous organic matter across the Lower Marl is likely representative of long-term background warming, culminating in peak EECO temperatures. The base of a hyperthermal, represented by carbon isotope excursion (CIE) previously identified at Mead Stream has been redefined in this study. High abundances of warm water, extreme salinity taxa coincide with the onset of this warming event.</p>

scholarly journals Early Eocene Palynology from Mead Stream, New Zealand

2021 ◽  
Author(s):  
◽  
Thomas Foster Cooper
Keyword(s):  
Organic Matter ◽  
New Zealand ◽  
Energy Transport ◽  
Limited Range ◽  
Early Eocene ◽  
High Resolution Data ◽  
Early Eocene Climatic Optimum ◽  
Carbon Isotope Excursion ◽  
Extreme Salinity ◽  
First Time

<p>This study documents the first detailed palynological analysis of early Eocene strata from the Lower Marl unit at Mead Stream, southern Marlborough, New Zealand. Examination of marine palynomorph assemblages and palynofacies analysis were used to improve biostratigraphic resolution and investigate paleoclimate across the Early Eocene Climatic Optimum (EECO; ~53–49 Ma)—a period characterised by the highest temperatures of the Paleogene. Early Eocene New Zealand dinocyst zones from NZE2–NZE4, and the Charlesdowniea coleothrypta zone are established across the Lower Marl for the first time in this study. Marine palynomorph assemblages originating in outer-neritic conditions and deposited on the upper slope represent low energy transport along the margin of a terrestrial discharge plume. Palynomorph assemblages do not provide insight into sea surface temperature (SST) trends. Palynomorph assemblages may reflect extremely low surface productivity. Cycles in organic matter between marine-dominant limestones to terrestrial-dominant marls, controlled by changes in temperature and seasonal precipitation, may represent orbital forcing by way of precession cycles; however the limited range of high resolution data from this study cannot statistically confirm this. An overall increase of allochthonous organic matter across the Lower Marl is likely representative of long-term background warming, culminating in peak EECO temperatures. The base of a hyperthermal, represented by carbon isotope excursion (CIE) previously identified at Mead Stream has been redefined in this study. High abundances of warm water, extreme salinity taxa coincide with the onset of this warming event.</p>

Late Paleocene-Early Eocene Foraminiferal Assemblage and Carbon Isotope Excursion Indicating Hyperthermal Events in Paleotropical Succession of Northwestern India

2021 ◽  
Vol 51 (1) ◽  
pp. 4-13
Author(s):  
Sonal Khanolkar ◽  
Tathagata Roy Choudhury ◽  
Pratul Kumar Saraswati ◽  
Santanu Banerjee
Keyword(s):  
Carbon Isotope ◽  
Detrended Correspondence Analysis ◽  
Western India ◽  
Early Eocene ◽  
Foraminiferal Assemblage ◽  
Trophic Conditions ◽  
Jaisalmer Basin ◽  
Early Eocene Climatic Optimum ◽  
Late Paleocene ◽  
Carbon Isotope Excursion

ABSTRACT This study focuses on marine sediments of the late Paleocene-early Eocene (∼55.5–49 Ma) interval from the Jaisalmer Basin of western India. It demarcates the Paleocene Eocene Thermal Maximum (PETM) using foraminiferal biostratigraphy and carbon isotope stratigraphy. A negative carbon isotope excursion of 4.5‰ delineates the PETM within the basin. We demarcate five foraminiferal biofacies using the detrended correspondence analysis. These reflect characteristics of ecology, bathymetry, relative age, and environment of deposition of the foraminifera. They record the response of foraminifera to the warmth of the PETM. Biofacies A was deposited within an inner neritic setting ∼55.5 Ma and includes benthic foraminifera Haplophragmoides spp., Ammobaculites spp., and Lenticulina spp. The presence of Pulsiphonina prima and Valvulineria scorbiculata in Biofacies B suggests an increase in runoff conditions in the basin. Fluctuating trophic conditions prevailed between ∼54–50 Ma. It is evidenced by alternating Biofacies C (endobenthic and chiloguembelinids of eutrophic conditions) and Biofacies D (epibenthic and acarininids of oligotrophic conditions). Biofacies E is dominated by deep-dwelling parasubbotinids, indicating an increase in bathymetry, possibly corresponding to the Early Eocene Climatic Optimum (∼49 Ma).

scholarly journals Paleoenvironmental analysis of early Eocene marl and limestone alternations from Mead Stream, New Zealand

2021 ◽  
Author(s):  
◽  
Sonja Peñafiel Bermudez
Keyword(s):  
New Zealand ◽  
Isotope Analysis ◽  
Acid Leaching ◽  
The Body ◽  
Early Eocene ◽  
Carbon Isotopic ◽  
Early Eocene Climatic Optimum ◽  
Aotearoa New Zealand ◽  
Paleoenvironmental Analysis ◽  
Radiolarian Assemblages

<p>This study integrates paleonotology and geochemistry to provide a paleoclimatic analysis of cyclic sedimentation in the Lower Marl at Mead Stream in Marlborough, Aotearoa/New Zealand. The alternating marl and limestone bedding in this outcrop coincide with the warmest period in the Paleogene, the Early Eocene Climatic Optimum (EECO).  An acetic acid leaching method was refined and used successfully to extract microfossils from the indurated limestones and marls from two intervals of the Lower Marl. The technique resulted in foraminiferal tests with improved surface ornament in comparison with samples that were processed using standard washing methodology.  The resulting paleontological assessment of leached foraminiferal and radiolarian assemblages coupled with XRF and stable isotope analysis revised the position and detailed the faunal response to the J hyperthermal at the initiation of the EECO. Microfossil assemblages and carbon isotopic data suggest that the J carbon isotopic excursion (CIE) may be a two-stage event. A new L-3 CIE and possible hyperthermal event was identified within the body of the EECO. Both the J and L-3 events contained acmes where Morozovella made up a quarter of the planktic foraminiferal specimens, suggesting the southern expansion of subtropical waters. Fluctuations of Acarinina and Subbotina foraminifera coinciding with the marl and limestone alternations may indicate climate cycles within these hyperthermals.</p>

The onset of the Early Eocene Climatic Optimum at Branch Stream, Clarence River valley, New Zealand

2015 ◽  
Vol 58 (3) ◽  
pp. 262-280 ◽  
Author(s):  
BS Slotnick ◽  
GR Dickens ◽  
CJ Hollis ◽  
JS Crampton ◽  
C Percy Strong ◽  
...  
Keyword(s):  
New Zealand ◽  
River Valley ◽  
Early Eocene ◽  
Early Eocene Climatic Optimum ◽  
Climatic Optimum

scholarly journals Climatic and environmental changes across the early Eocene climatic optimum at mid-Waipara River, Canterbury Basin, New Zealand

2020 ◽  
Vol 200 ◽  
pp. 102961 ◽  
Author(s):  
E.M. Crouch ◽  
C.L. Shepherd ◽  
H.E.G. Morgans ◽  
B.D.A. Naafs ◽  
E. Dallanave ◽  
...  
Keyword(s):  
New Zealand ◽  
Environmental Changes ◽  
Early Eocene ◽  
Early Eocene Climatic Optimum ◽  
Climatic Optimum

scholarly journals A geochemical and biostratigraphic approach to investigating regional changes in sandstone composition through time; an example from Paleocene–Eocene strata, Taranaki Basin, New Zealand

2020 ◽  
Vol 157 (9) ◽  
pp. 1473-1498
Author(s):  
Karen E. Higgs ◽  
Stuart Munday ◽  
Anne Forbes ◽  
Erica M. Crouch ◽  
Matthew W. Sagar
Keyword(s):  
New Zealand ◽  
Chemical Weathering ◽  
Heavy Minerals ◽  
Sediment Provenance ◽  
Trace Element Geochemistry ◽  
Early Eocene ◽  
Element Geochemistry ◽  
Major Element Composition ◽  
Early Eocene Climatic Optimum ◽  
Sandstone Composition

AbstractA geochemical and biostratigraphic approach has been applied to investigate the spatial and stratigraphic variability of Palaeogene sandstones from key wells in Taranaki Basin, New Zealand. Chronostratigraphic control is predominantly based on miospore zonation, while differences in the composition of Paleocene and Eocene sandstones are supported by geochemical evidence. Stratigraphic changes are manifested by a significant decrease in Na2O across the New Zealand miospore PM3b/MH1 early Eocene zonal boundary, at approximately 53.5 Ma. The change in Na2O is associated with a decrease in baseline concentrations of many other major (MnO, CaO, TiO2) and trace elements, and is interpreted to reflect a significant change in sandstone maturity. Paleocene sandstones are characterized by abundant plagioclase (albite and locally Na–Ca plagioclase), significant biotite and a range of heavy minerals, while Eocene sandstones are typically quartzose, with K-feldspar dominant over plagioclase, low mica contents and rare heavy minerals comprising a resistant suite. This change could reflect a change in provenance from local plutonic basement during the Paleocene Epoch to relatively quartz- and K-feldspar-rich granitic sources during Eocene time. However, significant quartz enrichment of Eocene sediment was also likely due to transportation reworking/winnowing along the palaeoshoreface and enhanced chemical weathering, driven in part by long-term global warming associated with the Early Eocene Climatic Optimum. The broad-ranging changes in major-element composition overprint local variations in sediment provenance, which are only detectable from the immobile trace-element geochemistry.

Foraminifera from the Eocene La Meseta Formation of Isla Marambio (Seymour Island), Antarctic Peninsula

2012 ◽  
Vol 24 (4) ◽  
pp. 408-416 ◽  
Author(s):  
Andrzej Gaździcki ◽  
Wojciech Majewski
Keyword(s):  
New Zealand ◽  
Early Eocene ◽  
West Antarctica ◽  
Shallow Marine ◽  
Lower Member ◽  
La Meseta Formation ◽  
Characteristic Species ◽  
First Time ◽  
Marine Nearshore ◽  
Seymour Island

AbstractBenthic foraminiferal assemblages are described for the first time from the early Eocene of West Antarctica. They come from the lower member (Telm1) of the La Meseta Formation of Isla Marambio (Seymour Island). Two distinctive assemblages, dominated by Nonionellina, Nonionella, Globocassidulina, and Eilohedra, as well as by Globocassidulina, Cribroelphidium, Guttulina, and Lobatula, indicate restricted, shallow marine, nearshore conditions. Their most characteristic species show distinct affinities with Eocene faunas of New Zealand and Patagonia, as well as with stratigraphically younger Antarctic foraminiferal communities.

scholarly journals Paleoenvironmental analysis of early Eocene marl and limestone alternations from Mead Stream, New Zealand

2021 ◽  
Author(s):  
◽  
Sonja Peñafiel Bermudez
Keyword(s):  
New Zealand ◽  
Isotope Analysis ◽  
Acid Leaching ◽  
The Body ◽  
Early Eocene ◽  
Carbon Isotopic ◽  
Early Eocene Climatic Optimum ◽  
Aotearoa New Zealand ◽  
Paleoenvironmental Analysis ◽  
Radiolarian Assemblages

<p>This study integrates paleonotology and geochemistry to provide a paleoclimatic analysis of cyclic sedimentation in the Lower Marl at Mead Stream in Marlborough, Aotearoa/New Zealand. The alternating marl and limestone bedding in this outcrop coincide with the warmest period in the Paleogene, the Early Eocene Climatic Optimum (EECO).  An acetic acid leaching method was refined and used successfully to extract microfossils from the indurated limestones and marls from two intervals of the Lower Marl. The technique resulted in foraminiferal tests with improved surface ornament in comparison with samples that were processed using standard washing methodology.  The resulting paleontological assessment of leached foraminiferal and radiolarian assemblages coupled with XRF and stable isotope analysis revised the position and detailed the faunal response to the J hyperthermal at the initiation of the EECO. Microfossil assemblages and carbon isotopic data suggest that the J carbon isotopic excursion (CIE) may be a two-stage event. A new L-3 CIE and possible hyperthermal event was identified within the body of the EECO. Both the J and L-3 events contained acmes where Morozovella made up a quarter of the planktic foraminiferal specimens, suggesting the southern expansion of subtropical waters. Fluctuations of Acarinina and Subbotina foraminifera coinciding with the marl and limestone alternations may indicate climate cycles within these hyperthermals.</p>

Spatial and temporal distribution of rainfall erosivity in New Zealand

Soil Research ◽  
2015 ◽  
Vol 53 (7) ◽  
pp. 815 ◽  
Author(s):  
Andreas Klik ◽  
Kathrin Haas ◽  
Anna Dvorackova ◽  
Ian C. Fuller
Keyword(s):  
New Zealand ◽  
Temporal Distribution ◽  
Annual Rainfall ◽  
Rainfall Erosivity ◽  
High Resolution Data ◽  
Topographic Features ◽  
Erosion Processes ◽  
Precipitation Records ◽  
First Time

Rainfall and its kinetic energy, expressed by rainfall erosivity, drives soil erosion processes by water. One of the most commonly used erosivity parameters is the rainfall-runoff erosivity factor R of the Revised Universal Soil Loss Equation. The goal of this study was to investigate for the first time the spatial distribution of annual rainfall erosivity in New Zealand. High-resolution data from 35 weather stations were used to calculate the R-factors. Based on these results, region-specific equations were developed and were applied by using long-term precipitation records from 597 stations. The values were interpolated with a geographic information system to generate a map showing spatial variations of rainfall erosivity. Annual R-values vary across both islands by a factor of 30, from <550 MJ mm ha–1 h–1 in parts of Central Otago to >16 000 MJ mm ha–1 h–1 in the Southern Alps. These large differences are related to climatic and topographic features. Nevertheless, the data show a high correlation to the precipitation. In most parts of New Zealand, highest erosivity values occurred in December and January, whereas the lowest values were observed in August.

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