scholarly journals Evolution of the North Horowhenua Coastal Depositional System in Response to Late Pleistocene Sea Level Changes

2021 ◽  
Author(s):  
◽  
Glenn Richard Hughes
Keyword(s):  
Sea Level ◽  
Tectonic Setting ◽  
Sea Level Changes ◽  
Last Interglacial ◽  
Shallow Marine ◽  
Marine Strata ◽  
Valley Fill ◽  
The North ◽  
Glacial Periods ◽  
And Sea Level

<p>The convergent tectonic setting of New Zealand has lead to the development of a series of anticlines and troughs resulting from folding and faulting of basement greywacke in southwest North Island. The most extensive of these is the Kairanga Trough spreading from the Horowhenua to the Manawatu, which lies between the uplifting Tararua Range and subsiding South Wanganui Basin. This trough was a major depocentre for fluvial and shallow marine strata during the Quaternary. By utilising a 280m deep borehole from the Kairanga Trough, this thesis investigates how climate and sea level variations affected sedimentation in the north Horowhenua District.   This borehole has recorded a near continuous record of climate and sea level change for the last 340ka. The lower part of the core is a marine sequence representing progressive infilling of the Kairanga Trough during 5th order (c.100ka) glacioeustatic fluctuations, which consequently produced 4 marine cyclothems. Transgressions and subsequent highstand periods are represented by shallow marine sediment, which were followed by fluvial aggradation during lowstand periods, then marine planation during subsequent transgressions. Cycle 1 developed during OIS 9 (340-300ka). Cycles 2 and 3 both formed during OIS 7 as a result of two closely spaced highstands centred around 245ka (OIS 7c) and 200ka (OIS 7a), which were separated by a period of lower sea level around 225ka (OIS 7b) that produced a disconformity. Cycle 4 formed during the Last Interglacial transgression (OIS 5e) and represents an incised valley fill. Progradation of a coastal strandplain and alluvial plain representing the latter stages of infilling of the Kairanga Trough with coastal and terrigenous sediment during the mid to late Last Interglacial and Glacial Periods is recorded in the sediment composing the top part of the borehole.</p>

scholarly journals Evolution of the North Horowhenua Coastal Depositional System in Response to Late Pleistocene Sea Level Changes

2021 ◽  
Author(s):  
◽  
Glenn Richard Hughes
Keyword(s):  
Sea Level ◽  
Tectonic Setting ◽  
Sea Level Changes ◽  
Last Interglacial ◽  
Shallow Marine ◽  
Marine Strata ◽  
Valley Fill ◽  
The North ◽  
Glacial Periods ◽  
And Sea Level

<p>The convergent tectonic setting of New Zealand has lead to the development of a series of anticlines and troughs resulting from folding and faulting of basement greywacke in southwest North Island. The most extensive of these is the Kairanga Trough spreading from the Horowhenua to the Manawatu, which lies between the uplifting Tararua Range and subsiding South Wanganui Basin. This trough was a major depocentre for fluvial and shallow marine strata during the Quaternary. By utilising a 280m deep borehole from the Kairanga Trough, this thesis investigates how climate and sea level variations affected sedimentation in the north Horowhenua District.   This borehole has recorded a near continuous record of climate and sea level change for the last 340ka. The lower part of the core is a marine sequence representing progressive infilling of the Kairanga Trough during 5th order (c.100ka) glacioeustatic fluctuations, which consequently produced 4 marine cyclothems. Transgressions and subsequent highstand periods are represented by shallow marine sediment, which were followed by fluvial aggradation during lowstand periods, then marine planation during subsequent transgressions. Cycle 1 developed during OIS 9 (340-300ka). Cycles 2 and 3 both formed during OIS 7 as a result of two closely spaced highstands centred around 245ka (OIS 7c) and 200ka (OIS 7a), which were separated by a period of lower sea level around 225ka (OIS 7b) that produced a disconformity. Cycle 4 formed during the Last Interglacial transgression (OIS 5e) and represents an incised valley fill. Progradation of a coastal strandplain and alluvial plain representing the latter stages of infilling of the Kairanga Trough with coastal and terrigenous sediment during the mid to late Last Interglacial and Glacial Periods is recorded in the sediment composing the top part of the borehole.</p>

A standardized database of Last Interglacial sea-level indicators in southeast Asia: Records from coral reef terraces in a tectonically complex region

2021 ◽  
Author(s):  
Kathrine Maxwell ◽  
Hildegard Westphal ◽  
Alessio Rovere
Keyword(s):  
Coral Reef ◽  
Southeast Asia ◽  
Sea Level ◽  
Tectonic Setting ◽  
Sea Level Change ◽  
The Philippines ◽  
Sea Level Changes ◽  
Last Interglacial ◽  
Level Change ◽  
Se Asia

&lt;p&gt;The Last Interglacial (LIG), as well as other warmer periods in the Earth&amp;#8217;s geologic history, provides an analogue for predicted warming conditions in the near future. Analysis of sea-level indicators during this period is important in constraining regional drivers of relative sea-level change (RSL) and in modeling future trajectories of sea-level rise. In southeast Asia, several studies have been done to examine LIG sea-level indicators such as coral reef terraces and tidal notches. A synthesis of the state-of-the-art of the LIG RSL indicators in the region, meanwhile, has yet to be done. We reviewed over 50 published works on the LIG RSL indicators in southeast Asia and used the framework of the World Atlas of Last Interglacial Shorelines (WALIS) in building a standardized database of previously published LIG RSL indicators in the region. In total, we identified 38 unique RSL indicators and inserted almost 140 ages in the database. Available data from Indonesia, the Philippines, and East Timor points to variable elevation of sea-level indicators during the LIG highlighting the complex tectonic setting of this region. Variable uplift rates (from as low as 0.02 to as high as 1.1 m/ka) were reported in the study areas echoing various collision and subduction processes influencing these sites. Although several age constraints and elevation measurements have been provided by these studies, more data is still needed to shed more light on the RSL changes in the region. With this effort under the WALIS framework, we hope to identify gaps in the LIG RSL indicators literature in SE Asia and recognize potential areas that can be visited for future work. We also hope that this initiative will help us further understand the different drivers of past sea-level changes in SE Asia and will provide inputs for projections of sea-level change in the future.&lt;/p&gt;

scholarly journals The last interglacial (MIS 5e) cycle at Little Bahama Bank: A history of climate and sea-level changes

2018 ◽  
Author(s):  
Anastasia Zhuravleva ◽  
Henning A. Bauch
Keyword(s):  
Sea Level ◽  
Ocean Circulation ◽  
Climatic Variability ◽  
Meridional Overturning Circulation ◽  
Sea Level Changes ◽  
Last Interglacial ◽  
Foraminiferal Assemblage ◽  
The Mean ◽  
Mis 5E ◽  
And Sea Level

Abstract. Shallow-water sediments of the Bahama region containing the last interglacial (MIS 5e) are ideal to investigate the region's sensitivity to past climatic and sea level changes. Here we present new faunal, isotopic and XRF-sediment core data from the northern slope of the Little Bahama Bank. The results suggest that the bank top remained flooded across the last interglacial plateau, ~ 129–117 ka, arguing for a relative sea level above −6 m for this time period. In addition, climatic variability, which today is closely coupled with movements of the intertropical convergence zone (ITCZ), is interpreted based on stable isotopes and foraminiferal assemblage records. During early MIS 5e, the mean annual ITCZ position moved northward in line with increased solar forcing and a recovered Atlantic Meridional Overturning Circulation (AMOC). The early MIS 5e warmth peak was intersected, however, by a millennial-scale cooling event, consistent with a southward shift in the mean annual ITCZ position. This tropical shift is ascribed to the transitional climatic regime of early MIS 5e, characterized by persistent high-latitude freshening and, thereby, unstable AMOC mode. Our records from the Bahama region demonstrate that not only was there a tight relation between local sedimentation regimes and last interglacial sea level history, via the atmospheric forcing we could further infer an intra-interglacial connectivity between the polar and subtropical latitudes that left its imprint also on the ocean circulation.

scholarly journals Origin of a deep buried valley system in Pleistocene deposits of the eastern central North Sea

1995 ◽  
Vol 12 ◽  
pp. 7-19
Author(s):  
Inger Salomonsen
Keyword(s):  
Sea Level ◽  
North Sea ◽  
River System ◽  
Sea Level Changes ◽  
Upper Pleistocene ◽  
The North ◽  
Late Tertiary ◽  
Deltaic Sedimentation ◽  
The North Sea ◽  
Glacial Periods

In the North Sea, the sedimentary development of the late Tertiary and early Quaternary was dominated by deltaic sedimentation in a fast subsiding basin. During the Pleistocene, pronounced climatic changes affected the sedimentation of the area and progradation of the delta systems ceased. The Middle and Upper Pleistocene sedimentary successions consist of alternations of marine and fluvial deposits, partly reworked during glacial periods. Seismic records from the Danish sector of the North Sea reveal numerous deep incisions cut down from various levels of the Middle and Upper Pleistocene successions. These incisions are concluded to form a pattern of buried valleys. Detailed seismic stratigraphic analysis shows the occurrence of various internal unconformities within these buried valleys. It is concluded that the valleys originate from a river system developed in periods of repeated sea-level changes. Pluvial erosion during glacial sea-level lowstand and glacial meltwater action is proposed to have been responsible for the origin of the valley system. Thus, in Middle and Upper Pleistocene glacial periods drainage and associated sediment transport occurred from Northwest and Central European land areas via a presently buried river system in the southeastern North Sea towards a depositional basin north and northwest of the Danish North Sea sector.

Climate and sea-level changes across a shallow marine Cretaceous-Palaeogene boundary succession in Patagonia, Argentina

Palaeontology ◽  
2017 ◽  
Vol 60 (4) ◽  
pp. 519-534 ◽  
Author(s):  
Johan Vellekoop ◽  
Femke Holwerda ◽  
Mercedes B. Prámparo ◽  
Veronica Willmott ◽  
Stefan Schouten ◽  
...  
Keyword(s):  
Sea Level ◽  
Sea Level Changes ◽  
Shallow Marine ◽  
And Sea Level

Has Earth ever been ice-free? Implications for glacio-eustasy in the Cretaceous greenhouse age using high-resolution sequence stratigraphy

2020 ◽  
Vol 133 (1-2) ◽  
pp. 243-252 ◽  
Author(s):  
Wen Lin ◽  
Janok P. Bhattacharya ◽  
Brian R. Jicha ◽  
Brad S. Singer ◽  
William Matthews
Keyword(s):  
High Resolution ◽  
Sea Level ◽  
Late Cretaceous ◽  
High Frequency ◽  
Tectonic Setting ◽  
Reciprocal Relationship ◽  
Sea Level Changes ◽  
Sea Levels ◽  
Shallow Marine ◽  
Water Tables

Abstract Controls on high-frequency sequences formed during super-greenhouse conditions in the Late Cretaceous Western Interior Seaway remain equivocal because of the active foreland basin tectonic setting and the lack of direct evidence of polar glaciations to support a glacio-eustatic origin. This paper quantifies eustatic sea-level changes based on high-resolution sequence stratigraphic analysis and improved chronometry of shallow marine deposits of the Late Cretaceous Gallup Sandstone in New Mexico, USA. Backstripping techniques remove tectonic and compactional subsidence and enable quantification of the magnitude of eustatic sea-level change, that allow evaluation of the dominant controls on the high-frequency sequences to resolve the role of orbitally controlled, climate-driven eustasy versus tectonics. Sixty-five parasequences, constituting 29 parasequence sets and 12 sequences are identified in the ∼1.2 m.y. duration of the Late Cretaceous Gallup system. New 40Ar/39Ar dating of bentonites constrains the durations of the individual parasequences, parasequence sets, and sequences, and that these match Milankovitch periodicity, indicating an orbital climate control. The magnitudes of sea-level changes between parasequences range between −28 m and +22 m, which are compatible with hypotheses of both aquifer and glacio-eustasy. Aquifer-eustasy predicts a reciprocal relationship between floodplain cycles and shallow marine sequences, such that aquifer drawdown and falling water tables should correlate to rising sea levels (highstands), whereas increased aquifer storage and rising water tables should correlate to falling sea levels (lowstands). Our preliminary observations show synchronous, versus reciprocal, relationships that may be more compatible with a glacio-eustatic origin. The results of this study support the hypothesis that the Cretaceous greenhouse was marked by high-frequency, low-amplitude glaciations driven by orbital climate cycles, but further work is required to evaluate the contribution of aquifer-eustasy.

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