Insolation-paced sea level during the Early Pleistocene, Taiwan

2021 ◽  
Author(s):  
Romain Vaucher ◽  
Shahin E. Dashtgard ◽  
Chorng-Shern Horng ◽  
Christian Zeeden ◽  
Antoine Dillinger ◽  
...  
Keyword(s):  
Sea Level ◽  
Benthic Foraminifera ◽  
Sediment Accumulation ◽  
Sediment Flux ◽  
Early Pleistocene ◽  
Glacial Cycles ◽  
Shallow Marine ◽  
Sea Level Fluctuations ◽  
Summer Insolation ◽  
O Isotope

<p>The Pleistocene was a phase of global cooling of the Earth through which glacial-interglacial cycles occurred, and the growth and decay of the ice-sheets resulted in quasi-cyclic sea-level fluctuations driven by orbital forcing. Despite that summer insolation is mostly controlled by precession, the records of the glacial cycles showcase a significant periodicity of ~41 kyrs during the Early Pleistocene forced by Earth’s obliquity (tilt) that varies the latitudinal distribution of insolation especially in high latitudes. The dominance of obliquity over precession in marine archives is commonly attributed to the in-phase effect of obliquity-related insolation versus the opposite-phased influence of precession, which may cancel out the summer insolation signal received by the southern and northern hemispheres.</p><p>Here, we present a clastic shallow marine record from the Cholan Formation (Early Pleistocene; Taiwan). Facies analysis indicates that quasi-cyclic deposition occurred in shoreface to offshore environments in the paleo-Taiwan Strait. The magnetobiostratigraphic framework indicates that the studied section occurs in the lower part of the Matuyama subchron (1.925 - 2.595 Ma) close to the lower limit of the Olduvai (1.925 Ma) normal polarity subchron. Comparison of the stratigraphy to a d<sup>18</sup>O isotope record of benthic foraminifera and orbital curves of precession and obliquity at the time of sediment accumulation reveals a good correlation between depositional cycles and the Northern Hemisphere summer insolation, demonstrating precession dominated sea-level fluctuations during the Early Pleistocene. These results underpin recent findings suggesting that d<sup>18</sup>O isotope records of benthic foraminifera have a more significant precession signal than previously described. This study also demonstrates that shallow-marine stratigraphic successions in high-accommodation and high-sedimentation basins can be outstanding climate archives, possibly even preserving sediment flux responding to half-precession cycles.</p>

Constraints on the amplitude of Mid-Pliocene (3.6–2.4 Ma) eustatic sea-level fluctuations from the New Zealand shallow-marine sediment record

2008 ◽  
Vol 367 (1886) ◽  
pp. 169-187 ◽  
Author(s):  
Tim R Naish ◽  
Gary S Wilson
Keyword(s):  
New Zealand ◽  
Sea Level ◽  
Sediment Accumulation ◽  
Ice Sheet ◽  
Deep Ocean ◽  
Antarctic Ice Sheet ◽  
Shallow Marine ◽  
Sea Level Fluctuations ◽  
Late Neogene ◽  
Sea Level Oscillations

Ice-volume calibrations of the deep-ocean foraminiferal δ 18 O record imply orbitally influenced sea-level fluctuations of up to 30 m amplitude during the Mid-Pliocene, and up to 30 per cent loss of the present-day mass of the East Antarctic Ice Sheet (EAIS) assuming complete deglaciation of the West Antarctic Ice Sheet (WAIS) and Greenland. These sea-level oscillations have driven recurrent transgressions and regressions across the world's continental shelves. Wanganui Basin, New Zealand, contains the most complete shallow-marine Late Neogene stratigraphic record in the form of a continuous cyclostratigraphy representing every 41 and 100 ka sea-level cycle since ca 3.6 Ma. This paper presents a synthesis of faunally derived palaeobathymetric data for shallow-marine sedimentary cycles corresponding to marine isotope stages M2–100 ( ca 3.4–2.4 Ma). Our approach estimates the eustatic sea-level contribution to the palaeobathymetry curve by placing constraints on total subsidence and decompacted sediment accumulation. The sea-level estimates are consistent with those from δ 18 O curves and numerical ice sheet models, and imply a significant sensitivity of the WAIS and the coastal margins of the EAIS to orbital oscillations in insolation during the Mid-Pliocene period of relative global warmth. Sea-level oscillations of 10–30 m were paced by obliquity.

scholarly journals Insolation-paced sea level and sediment flux during the early Pleistocene in Southeast Asia

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Romain Vaucher ◽  
Shahin E. Dashtgard ◽  
Chorng-Shern Horng ◽  
Christian Zeeden ◽  
Antoine Dillinger ◽  
...  
Keyword(s):  
Southeast Asia ◽  
Sea Level ◽  
Sediment Flux ◽  
Early Pleistocene ◽  
Geological Evidence ◽  
Orbital Parameters ◽  
Sea Level Fluctuations ◽  
Global Ice Volume ◽  
Nearshore Environments ◽  
Isotope Record

AbstractGlobal marine archives from the early Pleistocene indicate that glacial-interglacial cycles, and their corresponding sea-level cycles, have predominantly a periodicity of ~ 41 kyrs driven by Earth’s obliquity. Here, we present a clastic shallow-marine record from the early Pleistocene in Southeast Asia (Cholan Formation, Taiwan). The studied strata comprise stacked cyclic successions deposited in offshore to nearshore environments in the paleo-Taiwan Strait. The stratigraphy was compared to both a δ18O isotope record of benthic foraminifera and orbital parameters driving insolation at the time of deposition. Analyses indicate a strong correlation between depositional cycles and Northern Hemisphere summer insolation, which is precession-dominated with an obliquity component. Our results represent geological evidence of precession-dominated sea-level fluctuations during the early Pleistocene, independent of a global ice-volume proxy. Preservation of this signal is possible due to the high-accommodation creation and high-sedimentation rate in the basin enhancing the completeness of the stratigraphic record.

scholarly journals Deciphering tectonic, eustatic and surface controls on the 20 Ma-old Burdigalian transgression recorded in the Upper Marine Molasse in Switzerland

2019 ◽  
Author(s):  
Philippos Garefalakis ◽  
Fritz Schlunegger
Keyword(s):  
Sea Level ◽  
Depositional Environments ◽  
Sediment Supply ◽  
Sediment Flux ◽  
Crustal Material ◽  
Molasse Basin ◽  
Shallow Marine ◽  
Depositional Settings ◽  
Stratigraphic Architecture ◽  
Aar Massif

Abstract. The stratigraphic architecture of the Swiss Molasse basin reveals crucial information about the basin’s geometry, its evolution and the processes leading to the deposition of the clastic material. Nevertheless, the formation of the Upper Marine Molasse (OMM) and the controls on the related Burdigalian transgression are not fully understood yet. During these times, from c. 20 to 17 Ma, the Swiss Molasse basin was partly flooded by a peripheral shallow marine sea, striking SW – NE. We proceeded through detailed sedimentological and stratigraphic examinations of several sites across the entire Swiss Molasse basin in order to deconvolve the stratigraphic signals related surface and tectonic controls. Surface-related signals include stratigraphic responses to changes in eustatic sea level and sediment fluxes, while the focus on crustal-scale processes lies on the uplift of the Aar-massif at c. 20 Ma. Field examinations show, that the evolution of the Burdigalian seaway was characterized by (i) shifts in the depositional settings, (ii) changes in discharge directions, a deepening and widening of the basin, and (iv) phases of erosion and non-deposition. We relate these changes in the stratigraphic records to a combination of surface and tectonic controls at various scales. In particular, roll-back subduction of the European mantle lithosphere, delamination of crustal material and the associated rise of the Aar-massif most likely explain the widening of the basin particular at distal sites. In addition, the uplift of the Aar-massif was likely to have shifted the patterns of surface loads. These mechanisms could have caused a flexural adjustment of the foreland plate underneath the Molasse basin, which we use as mechanism to explain the establishment of distinct depositional environments and particularly the formation of subtidal-shoals where a lateral bulge is expected. In the Alpine hinterland, these processes occurred simultaneously with a period of fast tectonic exhumation accomplished through slip along the Simplon detachment fault, with the consequence that sediment flux to the basin decreased. It is possible that this reduction in sediment supply contributed to the establishment of marine conditions in the Swiss Molasse basin and thus amplified the effect related to the tectonically controlled widening of the basin. Because of the formation of shallow marine conditions, subtle changes in the eustatic sea level contributed to the occurrence several hiatus that chronicle periods of erosion and non-sedimentation. While these mechanisms are capable of explaining the establishment of the Burdigalian seaway and the formation of distinct sedimentological niches in the Swiss Molasse basin, the drainage reversal during OMM-times possibly requires a change in the tectonic processes at the slab scale. We conclude that sedimentological records can be used to decipher surface controls and lithospheric-scale processes in orogens from the stratigraphic record, provided that a detailed sedimentological and chronological database is available.

scholarly journals Lithostratigraphy and biostratigraphy of the Lower Carboniferous (Mississippian) carbonates of the southern Askrigg Block, North Yorkshire, UK

2016 ◽  
Vol 154 (2) ◽  
pp. 305-333 ◽  
Author(s):  
C. N. WATERS ◽  
P. CÓZAR ◽  
I. D. SOMERVILLE ◽  
R. B. HASLAM ◽  
D. MILLWARD ◽  
...  
Keyword(s):  
Shallow Water ◽  
Sea Level ◽  
Carbonate Ramp ◽  
Fault System ◽  
Lower Carboniferous ◽  
Shallow Marine ◽  
Sea Level Fluctuations ◽  
Algal Assemblages ◽  
Lower Palaeozoic ◽  
Southern Flank

AbstractA rationalized lithostratigraphy for the Great Scar Limestone Group of the southeast Askrigg Block is established. The basal Chapel House Limestone Formation, assessed from boreholes, comprises shallow-marine to supratidal carbonates that thin rapidly northwards across the Craven Fault System, onlapping a palaeotopographical high of Lower Palaeozoic strata. The formation is of late Arundian age in the Silverdale Borehole, its northernmost development. The overlying Kilnsey Formation represents a southward-thickening and upward-shoaling carbonate development on a S-facing carbonate ramp. Foraminiferal/algal assemblages suggest a late Holkerian and early Asbian age, respectively, for the uppermost parts of the lower Scaleber Force Limestone and upper Scaleber Quarry Limestone members, significantly younger than previously interpreted. The succeeding Malham Formation comprises the lower Cove Limestone and upper Gordale Limestone members. Foraminiferal/algal assemblages indicate a late Asbian age for the formation, contrasting with the Holkerian age previously attributed to the Cove Limestone. The members reflect a change from a partially shallow-water lagoon (Cove Limestone) to more open-marine shelf (Gordale Limestone), coincident with the onset of marked sea-level fluctuations and formation of palaeokarstic surfaces with palaeosoils in the latter. Facies variations along the southern flank of the Askrigg Block, including an absence of fenestral lime-mudstone in the upper part of the Cove Limestone and presence of dark grey cherty grainstone/packstone in the upper part the Gordale Limestone are related to enhanced subsidence during late Asbian movement on the Craven Fault System. This accounts for the marked thickening of both members towards the Greenhow Inlier.

scholarly journals Pleistocene sediment offloading and the global sulfur cycle

2015 ◽  
Vol 12 (10) ◽  
pp. 3043-3060 ◽  
Author(s):  
S. Markovic ◽  
A. Paytan ◽  
U. G. Wortmann
Keyword(s):  
Sea Level ◽  
Considerable Increase ◽  
Sediment Accumulation ◽  
Sulfur Cycle ◽  
Sea Level Fluctuations ◽  
Sediment Budgets ◽  
Shelf Sediment ◽  
Continental Shelves ◽  
Shelf Sediments ◽  
Pleistocene Sediment

Abstract. Quaternary sea level fluctuations have greatly affected the sediment budgets of the continental shelves. Previous studies suggested that this caused a considerable increase in the net loss of shelf sediments. Since sediment accumulation and erosion are closely tied to the formation and re-oxidation of pyrite, we use a high-resolution record of sulfur isotope ratios (34S / 32S) of marine sulfate to evaluate the implications of the so-called "shelf sediment offloading" on the global sulfur cycle. Modeling of our δ34S record suggests that erosion during sea level lowstands was only partly compensated by increased sedimentation during times of rising sea level and sea level highstands. Furthermore, our data suggests that shelf systems reached a new equilibrium state about 700 ka, which considerably slowed or terminated shelf sediment offloading.

scholarly journals Reconstructing the evolution of ice sheets, sea level, and atmospheric CO<sub>2</sub> during the past 3.6 million years

2021 ◽  
Vol 17 (1) ◽  
pp. 361-377
Author(s):  
Constantijn J. Berends ◽  
Bas de Boer ◽  
Roderik S. W. van de Wal
Keyword(s):  
Sea Level ◽  
Radiative Forcing ◽  
Climate Model ◽  
Ice Sheets ◽  
Early Pleistocene ◽  
Glacial Cycles ◽  
Proxy Data ◽  
Late Pliocene ◽  
Ice Volume ◽  
The Past

Abstract. Understanding the evolution of, and the interactions between, ice sheets and the global climate over geological timescales is important for being able to project their future evolution. However, direct observational evidence of past CO2 concentrations, and the implied radiative forcing, only exists for the past 800 000 years. Records of benthic δ18O date back millions of years but contain signals from both land ice volume and ocean temperature. In recent years, inverse forward modelling has been developed as a method to disentangle these two signals, resulting in mutually consistent reconstructions of ice volume, temperature, and CO2. We use this approach to force a hybrid ice-sheet–climate model with a benthic δ18O stack, reconstructing the evolution of the ice sheets, global mean sea level, and atmospheric CO2 during the late Pliocene and the Pleistocene, from 3.6 million years (Myr) ago to the present day. During the warmer-than-present climates of the late Pliocene, reconstructed CO2 varies widely, from 320–440 ppmv for warm periods to 235–250 ppmv for the early glacial excursion ∼3.3 million years ago. Sea level is relatively stable during this period, with maxima of 6–14 m and minima of 12–26 m during glacial episodes. Both CO2 and sea level are within the wide ranges of values covered by available proxy data for this period. Our results for the Pleistocene agree well with the ice-core CO2 record, as well as with different available sea-level proxy data. For the Early Pleistocene, 2.6–1.2 Myr ago, we simulate 40 kyr glacial cycles, with interglacial CO2 decreasing from 280–300 ppmv at the beginning of the Pleistocene to 250–280 ppmv just before the Mid-Pleistocene Transition (MPT). Peak glacial CO2 decreases from 220–250 to 205–225 ppmv during this period. After the MPT, when the glacial cycles change from 40 to 80 120 kyr cyclicity, the glacial–interglacial contrast increases, with interglacial CO2 varying between 250–320 ppmv and peak glacial values decreasing to 170–210 ppmv.

scholarly journals Pleistocene sediment offloading and the global sulfur cycle

2015 ◽  
Vol 12 (2) ◽  
pp. 1205-1245 ◽  
Author(s):  
S. Markovic ◽  
A. Paytan ◽  
U. G. Wortmann
Keyword(s):  
Sea Level ◽  
Considerable Increase ◽  
Sediment Accumulation ◽  
Sulfur Cycle ◽  
Sea Level Fluctuations ◽  
Sediment Budgets ◽  
Shelf Sediment ◽  
Continental Shelves ◽  
Shelf Sediments ◽  
Pleistocene Sediment

Abstract. Quaternary sea level fluctuations have greatly affected the sediment budgets of the continental shelves. Previous studies suggested that this caused a considerable increase in the net loss of shelf sediments. Since sediment accumulation and erosion are closely tied to the formation and re-oxidation of pyrite, we use a high resolution record of sulfur isotope ratios (34S / 32S) of marine sulfate to evaluate the implications of the so called "shelf sediment offloading" on the global sulfur cycle. Modeling of our δ34S record suggests that erosion during sea level lowstands was only partly compensated by increased sedimentation during times of rising sea level and sea level highstands. Furthermore, our data suggests that shelf systems reached a new equilibrium state about 700 kyr ago, which considerably slowed or terminated shelf sediment offloading.

scholarly journals An assessment of the influence of orbital forcing on Late Pliocene global sea-level using a shallow-marine sedimentary record from the Wanganui Basin, New Zealand

2021 ◽  
Author(s):  
◽  
Juliet Perry Sefton
Keyword(s):  
New Zealand ◽  
Sea Level ◽  
Benthic Foraminifera ◽  
Volume Changes ◽  
Shallow Marine ◽  
Late Pliocene ◽  
Ice Volume ◽  
Global Ice Volume ◽  
Global Sea Level ◽  
Water Depths

<p>Classical Milankovitch Theory suggests variance in the orbital cycles of precession (21,000 year) modulated by eccentricity (~100,000 year) and obliquity (41,000 year) should have a profound influence on polar insolation and ice volume. However, the globally-integrated ice volume proxy record (benthic δ¹⁸O) during the Late Pliocene (3.0-2.6 Ma) is dominated by obliquity-paced cycles, and lacks a significant precession component. A number of conceptual hypotheses have been proposed to explain this “41,000 year problem”, but palaeoclimate records independent of the benthic δ¹⁸O record are required to test these hypotheses.  The Wanganui Basin, New Zealand, contains a well-dated, shallow-marine Neogene sedimentary succession that is widely recognised as an important site for examining sea-level/ice volume changes at orbital frequencies. In this study, the shallow-marine Late Pliocene Mangaweka Mudstone is examined at an orbital-scale resolution (~3-5 kyr sampling) along a continuous 672 metre thick (true thickness) outcropping road section on Watershed Road between the Rangitikei and Turakina River valleys.  Two modern analogue-calibrated water depth proxies were used to evaluate palaeobathymetric changes: (i) sediment texture and (ii) benthic foraminifera census data. An overall trend of shallowing to inner-shelf water depths occurs up-section, but is superimposed by higher frequency fluctuations. For the lowermost ~400 metres of the section, in situ benthic foraminifera assemblages indicate water depths >100 metres. As wave-induced sand transport does not occur on the modern Manawatu-Wanganui outer-shelf, and modern wave climates are assumed to be analogous to the Pliocene, it is concluded that the sediment grainsize approach is not an appropriate proxy for reconstruction water depth changes in the lower ~400 metres of section.  An integrated magneto-, bio- and tephrostratigraphy was developed that constrains the outcrop succession to between ~3.0 Ma and 2.58 Ma. Nine distinct cycles spanning ~400,000 years are identified in the grainsize and benthic foraminifera assemblages. Within the uncertainty of the age model, the Mangaweka Mudstone grainsize cycles can be matched one-for-one to the δ¹⁸O glacial-interglacial cycles, as they display a similar pattern in terms of frequency and amplitude. The frequency of the Mangaweka Mudstone cycles (and the corresponding interval in the benthic δ¹⁸O record) are dominated by the ~40,000 year obliquity cycle, but with a subordinate eccentricity component. Therefore, the fluctuations in the grainsize and benthic foraminifera proxies likely represent an indirect response to global sea-level fluctuations via their effect on continental shelf sediment transport mechanisms (non-wave) with the orbitally-paced transgression and regression of the shoreline on a restricted palaeo- continental shelf.  The implications for the orbital theory of the ice ages are that during the Late Pliocene, global ice volume changes responded primarily to obliquity, and the precession influences were either: (i) too low in amplitude to have influenced the grainsize and benthic foraminifera assemblages in the Mangaweka Mudstone depositional environment, or (ii) cancelled-out in global ice volume and sea-level changes because precession forcing is anti-phased between the hemispheres.</p>

Sign in / Sign up

Export Citation Format

Share Document