scholarly journals IODP Expedition 318: From Greenhouse to Icehouse at the Wilkes Land Antarctic Margin

2011 ◽  
Vol 12 ◽  
pp. 15-23 ◽  
Author(s):  
C. Escutia ◽  
H. Brinkhuis ◽  
A. Klaus ◽  

Integrated Ocean Drilling Program (IODP) Expedition 318, Wilkes Land Glacial History, drilled a transect of sites across the Wilkes Land margin of Antarctica to provide a long-term record of the sedimentary archives of Cenozoic Antarctic glaciation and its intimate relationships with global climatic and oceanographic change. The Wilkes Land drilling program was undertaken to constrain the age, nature, and paleoenvironment of the previously only seismically inferred glacial sequences. The expedition (January–March 2010) recovered ~2000 meters of high-quality middle Eocene–Holocene sediments from water depths between 400 m and 4000 m at four sites on the Wilkes Land rise (U1355, U1356, U1359, and U1361) and three sites on the Wilkes Land shelf (U1357, U1358, and U1360). <br><br> These records span ~53 million years of Antarctic history, and the various seismic units (WL-S4–WL-S9) have been successfully dated. The cores reveal the history of the Wilkes Land Antarctic margin from an ice-free “greenhouse” Antarctica, to the first cooling, to the onset and erosional consequences of the first glaciation and the subsequent dynamics of the waxing and waning ice sheets, all the way to thick, unprecedented "tree ring style" records with seasonal resolution of the last deglaciation that began ~10,000 y ago. The cores also reveal details of the tectonic history of the Australo-Antarctic Gulf from 53 Ma, portraying the onset of the second phase of rifting between Australia and Antarctica, to ever-subsiding margins and deepening, to the present continental and ever-widening ocean/continent configuration. <br><br> doi:<a href="http://dx.doi.org/10.2204/iodp.sd.12.02.2011" target="_blank">10.2204/iodp.sd.12.02.2011</a>

2012 ◽  
Vol 14 ◽  
pp. 34-38 ◽  
Author(s):  
S. T. Toczko ◽  
A. J. Kopf ◽  
E. Araki ◽  

The Nankai Trough Seismogenic Zone Experiment (NanTroSEIZE) is a major long-term drilling project designed to investigate the seismogenic behavior of subduction zone plate boundaries. Integrated Ocean Drilling Program (IODP) Expedition 332 deployed a long-term borehole monitoring system (LTBMS), an advanced Circulation Obviation Retrofit Kit (CORK)-type observatory. The recovery of pressure and temperature data from a temporary observatory (SmartPlug) deployed during IODP Expedition 319 helped prove the SmartPlug concept. The permanent LTBMS was deployed n the upper 1000 m of Site C0002, while the SmartPlug was recovered from Site C0010 and replaced with a more capable "GeniusPlug", incorporating an extension with a geochem-ical sampler and biological experiment to the original SmartPlug design. SmartPlug pressure and temperature data showed signs of transient pressure events. <br><br> doi:<a href="http://dx.doi.org/10.2204/iodp.sd.14.04.2012" target="_blank">10.2204/iodp.sd.14.04.2012</a>


2021 ◽  
Author(s):  
Julia Gutierrez-Pastor ◽  
Carlota Escutia ◽  
Ursula Röhl ◽  
Ariadna Salabarnada ◽  
Francisco Jimenez-Espejo

&lt;p&gt;During the Holocene, 180 m of diatom ooze sediments were deposited in the Antarctic Wilkes Land margin continental shelf at site U1357A (Integrated Ocean Drilling Program Expedition 318, Escutia et al., 2011). Holocene sediments are dominated by rhythmic laminated deposits above a poorly sorted gravelly siltstone diamicton from the Last Glacial Maximum (LGM). CT-scans reveal three events of gravel/sand/silt sediments interbedded within the laminated sediments and interpreted as ice rafted debris (IRD). &amp;#160;Two of these events (from 185,1 to 185,45 and 174, 8 to 175,37 meters below seafloor, mbsf) are characterized by dispersed large clasts (1-5cm) within a muddy matrix at the base, transitioning to the top to millimetre-size clasts that are either aligned with the dark and light laminae or dispersed. A third event (176,2 to 177,2 mbsf) is characterized by a structureless sediment sequence with high concentrations of dispersed clasts that are up to 1-2 cm size. We used ImageJ/Fiji software, to conduct a quantitative analysis of grains bigger than 1mm in CT Scan 3D images. Measured parameters include grain size (Feret length), grain orientation (Feret angle), circularity and roundness, among other. In addition, grey scale profiles have been created from the sediment CT-scan images as a density proxy. Quantitative data and density profiles have been used to aid the sedimentological characterization of the Holocene deglaciation section and to infer depositional environment and patterns of deglaciation.&lt;/p&gt;&lt;p&gt;Escutia, C., Brinkhuis, H., Klaus, A., and the Expedition 318 Scientists,&amp;#160;Proc. IODP,&amp;#160;318: Site 1357. Tokyo (Integrated Ocean Drilling Program Management International, Inc.). doi:10.2204/&amp;#8203;iodp.proc.318.105.2011&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;


1962 ◽  
Vol S7-IV (2) ◽  
pp. 182-200
Author(s):  
M. V. Muratov

Abstract Recent literature on the tectonic evolution of the Alpine chain in eastern Europe and Asia Minor is reviewed. Two major periods are recognized in describing the tectonic history of the region. The first embraces all the Paleozoic, ending with the Hercynian orogeny, and probably represents an early period of geosynclinal evolution. The second period is represented by a geosynclinal stage, including the Mesozoic and part of the Paleogene up to the end of the Oligocene, and a terminal stage of orogenesis embracing the Neogene and Quaternary. The geosynclinal stage of the second period can be divided into three phases--an early phase embracing the Triassic, lower and middle and perhaps the upper Jurassic and Cretaceous, and characterized by formation of the first Triassic basins on the peneplaned Paleozoic landscape; a second phase, Cretaceous-middle Eocene, characterized by enlargement of the geosynclines and deposition of flysch; and a third phase which began after the end of the middle Eocene, characterized by closing of the geosynclines. Oceanic trenches which developed in the Black Sea and the southern Caspian, Marmara, Aegean, Ionian and eastern Mediterranean seas are recent structures not connected with the geosynclinal evolution and are superimposed on the continental surface of the geosynclinal structures. The arrangement of the depressions and the uplift during the geosynclinal stage were determined by abyssal faults imposed during the Paleozoic. Magmatic intrusions and volcanism developed in the late geosynclinal phases.


Geology ◽  
2007 ◽  
Vol 35 (11) ◽  
pp. 1051 ◽  
Author(s):  
Akihiro Kano ◽  
Timothy G. Ferdelman ◽  
Trevor Williams ◽  
Jean-Pierre Henriet ◽  
Tsuyoshi Ishikawa ◽  
...  

2015 ◽  
Vol 9 (2) ◽  
pp. 65 ◽  
Author(s):  
Michael Passow ◽  
Hélder Pereira ◽  
Leslie Peart

Recentemente, o Brasil aderiu ao Integrated Ocean Drilling Program, que realiza expedições científicas em todo o mundo. Isso permitiu que cientistas brasileiros pudessem participar na exploração do fundo do oceano nas imediações de uma fossa oceânica ao largo da Costa Rica. A perfuração do fundo do oceano para fins científicos foi proposta pela primeira vez em 1957 e começou na década de 60 do século XX. Em 1968, naquela que foi apenas a sua terceira expedição, o “Glomar Challenger” recuperou amostras de rochas e sedimentos dos dois lados da dorsal média-oceânica no Atlântico Sul, e revelou a expansão dos fundos oceânicos. Antes da capacidade de perfurar o fundo do oceano a grandes profundidades, os cientistas apenas tinham à sua disposição testemunhos obtidos com amostradores de tipo “pistão”. Os microfósseis obtidos a partir desses testemunhos têm permitido fazer muitas descobertas sobre as oscilações climáticas da Terra. Nas expedições realizadas atualmente pelo “JOIDES Resolution”, pelo “Chikyu”, e pelas plataformas de perfuração das missões específicas, continuam a surgir descobertas impressionantes que têm contribuído para melhorar a compreensão da história geológica do nosso planeta. Nos últimos anos, vários educadores têm acompanhado os cientistas durante as expedições, e criaram vários materiais educativos e de divulgação destinadas a estudantes e ao público em geral.


Author(s):  
Paul F. Green ◽  
Peter Japsen

Apatite fission-track analysis (AFTA) data in two Upper Jurassic core samples from the 231 m deep Blokelv-1 borehole, Jameson Land, East Greenland, combined with vitrinite reflectance data and regional AFTA data, define three palaeo-thermal episodes. We interpret localised early Eocene (55– 50 Ma) palaeotemperatures as representing localised early Eocene heating related to intrusive activity whereas we interpret late Eocene (40–35 Ma) and late Miocene (c. 10 Ma) palaeotemperatures as representing deeper burial followed by successive episodes of exhumation. For a palaeogeothermal gradient of 30°C/km and likely palaeo-surface temperatures, the late Eocene palaeotemperatures require that the Upper Jurassic marine section in the borehole was buried below a 2750 m thick cover of Upper Jurassic – Eocene rocks prior to the onset of late Eocene exhumation. As these sediments are now near outcrop at c. 200 m above sea level, they have been uplifted by at least 3 km since maximum burial during post-rift thermal subsidence. The results are consistent with estimates of rock uplift on Milne Land since the late Eocene and with interpretation of Ocean Drilling Program (ODP) data off South-East Greenland suggesting that mid-Cenozoic uplift of the margin triggered the marked influx of coarse clastic turbidites during the late Oligocene above a middle Eocene to upper Oligocene hiatus.


2021 ◽  
Vol 17 (6) ◽  
pp. 2393-2425
Author(s):  
Peter K. Bijl ◽  
Joost Frieling ◽  
Margot J. Cramwinckel ◽  
Christine Boschman ◽  
Appy Sluijs ◽  
...  

Abstract. Sea surface temperature (SST) reconstructions based on isoprenoid glycerol dialkyl glycerol tetraether (isoGDGT) distributions from the Eocene southwest (SW) Pacific Ocean are unequivocally warmer than can be reconciled with state-of-the-art fully coupled climate models. However, the SST signal preserved in sedimentary archives can be affected by contributions of additional isoGDGT sources. Methods now exist to identify and possibly correct for overprinting effects on the isoGDGT distribution in marine sediments. Here, we use the current proxy insights to (re-)assess the reliability of the isoGDGT-based SST signal in 69 newly analyzed and 242 reanalyzed sediments at Ocean Drilling Program (ODP) Site 1172 (East Tasman Plateau, Australia) following state-of-the-art chromatographic techniques. We compare our results with paleoenvironmental and paleoclimatologic reconstructions based on dinoflagellate cysts. The resulting ∼ 130 kyr resolution Maastrichtian–Oligocene SST record based on the TetraEther indeX of tetraethers with 86 carbon atoms (TEX86) confirms previous conclusions of anomalous warmth in the early Eocene SW Pacific and remarkably cool conditions during the mid-Paleocene. Dinocyst diversity and assemblages show a strong response to the local SST evolution, supporting the robustness of the TEX86 record. Soil-derived branched GDGTs stored in the same sediments are used to reconstruct mean annual air temperature (MAAT) of the nearby land using the Methylation index of Branched Tetraethers with 5-methyl bonds (MBT'5me) proxy. MAAT is consistently lower than SST during the early Eocene, independent of the calibration chosen. General trends in SST and MAAT are similar, except for (1) an enigmatic absence of MAAT rise during the Paleocene–Eocene Thermal Maximum and Middle Eocene Climatic Optimum, and (2) a subdued middle–late Eocene MAAT cooling relative to SST. Both dinocysts and GDGT signals suggest a mid-shelf depositional environment with strong river runoff during the Paleocene–early Eocene progressively becoming more marine thereafter. This trend reflects gradual subsidence and more pronounced wet/dry seasons in the northward-drifting Australian hinterland, which may also explain the subdued middle Eocene MAAT cooling relative to that of SST. The overall correlation between dinocyst assemblages, marine biodiversity and SST changes suggests that temperature exerted a strong influence on the surface-water ecosystem. Finally, we find support for a potential temperature control on compositional changes of branched glycerol monoalkyl glycerol tetraethers (brGMGTs) in marine sediments. It is encouraging that a critical evaluation of the GDGT signals confirms that most of the generated data are reliable. However, this also implies that the high TEX86-based SSTs for the Eocene SW Pacific and the systematic offset between absolute TEX86-based SST and MBT'5me-based MAAT estimates remain without definitive explanation.


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