An extensive late Cenozoic terrestrial record of multiple glaciations preserved in the Tintina Trench of west-central Yukon: stratigraphy, paleomagnetism, paleosols, and pollenThis is a companion paper to Barendregt et al., also in this issue.Geological Survey of Canada Contribution 20100035.

2010 ◽  
Vol 47 (7) ◽  
pp. 1003-1028 ◽  
Author(s):  
Alejandra Duk-Rodkin ◽  
René W. Barendregt ◽  
James M. White
Keyword(s):  
Companion Paper ◽  
Middle Pleistocene ◽  
Glacial Sediments ◽  
Late Pliocene ◽  
Early Tertiary ◽  
West Central ◽  
Glacial Chronology ◽  
Stratigraphic Nomenclature ◽  
Multiple Sequences ◽  
Age Constraints

The Tintina Trench in west-central Yukon is a late Miocene graben formed along the antecedent early Tertiary Tintina fault. Since its formation the trench has served as a sediment trap for alluvial and glacial deposits. An extensive record of preglacial, glacial, and interglacial sediments spanning the late Pliocene to late Pleistocene has been preserved and is exposed today in modern landslide scars. This sedimentary record comprises multiple sequences of tills, outwash, mudflows, loess, and paleosols. The glacial sediments are the product of both local (montane) and regional (Cordilleran) ice advances that channeled into the trench, while loess and well-developed paleosols (brunisols and luvisols) reflect nonglacial and interglacial conditions, respectively. The Tintina Trench exposures provide the most complete record of glaciations for the region. Paleomagnetism, paleosols, and palynology provide age constraints for the geological events. A formal stratigraphic nomenclature is proposed for this region. The name West Tintina Trench Allogroup is assigned to the glacial–interglacial and nonglacial strata that occurs above a major regional Miocene–Pliocene unconformity. The allogroup spans the late Pliocene (3.6 Ma) to middle Pleistocene (0.126 Ma), based on magnetostratigraphy and pollen data. The sequence includes an alluvial deposit at the base, overlain by an extensive sequence of tills and outwash, and capped by loess. Paleosols and weathering horizons occur throughout the sequence. Tintina Trench; Beringia; glacial chronology; magnetostratigraphy; early and middle Pleistocene; Yukon paleoenvironments; Yukon paleosols; Yukon pollen; North American glaciations; West Tintina Trench Allogroup.

Paleomagnetic evidence for multiple late Cenozoic glaciations in the Tintina Trench, west-central Yukon, CanadaThis article is a companion paper to Duk-Rodkin et al., also in this issue.

2010 ◽  
Vol 47 (7) ◽  
pp. 987-1002 ◽  
Author(s):  
René W. Barendregt ◽  
Randolph J. Enkin ◽  
Alejandra Duk-Rodkin ◽  
Judith Baker
Keyword(s):  
Companion Paper ◽  
Opposite Polarity ◽  
Middle Pleistocene ◽  
Late Cenozoic ◽  
West Central ◽  
Matuyama Chron ◽  
Continental Divide ◽  
Normal Polarity ◽  
Brunhes Chron ◽  
Trench Area

The Tintina Trench in west-central Yukon has preserved an extensive record of late Cenozoic preglacial, glacial, and interglacial deposits. These deposits comprise multiple sequences of tills, outwash, loesses, and paleosols. The sediments that were laid down directly by ice (tills) are of both local (montane) and regional (Cordilleran) provenance. The Tintina Trench area was impacted repeatedly by montane ice from the southern Ogilvie Mountains to the northwest (2500 m above sea level (asl)), and also repeatedly along its southern extent by Cordilleran ice from the Selwyn Mountains to the east (2759 m asl), the latter forming the continental divide in this region. We report here the magnetostratigraphy of three sections: Rock Creek (64°13′N, 139°07′W), West Fifteenmile River (64°29′N, 139°55′W), and East Fifteenmile River (64°23′N, 139°48′W). The majority of the units identified at these sections record late Pliocene to mid-Pleistocene glaciations, although relatively thin surficial sequences of late middle Pleistocene to late Pleistocene loesses and tills are present as well. Of the 11 units described in the Tintina Trench, seven have normal polarity, three have reversed polarity, and one has an undefined polarity. These units span about 3.0 million years. It appears that most of the polarity chrons and subchrons of the late Cenozoic are present and that the sequence of six reversals record at least 10 glaciations (three in the Brunhes Chron and seven in the Matuyama Chron), and 11 interglaciations (four in the Brunhes Chron and seven in the Matuyama Chron). The interglacials are recorded as either paleosols or unconformities between glacial or loess units having opposite polarity. While not all Matuyama Chron glacial and interglacial cycles recorded in marine isotopic records are seen on land, the terrestrial records found in the Tintina Trench have thus far proven to be the most complete in terms of the polarity record. While no absolute ages were obtained from the sediments in the trench, the extensive polarity sequence constrains the timing of glaciations to a considerably greater degree than was previously possible for this region. The magnetostratigraphy of the trench sites are compared with the glacial, glaciofluvial, and loessic deposits at the nearby Klondike River valley and Fort Selkirk sites, central Yukon, where tephras and basalts provide absolute ages, and stratigraphic units contain an extensive late Cenozoic climate proxy for northwestern North America (eastern Beringia). In this study, we present new paleomagnetic polarity data and establish a magneto-lithostratigraphy describing preglacial, glacial, and interglacial deposits in the Tintina Trench. These deposits are referred to as the West Tintina Trench Allogroup and provide a broad framework for establishing a paleoclimate record for the northern Canadian Cordillera.

scholarly journals Age limits on Middle Pleistocene glacial sediments from OSL dating, north Norfolk, UK

2008 ◽  
Vol 27 (13-14) ◽  
pp. 1363-1377 ◽  
Author(s):  
Steven M. Pawley ◽  
Richard M. Bailey ◽  
James Rose ◽  
Brian S.P. Moorlock ◽  
Richard J.O. Hamblin ◽  
...  
Keyword(s):  
Osl Dating ◽  
Middle Pleistocene ◽  
Glacial Sediments ◽  
Age Limits

Tectonic and climatic controls on coastal sedimentation: The Late Pliocene–Middle Pleistocene of northeastern Rhodes, Greece

2006 ◽  
Vol 187 (3-4) ◽  
pp. 159-181 ◽  
Author(s):  
Jean-Jacques Cornée ◽  
Pierre Moissette ◽  
Sébastien Joannin ◽  
Jean-Pierre Suc ◽  
Frédéric Quillévéré ◽  
...  
Keyword(s):  
Middle Pleistocene ◽  
Late Pliocene ◽  
Coastal Sedimentation

scholarly journals An optimized multi-proxy, multi-site Antarctic ice and gas orbital chronology (AICC2012): 120–800 ka

2013 ◽  
Vol 9 (4) ◽  
pp. 1715-1731 ◽  
Author(s):  
L. Bazin ◽  
A. Landais ◽  
B. Lemieux-Dudon ◽  
H. Toyé Mahamadou Kele ◽  
D. Veres ◽  
...  
Keyword(s):  
Ice Core ◽  
Ice Cores ◽  
Companion Paper ◽  
Polar Ice ◽  
Uncertainty Range ◽  
Air Content ◽  
Dating Method ◽  
Long Timescales ◽  
Age Constraints ◽  
Mis 5

Abstract. An accurate and coherent chronological framework is essential for the interpretation of climatic and environmental records obtained from deep polar ice cores. Until now, one common ice core age scale had been developed based on an inverse dating method (Datice), combining glaciological modelling with absolute and stratigraphic markers between 4 ice cores covering the last 50 ka (thousands of years before present) (Lemieux-Dudon et al., 2010). In this paper, together with the companion paper of Veres et al. (2013), we present an extension of this work back to 800 ka for the NGRIP, TALDICE, EDML, Vostok and EDC ice cores using an improved version of the Datice tool. The AICC2012 (Antarctic Ice Core Chronology 2012) chronology includes numerous new gas and ice stratigraphic links as well as improved evaluation of background and associated variance scenarios. This paper concentrates on the long timescales between 120–800 ka. In this framework, new measurements of δ18Oatm over Marine Isotope Stage (MIS) 11–12 on EDC and a complete δ18Oatm record of the TALDICE ice cores permit us to derive additional orbital gas age constraints. The coherency of the different orbitally deduced ages (from δ18Oatm, δO2/N2 and air content) has been verified before implementation in AICC2012. The new chronology is now independent of other archives and shows only small differences, most of the time within the original uncertainty range calculated by Datice, when compared with the previous ice core reference age scale EDC3, the Dome F chronology, or using a comparison between speleothems and methane. For instance, the largest deviation between AICC2012 and EDC3 (5.4 ka) is obtained around MIS 12. Despite significant modifications of the chronological constraints around MIS 5, now independent of speleothem records in AICC2012, the date of Termination II is very close to the EDC3 one.

scholarly journals Northern Mediterranean climate since the Middle Pleistocene: a 637 ka stable isotope record from Lake Ohrid (Albania/Macedonia)

2016 ◽  
Vol 13 (6) ◽  
pp. 1801-1820 ◽  
Author(s):  
Jack H. Lacey ◽  
Melanie J. Leng ◽  
Alexander Francke ◽  
Hilary J. Sloane ◽  
Antoni Milodowski ◽  
...  
Keyword(s):  
Climate Change ◽  
Isotope Composition ◽  
Biological Evolution ◽  
Winter Precipitation ◽  
Middle Pleistocene ◽  
Lake Ohrid ◽  
Climate Conditions ◽  
Glacial Sediments ◽  
Core Profile ◽  
Environmental Events

Abstract. Lake Ohrid (Macedonia/Albania) is an ancient lake with unique biodiversity and a site of global significance for investigating the influence of climate, geological, and tectonic events on the generation of endemic populations. Here, we present oxygen (δ18O) and carbon (δ13C) isotope data from carbonate over the upper 243 m of a composite core profile recovered as part of the Scientific Collaboration on Past Speciation Conditions in Lake Ohrid (SCOPSCO) project. The investigated sediment succession covers the past ca. 637 ka. Previous studies on short cores from the lake (up to 15 m, < 140 ka) have indicated the total inorganic carbon (TIC) content of sediments to be highly sensitive to climate change over the last glacial–interglacial cycle. Sediments corresponding to warmer periods contain abundant endogenic calcite; however, an overall low TIC content in glacial sediments is punctuated by discrete bands of early diagenetic authigenic siderite. Isotope measurements on endogenic calcite (δ18Oc and δ13Cc) reveal variations both between and within interglacials that suggest the lake has been subject to palaeoenvironmental change on orbital and millennial timescales. We also measured isotope ratios from authigenic siderite (δ18Os and δ13Cs) and, with the oxygen isotope composition of calcite and siderite, reconstruct δ18O of lake water (δ18Olw) over the last 637 ka. Interglacials have higher δ18Olw values when compared to glacial periods most likely due to changes in evaporation, summer temperature, the proportion of winter precipitation (snowfall), and inflow from adjacent Lake Prespa. The isotope stratigraphy suggests Lake Ohrid experienced a period of general stability from marine isotope stage (MIS) 15 to MIS 13, highlighting MIS 14 as a particularly warm glacial. Climate conditions became progressively wetter during MIS 11 and MIS 9. Interglacial periods after MIS 9 are characterised by increasingly evaporated and drier conditions through MIS 7, MIS 5, and the Holocene. Our results provide new evidence for long-term climate change in the northern Mediterranean region, which will form the basis to better understand the influence of major environmental events on biological evolution within Lake Ohrid.

New and revised magnetostratigraphic age constraints on the Akchagylian (late Pliocene) five-fold expansion of the Caspian Sea.

2021 ◽  
Author(s):  
Sergei Lazarev ◽  
Klaudia Kuiper ◽  
Oriol Oms ◽  
Maia Bukhsianidze ◽  
Davit Vasilyan ◽  
...  
Keyword(s):  
Caspian Sea ◽  
Fold Increase ◽  
Climatic Conditions ◽  
Global Ocean ◽  
Geological Time ◽  
The Caspian Sea ◽  
Late Pliocene ◽  
Age Model ◽  
Radioisotopic Dating ◽  
Age Constraints

&lt;p&gt;The late Pliocene Akchagylian transgression in the Caspian Basin led to a five-fold increase of the Caspian Sea surface water, extending the basin to the vast areas of Central Asia, Caucasian foreland (Kura Basin) and the Russian Plate. It also changed the regional climatic conditions by making the Pliocene glaciation milder. Later, establishment of hydrological connection between the Caspian Sea and the global ocean known as the &amp;#8220;Akchagylian flooding&amp;#8221; enabled active fauna migrations transforming the paleoecology of the region. Despite a relatively well constrained palaeoenvironmental history, the Akchagylian still lacks a univocal age model and two major age constraints exist - the &amp;#8220;long&amp;#8221; (3.6-1.8 Ma) and the &amp;#8220;short&amp;#8221; Akchagylian (2.7-2.1 Ma). In this study, we resolve the age contradictions by magnetostratigraphic and &lt;sup&gt;40&lt;/sup&gt;Ar/&lt;sup&gt;39&lt;/sup&gt;Ar dating of several sections in the Kura Basin. With our new data, we further revise magnetostratigraphy and &lt;sup&gt;40&lt;/sup&gt;Ar/&lt;sup&gt;39&lt;/sup&gt;Ar constraints in 25 sections across the Kura Basin and Turkmenistan. We propose a new unified age model for the Akchagylian Stage: 1. Akchagylian transgression at 2.95&amp;#177;0.02 Ma; 2. Caspian-Arctic connection (2.75&amp;#8211;2.45 Ma); 3. &amp;#8220;Desalinated&amp;#8221; Akchagylian between 2.45-2.13 Ma; 4. Akchagylian-Apsheronian boundary at 2.13 Ma correlated to the Reunion subchron (C2r.1n). Our data shows, that magnetostratigraphy requires a careful assessment of sedimentation rates and support from other proxies such as sedimentology, biostratigraphy and radioisotopic dating. The new ages constrain a much shorter (2.95&amp;#8211;2.1 Ma) Akchagylian than in previously mentioned regional geological time scales (3.6&amp;#8211;1.8 Ma) and strongly appeal to reconsider the ages of numerous archaeological and mammalian sites in the south Caspian region.&lt;/p&gt;

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