Sequence stratigraphy and depositional history of the Baranof Fan: Insights for Cordilleran Ice Sheet outflow to the Gulf of Alaska

2019 ◽  
Vol 132 (1-2) ◽  
pp. 353-372
Author(s):  
Jiajia Zhang ◽  
Sean P.S. Gulick
Keyword(s):  
Deep Sea ◽  
Ice Sheet ◽  
Coupled System ◽  
Gulf Of Alaska ◽  
Coast Range ◽  
Depositional History ◽  
Sediment Distribution ◽  
Sequence Correlation ◽  
History Of ◽  
Cordilleran Ice Sheet

AbstractThe Baranof Fan is one of three large Alaska deep-sea fans that preserve sedimentary records reflecting both tectonic and climatic processes. However, lack of drill sites in the Baranof Fan makes the depositional history across the southeastern Alaska margin still poorly understood. Sequence correlation from the adjacent Surveyor Fan to the Baranof Fan provides updated age constraints on the Baranof Fan evolution history. Results show that both the Baranof and Surveyor Fans are dominantly glacial and initiated ca. 2.8 Ma and expanded rapidly since ca. 1.2 Ma in response to the major glaciation events; these results place the deposition of the Baranof Fan younger than previously thought (ca. 7 Ma). The glacially influenced Baranof Fan contains two sub-fans that are laterally stacked with their depocenters migrating southeastward. Each sub-fan developed multiple channels that young southeastward as channel avulsion, coevolution, and tectonic beheading progressed over the past ∼2.8 m.y. Tectonic reconstruction suggests that the Baranof Fan is sourced from the Coast Range via shelf-crossing troughs near the Chatham Strait and Dixon Entrance and thus represents a major outflow for the Cordilleran Ice Sheet during glaciations; the Chatham Strait is the major conduit that has fed most of the Baranof Fan channels. Comparatively, the Surveyor Fan is sourced predominantly from the St. Elias Range where a confluence of orogenesis and glaciations are a coupled system and only partly from the Coast Range via the Icy Strait. It is concluded that the formation and expansion of the Cordilleran Ice Sheet has determined the timing of the Baranof Fan deposition, yet Pacific–North America strike-slip motion has influenced the Baranof Fan sediment distribution, as previously suggested, via a series of southeastward avulsing channels and resultant southeastward migration of deep-sea depocenters.

scholarly journals Investigating the glacial history of the northern sector of the Cordilleran Ice Sheet with cosmogenic 10Be concentrations in quartz

2010 ◽  
Vol 29 (25-26) ◽  
pp. 3630-3643 ◽  
Author(s):  
Arjen P. Stroeven ◽  
Derek Fabel ◽  
Alexandru T. Codilean ◽  
Johan Kleman ◽  
John J. Clague ◽  
...  
Keyword(s):  
Ice Sheet ◽  
Glacial History ◽  
History Of ◽  
Cordilleran Ice Sheet ◽  
Cosmogenic 10Be ◽  
Northern Sector

scholarly journals Late Pliocene Cordilleran Ice Sheet development with warm northeast Pacific sea surface temperatures

2020 ◽  
Vol 16 (1) ◽  
pp. 299-313 ◽  
Author(s):  
Maria Luisa Sánchez-Montes ◽  
Erin L. McClymont ◽  
Jeremy M. Lloyd ◽  
Juliane Müller ◽  
Ellen A. Cowan ◽  
...  
Keyword(s):  
Ocean Circulation ◽  
Ice Sheet ◽  
Gulf Of Alaska ◽  
Sea Surface ◽  
Early Pleistocene ◽  
Late Pliocene ◽  
Subarctic Pacific ◽  
Cordilleran Ice Sheet ◽  
Forcing Mechanisms ◽  
Atmospheric Co2 Concentrations

Abstract. The initiation and evolution of the Cordilleran Ice Sheet are relatively poorly constrained. International Ocean Discovery Program (IODP) Expedition 341 recovered marine sediments at Site U1417 in the Gulf of Alaska (GOA). Here we present alkenone-derived sea surface temperature (SST) analyses alongside ice-rafted debris (IRD), terrigenous, and marine organic matter inputs to the GOA through the late Pliocene and early Pleistocene. The first IRD contribution from tidewater glaciers in southwest Alaska is recorded at 2.9 Ma, indicating that the Cordilleran Ice Sheet extent increased in the late Pliocene. A higher occurrence of IRD and higher sedimentation rates in the GOA during the early Pleistocene, at 2.5 Ma, occur in synchrony with SSTs warming on the order of 1 ∘C relative to the Pliocene. All records show a high degree of variability in the early Pleistocene, indicating highly efficient ocean–climate–ice interactions through warm SST–ocean evaporation–orographic precipitation–ice growth mechanisms. A climatic shift towards ocean circulation in the subarctic Pacific similar to the pattern observed during negative Pacific Decadal Oscillation (PDO) conditions today occurs with the development of more extensive Cordilleran glaciation and may have played a role through increased moisture supply to the subarctic Pacific. The drop in atmospheric CO2 concentrations since 2.8 Ma is suggested as one of the main forcing mechanisms driving the Cordilleran glaciation.

Time of Maximum Late Wisconsin Glaciation, West Coast of Canada

1990 ◽  
Vol 34 (3) ◽  
pp. 282-295 ◽  
Author(s):  
Bertrand Blaise ◽  
John J. Clague ◽  
Rolf W. Mathewes
Keyword(s):  
West Coast ◽  
North Pacific ◽  
Deep Sea ◽  
North Pacific Ocean ◽  
Ice Sheet ◽  
Late Glacial ◽  
Western Margin ◽  
The Core ◽  
Queen Charlotte Islands ◽  
Cordilleran Ice Sheet

AbstractNew data from a deep-sea core in the eastern North Pacific Ocean indicate that the western margin of the Late Wisconsin Cordilleran Ice Sheet began to retreat from its maximum position after 15,600 yr B.P. Ice-rafted detritus is present in the core below the 15,600 yr B.P. level and was deposited while lobes of the Cordilleran Ice Sheet advanced across the continental shelf in Queen Charlotte Sound, Hecate Strait, and Dixon Entrance. The core data are complemented by stratigraphic evidence and radiocarbon ages from Quaternary exposures bordering Hecate Strait and Dixon Entrance. These indicate that piedmont lobes reached the east and north shores of Graham Island (part of the Queen Charlotte Islands) between about 23,000 and 21,000 yr B.P. Sometime thereafter, but before 15,000–16,000 yr B.P., these glaciers achieved their greatest Late Wisconsin extent. Radiocarbon ages of late-glacial and postglacial sediments from Queen Charlotte Sound, Hecate Strait, and adjacent land areas show that deglaciation began in these areas before 15,000 yr B.P. and that the shelf was completely free of ice by 13,000 yr B.P.

scholarly journals Zechstein Salt Denmark. Salt Research Project EFP-81. Volume II: Stratigraphy

1984 ◽  
Vol 1 (2) ◽  
pp. 1-110
Author(s):  
Fritz Lyngsie Jacobsen ◽  
Martin Sønderholm ◽  
Niels Springer
Keyword(s):  
Rock Salt ◽  
Deep Sea ◽  
Major Part ◽  
Fine Sand ◽  
General Description ◽  
Shallow Sea ◽  
Depositional History ◽  
Bituminous Shale ◽  
History Of ◽  
Zechstein Salt

In the Danish part of the Norwegian-Danish Basin 4 cycles of Zechstein evaporites are described. The oldest cycle Z1 is composed of bituminous shale, carbonates, anhydrite, rock salt and, in one well, a potassium mineralization. The older cycle Z2 is composed of bituminous shale, carbonate, anhydrite, rock salt and magnesium - potassium minerals. These latter minerals make up the Veggerby zone, which resembles the German Floz Stassfurt. The younger cycle Z3 is composed of shale, fine sand, subordinate anhydrite and reddish coloured rock salts with two minor potassium mineralizations. The youngest cycle Z4 is composed of shaly sands, subordinate anhydrite and rock salt. No younger cycles are observed. The depositional history of the Danish Zechstein evaporites is given. A strong subsidence of the Norwegian-Danish Basin was initiated at the end of the Rotliegendes and the beginning of the Zechstein. During Zechstein the basin was filled with relatively deep sea sedimentated evaporites in Z1 and in the major part of Z2. From the termination of Z2 to the end of Z4 shallow sea sediments were the dominating type. In connection with the general description is given an outline of the movements of the salt with pillow stage in Late Bunter and with the diapiric movements from Jurassic to recently. Cap rocks are shortly discussed. A summary of the drilling practise is given. The economic geology in relation to the Zechstein is discussed with respect to hydrocarbons, potash and different uses of rock salt.

Phasing of millennial-scale climate variability in the Pacific and Atlantic Oceans

Science ◽  
2020 ◽  
Vol 370 (6517) ◽  
pp. 716-720 ◽  
Author(s):  
Maureen H. Walczak ◽  
Alan C. Mix ◽  
Ellen A. Cowan ◽  
Stewart Fallon ◽  
L. Keith Fifield ◽  
...  
Keyword(s):  
North Pacific ◽  
Ice Sheet ◽  
Gulf Of Alaska ◽  
Ocean Dynamics ◽  
Laurentide Ice Sheet ◽  
Close Coupling ◽  
Carbon 14 ◽  
The Pacific ◽  
Cordilleran Ice Sheet ◽  
Millennial Scale

New radiocarbon and sedimentological results from the Gulf of Alaska document recurrent millennial-scale episodes of reorganized Pacific Ocean ventilation synchronous with rapid Cordilleran Ice Sheet discharge, indicating close coupling of ice-ocean dynamics spanning the past 42,000 years. Ventilation of the intermediate-depth North Pacific tracks strength of the Asian monsoon, supporting a role for moisture and heat transport from low latitudes in North Pacific paleoclimate. Changes in carbon-14 age of intermediate waters are in phase with peaks in Cordilleran ice-rafted debris delivery, and both consistently precede ice discharge events from the Laurentide Ice Sheet, known as Heinrich events. This timing precludes an Atlantic trigger for Cordilleran Ice Sheet retreat and instead implicates the Pacific as an early part of a cascade of dynamic climate events with global impact.

Quaternary stratigraphy and history, Williams Lake, British Columbia

1987 ◽  
Vol 24 (1) ◽  
pp. 147-158 ◽  
Author(s):  
John J. Clague
Keyword(s):  
British Columbia ◽  
Late Quaternary ◽  
Ice Sheet ◽  
Stream Channels ◽  
Valley Fill ◽  
Braided Streams ◽  
History Of ◽  
Late Wisconsinan ◽  
Cordilleran Ice Sheet ◽  
Sand And Gravel

Thick valley-fill sediments in the vicinity of Williams Lake, British Columbia, provide a detailed record of the late Quaternary history of an area near the centre of the former Cordilleran Ice Sheet. Stratigraphic units assigned to the late Wisconsinan Fraser Glaciation, the preceding (penultimate) glaciation, and the present interglaciation are described. Especially noteworthy are (1) thick units of sand and gravel deposited by braided streams, perhaps during periods of ice-sheet growth; and (2) complex glaciolacustrine sediments that accumulated in ice-dammed lakes during periods of deglaciation.Glaciers from the Coast and Cariboo mountains coalesced and flowed north over central British Columbia during late Wisconsinan time. Fraser Glaciation advance sediments and older Pleistocene deposits were partially removed by this ice sheet, and the eroded remnants were mantled with till. At the end of the Fraser Glaciation, the Cordilleran Ice Sheet downwasted and retreated southward along an irregular front across the study area. Parts of the ice sheet stagnated and disintegrated into tongues confined to valleys. Sediment carried by melt streams flowing from decaying ice masses was deposited in glacial lakes, in stream channels, and on floodplains.

scholarly journals Sediment Layers Pinpoint Periods of Climatic Change

Eos ◽  
2020 ◽  
Vol 101 ◽  
Author(s):  
Katherine Kornei
Keyword(s):  
Pacific Ocean ◽  
Climatic Change ◽  
Sediment Cores ◽  
Ice Sheet ◽  
Gulf Of Alaska ◽  
The Pacific ◽  
The Pacific Ocean ◽  
Cordilleran Ice Sheet ◽  
Sediment Layers

Researchers studying sediment cores from the Gulf of Alaska have pinpointed when the Cordilleran Ice Sheet, now extinct, disgorged icebergs into the Pacific Ocean.

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