Glacial-Marine Sedimentation Processes and Lithofacies of Temperate Tidewater Glaciers, Glacier Bay, Alaska

Over 5000 harbor seals haul out on icebergs calved from tidewater glaciers in Muir and Johns Hopkins inlets in Glacier Bay, Alaska. During June, these sites are used primarily by parous females and pups, and in August, by molting seals. The number of mothers and pups was higher than expected for the total number of seals in Glacier Bay, indicating an immigration of some parturient females from outside Glacier Bay. The number of seals counted varied throughout the day with greatest numbers around midday. In Muir Inlet the number of seals hauled out was positively correlated with percent ice cover. Ice that is suitable for hauling out may presently limit the abundance of seals in this area. The retreat of Muir Glacier has dramatically reduced the ice available to seals and, if it continues, will likely result in the elimination of drift-ice habitat in the near future. Seals from both inside and outside Glacier Bay apparently use ice habitat in Muir and Johns Hopkins inlets when giving birth, when nursing pups, and when moulting for protection from terrestrial and marine predators, and because it is relatively abundant and easily accessible at all tides and times.

Download Full-text

A Model for Sedimentation by Tidewater Glaciers

Annals of Glaciology ◽

10.3189/172756481794352306 ◽

1981 ◽

Vol 2 ◽

pp. 129-134 ◽

Cited By ~ 175

Author(s):

Ross D. Powell

Keyword(s):

Sea Water ◽

Tidewater Glaciers ◽

Glacier Bay ◽

Water Characteristics ◽

Sediment Types ◽

Preliminary Model ◽

Facies Associations ◽

Glacial Dynamics ◽

Iceberg Calving ◽

Channel Constriction

Sampling of sediment from the fjord floor in front of tidewater glaciers in Glacier Bay, Alaska, has provided information about processes in this restricted glacimarine (Dreimanis 1979) setting. Sediment sampling, in conjunction with oceanographic and glacial dynamics data, has also enabled the discrimination of sediment types and their facies associations. Deposits are strongly controlled by: sea-water characteristics, position and sediment discharge of melt-water streams, iceberg calving, and rate of glacierfront retreat.Five distinct facies associations have been found to reflect glacier-fjord regimes. The facies associations and ice-fjord conditions responsible for them form the basis for constructing a preliminary model for glacimarine sedimentation by tidewater glaciers. The model can be used to predict (i) rapid retreat of an actively calving ice front, (ii) slow retreat or stabilization of a calving ice front at a channel constriction, (iii) stabilization of a melting (very rarely calving) ice front when the glacier base is near tidewater elevation, and (iv) large outwash delta progradation into a fjord when the ice front retreats onto land. This model can be used to interpret facies associations found in a stratigraphic record.

Download Full-text

The problem of genesis of quaternary deposits of the Barents Sea as a reflection of the overall crisis of glacial theory

Арктика и Антарктика ◽

10.7256/2453-8922.2020.4.34164 ◽

2020 ◽

pp. 80-102

Author(s):

Rudol'f Borisovich Krapivner

Keyword(s):

High Latitude ◽

Barents Sea ◽

Quaternary Sediments ◽

The Barents Sea ◽

Marine Sedimentation ◽

Seismic Image ◽

Degree Of Consolidation ◽

River Valleys ◽

Acoustic Profiling ◽

Sedimentation Processes

This article continues the discussion on quaternary geology and paleogeography of the vast and well-studied shelf of the Barents Sea. The object this research is the relief and quaternary formations of the Barents shelf. The data of seismic-acoustic profiling and materials of engineering-geological drilling were used. Since the Barents shelf is a high-latitude area of Holocene sedimentation, the author analyzes various aspects of the quaternary sediments genesis, taking into account the geographic zoning of marine sedimentation processes and an increase in the gravitational consolidation of sediments down through the section. The genetic link between the microstructure and the degree of consolidation of clayey sediments with their seismic image was revealed, which was considered in interpretation of seismic profiling materials. Over the Barents shelf, the cover of weakly consolidated sediments of the last marine transgression is separated from the underlying morainelike or pre-quaternary sediments by a diachronous boundary of stratigraphic and sometimes angular unconformity. The transgression is not of glacioeustatic, but of tectonic nature. During the hiatus that preceded it, an erosional relief with river valleys and their tributaries was formed, the main features of which have been preserved in the northern deep-water part of the sea. The conclusion is argued that approbation of the glacial theory on the example of high-latitude Arctic shelf contradicts the facts and main provisions of glaciology, reflecting the overall crisis of this theory.

Download Full-text

Constraining the regional uplift rate of the Corinth Isthmus area (Greece), through biostratigraphic and tectonic data

Zeitschrift für Geomorphologie Supplementary Issues ◽

10.1127/zfg_suppl/2019/0609 ◽

2019 ◽

Vol 62 (2) ◽

pp. 127-142 ◽

Cited By ~ 1

Author(s):

Aggelos Pallikarakis ◽

Ioannis Papanikolaou ◽

Klaus Reicherter ◽

Maria Triantaphyllou ◽

Margarita Dimiza ◽

...

Keyword(s):

Active Faults ◽

Middle Pleistocene ◽

Published Data ◽

Uplift Rate ◽

Slip Rates ◽

Corinth Gulf ◽

Marine Sedimentation ◽

Fault Slip Rates ◽

Uplift Rates ◽

Sedimentation Processes

The eastern Corinth Gulf is constantly uplifted at least since Middle Pleistocene. This uplift is the combined result of the regional uplift and the activity of major active faults which influence the area. These tectonic movements which control the sedimentation processes of the study area resulted in a complex stratigraphy, paleogeography and paleoenvironment of the Corinth Isthmus. Stratigraphy supported with nannofossil biozonation data, demonstrates that marine sedimentation processes occurred during MIS 7 and MIS 5, providing some important constraints regarding the uplift rate of the area. An 0.22 ± 0.12 mm/yr uplift rate is extracted through nannofossils biozonation which is in agreement with published data from U/Th coral dating in a neighboring setting, adding confidence to the measured uplift rates. In order to constrain the regional uplift of the area, the influence of the surrounding active faults has been extracted. The latter has been implemented by extracting the influence of each individual active fault to the study site (using the fault geometry, fault slip-rates, the fault dip and the fault footwall uplift/ hangingwall subsidence ratio), in order to calculate the regional uplift rate. By considering the stratigra- phy and the biostratigraphy of the eastern part of the Corinth Isthmus and by extracting the influence of the active faults, a~0.34 ± 0.04 mm/yr regional uplift is calculated.

Download Full-text

Glacimarine sedimentation processes at Kronebreen and Kongsvegen, Svalbard

Journal of Glaciology ◽

10.3189/002214311798043708 ◽

2011 ◽

Vol 57 (205) ◽

pp. 841-847 ◽

Cited By ~ 22

Author(s):

Laura M. Kehrl ◽

Robert L. Hawley ◽

Ross D. Powell ◽

Julie Brigham-Grette

Keyword(s):

Water Depth ◽

Current Position ◽

Tidewater Glaciers ◽

Glacier Terminus ◽

Gravity Flows ◽

Grounding Line ◽

Relative Water ◽

Iceberg Calving ◽

Reduced Water ◽

Sedimentation Processes

AbstractTidewater glaciers deposit sediment at their terminus, thereby reducing the relative water depth. Reduced water depth can lead to increased glacier stability through decreased rates of iceberg calving, glacier thinning and submarine melting. Here we investigate sedimentation processes at the termini of Kronebreen and Kongsvegen, Svalbard. We mapped the fjord floor bathymetry in August 2009 and calculate sedimentation rates based on our bathymetry and that from a similar study in 2005. A grounding-line fan is developing near the current position of the subglacial stream. An older, abandoned grounding-line fan that likely formed between ∼1987 and 2001 is degrading near the middle of the ice front. Our findings indicate that sediment gravity flows reduce the height of the sediment mound forming at the glacier terminus. The future impact of glacimarine sedimentation processes on glacier stability will depend on the net balance between the observed gravity flows and sediment deposition.

Download Full-text

Tree-ring dates on two pre-Little Ice Age advances in Glacier Bay National Park and Preserve, Alaska, USA

Quaternary Research ◽

10.1016/j.yqres.2011.05.005 ◽

2011 ◽

Vol 76 (2) ◽

pp. 190-195 ◽

Cited By ~ 10

Author(s):

Gregory C. Wiles ◽

Daniel E. Lawson ◽

Eva Lyon ◽

Nicholas Wiesenberg ◽

R. D. D'Arrigo

Keyword(s):

Tree Ring ◽

Ring Width ◽

Ice Age ◽

Tree Ring Chronology ◽

Main Trunk ◽

Southeast Alaska ◽

Tidewater Glaciers ◽

Glacier Bay ◽

Glacier System ◽

Glacial Expansion

AbstractTwo interstadial tree ring-width chronologies from Geikie Inlet, Glacier Bay Southeast, Alaska were built from 40 logs. One of these chronologies has been calendar dated to AD 224–999 (775 yr) crossdating with a living ring-width chronology from Prince William Sound, Alaska. Trees in this chronology were likely killed through inundation by sediments and meltwater from the advancing Geikie Glacier and its tributaries ca. AD 850. The earlier tree-ring chronology spans 545 yr and is a floating ring-width series tied to radiocarbon ages of about 3000 cal yr BP. This tree-ring work indicates two intervals of glacial expansion by the Geikie Glacier system toward the main trunk glacier in Glacier Bay between 3400 and 3000 cal yr BP and again about AD 850. The timing of both expansions is consistent with patterns of ice advance at tidewater glaciers in other parts of Alaska and British Columbia about the same time, and with a relative sea-level history from just outside Glacier Bay in Icy Strait. This emerging tree-ring dated history builds on previous radiocarbon-based glacial histories and is the first study to use tree-ring dating to assign calendar dates to glacial activity for Glacier Bay.

Download Full-text

Glacial marine sedimentation from tidewater glaciers in the Canadian High Arctic

Geological Society of America Special Papers - Glacial marine sedimentation; Paleoclimatic significance ◽

10.1130/spe261-p95 ◽

1991 ◽

pp. 95-106 ◽

Cited By ~ 16

Author(s):

Thomas G. Stewart

Keyword(s):

High Arctic ◽

Canadian High Arctic ◽

Tidewater Glaciers ◽

Marine Sedimentation

Download Full-text

Overpressure Identification Using The Eaton Method on The Gumai Formation of Geragai Graben, Jambi Sub Basin

Proc. Indon. Petrol. Assoc., Digital Technical Conference, 2020 ◽

10.29118/ipa20-sg-180 ◽

2020 ◽

Author(s):

A. O. Marnila

Keyword(s):

Pressure Data ◽

Stratigraphic Sequence ◽

Fine Grained ◽

Marine Sedimentation ◽

Plot Analysis ◽

Significant Reversal ◽

Porosity And Permeability ◽

Upper Level ◽

Type Data ◽

Fine Grained Sand

Geragai graben is located in the South Sumatera Basin. It was formed by mega sequence tectonic process with various stratigraphic sequence from land and marine sedimentation. One of the overpressure indication zones in the Geragai graben is in the Gumai Formation, where the sedimentation is dominated by fine grained sand and shale with low porosity and permeability. The aim of the study is to localize the overpressure zone and to analyze the overpressure mechanism on the Gumai Formation. The Eaton method was used to determine pore pressure value using wireline log data, pressure data (RFT/FIT), and well report. The significant reversal of sonic and porosity log is indicating an overpressure presence. The cross-plot analysis of velocity vs density and fluid type data from well reports were used to analyze the causes of overpressure in the Gumai Formation. The overpressure in Gumai Formation of Geragai graben is divided into two zones, they are in the upper level and lower level of the Gumai Formation. Low overpressure have occurred in the Upper Gumai Formation and mild overpressure on the Lower Gumai Formation. Based on the analyzed data, it could be predicted, that the overpressure mechanism in the Upper Gumai Formation might have been caused by a hydrocarbon buoyancy, whereas in the Lower Gumai Formation, might have been caused by disequilibrium compaction as a result of massive shale sequence.

Download Full-text