Stratigraphy, age, and paleogeography of the Eocene Chuckanut Formation, northwest Washington

1984 ◽  
Vol 21 (1) ◽  
pp. 92-106 ◽  
Author(s):  
Samuel Y. Johnson
Keyword(s):  
Large Scale ◽  
Middle Eocene ◽  
Alluvial Fan ◽  
Fluvial System ◽  
Upper Eocene ◽  
Meandering River ◽  
The North ◽  
River Deposits ◽  
Metamorphic Terranes ◽  
Eastern Washington

The Eocene Chuckanut Formation of Washington's North Cascades comprises as much as 6000 m of alluvial strata and is one of the thickest nonmarine sequences in North America. It is exposed in several disconnected outcrop belts that are remnants of what was probably an extensive fluvial system in western Washington. In this study, seven stratigraphic members are defined in the main outcrop belt of the Chuckanut Formation near the town of Bellingham. Their ages, based on fission-track zircon dates, palynologic studies, and correlation by mapping, extend from the Early to the Late Eocene.Three types of fluvial systems contributed to the Chuckanut Formation and are distinguished on the basis of their lithology, sedimentology, and petrology. The first comprises fine-load meandering-river deposits of the Lower Eocene Bellingham Bay Member and the Middle Eocene Slide Member. Sandstones are arkosic and had their main source in rapidly uplifted, high-grade metamorphic terranes in eastern Washington. The second type comprises braided- and coarse-load meandering-river deposits of the Middle to Upper Eocene Padden Member. The Padden Member occurs only in the western part of the outcrop belt and was derived form the Coast Plutonic Complex of southern British Columbia to the north. Sandstones are arkosic but are richer in lithic fragments than sandstones of the underlying Bellingham Bay Member and interfingering Slide Member. The third fluvial-system type comprises conglomerate-rich braided-river and alluvial-fan deposits of the lower Middle Eocene Governors Point Member and the Middle to Upper (?) Eocene Maple Falls, Warnick, and Bald Mountain members. Sandstones from these units are both lithic and arkosic. These strata were locally derived from uplifts on the northern basin margin.The petrology of down-basin correlatives of the Chuckanut Formation on the northeast Olympic Peninsula is incompatible with derivation through the Chuckanut fluvial system. This petrologic contrast supports a model for large-scale Eocene dextral offsets in the continental margin of Washington.

scholarly journals Late oligocene–early miocene shortening in the Thrace Basin, northern Aegean

2021 ◽  
Author(s):  
Ümitcan Erbil ◽  
Aral I. Okay ◽  
Aynur Hakyemez
Keyword(s):  
Large Scale ◽  
Middle Eocene ◽  
Early Miocene ◽  
Fold Axis ◽  
Late Oligocene ◽  
The Balkans ◽  
Sedimentary Sequences ◽  
The North ◽  
Early Oligocene ◽  
Thrace Basin

AbstractLate Cenozoic was a period of large-scale extension in the Aegean. The extension is mainly recorded in the metamorphic core complexes with little data from the sedimentary sequences. The exception is the Thrace Basin in the northern Aegean, which has a continuous record of Middle Eocene to Oligocene marine sedimentation. In the Thrace Basin, the Late Oligocene–Early Miocene was characterized by north-northwest (N25°W) shortening leading to the termination of sedimentation and formation of large-scale folds. We studied the stratigraphy and structure of one of these folds, the Korudağ anticline. The Korudağ anticline has formed in the uppermost Eocene–Lower Oligocene siliciclastic turbidites with Early Oligocene (31.6 Ma zircon U–Pb age) acidic tuff beds. The turbidites are underlain by a thin sequence of Upper Eocene pelagic limestone. The Korudağ anticline is an east-northeast (N65°E) trending fault-propagation fold, 9 km wide and 22 km long and with a subhorizontal fold axis. It is asymmetric with shallowly-dipping northern and steeply-dipping southern limbs. Its geometry indicates about 1 km of shortening in a N25°W direction. The folded strata are unconformably overlain by Middle Miocene continental sandstones, which constrain the age of folding. The Korudağ anticline and other large folds in the Thrace Basin predate the inception of the North Anatolian Fault (NAF) by at least 12 myr. The Late Oligocene–Early Miocene (28–17 Ma) shortening in the Thrace Basin and elsewhere in the Balkans forms an interlude between two extensional periods, and is probably linked to changes in the subduction dynamics along the Hellenic trench.

Transgressive Upper Eocene in Palestine

1943 ◽  
Vol 80 (3) ◽  
pp. 107-110
Author(s):  
M. Avnimelech
Keyword(s):  
Middle Eocene ◽  
Upper Eocene ◽  
The North ◽  
Upper Oligocene ◽  
North Eastern ◽  
Eastern Border

Several years ago I wrote a number of papers on the results of my investigations in a synclinal area near Megiddo, south-east of Mount Carmel, which I called “ the syncline of Megiddo ”. In the thick Eocene series of this syncline two distinct horizons of Lower and Upper Lutetian have been recognized. Above the Lutetian beds some patches of transgressive Upper Oligocene are preserved. Unfortunately the publications were based on investigations of only the north-eastern border of the whole synclinal region, further field explorations having been made impossible by the riots in 1936−39. In the summer of 1942 I renewed my fieldwork, which has led to a discovery of an Upper Eocene transgression over a probable Middle Eocene series.

Late Jurassic - Early Cretaceous paleoenvironmental evolution of the Transbaikal basins (SE Siberia): implications for the Mongol-Okhotsk orogeny

2017 ◽  
Vol 188 (1-2) ◽  
pp. 9 ◽  
Author(s):  
Marc Jolivet ◽  
Anastasia Arzhannikova ◽  
Andrei Frolov ◽  
Sergei Arzhannikov ◽  
Natalia Kulagina ◽  
...  
Keyword(s):  
Early Cretaceous ◽  
Middle Jurassic ◽  
Late Jurassic ◽  
Tectonic Setting ◽  
Alluvial Fan ◽  
Crustal Thickening ◽  
Compressive Deformation ◽  
Transbaikal Region ◽  
Meandering River ◽  
The North

The Late Jurassic - Early Cretaceous tectonic evolution of SE Siberia was marked by the closure of the Mongol-Okhotsk ocean. While this geodynamic event led to compressive deformation and denudation in a wide area encompassing the North-Altay, Sayan and Baikal Patom ranges, it was contemporaneous to widespread extension from the Transbaikal region situated immediately north of the suture zone to the Pacific plate, affecting eastern Mongolia and northeastern China. In this study we review the paleontological and sedimentological data available in the Russian literature and provide new macro-floral and palynological data from the Mesozoic sediments of three Transbaikal basins. These data are used to describe the paleoenvironmental and paleoclimatic evolution of the Transbaikal area in order to assess the topographic evolution of the region in relation with the closure of the Mongol-Okhotsk ocean. We establish that the Transbaikal basins evolved in a continuously extensional tectonic setting from at least the Early-Middle Jurassic to the Early Cretaceous. The associated sedimentary environments are characterized by retrogradation from alluvial fan–braided river dominated systems prevailing during the Early to Middle Jurassic initial opening of the basins to meandering river– lacustrine systems that developed during the Late Jurassic - Early Cretaceous interval. No evidence of high relief topography was found and we conclude that, while compression and denudation occurred in the North Altai, Sayan and Patom ranges, in the Transbaikal region, the docking of the Mongolia-North China continent to Siberia was a “soft collision” event, possibly involving a major strike-slip displacement that did not lead to an orogenic event implying strong compressive deformation, crustal thickening and topography building.

Paleoenvironments, paleoclimates and sequences of Westphalian deposits of Lorraine coal basin (Upper Carboniferous, NE France)

2005 ◽  
Vol 176 (3) ◽  
pp. 301-315 ◽  
Author(s):  
Alain Izart ◽  
Christian Palain ◽  
Fabrice Malartre ◽  
Stéphanie Fleck ◽  
Raymond Michels
Keyword(s):  
Flood Plain ◽  
Alluvial Fan ◽  
Well Logs ◽  
Water Flooding ◽  
Cylindrical Shape ◽  
Braided River ◽  
Coal Basin ◽  
Meandering River ◽  
Period 2 ◽  
River Deposits

Abstract Facies and sequences of the Westphalian C are identified in cores and well logs of three boreholes and three seismic lines supplied by Conoco-Phillips from the Lorraine coal Basin. The lithofacies associations suggest various paleoenvironments and sequences during the Westphalian C. Decameter-thick sedimentary bodies display alluvial fan deposits in the northwestern border of the basin (Chaumont borehole). Decametric sedimentary bodies constituted either of conglomeratic and sandy facies with cylindrical shape in well logs represent braided river deposits, or alternations of fining and coarsening upward sequences with sandy, silty and clayey facies with bell and funnel shapes in well log correspond to meander river and lacustrine deltaic deposits in the Saulcy and Lorettes boreholes. Three fining upward third order sequences in the center of the basin in the Lorettes and Saulcy boreholes represent a period 1 with braided river deposits, a period 2 with flood plain, lake and meandering river deposits and a period 3 with anastomosed or meandering river deposits. Period 1 is correlated with a subsidence period in the basin and uplift of the borders, period 2 with the maximum fresh water flooding period with flood plain or lake deposits and period 3 with the filling period. The seismic profiles of Conoco-Phillips confirm the tectonic structures described by previous authors in Lorraine Basin. We agree that this basin was a strike-slip basin as demonstrated by previous authors with depocenters near the South Hunsrück and Metz faults from the Westphalian to the Permian. Biomarkers show that paleoclimate changes (wet/dry) of weak amplitude in the equatorial climate could also modify the sedimentation of this basin and act on sequences of second order.

Sedimentation and tectonics of the lower and middle Eocene Swauk Formation in eastern Swauk Basin, central Cascades, central Washington

1988 ◽  
Vol 25 (7) ◽  
pp. 1020-1036 ◽  
Author(s):  
Stephen B. Taylor ◽  
Samuel Y. Johnson ◽  
Gregory T. Fraser ◽  
James W. Roberts
Keyword(s):  
Pacific Northwest ◽  
Middle Eocene ◽  
Sediment Accumulation ◽  
Strike Slip ◽  
Alluvial Fan ◽  
Meandering River ◽  
Early Tertiary ◽  
The Pacific ◽  
River Meandering ◽  
Stratigraphic Thickness

The Swauk Basin lies between the Straight Creek and Entiat–Leavenworth fault systems in the central Cascades of Washington and is one of several early Tertiary strike-slip basins in the Pacific Northwest. In this paper, seven informal stratigraphic units are recognized in the lowest portion of the basin fill—the lower and middle Eocene Swauk Formation—in the eastern part of the basin. These units have a stratigraphic thickness of more than 4800 m and were deposited in alluvial fan, braided river, meandering river(?), lacustrine-deltaic, and lacustrine environments. Rapid facies changes and reversals in paleocurrent directions indicate numerous tectonically controlled drainage reorganizations. Sediments were mainly derived from crystalline rocks to the east, north, and west (?), and sediment accumulation rates were high (about 64 cm/1000 years). The Leavenworth fault has a complex history and, periodically, formed the eastern margin of Swauk Basin. During the final phases and shortly after deposition of the Swauk Formation, the vertical sense of slip on the Leavenworth fault reversed itself and the trace of the fault shifted westward, leading to formation of the Chiwaukum Graben. Following deposition, the Swauk Formation was deformed into west-northwest-trending folds and then intruded by north–northeast-trending dike swarms. Based on similarities with other well-documented strike-slip basins, we conclude that strike-slip faulting was the main control on the deposition and deformation of the Swauk Formation.

River Environments, Climate Change, and Human Impact

2005 ◽  
Author(s):  
Eduard Koster
Keyword(s):  
North Sea ◽  
Large Scale ◽  
Western Europe ◽  
Management Practices ◽  
Drainage System ◽  
River System ◽  
Fluvial System ◽  
The North ◽  
The North Sea ◽  
The Baltic

In this chapter a short overview of the evolution, geomorphological expression, sedimentary records, and discharge and sediment regimes of the major rivers in western Europe is presented. The rivers Elbe, Weser, Rhine, Meuse, Scheldt, Seine, Loire, Garonne, Rhône, and Danube will be separately reviewed but not necessarily in this order and not with equal attention. Emphasis is placed on the Quaternary record and most issues are exemplified by a discussion on phenomena and processes in the Rhine–Meuse delta. As almost all these rivers are strongly influenced by man’s activities, attention is also focused on river management practices, both in a historic context and at present. Finally, modern concepts and plans concerning river conservation and rehabilitation are briefly examined. The foundations of the modern drainage system in north-western Europe were laid in the Miocene when earth movements associated with Alpine orogenesis and the opening of the North Atlantic were at their height (Gibbard 1988). During the Late Tertiary–Early Quaternary the North Sea basin was dominated by an extensive fluvial system that drained the Fennoscandian and Baltic shield through the present Baltic Sea (Overeem et al. 2001; Fig. 6.2). The dimensions of this (former) drainage system were enormous; through empirical relationships based on recent fluvio-deltaic systems the drainage area is estimated to have been in the order of 1.1 × 106 km2. Cenozoic marine and fluvial sediments reach a thickness of more than 3,500 m in the North Sea basin. Quaternary sediments with a thickness of over 1,000 m imply a tenfold increase in sedimentation during this period in comparison to the Tertiary infilling. The fluvial system of Miocene to Middle Pleistocene age has been referred to as the Baltic River system (Bijlsma 1981). It is also designated as the Eridanos delta system by Overeem et al. (2001) named after the legendary Eridanos river in northern Europe mentioned in Greek records (7th century BC). In a seismo-stratigraphic study Overeem et al. (2001) have documented the large-scale basin-fill architecture in terms of external forcing by tectonics, sea-level variations, and climate. The development of this drainage system is attributed to the simultaneous Neogene uplift of the Fennoscandian Shield and the accelerated subsidence of the North Sea basin.

I.— Notes on an Expedition to the Fayûm, Egypt, with Descriptions of Some New Mammals

1903 ◽  
Vol 10 (8) ◽  
pp. 337-343 ◽  
Author(s):  
C. W. Andrews
Keyword(s):  
Middle Eocene ◽  
Upper Eocene ◽  
Large Collection ◽  
The North ◽  
Lake Beds

In the following note I propose to give a brief account of the chief results obtained during an expedition to the Fayûm in the early part of the present year (1903). The localities in which collections were made lie to the north of the lake Birket-el-Kerun, and are almost the same as those examined on previous occasions. Practically nothing was found in the Middle Eocene beds, but from those of Upper Eocene age a fairly large collection of vertebrate remains, including several new forms, was obtained. A few interesting tilings were also found in the Quaternary lake-beds in the neighbourhood of Schweinfurth's Temple (Qasr-es-Sagha); these will be referred to more fully below.

Les limites septentrionales de l'Eocene du bassin d'Aquitaine

1956 ◽  
Vol S6-VI (1-3) ◽  
pp. 211-219
Author(s):  
Henri Schoeller
Keyword(s):  
Middle Eocene ◽  
Far East ◽  
General Tendency ◽  
Upper Eocene ◽  
The North ◽  
Aquitaine Basin

Abstract Examination of all available borings shows that in the Aquitaine basin, France, the marine Lutetian (Eocene) transgression extended as far east as Monsegur, and that continental Lutetian beds were deposited around the edges of Cretaceous outcrops to the north and east. Continental sedimentation was essentially detrital--coarse sands and gravels. Although marine Lutetian beds overlap marine Paleocene strata toward the east, their northern limits are essentially the same. This has been found to be a general tendency of Tertiary seas in the Aquitaine basin. In the upper Eocene the sea retreated, but equivalent extensive continental sediments are rarely as coarse as those of the middle Eocene.

Recent and ancient fluvial deposition systems in the Amazonian foreland basin, Peru

1992 ◽  
Vol 129 (3) ◽  
pp. 293-306 ◽  
Author(s):  
Matti Räsänen ◽  
Ron Neller ◽  
Jukka Salo ◽  
Högne Jungner
Keyword(s):  
Large Scale ◽  
Amazon Basin ◽  
Drainage System ◽  
Foreland Basin ◽  
Depositional Environments ◽  
Alluvial Fan ◽  
Fluvial System ◽  
Climatic Oscillations ◽  
Northern Peru ◽  
Foreland Deformation

AbstractStill active Sub-Andean foreland deformation is suggested to have syndepositionally modified the fluvial depositional environments in the Peruvian Amazonian foreland basin throughout Neogene-Quaternary time. Modern fluvial aggradation continues to proceed on a large scale (c. 120 000 km2) in two differing depositional systems. Firstly, various multistoried floodbasin deposits are derived from the meandering and anastomosing rivers within the subsiding intraforeland basins. Secondly, in the northern part of the Pastaza-Marañon basin the largest known Holocene alluvial fan-like formation (c. 60 000 km2) composed of reworked, volcaniclastic debris derived from active Ecuadorian volcanoes, has been identified.The widespread, poorly known, dissected surface alluvium (terra firme) which covers the main part of the Peruvian Amazonian foreland basin shows further evidence of long-term foreland deformation, and terraces indicate both the effects of tectonism and Pleistocene climatic oscillations. In northern Peru, the surface alluvium was deposited by a Tertiary fluvial system with palaeocurrents to the west and northwest into the Andean foreland basin. In southern Peru, the respective surficial alluvium was part of a post-Miocene fluvial system flowing northeast into the main Amazon basin. Both systems were gradually abandoned when the eastward migrating Andean foreland deformation led to the more distinctive partitioning of the intraforeland basins, and the modern drainage system was created.

Why Has There Been No People’s Power Rebellion in North Korea?

2018 ◽  
pp. 1-34
Author(s):  
Andrew Jackson
Keyword(s):  
Rural Areas ◽  
North Korea ◽  
Large Scale ◽  
Political Elite ◽  
Information Control ◽  
Al Jazeera ◽  
The North ◽  
New Information ◽  
Effective System ◽  
The Right

One scenario put forward by researchers, political commentators and journalists for the collapse of North Korea has been a People’s Power (or popular) rebellion. This paper analyses why no popular rebellion has occurred in the DPRK under Kim Jong Un. It challenges the assumption that popular rebellion would happen because of widespread anger caused by a greater awareness of superior economic conditions outside the DPRK. Using Jack Goldstone’s theoretical expla-nations for the outbreak of popular rebellion, and comparisons with the 1989 Romanian and 2010–11 Tunisian transitions, this paper argues that marketi-zation has led to a loosening of state ideological control and to an influx of infor-mation about conditions in the outside world. However, unlike the Tunisian transitions—in which a new information context shaped by social media, the Al-Jazeera network and an experience of protest helped create a sense of pan-Arab solidarity amongst Tunisians resisting their government—there has been no similar ideology unifying North Koreans against their regime. There is evidence of discontent in market unrest in the DPRK, although protests between 2011 and the present have mostly been in defense of the right of people to support themselves through private trade. North Koreans believe this right has been guaranteed, or at least tacitly condoned, by the Kim Jong Un government. There has not been any large-scale explosion of popular anger because the state has not attempted to crush market activities outright under Kim Jong Un. There are other reasons why no popular rebellion has occurred in the North. Unlike Tunisia, the DPRK lacks a dissident political elite capable of leading an opposition movement, and unlike Romania, the DPRK authorities have shown some flexibility in their anti-dissent strategies, taking a more tolerant approach to protests against economic issues. Reduced levels of violence during periods of unrest and an effective system of information control may have helped restrict the expansion of unrest beyond rural areas.

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