scholarly journals New geological framework for Western Amazonia (Brazil) and implications for biogeography and evolution

2005 ◽  
Vol 63 (1) ◽  
pp. 78-89 ◽  
Author(s):  
Dilce de Fátima Rossetti ◽  
Peter Mann de Toledo ◽  
Ana Maria Góes
Keyword(s):  
Image Interpretation ◽  
Flood Plain ◽  
Climatic Conditions ◽  
Early Pleistocene ◽  
Fluvial System ◽  
Depositional History ◽  
Lake System ◽  
History Of ◽  
Amazon Biodiversity

Although many of the current hypotheses to explain the origin and distribution of the Amazon biodiversity has been based directly or indirectly on geological data, the reconstruction of the geological history of the Amazon region is still inadequate to analyze its relationship with the biodiversity. This work has the main goal to characterize the sedimentary successions formed in the Brazilian Amazon in the Neogene-Quaternary discussing the evolution of the depositional systems through time and analyzing their main controlling mechanisms in order to fill up this gap. Radar image interpretation, sedimentological studies, and radiocarbon dating allowed the mapping of Plio-Pleistocene to Holocene units along the Solimões-Amazonas River, Brazil. This integrated work led to the characterization of five sedimentary successions overlying Miocene deposits of the Solimões/Pebas Formation, which include the following: Içá Formation (Plio-Pleistocene), deposits Q1 (37,400–43,700 14C yr B.P.), deposits Q2 (27,200 14C yr B.P.), deposits Q3 (6730–2480 14C yr B.P.), and deposits Q4 (280–130 14C yr B.P.). These deposits occur mostly to the west of Manaus, forming NW–SE elongated belts that are progressively younger from SW to NE, indicating a subsiding basin with a depocenter that migrated to the NE. The reconstruction of the depositional history is consistent with significant changes in the landscapes. Hence, the closure of a large lake system at the end of the Miocene gave rise to the development of a Plio-Pleistocene fluvial system. This was yet very distinct from the modern drainage, with shallow, energetic, highly migrating, braided to anastomosed channels having an overall northeast outlet. This fluvial system formed probably under climatic conditions relatively drier than today's. During the early Pleistocene, there was pronounced erosion, followed by a renewed depositional phase ca. 40,000 14C yr B.P., with the development of prograding lobes and/or crevasse splays associated with a lake system (i.e., fan-delta) and/or fluvial flood plain areas. After a period of erosion, a fluvial system with eastward draining channels started to develop at around 27,000 14C yr B.P. The fluvial channels were overflooded in mid-Holocene time. This flooding is attributed to an increased period of humidity, with a peak between 5000 and 2500 14C yr B.P. The data presented herein support that, rather than being a monotonous area, the Amazonia was a place with frequent changes in landscape throughout the Neogene-Quaternary, probably as a result of climatic and tectonic factors. We hypothesize that these changes in the physical environment stressed the biota, resulting in speciation and thus had a great impact on modern biodiversity.

THE DEPOSITIONAL HISTORY OF A PORTION OF THE NORTH PERTH BASIN—A SINGLE WELL DIPMETER ANALYSIS

1971 ◽  
Vol 11 (1) ◽  
pp. 90
Author(s):  
K. J. Bird ◽  
W. F. Coleman ◽  
H. Crocker
Keyword(s):  
First Generation ◽  
Source Area ◽  
Lower Triassic ◽  
Flood Plain ◽  
Upper Jurassic ◽  
Lower Jurassic ◽  
Depositional History ◽  
The North ◽  
Single Well ◽  
History Of

Four-arm dipmeter interpretation has been integrated with other wireline logs, lithologic and palaeontologic data, and regional geology to arrive at a history of the deposition in a portion of the North Perth Basin.The Permian sediments were deposited in a moderate to low energy, paralic to marine environment. They were unconformably overlain by a thin transgressive Lower Triassic sand and deepwater marine shale. The Middle Triassic sediments were deposited as a regressive marine sequence under the influence of a strong southwesterly uplift, and culminated in piedmont talus deposits of Upper Triassic age.In the Lower Jurassic this area evolved through a flood-plain environment to a paralic environment with a northeast-southwest oriented coastline and a northern source area. During the Middle Jurassic gentle crustal movements, coupled with an increasingly active northern and eastern source area, resulted in several cycles of nearshore deposition, and finally a marine transgression.Subsequent violent tectonic uplift to the east in the Upper Jurassic produced massive first generation sands which were deposited in a mainly continental environment.

scholarly journals The geometry and stratigraphic position of the Maassluis Formation (western Netherlands and southeastern North Sea)

2004 ◽  
Vol 83 (2) ◽  
pp. 93-99 ◽  
Author(s):  
H.S.M. Jansen ◽  
J. Huizer ◽  
J.W.A. Dijkmans ◽  
C. Mesdag ◽  
J.E. van Hinte
Keyword(s):  
Coarse Grained ◽  
Early Pleistocene ◽  
The West ◽  
Depositional History ◽  
Offshore Area ◽  
Coastal Marine ◽  
Subtidal Environment ◽  
Stratigraphic Position ◽  
History Of ◽  
River Deposits

AbstractThe geometry and depositional history of the Maassluis Formation is described from an East-West oriented transect located in the west-central Netherlands and P- and Q-blocks in the Dutch offshore area. The Late Pliocene to Early Pleistocene Maassluis Formation was deposited under near coastal marine conditions. Two distinct facies are distinguished: (1) medium grained sands with a blocky GR/SP-log pattern that were deposited under intertidal and aeolian conditions and (2) medium to coarse grained sands deposited in a subtidal environment showing a clear coarsening upward trend. The lower part of the Maassluis Formation is laterally equivalent to the shallow marine Oosterhout Formation and gets progressively younger towards the West. The upper part is lateral equivalent to estuarine and mudflat deposits (Balk Member, c.q. Peize Formation) in the central part of The Netherlands and to river deposits (Peize Formation) further to the East.

Depositional history of the Miocene Lake Sinj (Dinaride Lake System, Croatia): a long-lived hard-water lake in a pull-apart tectonic setting

2008 ◽  
Vol 41 (3) ◽  
pp. 431-452 ◽  
Author(s):  
Oleg Mandic ◽  
Davor Pavelić ◽  
Mathias Harzhauser ◽  
Jožica Zupanič ◽  
Doris Reischenbacher ◽  
...  
Keyword(s):  
Tectonic Setting ◽  
Hard Water ◽  
Depositional History ◽  
Lake System ◽  
Water Lake ◽  
History Of

Depositional history of the fluvial Lower Carboniferous Sortebakker Formation, Wandel Sea Basin, eastern North Greenland

2000 ◽  
pp. 65-77 ◽  
Author(s):  
Finn Dalhoff ◽  
Lars Stemmerik
Keyword(s):  
Flood Plain ◽  
South Coast ◽  
Facies Association ◽  
Depositional History ◽  
Lower Carboniferous ◽  
Depositional System ◽  
Facies Associations ◽  
History Of ◽  
Different Parts ◽  
North Greenland

NOTE: This article was published in a former series of GEUS Bulletin. Please use the original series name when citing this article, for example: Dalhoff, F., & Stemmerik, L. (2000). Depositional history of the fluvial Lower Carboniferous Sortebakker Formation, Wandel Sea Basin, eastern North Greenland. Geology of Greenland Survey Bulletin, 187, 65-77. https://doi.org/10.34194/ggub.v187.5195 _______________ The Lower Carboniferous non-marine Sortebakker Formation is restricted to the south coast of Holm Land. It is estimated to exceed 1000 m in thickness and is subdivided by a low-angle disconformity into a lower mudstone-dominated unit (c. 335 m) and an upper sand-dominated unit (c. 665 m). The lower mudstone-dominated succession consists of stacked 0.5–6 m thick fining-upward cycles of fine- to medium-grained sandstone and mudstone. Cycles in the upper part of the formation are up to 20 m thick. They are dominated by thick tabular sandstones up to 13 m thick overlain by shaly units that resemble those in the lower mudstone dominated cycles. Six facies associations are identified and together describe a fluviatile–lacustrine depositional system. Five of the facies associations characterise different parts of a meandering riverdominated flood plain whereas the sixth facies association represents more permanent lakes.

scholarly journals Characterization of Annur and Bedakam Ecotypes of Coconut from Kerala State, India, Using Microsatellite Markers

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
M. K. Rajesh ◽  
K. Samsudeen ◽  
P. Rejusha ◽  
C. Manjula ◽  
Shafeeq Rahman ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Microsatellite Markers ◽  
West Coast ◽  
Clustering Analysis ◽  
Climatic Conditions ◽  
Breeding Programs ◽  
Wide Range ◽  
History Of ◽  
Kerala State

The coconut palm is versatile in its adaptability to a wide range of soil and climatic conditions. A long history of its cultivation has resulted in development of many ecotypes, which are adapted to various agro-eco factors prevalent in a particular region. These ecotypes usually are known by the location where they are grown. It is important to explore such adaptation in the coconut population for better utilization of these ecotypes in coconut breeding programs. The aim of the present study was to identify the genetic diversity of the Bedakam and Annur ecotypes of coconut and compare these ecotypes with predominant West Coast Tall (WCT) populations, from which they are presumed to have been derived, using microsatellite markers. All the 17 microsatellite markers used in the study revealed 100% polymorphism. The clustering analysis showed that Annur and Bedakam ecotypes were two separate and distinct populations compared to WCT. It was also evident from the clustering that Annur ecotype was closer to WCT than Bedakam ecotype.

Depositional history of the southeastern outcrop belt of the Chuckanut Formation: implications for the Darrington – Devil's Mountain and Straight Creek fault zones, Washington (U.S.A.)

1994 ◽  
Vol 31 (12) ◽  
pp. 1727-1743 ◽  
Author(s):  
James E. Evans ◽  
R. John Ristow Jr.
Keyword(s):  
Fault Zone ◽  
Middle Eocene ◽  
Fault Zones ◽  
Early Eocene ◽  
Fluvial System ◽  
Sediment Sources ◽  
Depositional History ◽  
Source Areas ◽  
Depositional System ◽  
History Of

The southeastern outcrop belt of the Eocene Chuckanut Formation contains the erosional remnants of a larger depositional system. In the study area, the Chuckanut Formation can be split into four units based upon differences in age, lithology, sedimentology, paleocurrents, and provenance relationships. The Coal Mountain unit (Early Eocene) represents a southwest-flowing fluvial system that shows no evidence for fault control of drainage. The overlying Higgins Mountain unit (early Middle Eocene) represents a northeast-flowing fluvial system east of the Devil's Mountain fault zone (DMFZ), with lithologies derived from western source areas. The Sperry Peak unit (early Middle Eocene) represents a fluvial system with a wide dispersion of paleocurrent azimuths and a possible mixture of sediment source areas. We believe the Sperry Peak unit was deposited in a fault-wedge graben at the junction of the DMFZ and Straight Creek fault zone (SCFZ), with sediment sources from both east and west. The Grade Creek unit (age unknown) is a fluvial unit found along the trace of the SCFZ with paleo-flow subparallel to the fault zone. The sedimentary evidence suggests that onset of Paleogene faulting on the DMFZ and SCFZ was at about 50–48 Ma, while movement on the Darrington fault zone may have been later (post-42 Ma).

Subversive Mobilities

Transfers ◽  
2013 ◽  
Vol 3 (1) ◽  
pp. 7-25 ◽  
Author(s):  
Mikkel Thelle
Keyword(s):  
Public Space ◽  
Cultural History ◽  
Turn Of The Century ◽  
Public Action ◽  
History Of ◽  
Urban Conflict

The article approaches mobility through a cultural history of urban conflict. Using a case of “The Copenhagen Trouble,“ a series of riots in the Danish capital around 1900, a space of subversive mobilities is delineated. These turn-of-the-century riots points to a new pattern of mobile gathering, the swarm; to a new aspect of public action, the staging; and to new ways of configuring public space. These different components indicate an urban assemblage of subversion, and a new characterization of the “throwntogetherness“ of the modern public.

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