Download or read book A Reconstruction of Holocene Sea Level Change Between 6 180 to 3 640 Cal Years BP for the Gordano Valley Using Foraminifera written by Joel Pimm and published by . This book was released on 2007 with total page 84 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Quantifying Holocene Sea level Change Using Intertidal Foraminifera written by Benjamin P. Horton and published by . This book was released on 2006 with total page 97 pages. Available in PDF, EPUB and Kindle. Book excerpt: Salt-marsh foraminifera have been used to reconstruct Holocene sea-level changes from coastlines around the world. In this work, we compile the results of surface foraminiferal surveys from fifteen study sites located on the east, south and west coasts of Great Britain, and the west coast of Ireland. These data, which comprise 236 samples and 84 species, are used to summarize the contemporary distributions of intertidal foraminifera around the British Isles, and to examine the environmental controls governing them.

Download or read book Reconstruction of Holocene Sea level Changes Using Foraminifera and Vertical Tectonic Movements Ohiwa Harbour Bay of Plenty New Zealand written by Emma Wiggins and published by . This book was released on 2002 with total page 90 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Holocene Paleoenvironmental Reconstruction of Depositional Environments on the Sunda Shelf Southwest South China Sea Using a Multidisciplinary Approach written by Michael R Twarog and published by . This book was released on 2018 with total page 116 pages. Available in PDF, EPUB and Kindle. Book excerpt: The last glacial maximum, ca. 21,000 years ago, caused a fall in eustatic sea level of ca. 120 m below present. The low-gradient, shallow Sunda Shelf, Southeast Asia was subaerially exposed during this sea-level lowstand and experienced rising sea level thereafter. Sea level rose to a +1.3––5 m highstand ca. 6,500 cal yr BP, and then fell to modern sea level. The objective of this research is to characterize environmental change on the Sunda Shelf in response to the post-glacial rising eustatic sea level. To address this objective, six gravity cores were collected along a transect crossing the paleo-Chao Phraya incised river valley complex between peninsular Malaysia and southern Vietnam. Thirteen AMS radiocarbon samples, 130 bulk sediment magnetic susceptibility samples (BMS), 66 X-ray fluorescence spectrometry (XRF) samples, and 54 samples for the analysis of foraminiferal assemblages were used to characterize change in the depositional environments of the cored sediments. BMS, XRF, and foraminiferal analysis distinguish two main units. Unit 1 is found in the lower part of the cores and typically contains more terrestrial material than sediments further up-core as shown by higher BMS values, higher % Ti, % Al, % Fe, and lower indicators of marine influence, for example, lower % Ca, % planktonic foraminifera, and percentages of deeper water benthic foraminifera such as Heterolepa dutemplei. Unit 2 is characterized by a significant increase in % Ca, % Heterolepa dutemplei and % planktonic foraminifera ca. 6,500 cal yr BP. Unit 1 is consistent with shallower water depths and is part of a transgressive systems tract (TST, ca. 1 m thick) that terminates ca. 6,500 cal yr BP. Unit 2 represents the overlying highstand systems tract (HST, ca. 1 m thick) and is characterized by an increase in % planktonics, % Ca, and shifts in benthic foraminiferal assemblages, indicating deeper water conditions than the sediments below. This shift from a TST to a HST ca. 6500 cal yr BP is consistent with the Sunda Shelf sea-level record.

Download or read book A Foraminiferal Modern Analogue for Reconstructing Holocene Relative Sea level Change in South Wales UK written by Adrian Kolander and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Quantifying Holocene Sea leval Change Using Intertidal Foraminifera written by Benjamin P. Horton and published by . This book was released on 2006 with total page 97 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Application of Intertidal Salt marsh Foraminifera to Reconstruct Late Holocene Sea level Change at Kariega Estuary South Africa written by Kate Leigh Strachan and published by . This book was released on 2013 with total page 200 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Holocene Paleoenvironmental Reconstruction of the Sunda Shelf Off Northeastern Peninsular Malaysia written by Emily I. Harrison and published by . This book was released on 2017 with total page 109 pages. Available in PDF, EPUB and Kindle. Book excerpt: In order to understand Holocene paleoenvironmental evolution of the western Sunda Shelf (southern South China Sea), two gravity cores TER15-GC10A and TER15-GC9A were collected (2015) 33 and 37 km offshore of Kuala Terengganu (KT), Peninsular Malaysia at ca. 60 m water depth. The cores were sampled every 1 cm and analyzed for three paleoenvironmental proxies; 1) bulk sediment magnetic susceptibility (BMS); 2) elemental analysis by x-ray fluorescence (XRF) spectrometry, and 3) foraminiferal content. Radiocarbon age estimates indicate that cores have a maximum age of ca. 8,400 cal. yr BP. BMS values decrease up-core (1.95 x 10-4-1.04 x 10-4 SI). XRF data also indicate a decrease up-core for Al (12.82%-17.05%), Fe (5.45%-3.65%), and Ti (0.78%-0.61%) with an inverse relationship to the concentration of Ca (3.29%-7.77%). This is interpreted to reflect a decrease in amount of terrestrial material supplied to the shelf over the last ca. 8,400 years, a dilution of detrital material by the local productivity of marine carbonates, and/or a stabilization of sea level. Cluster analysis indicates four groups of benthic foraminifera within the two cores. Within all four clusters Textularia sp. A, Heterolepa dutemplei, Asterorotalia milletti, and Hanzawaia nipponica were the most abundant species. Within three of the four groups, Textularia sp. A was the most abundant. Benthic foraminiferal assemblages, along with the presence of planktonic foraminifera suggest an open inner-shelf marine environment. Within the two cores, three paleoenvironmental episodes were recognized. The first episode occurred from ca. 8,400 cal. yr BP to ca. 6,500 cal. yr BP and was characterized by relatively high terrigenous input. At the beginning of this episode, sea level was at about -5 m rising to a maximum height of around +5 m by the mid-Holocene highstand (6,500 BP). The second episode (6,500 cal. yr BP-4,000 cal. yr BP) was transitional, from the relatively high influence of terrigenous material to a third episode, which ranged from 4,000 cal. yr BP-1,000 cal. yr BP, and was characterized by lower terrigenous influence and higher marine influence. During this episode, sea-level fell to its current position.

Download or read book Pleistocene Holocene Sea Level Change in the Georgia Bight written by Sherri Lynn Littman and published by . This book was released on 2000 with total page 144 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Notes on Foraminifera and Sea Level Change written by Dennis Curry and published by . This book was released on with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Reconstruction of Holocene Paleoclimate Based on Benthic Foraminiferal Assemblages from Soledad Basin written by Nivedita Mehrota and published by . This book was released on 2011 with total page 83 pages. Available in PDF, EPUB and Kindle. Book excerpt: The variation in paleoclimate during the last deglaciation and Holocene were evaluated based on physical and biological variation in the bottom water oxygen level on the Baja margin in Soledad Basin. Sediment from core OXMZ MV99-PC14 raised from a depth of 540m off the Magdalena Margin of Baja California, Mexico was analyzed for the presence of benthic foraminifera, which are presumed to respond to marine productivity and change in bottom water oxygen. This location is an ideal location to study paleoclimate oscillation and ocean and atmospheric interactions due to its shallow sill depth (290m), high sediment rate (~110cm/kr), sensitivity to El Niño Southern Oscillation (ENSO) and ENSO-like variations. Computed Benthic Foraminiferal Oxygen Index (BFOI) and productivity (DSR-Factor3) variations down core showed enhanced productivity and low oxygen during the Mid Holocene. ENSO-like signals were recorded during the Mid Holocene (4-10 cal BP) when the climate witnessed a cold La Niña-like state. A changing pattern of ocean circulation, depth of thermocline and fluctuations in productivity occurred throughout Holocene in Soledad Basin. This was mainly due to the changing budget of oxygen, created primarily by variations in productivity which had an inverse relationship with oxygen levels. Similar variability was found in low and high latitude paleoclimate records from Chukchi shelf, Cariaco Basin, Santa Barbara basin, Point Conception, and Baja California.

Download or read book Holocene Stratigraphy and Paleoenvironmental Change of Pamlico Sound North Carolina USA written by Nicholas Zaremba and published by . This book was released on 2014 with total page 109 pages. Available in PDF, EPUB and Kindle. Book excerpt: Holocene Stratigraphy and Paleoenvironmental Change of Pamlico Sound, North Carolina, USA by Nicholas Zaremba September, 2014 Directors of Thesis: David Mallinson and Eduardo Leorri Major Department: Geological Sciences. Understanding how coastal systems respond to changes in climate is becoming more important due to the current increased rate of sea-level rise and possible increased hurricane intensity in the future. While coastal ecosystems represent only 10% of Earth's surface, more than 20% of the world's population resides within 100 km of the coastline and within 100 m of sea level, which highlights the need to understand the past effects of sea-level rise and climate change on barrier island systems. In North Carolina, USA the barrier island system in the northern portion of the state (the Outer Banks) extends for ca. 270 km of the state's coast and provides a dynamic boundary between the ocean and two large estuarine water bodies, Albemarle and Pamlico Sound. This study expands upon previous work which identified two periods of increased marine influence within Pamlico Sound interpreted to be the result of extensive barrier island segmentation synchronous with periods of rapid climate change (RCC) during the late Holocene. Approximately 470 km of high resolution geophysical data, 850 bulk sediment magnetic susceptibility sediment samples and ca. 600 sediment analyses were constrained by 108 radiocarbon age estimates derived from 52 vibracores to better understand the Holocene stratigraphy of Pamlico Sound and how the periods of RCC affected the stratigraphic architecture of the Sound. According to previous work, estuarine waters prevailed within the paleovalleys of Pamlico Sound as early as ca. 7500 cal BP and Pleistocene interfluves provided protection for the paleovalleys from the Atlantic Ocean until ca. 5500 cal BP, when the interfluves were flooded by rising sea-level, this interpretation is based on a conservative sea-level rise. However, the data provided in this study indicates that there is no evidence of a change in depositional environment at ca. 5500 cal BP. If the 5500 cal BP flooding of the Pleistocene interfluves is accurate, then Holocene barrier islands must have been present to explain the presence of estuarine deposits within the paleovalleys. At ca. 4000 cal BP, an increase in marine influence and sand content is detected in multiple cores within the northern basin and is interpreted to be the result of increased segmentation of barrier islands. This deposit is mainly recorded within the paleovalleys of Pamlico Sound; and is only preserved on a few interfluves as a result of base level being too low. Reformation of the barrier islands occurred sometime from 3500 to 2500 cal BP; suggested by muddy deposits with low brackish estuarine foraminiferal assemblages. At ca. 1200 cal BP, a sudden increase in marine influence is detected throughout southeastern Pamlico Sound; a sandy deposit is interpreted to be the result of extensive segmentation of the barrier islands during the Medieval Climate Anomaly (MCA). Geophysical data suggests the segmentation of the barriers was large in magnitude to allow for deposition of large lobate shoals (the MCA shoals). Further refinement of a local sea-level curve is required to understand the mechanisms responsible for the 4000 cal BP marine influenced deposit. The error range of the North Carolina sea-level curve loosely constrain the initial flooding of the Pleistocene interfluves anytime from 5500 to 4000 cal BP rather than before 7000 cal BP as previously postulated. Therefore, it is difficult to hypothesize about the mechanism responsible for the 4000 cal BP sandy deposit without a more refined local sea level curve. However, data from this study combined with other research suggest that the 1200 cal BP deposit was likely caused by an increase in hurricane activity or intensity during the MCA. Furthermore this study has provided an estimate on the volume (1.1x109 km3) of silt and clay deposited within the northern basin of Pamlico Sound since ca. 4000 cal BP; this has aided in creating a carbon sequestration budget for the system.

Download or read book Holocene Sea level Change in the Dysynni Valley written by Caitlin Nagle and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Late Holocene Paleoclimate Reconstruction of the Northern Gulf of Aqaba Using Foraminifera as a Proxy written by Julie Louise Galloway and published by . This book was released on 2011 with total page 131 pages. Available in PDF, EPUB and Kindle. Book excerpt: A multiproxy analyses of sediment from a 4.3 m core extracted from 25 m water depth on the shelf of the northern Gulf of Aqaba suggest shifts in depositional environments over the past 4000 yrs. Foraminifera assemblages, grain-size distribution, sediment characterization, and radiocarbon age dating indicate several eco-stratigraphic zones including two periods of aridity from ~3900 to 2900 yr BP and ~1130 yr BP to present, a transitional period from ~2900 to 2500 yr BP, and an abrupt shift to wetter conditions between ~2500 to 1130 yr BP. Furthermore, this study records two foraminifera-barren horizons at 170 and 190 cm that correlate to grain size anomalies at that depth. A tsunami wave generated sometime during 2200-1800 yr BP is one possible explanation for this occurrence. Seismic stratigraphy indicates a reflector at approximately 3 m below the seafloor that delineates the boundary between a relict, coral fringing reef horizon, U8, and the overlying U9 strata. Sedimentation rates that adjust for sediment compaction suggest the sequence lies near the foraminifera-barren horizons at ~200 cm in the core. These data signify a dramatic environmental event possibly corresponding to reef termination on the Northern Gulf of Aqaba shelf.

Download or read book Holocene Sea level Change in the Pacific Northwest written by Ian Hutchinson and published by . This book was released on 1992 with total page 122 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Agglutinated Foraminifera as Indicators of Salt Marsh Development in Relation to Late Holocene Sea Level Rise Great Marshes at Barnstable Massachusetts written by Sacha Rijk and published by . This book was released on 1995 with total page 188 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Reconstruction of Holocene Sea levels Using Diatom and Pollen based Microfossil Transfer Functions West Coast of Scotland UK written by and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: