scholarly journals Late Holocene Pollen Record of Environmental Changes in Karimata Strait, Sunda Shelf Region

2019 ◽  
Vol 6 (1) ◽  
Author(s):  
Eko Yulianto ◽  
Woro Sri Sukapti ◽  
Kresna Tri Dewi
Keyword(s):  
Late Holocene ◽  
Environmental Changes ◽  
Pollen Record ◽  
Sunda Shelf ◽  
Karimata Strait ◽  
Shelf Region

scholarly journals PERUBAHAN LINGKUNGAN DAN EVOLUSI MANGROVE DI PULAU BELITUNG SELAMA HOLOSEN AKHIR BERDASARKAN REKAMAN POLEN

2019 ◽  
Vol 17 (2) ◽  
Author(s):  
Woro Sri Sukapti ◽  
Eko Yulianto ◽  
Praptisih Praptisih
Keyword(s):  
Environmental Change ◽  
Sea Level ◽  
Late Holocene ◽  
Environmental Changes ◽  
Onset Time ◽  
Pollen Record ◽  
Shelf Area ◽  
Level Fluctuation ◽  
Sunda Shelf ◽  
Sea Level Fluctuation

Studi sejarah fluktuasi muka air laut dan perubahan lingkungan di Paparan Sunda masih sedikit dilakukan. Ada dua isu yang saling terkait yang menjadi permasalahan utama terkait dengan perubahan muka air laut di wilayah ini yaitu kurangnya rekaman data fluktuasi muka air laut dan perubahan lingkungan selama kurun waktu mid-late Holosen dengan kualitas yang bagus. Hal itu memiliki konsekwensi terhadap munculnya isu kedua yaitu tidak terdefinisikannya secara jelas dan tepat baik waktu maupun besaran posisi muka air laut pada saat mid-Holosen. Penelitian ini dilakukan untuk merekonstruksi perubahan lingkungan selama Holosen Akhir di wilayah Paparan Sunda menggunakan rekaman polen endapan mangrove. Pemboran tangan dilakukan guna pengamatan stratigrafi dan pengambilan sampel untuk analisis-analisis sedimentologi dan mikropaleontologi di laboratorium. Hasil studi ini menunjukkan bahwa perubahan lingkungan terjadi di Pulau Belitung selama setidaknya 1500 tahun terakhir sebagai akibat dari proses progradasi. Proses ini menyebabkan garis pantai terus maju hingga mencapai posisi saat ini. Endapan mangrove di lokasi penelitian juga merekam kejadian insidentil yang secara hipotetis diduga sebagai peristiwa tsunami akibat letusan Krakatau yang terjadi pada tahun 1883 AD dan sekitar 535-536 AD.Kata Kunci: Belitung, polen, mangrove, Mid-Holosen, Krakatau, muka laut, perubahan lingkungan.There is only minor study on sea-level fluctuation and environmental change in Sunda Shelf. The main isues in this area are lacking good quality of sea-level fluctuation and environmental change record during mid-late Holocene in which accordingly the onset time and sea-level height of the Mid-Holocene Maximum Transgression event have not been well defined. This study aims to reconstruct environmental changes during late Holocene in the Sunda Shelf area based on mangrove pollen record. Hand-auger was applied to make stratigraphic observation and sampling for sedimentological and micropaleontological analyses in the laboratory. Result of this study shows environmental changes occured within the last ca.1500 years due to coastal progradation in Belitung. This progradation shifted the coastal line seaward to attain the present position. The pollen record also reflects rapid and brief changes that may hypothetically be interpreted as the 535-536 AD and 1883 AD Krakatau tsunamis.Keywords: Belitung, pollen, mangroves, Mid-Holocene, Krakatau, sea level, environmental changes.

scholarly journals Western equatorial African forest-savanna mosaics: a legacy of late Holocene climatic change?

2009 ◽  
Vol 5 (1) ◽  
pp. 341-367 ◽  
Author(s):  
A. Ngomanda ◽  
A. Chepstow-Lusty ◽  
M. Makaya ◽  
C. Favier ◽  
P. Schevin ◽  
...  
Keyword(s):  
Environmental History ◽  
Late Holocene ◽  
Environmental Changes ◽  
Elaeis Guineensis ◽  
Coastal Region ◽  
Climatic Conditions ◽  
Rapid Decline ◽  
Pollen Record ◽  
Secondary Forests ◽  
Equatorial Africa

Abstract. Past vegetation and climate changes reconstructed using two pollen records from Lakes Maridor and Nguène, Gabon, provide new insights into the environmental history of western equatorial African rainforests during the last 4500 cal yr BP. The Lake Maridor pollen record indicates that the coastal savannas of western equatorial Africa did not exist during the mid-Holocene and instead the region was covered by evergreen rainforests. In the Lake Nguène pollen record, a rapid decline of hygrophilous evergreen rainforest occurred around 4000 cal yr BP, synchronously with grassland expansion around Lake Maridor. The establishment of coastal savannas in Gabon suggests decreasing humidity at the onset of the late Holocene. The marked reduction in evergreen rainforest and subsequent savanna expansion was associated with the colonization of secondary forests dominated by the palm, Elaeis guineensis, in the coastal region and the shrub, Alchornea cordifolia, further inland. A return to wetter climatic conditions from about 1400 cal yr BP led to the renewed spread of evergreen rainforest inland, whereas a forest-savanna mosaic still persists in the coastal region. There is no evidence to suggest that the major environmental changes observed are driven by human impact.

scholarly journals Late-Holocene landscape evolution and human presence in the northern Danube delta (Chilia distributary lobes)

The Holocene ◽  
2021 ◽  
pp. 095968362110191
Author(s):  
Luminița Preoteasa ◽  
Alfred Vespremeanu-Stroe ◽  
Anca Dan ◽  
Laurențiu Țuțuianu ◽  
Cristian Panaiotu ◽  
...  
Keyword(s):  
Middle Ages ◽  
Economic History ◽  
Late Holocene ◽  
Environmental Changes ◽  
Land Use Changes ◽  
Sedimentary Facies ◽  
The Black Sea ◽  
Danube Delta ◽  
Human Presence ◽  
Historical Texts

This paper documents the Late-Holocene environmental changes and human presence in the northern Danube delta using a multidisciplinary approach that combines geoscientific data with archaeological findings, historical texts, and maps. It follows the formation and progression of the Chilia distributary and the reconfiguration of socioeconomic activities. Sedimentary facies identified on five new cores by changes in texture properties, magnetic susceptibility, geochemistry, and macro- and microfauna composition together with the newly obtained chronology constrain the complex evolution of the Chilia branch as filling in a long-lasting bay and then of a giant lagoon (Thiagola) which covered most of the northern delta since the Old Danube lobe inception (ca. 7500 yrs BP) till modern Chilia development. It initiated during the Greek Antiquity (ca. 2500 yrs ar BP) at the delta apex, while in Roman times (ca. 1800 yrs BP) it pursued its slow flowing into the vast Thiagola Lagoon. The most dramatic transformations occurred in the last 800 years when the river passed east of the Chilia promontory, rapidly went through the present-day Matița-Merhei basin (several decades), and created its first open-sea outlet. Solid discharge increased in two distinct periods, once in the Middle Ages (ca. 750 yrs BP) and then in the Modern Period (ca. 150 yrs BP) due to human-induced land-use changes in the Danube watershed. The chronology of the cultural remains on the pre-deltaic Chilia promontory and the multiproxy analysis of a sediment core retrieved nearby downstream suggest the terrestrial connection of the island with the mainland in ancient times. The hitherto contended issue of the old Thiagola Lagoon and its location are redefined here, as are the original identifications of ancient and medieval toponyms and hydronyms, especially for Chilia-Licostomo, Byzantine, Genoese, Moldavian, Ottoman, and Russian trading point of great importance in the political and economic history of the Black Sea and neighboring regions.

Late Pleistocene and Holocene Paleoenvironments of Chalco Lake, Central Mexico

1993 ◽  
Vol 40 (3) ◽  
pp. 332-342 ◽  
Author(s):  
Maria Socorro Lozano-Garcı́a ◽  
Beatriz Ortega-Guerrero ◽  
Margarita Caballero-Miranda ◽  
Jaime Urrutia-Fucugauchi
Keyword(s):  
Volcanic Activity ◽  
Lake Level ◽  
Environmental Changes ◽  
Late Quaternary ◽  
Cold Climate ◽  
Central Mexico ◽  
Pollen Record ◽  
Loss On Ignition ◽  
Southeastern Part ◽  
Saline Marsh

AbstractIn order to establish paleoenvironmental conditions during the late Quaternary, four cores from the Basin of Mexico (central Mexico) were drilled in Chalco Lake, located in the southeastern part of the basin. The upper 8 m of two parallel cores were studied, using paleomagnetic, loss-on-ignition, pollen, and diatom analyses. Based on 11 14C ages, the analyzed record spans the last 19,000 14C yr B.P. Volcanic activity has affected microfossil abundances, both directly and indirectly, resulting in absence or reduction of pollen and diatom assemblages. Important volcanic activity took place between 19,000 and 15,000 yr B.P. when the lake was a shallow alkaline marsh and an increase of grassland pollen suggests a dry, cold climate. During this interval, abrupt environmental changes with increasing moisture occurred. From 15,000 until 12,500 yr B.P. the lake level increased and the pollen indicates wetter conditions. The highest lake level is registered from 12,500 to ca. 9000 yr B.P. The end of the Pleistocene is characterized by an increase in humidity. From 9000 until ca. 3000 yr B.P. Chalco Lake was a saline marsh and the pollen record indicates warmer conditions. After 3000 yr B.P. the lake level increased and human disturbance dominates the lacustrine record.

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