Records and causes of Holocene salinity shifts in Laguna de Bay, Philippines
A 7000-year record of salinity shifts from molluscan and diatom assemblages and verified geochemical salinity proxies (C/S, S, Sr, Ca, and Sr/Ba) is reconstructed from Philippines' largest freshwater lake Laguna de Bay. The salinity shifts are interplays of millennial-scale sea level change, ce...
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| Format: | Journal Article |
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Pergamon-Elsevier Science Ltd
2014
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| Online Access: | http://hdl.handle.net/20.500.11937/30255 |
| _version_ | 1848753036109807616 |
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| author | Jaraula, Caroline Siringan, F. Klingel, R. Sato, H. Yokoyama, Y. |
| author_facet | Jaraula, Caroline Siringan, F. Klingel, R. Sato, H. Yokoyama, Y. |
| author_sort | Jaraula, Caroline |
| building | Curtin Institutional Repository |
| collection | Online Access |
| description | A 7000-year record of salinity shifts from molluscan and diatom assemblages and verified geochemical salinity proxies (C/S, S, Sr, Ca, and Sr/Ba) is reconstructed from Philippines' largest freshwater lake Laguna de Bay. The salinity shifts are interplays of millennial-scale sea level change, centennial-scale tectonic activity from the West Marikina Valley Fault (WMVF) and decadal-scale climatic changes. Currently only 1 m above mean sea level, the lake is connected to Manila Bay through the Pasig-Napindan River, which meanders across a densely populated “Parañaque Strip” partly occupied by metropolitan Manila. The controversial WMVF borders the lake on its western shore. Our 10.5 m sediment core from the western lobe reveal that the deposits are from a marine environment deposited 6600 cal BP to 4700 cal BP during a sea level still stand above present mean sea level (apmsl) in Southeast Asia and the Philippines. Episodic decreases in salinity with 260 y cycles were traced to the activity of the WMVF that would have accounted for at least 6 m of uplift of the Parañaque Strip. The vertical component of movement raised a sill and emergent landmass that started to isolate the Paleo-Laguna de Bay from Manila Bay. Subsequent episodic uplifts and sea level fall decreased depths to intertidal levels by 4700 cal BP, salinity to brackish but highly-influenced by marine waters by 4100 cal BP and to freshwater by 3100 cal BP. The latest salinity increase since mid-1960 is attributed to renewed saltwater incursion due to abnormally dry years, low lake levels, and Pasig River delta plain subsidence. |
| first_indexed | 2025-11-14T08:18:07Z |
| format | Journal Article |
| id | curtin-20.500.11937-30255 |
| institution | Curtin University Malaysia |
| institution_category | Local University |
| last_indexed | 2025-11-14T08:18:07Z |
| publishDate | 2014 |
| publisher | Pergamon-Elsevier Science Ltd |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | curtin-20.500.11937-302552017-09-13T15:30:51Z Records and causes of Holocene salinity shifts in Laguna de Bay, Philippines Jaraula, Caroline Siringan, F. Klingel, R. Sato, H. Yokoyama, Y. Coastal lakes Holocene sea level Paleolimnology Marikina Valley fault Salinity proxy records A 7000-year record of salinity shifts from molluscan and diatom assemblages and verified geochemical salinity proxies (C/S, S, Sr, Ca, and Sr/Ba) is reconstructed from Philippines' largest freshwater lake Laguna de Bay. The salinity shifts are interplays of millennial-scale sea level change, centennial-scale tectonic activity from the West Marikina Valley Fault (WMVF) and decadal-scale climatic changes. Currently only 1 m above mean sea level, the lake is connected to Manila Bay through the Pasig-Napindan River, which meanders across a densely populated “Parañaque Strip” partly occupied by metropolitan Manila. The controversial WMVF borders the lake on its western shore. Our 10.5 m sediment core from the western lobe reveal that the deposits are from a marine environment deposited 6600 cal BP to 4700 cal BP during a sea level still stand above present mean sea level (apmsl) in Southeast Asia and the Philippines. Episodic decreases in salinity with 260 y cycles were traced to the activity of the WMVF that would have accounted for at least 6 m of uplift of the Parañaque Strip. The vertical component of movement raised a sill and emergent landmass that started to isolate the Paleo-Laguna de Bay from Manila Bay. Subsequent episodic uplifts and sea level fall decreased depths to intertidal levels by 4700 cal BP, salinity to brackish but highly-influenced by marine waters by 4100 cal BP and to freshwater by 3100 cal BP. The latest salinity increase since mid-1960 is attributed to renewed saltwater incursion due to abnormally dry years, low lake levels, and Pasig River delta plain subsidence. 2014 Journal Article http://hdl.handle.net/20.500.11937/30255 10.1016/j.quaint.2014.08.048 Pergamon-Elsevier Science Ltd restricted |
| spellingShingle | Coastal lakes Holocene sea level Paleolimnology Marikina Valley fault Salinity proxy records Jaraula, Caroline Siringan, F. Klingel, R. Sato, H. Yokoyama, Y. Records and causes of Holocene salinity shifts in Laguna de Bay, Philippines |
| title | Records and causes of Holocene salinity shifts in Laguna de Bay, Philippines |
| title_full | Records and causes of Holocene salinity shifts in Laguna de Bay, Philippines |
| title_fullStr | Records and causes of Holocene salinity shifts in Laguna de Bay, Philippines |
| title_full_unstemmed | Records and causes of Holocene salinity shifts in Laguna de Bay, Philippines |
| title_short | Records and causes of Holocene salinity shifts in Laguna de Bay, Philippines |
| title_sort | records and causes of holocene salinity shifts in laguna de bay, philippines |
| topic | Coastal lakes Holocene sea level Paleolimnology Marikina Valley fault Salinity proxy records |
| url | http://hdl.handle.net/20.500.11937/30255 |