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Such evidence would include constructional beach ridges and other coastal
deposits, erosional scarps and wave-cut notches, encrusting marine fossils on outcrops (oysters, barnacles, etc.), marine/estuarine strata exposed along stream cutbanks or in excavations, and elevated fossil corals and reefs.
I would pay special attention to areas where previous researchers documented
such evidence and evaluate their measurements and interpretations. Particular
emphasis would be placed on the survey of river systems because I expected that
former sea-level highstand deposits, if present, would be exposed in cut-banks near
the landward margin of the coastal plain where streams dissect these older sediments. These surveys would be conducted using small watercraft, a four-wheeled
drive vehicle, or on foot, as conditions dictated.
I obtained a grant from the Malaysian Ministry of Science, Technology and
Innovation to undertake this work. “Expedisi Malaysia’s Sea Level History” was
soon underway! This project was to become a land and sea adventure that took me
to almost every island, coastal zone, and on many of the rivers in both Peninsular
Malaysia and Malaysian Borneo (Figs. 5.1, 5.2 and 5.3). I found many clues to
Malaysia’s sea level past and had the privilege of seeing much of the entire country.
I visited most of her coastal communities and experienced the vibrant way of life
supported by Malaysia’s relationship to the sea.
More Questions than Answers
The primary question for my research was: Is Sundaland, the crustal block centered
on the Sunda Shelf (Fig. 5.1), in fact, vertically stable? My four hypotheses were as
follows.
1. If the Malaysia region, or portions thereof, have been tectonically stable or experienced uplift during the last several million years then there should be an emergent (exposed on land) record of sea-level highstands that occurred during this
time period.
2. If the region, or portions thereof, have been slowly subsiding, emergent coastal
deposits will only consist of sediments associated with the mid-Holocene (the
last) relative sea-level highstand ~6000 years ago. Any pre-Holocene sea-level
highstand deposits will be preserved in the subsurface below modern sea level.
3. If evidence for higher than present pre-Holocene sea levels is found, we can
begin to develop the region’s relative sea-level highstand history based on sedimentologic characteristics, stratigraphic relationships, elevations, and ages.
4. If evidence for higher than present pre-Holocene sea levels is not found, the following possibilities would be considered. Evidence has been removed by erosional processes associated with subsequent marine transgressions. Evidence is
so intensely weathered and eroded by terrestrial processes that it is unrecognizable. Long-term regional subsidence has resulted in non-deposition on the presently emergent landscape.
P. R. Parham
Such evidence would include constructional beach ridges and other coastal
deposits, erosional scarps and wave-cut notches, encrusting marine fossils on outcrops (oysters, barnacles, etc.), marine/estuarine strata exposed along stream cutbanks or in excavations, and elevated fossil corals and reefs.
I would pay special attention to areas where previous researchers documented
such evidence and evaluate their measurements and interpretations. Particular
emphasis would be placed on the survey of river systems because I expected that
former sea-level highstand deposits, if present, would be exposed in cut-banks near
the landward margin of the coastal plain where streams dissect these older sediments. These surveys would be conducted using small watercraft, a four-wheeled
drive vehicle, or on foot, as conditions dictated.
I obtained a grant from the Malaysian Ministry of Science, Technology and
Innovation to undertake this work. “Expedisi Malaysia’s Sea Level History” was
soon underway! This project was to become a land and sea adventure that took me
to almost every island, coastal zone, and on many of the rivers in both Peninsular
Malaysia and Malaysian Borneo (Figs. 5.1, 5.2 and 5.3). I found many clues to
Malaysia’s sea level past and had the privilege of seeing much of the entire country.
I visited most of her coastal communities and experienced the vibrant way of life
supported by Malaysia’s relationship to the sea.
More Questions than Answers
The primary question for my research was: Is Sundaland, the crustal block centered
on the Sunda Shelf (Fig. 5.1), in fact, vertically stable? My four hypotheses were as
follows.
1. If the Malaysia region, or portions thereof, have been tectonically stable or experienced uplift during the last several million years then there should be an emergent (exposed on land) record of sea-level highstands that occurred during this
time period.
2. If the region, or portions thereof, have been slowly subsiding, emergent coastal
deposits will only consist of sediments associated with the mid-Holocene (the
last) relative sea-level highstand ~6000 years ago. Any pre-Holocene sea-level
highstand deposits will be preserved in the subsurface below modern sea level.
3. If evidence for higher than present pre-Holocene sea levels is found, we can
begin to develop the region’s relative sea-level highstand history based on sedimentologic characteristics, stratigraphic relationships, elevations, and ages.
4. If evidence for higher than present pre-Holocene sea levels is not found, the following possibilities would be considered. Evidence has been removed by erosional processes associated with subsequent marine transgressions. Evidence is
so intensely weathered and eroded by terrestrial processes that it is unrecognizable. Long-term regional subsidence has resulted in non-deposition on the presently emergent landscape.
P. R. Parham