Geologic Records of High Sea Levels Completed
Coral reef marine terraces
Talafofo Beach, Saipan
Coral/algal heads in an ancient reef
Oahu, Hawaii
Fossil coral reefs indicate earlier “high water mark”
Windley Key quarry, Florida
This project studies past high sea levels on coastlines that preserve fossil coral reefs or marine terraces. We ascertain the magnitudes of sea-level high stands by field mapping, stratigraphic measurements, and precise elevation measurements. Geochronology is accomplished by radiocarbon dating of mollusks (for Holocene-to-last-glacial deposits), uranium-series dating of corals (for high-sea stands back to about 500,000 years old) and strontium-isotope measurements of mollusks (for high-sea stands older than about 300,000 years). It is possible to determine the past water temperatures of the oceans during these high sea stands by detailed paleozoogeographic interpretations of fossil mollusk assemblages, a time-tested traditional method of paleoclimatic studies in marine settings. We also study the effects of sea level changes on coastal river systems and dunes.
The geomorphic record of sea level change on an uplifting coastline
On a tectonically active coast, such as California, changes in sea level are recorded as marine terraces, wave-cut benches that formed in the surf zone during interglacial periods, but are now above sea level due to uplift. Wave-cut benches also form during glacial periods, but these are offshore and underwater during interglacial periods. If uplift is continuous over time, a “stair step” type of landscape develops, as shown here, with each successively higher terrace corresponding to a successively older interglacial period.
[Reference: Imbrie, J., Hays, J.D., Martinson, D.G., McIntyre, A., Mix, A.C., Morley, J.J., Pisias, N.G., Prell, W.L., Shackleton, N.J., 1984, The orbital theory of Pleistocene climate: Support from a revised chronology of the marine δ18O record, in Berger, A., Imbrie, J., Hays, J., Kukla, G., and Saltzman, B., eds., Milankovitch and climate: Understanding the response to astronomical forcing: Dordrecht, D. Reidel Publishing Company, p. 269-305.]
The geomorphic record of sea level change on a stable or subsiding coastline
Why is this research important?
One of the most pressing issues in studies of climate change is the possible rise of sea level due to loss of major ice sheets, which would impact population, infrastructure, and habitats along the world's coastlines. It is not known which polar ice sheets (Greenland, West Antarctic, East Antarctic) are most at risk for mass loss that could contribute to sea level rise. Furthermore, it is not known what the possible magnitude of sea level rise is under interglacial climate conditions, how rapidly sea level may rise, or how long high sea levels may be retained. The goals of this project are to shed light on these questions by studying warm climate analogs of the geologic past.
How high was sea level during the last interglacial period?
Key unanswered questions about past interglacial sea levels
The research conducted by this project attempts to answer these questions raised in the Intergovernmental Panel on Climate Change (IPCC) 2014 report:
- The timing of past interglacial sea-level high stands
- Marine paleotemperatures during past high-sea stands
- Magnitudes of past interglacial high-sea stands
- Rates of sea level rise
Results
What have we learned from the last interglacial?
What fossil corals can tell us
Corals are the only organisms that take up uranium from the ocean. Thus, they are the only fossils that we can use for high-precision uranium-series dating, one of our major tools to determine ages of marine deposits.
How long did the last interglacial period last?
These maps show the places where we have found either fossil coral reefs (tropical locations) or coral-bearing marine terraces (California) that have been dated by uranium-series methods to the last interglacial period. On each map, you can see the range of ages we have gotten from dating these corals that tell us how long this high-sea stand lasted.
How high was sea level in the last interglacial period?
How warm was the ocean during the last interglacial period?
It is possible to determine the past water temperatures of the oceans during these high sea stands by detailed paleozoogeographic interpretations of fossil mollusk assemblages, a time-tested traditional method of paleoclimatic studies in marine settings. These maps show how marine invertebrates, now found only in warm waters farther south at present, expanded northward beyond their present ranges, during a warm last interglacial period.
The photo galleries show current Project study locations.
Below are publications associated with this project.
From the Island of the Blue Dolphins: A unique 19th century cache feature from San Nicolas Island, California
The contributions of Donald Lee Johnson to understanding the Quaternary geologic and biogeographic history of the California Channel Islands
Tectonic influences on the preservation of marine terraces: Old and new evidence from Santa Catalina Island, California
Sea-level history of past interglacial periods: New evidence from uranium-series dating of corals from Curaçao, Leeward Antilles islands
Sea-level history during the Last Interglacial complex on San Nicolas Island, California: implications for glacial isostatic adjustment processes, paleozoogeography and tectonics
Sea-level history of the past two interglacial periods: New evidence from U-series dating of reef corals from south Florida
History of the Greenland Ice Sheet: paleoclimatic insights
The origin and paleoclimatic significance of carbonate sand dunes deposited on the California Channel Islands during the last glacial period
A cool eastern Pacific Ocean at the close of the Last Interglacial complex
Ice sheets and sea level: response
Paleoclimatic evidence for future ice-sheet instability and rapid sea-level rise
Quaternary sea level history of the United States
- Overview
This project studies past high sea levels on coastlines that preserve fossil coral reefs or marine terraces. We ascertain the magnitudes of sea-level high stands by field mapping, stratigraphic measurements, and precise elevation measurements. Geochronology is accomplished by radiocarbon dating of mollusks (for Holocene-to-last-glacial deposits), uranium-series dating of corals (for high-sea stands back to about 500,000 years old) and strontium-isotope measurements of mollusks (for high-sea stands older than about 300,000 years). It is possible to determine the past water temperatures of the oceans during these high sea stands by detailed paleozoogeographic interpretations of fossil mollusk assemblages, a time-tested traditional method of paleoclimatic studies in marine settings. We also study the effects of sea level changes on coastal river systems and dunes.
The geomorphic record of sea level change on an uplifting coastline
On a tectonically active coast, such as California, changes in sea level are recorded as marine terraces, wave-cut benches that formed in the surf zone during interglacial periods, but are now above sea level due to uplift. Wave-cut benches also form during glacial periods, but these are offshore and underwater during interglacial periods. If uplift is continuous over time, a “stair step” type of landscape develops, as shown here, with each successively higher terrace corresponding to a successively older interglacial period.
[Reference: Imbrie, J., Hays, J.D., Martinson, D.G., McIntyre, A., Mix, A.C., Morley, J.J., Pisias, N.G., Prell, W.L., Shackleton, N.J., 1984, The orbital theory of Pleistocene climate: Support from a revised chronology of the marine δ18O record, in Berger, A., Imbrie, J., Hays, J., Kukla, G., and Saltzman, B., eds., Milankovitch and climate: Understanding the response to astronomical forcing: Dordrecht, D. Reidel Publishing Company, p. 269-305.]
The geomorphic record of sea level change on a stable or subsiding coastline
Why is this research important?
One of the most pressing issues in studies of climate change is the possible rise of sea level due to loss of major ice sheets, which would impact population, infrastructure, and habitats along the world's coastlines. It is not known which polar ice sheets (Greenland, West Antarctic, East Antarctic) are most at risk for mass loss that could contribute to sea level rise. Furthermore, it is not known what the possible magnitude of sea level rise is under interglacial climate conditions, how rapidly sea level may rise, or how long high sea levels may be retained. The goals of this project are to shed light on these questions by studying warm climate analogs of the geologic past.
How high was sea level during the last interglacial period?
Key unanswered questions about past interglacial sea levels
The research conducted by this project attempts to answer these questions raised in the Intergovernmental Panel on Climate Change (IPCC) 2014 report:
- The timing of past interglacial sea-level high stands
- Marine paleotemperatures during past high-sea stands
- Magnitudes of past interglacial high-sea stands
- Rates of sea level rise
Results
What have we learned from the last interglacial?
What fossil corals can tell us
Corals are the only organisms that take up uranium from the ocean. Thus, they are the only fossils that we can use for high-precision uranium-series dating, one of our major tools to determine ages of marine deposits.
How long did the last interglacial period last?
These maps show the places where we have found either fossil coral reefs (tropical locations) or coral-bearing marine terraces (California) that have been dated by uranium-series methods to the last interglacial period. On each map, you can see the range of ages we have gotten from dating these corals that tell us how long this high-sea stand lasted.
How high was sea level in the last interglacial period?
How warm was the ocean during the last interglacial period?
It is possible to determine the past water temperatures of the oceans during these high sea stands by detailed paleozoogeographic interpretations of fossil mollusk assemblages, a time-tested traditional method of paleoclimatic studies in marine settings. These maps show how marine invertebrates, now found only in warm waters farther south at present, expanded northward beyond their present ranges, during a warm last interglacial period.
- Multimedia
The photo galleries show current Project study locations.
- Publications
Below are publications associated with this project.
Filter Total Items: 27From the Island of the Blue Dolphins: A unique 19th century cache feature from San Nicolas Island, California
A cache feature salvaged from an eroding sea cliff on San Nicolas Island produced two redwood boxes containing more than 200 artifacts of Nicoleño, Native Alaskan, and Euro-American origin. Outside the boxes were four asphaltum-coated baskets, abalone shells, a sandstone dish, and a hafted stone knife. The boxes, made from split redwood planks, contained a variety of artifacts and numerous unmodifAuthorsJon M. Erlandson, Lisa Thomas-Barnett, René L. Vellanoweth, Steven J. Schwartz, Daniel R. MuhsThe contributions of Donald Lee Johnson to understanding the Quaternary geologic and biogeographic history of the California Channel Islands
Over a span of 50 years, native Californian Donald Lee Johnson made a number of memorable contributions to our understanding of the California Channel Islands. Among these are (1) recognizing that carbonate dunes, often cemented into eolianite and derived from offshore shelf sediments during lowered sea level, are markers of glacial periods on the Channel Islands; (2) identifying beach rock on theAuthorsDaniel R. MuhsTectonic influences on the preservation of marine terraces: Old and new evidence from Santa Catalina Island, California
The California Channel Islands contain some of the best geologic records of past climate and sea-level changes, recorded in uplifted, fossil-bearing marine terrace deposits. Among the eight California Channel Islands and the nearby Palos Verdes Hills, only Santa Catalina Island does not exhibit prominent emergent marine terraces, though the same terrace-forming processes that acted on the other ChAuthorsR. Randall Schumann, Scott A. Minor, Daniel R. Muhs, Lindsey T. Groves, John P. McGeehinSea-level history of past interglacial periods: New evidence from uranium-series dating of corals from Curaçao, Leeward Antilles islands
Curaçao has reef terraces with the potential to provide sea-level histories of interglacial periods. Ages of the Hato (upper) unit of the “Lower Terrace” indicate that this reef dates to the last interglacial period, Marine Isotope Stage (MIS) 5.5. On Curaçao, this high sea stand lasted at least 8000 yr (~ 126 to ~ 118 ka). Elevations and age of this reef show that late Quaternary uplift rates onAuthorsDaniel R. Muhs, John M. Pandolfi, Kathleen R. Simmons, R. Randall SchumannSea-level history during the Last Interglacial complex on San Nicolas Island, California: implications for glacial isostatic adjustment processes, paleozoogeography and tectonics
San Nicolas Island, California has one of the best records of fossiliferous Quaternary marine terraces in North America, with at least fourteen terraces rising to an elevation of ~270 m above present-day sea level. In our studies of the lowest terraces, we identified platforms at 38-36 m (terrace 2a), 33-28 m (terrace 2b), and 13-8 m (terrace 1). Uranium-series dating of solitary corals from theseAuthorsDaniel R. Muhs, Kathleen R. Simmons, R. Randall Schumann, Lindsey T. Groves, Jerry X. Mitrovica, Deanna LaurelSea-level history of the past two interglacial periods: New evidence from U-series dating of reef corals from south Florida
As a future warm-climate analog, much attention has been directed to studies of the Last Interglacial period or marine isotope substage (MIS) 5.5, which occurred ∼120,000 years ago. Nevertheless, there are still uncertainties with respect to its duration, warmth and magnitude of sea-level rise. Here we present new data from tectonically stable peninsular Florida and the Florida Keys that provide eAuthorsDaniel R. Muhs, Kathleen Simmons, R. Randall Schumann, R. B. HalleyHistory of the Greenland Ice Sheet: paleoclimatic insights
Paleoclimatic records show that the GreenlandIce Sheet consistently has lost mass in response to warming, and grown in response to cooling. Such changes have occurred even at times of slow or zero sea-level change, so changing sea level cannot have been the cause of at least some of the ice-sheet changes. In contrast, there are no documented major ice-sheet changes that occurred independent of temAuthorsRichard B. Alley, John T. Andrews, J. Brigham-Grette, G.K.C. Clarke, Kurt M. Cuffey, J. J. Fitzpatrick, S. Funder, S.J. Marshall, G. H. Miller, J.X. Mitrovica, D.R. Muhs, B. L. Otto-Bliesner, L. Polyak, J.W.C. WhiteThe origin and paleoclimatic significance of carbonate sand dunes deposited on the California Channel Islands during the last glacial period
No abstract available.AuthorsDaniel R. Muhs, Gary Skipp, R. Randall Schumann, Donald L. Johnson, John P. McGeehin, Jossh Beann, Joshua Freeman, Timothy A. Pearce, Zachary Muhs RowlandA cool eastern Pacific Ocean at the close of the Last Interglacial complex
New high-precision thermal ionization mass-spectrometric (TIMS) U-series ages of solitary corals (Balanophyllia elegans) from several marine terrace localities along the California and southern Oregon coasts date to the ???80,000 yr BP high stand of sea, correlative with marine isotope substage 5a, late in the last interglacial complex. Ages of multiple corals from localities north of Point An??oAuthorsD.R. Muhs, K. R. Simmons, G. L. Kennedy, K. R. Ludwig, L.T. GrovesIce sheets and sea level: response
No abstract available.AuthorsJonathan T. Overpeck, Bette L. Otto-Bliesner, Gifford H. Miller, Richard B. Alley, Daniel R. Muhs, Shawn J. MarshallPaleoclimatic evidence for future ice-sheet instability and rapid sea-level rise
Sea-level rise from melting of polar ice sheets is one of the largest potential threats of future climate change. Polar warming by the year 2100 may reach levels similar to those of 130,000 to 127,000 years ago that were associated with sea levels several meters above modern levels; both the Greenland Ice Sheet and portions of the Antarctic Ice Sheet may be vulnerable. The record of past ice-sheetAuthorsJ. T. Overpeck, B. L. Otto-Bliesner, G. H. Miller, D.R. Muhs, R. B. Alley, J.T. KiehlQuaternary sea level history of the United States
No abstract available.AuthorsD.R. Muhs, J.F. Wehmiller, K. R. Simmons, L.L. York