About

Tamara Pico is an Assistant Professor in the Earth & Planetary Sciences division within the Physical & Biological Sciences Division at UC Santa Cruz. Her research centers on using solid Earth deformation as a lens to understand the coupling between ice sheets, sea level, and landscapes in the past. She employs glacial isostatic adjustment modeling as a tool to infer variations in past ice sheets and to understand how landscapes record solid Earth deformation over the ice age. Pico holds an A.B. in Chemistry from Princeton University, earned in 2014, along with certificates in Material Science & Engineering, Engineering Biology, and French Language & Culture. She completed her Ph.D. in Earth & Planetary Sciences at Harvard University in 2019, with a secondary field in Women, Gender, & Sexuality Studies. Her academic background and research focus contribute to advancing understanding of Earth's past climate and geological processes.

Research topics

• Geology
• Paleontology
• Climatology
• Oceanography

Selected publications

• The effect of sediment loading from the Río de la Plata: driving regional sea-level variability

  2026-03-14

  articleOpen access

  Sea-level reconstructions are essential for evaluating models of ice-sheet stability and climate change, but their interpretation is often confounded by sea-level signals produced by multiple processes, including the Earth’s deformation in response to sediment loading. Here we show that accounting for sediment isostasy resolves long-standing inconsistencies among Marine Isotopic Stage (MIS) 5a and 5e sea-level records from the Río de la Plata estuary, reducing mismatches by up to an order of magnitude. This result demonstrates that regional sedimentary histories can bias relative sea-level estimates by several meters compared with conventional approaches based only on glacial isostatic adjustment (GIA). We also show that sediment loading has affected relative sea level across the Holocene and may continue to influence present-day tide-gauge observations in the region. Together, these findings emphasize the need for regionally detailed sedimentation histories rather than reliance on global compilations alone, and they motivate expanded shelf coring and seismic surveying.

  PublisherDOI

• Exploring the impact of Cordilleran Ice Sheet size on marine-terminating ice stream grounding line dynamics

  Quaternary Science Reviews · 2025-06-02 · 1 citations

  articleOpen access1st authorCorresponding

  The growth and retreat of the Cordilleran Ice Sheet prior to the Last Glacial Maximum, during Marine Isotope Stage 3 (MIS 3; 57 ka to 29 ka), is elusive. Yet ice sheet size impacts underlying topography through glacial isostatic adjustment, which can modulate ice stream grounding zone dynamics. In this study, we explore bounds on MIS 3 Cordilleran Ice Sheet volume, and predict how topographic change due to glacial isostatic adjustment would shift the zones where grounding lines can persist for key Cordilleran ice streams. We identified three key ice streams (Yakutat Sea Valley, Skeena Valley, Juan de Fuca Strait), two of which are located near sites with sediment cores recording active ice dynamics across this time interval. We used the reconstructed bedrock topography for these ice streams to assess how glacial isostatic adjustment would change the potential zones of grounding line persistence, based on plausible end-member Cordilleran Ice Sheet histories. We found that glacial isostatic adjustment shifts the locations of persistent grounding line zones differently, based on the location of the Cordilleran ice stream with respect to the predicted spatial pattern of topographic change. Depending on the size of the Cordilleran Ice Sheet in the period leading into the Last Glacial Maximum, glacial isostatic adjustment could have acted to either stabilize or destabilize marine-terminating grounding lines across the Pacific shelf. Future work refining the Cordilleran Ice Sheet history across the glacial build-up phase will disentangle the role of solid Earth feedbacks on grounding line dynamics for individual ice streams, and provide insight into the mechanisms causing abrupt climate events, ranging from rapid ice discharge to megafloods, documented in the North Pacific across the last ice age. • Size of MIS 3 Cordilleran Ice Sheet modulates topography beneath ice streams. • Glacial isostatic adjustment shifts Cordilleran ice stream grounding zones. • Solid Earth impacts ice stream stability and response to climate forcing.

  PublisherDOI

• Melting the Marinoan Snowball Earth: The impact of deglaciation duration on the sea-level history of continental margins

  Abstracts with programs - Geological Society of America · 2025-01-01

  article
  PublisherDOI

• Converging evidence constrains Late Pleistocene Bering Land Bridge history

  Quaternary Science Advances · 2025-08-12 · 1 citations

  articleOpen access

  The Bering Land Bridge was an important biotic corridor and climatic modifier during the Pleistocene (2.58 million to 11,700 thousand years ago [ka]). Understanding when the land bridge was most recently exposed reveals insights into past climate, the modern distribution of plants and animals, and potential human migration into the Americas. While the timing of the most recent flooding of the land bridge has been constrained to during the last deglaciation, the timing of its most recent exposure before the Last Glacial Maximum (LGM, 26.5–19 ka) is less clear. Here, we combine data from three disciplines— paleoceanography, sea level reconstruction, and terrestrial paleogenomics—to constrain the most recent exposure of the Bering Land Bridge to shortly before the LGM, 30–40 kyr later than previously suggested by comparisons of eustatic sea level reconstructions with the modern Bering Strait Sill depth. These results have implications for understanding the timing and nature of human arrival in the Americas and highlight the importance of interdisciplinary collaboration across paleoclimatology and paleoecology for refining Pleistocene environmental history. • Combines interdisciplinary datasets to constrain the timing of the last opening of the Bering Land Bridge. • Illustrates the use of genetics as a paleoproxy for investigating questions of paleogeography. • Provides background information on all proxies to enhance accessibility for a broad, interdisciplinary audience. • Outlines future directions for Bering Land Bridge research and emphasizes the importance of new tools in Quaternary sciences.

  PublisherDOI

• Impact of glacial isostatic adjustment on zones of potential grounding line persistence in the Ross Sea Embayment (Antarctica) since the Last Glacial Maximum

  ˜The œcryosphere · 2025-08-06

  articleOpen access

  Abstract. Ice streams in the Ross Sea Embayment (West Antarctica) retreated up to 1000 km since the Last Glacial Maximum (LGM). One way that bathymetry influenced this retreat was through the presence of local bathymetric highs, or pinning points, which decreased ice flux through the grounding line and slowed grounding line retreat. During this time, glacial isostatic adjustment vertically shifted the underlying bathymetry, altering the grounding line flux. Continental-scale modeling efforts have demonstrated how solid Earth–ice sheet interactions impact the deglacial retreat of marine ice sheets; however, these models are too coarse to resolve small-scale bathymetric features. We pair a high-resolution bathymetry model with a simple model of grounding line stability in an ensemble approach to predict zones of potential grounding line persistence in the Ross Sea Embayment for given combinations of surface mass balance rate, degree of ice shelf buttressing, basal friction coefficient, and bathymetry (corrected for glacial isostatic adjustment using three different ice sheet histories). We find that isostatic depression within the interior of the Ross Sea Embayment during the LGM restricts zones where grounding lines can persist to near the edge of the continental shelf. Most grounding lines cannot persist near the present-day grounding line until sufficient uplift has occurred (mid-Holocene; ∼ 5 ka), and this uplift causes a net upstream migration of grounding line persistence zones across the deglaciation. Additionally, our results show that coarse-resolution bathymetry underpredicts possible stable grounding line positions, particularly near the present-day grounding line, highlighting the importance of bathymetric resolution in capturing the impact of glacial isostatic adjustment on ice stream stability.

  PublisherOA PDFDOI

• Glacial isostatic adjustment shifted early Holocene river hydrology in Maine, USA

  Geology · 2025-03-07 · 1 citations

  article

  Abstract Glacial isostatic adjustment produces crustal deformation capable of altering the slope of the landscape and diverting surface water drainage, thereby modulating the hydraulic conditions that govern river evolution. These effects can be especially important near the margins of ice sheets. In Maine, USA, post-glacial changes in sedimentation within major river systems have been interpreted as the result of regional tilting and drainage rerouting due to glacial isostatic adjustment. In this study, we model isostatic adjustment driven by retreat of the Laurentide Ice Sheet, quantify the associated tilting and drainage rerouting, and explore how these changes impacted sediment transport in Maine's rivers. Through an analysis of changes to river slope and drainage area produced by glacial isostatic adjustment, we show that ice sheet retreat altered the median sediment grain size that rivers could entrain. We also find support for previous estimates of the timing and direction of drainage reversal at Moosehead Lake, Maine's largest lake. Our results suggest that the history of sedimentation in Maine's rivers reflects time-dependent effects of glacial isostatic adjustment that are superimposed on any changes in runoff associated with deglaciation. Further, our case study demonstrates that isostatic adjustment affects alluvial channel evolution and sediment delivery to the coastline for several millennia after an ice sheet retreats.

  PublisherDOI

• Sediment loading from the Río de la Plata as a driver of regional sea-level variability

  Earth and Planetary Science Letters · 2025-11-27

  preprintOpen access

  Sea-level reconstructions are critical benchmarks for testing models of ice-sheet stability and climate change. Their interpretation, however, is complicated by sea-level changes driven by different processes, among which the Earth’s response to sediment loading. Here we show that incorporating sediment isostasy reduces long-standing discrepancies among Marine Isotopic Stage (MIS) 5a and 5e records from the Río de la Plata estuary by up to an order of magnitude, demonstrating that regional sedimentary histories can shift relative sea-level estimates by several meters compared to traditional GIA-based approaches. We further demonstrate that sediment loading has influenced relative sea level throughout the Holocene and continues to affect modern tide-gauge records from the area. These findings underscore the importance of regionally resolved sedimentation histories, in contrast to approaches based solely on global compilations, and highlight the need for expanded shelf coring and seismic surveys.

  PublisherDOI

• Impact of glacial isostatic adjustment on zones of potential grounding line stability in the Ross Sea Embayment (Antarctica) since the Last Glacial Maximum

  2024-12-16 · 1 citations

  preprintOpen access

  Abstract. Ice streams in the Ross Sea Embayment (West Antarctica) retreated up to 1,000 kilometers since the Last Glacial Maximum, constituting one of the largest changes in deglacial Antarctic ice sheet volume and extent. One way that bathymetry influenced this retreat was through the presence of local bathymetric highs, or “pinning points”, which decreased ice flux through the grounding line and slowed grounding line retreat. During this time, glacial isostatic adjustment vertically shifted the underlying bathymetry, altering the grounding line flux. Continental scale modeling efforts have demonstrated the impact of solid Earth-ice sheet interactions on the deglacial retreat of marine ice sheets, however, these models are too coarse to resolve small scale bathymetric features. We pair a high-resolution bathymetry model with a simple model of grounding line stability in an ensemble approach to predict zones of potential grounding line stability in the Ross Sea Embayment for given combinations of surface mass balance rate, degree of ice shelf buttressing, basal friction coefficient, and bathymetry (corrected for glacial isostatic adjustment using three different ice sheet histories). We find that isostatic depression within the interior of the Ross Sea Embayment during the Last Glacial Maximum restricts zones of potential grounding line stability to near the edge of the continental shelf. Zones of potential grounding line stability do not appear near the present-day grounding line until sufficient uplift has occurred (mid-Holocene; ~5 ka), resulting in a net upstream migration of zones of potential grounding line stability across the deglaciation. Additionally, our results show that coarse resolution bathymetry underpredicts possible stable grounding line positions, particularly near the present-day grounding line, highlighting the importance of bathymetric resolution in capturing the impact of glacial isostatic adjustment on ice stream stability.

  PublisherDOI

• Input and output used in publication "Glacial isostatic adjustment shapes proglacial lakes over glacial cycles"

  Zenodo (CERN European Organization for Nuclear Research) · 2024-05-06

  datasetOpen access

  Here we provide the input ice history and topography used for the modeling along with the output sea level and proglacial lake volume & geometries. Please see the read.me file and publication for details. Note that version 1 had incorrect files saved for some of the output, including the default run LAM_PC. Please use version 2 when recreating our results.

  PublisherDOI

• Melting the Marinoan Snowball Earth: The impact of deglaciation duration on the sea-level history of continental margins

  Earth and Planetary Science Letters · 2024-11-24 · 3 citations

  articleOpen access

  • Modeled sea-level histories resulting from the deglaciation of Snowball Earth. • Short deglacial durations result in a limited range of sea-level patterns. • Longer deglaciations can drive two distinct intervals of sea-level rise and fall. • Long deglaciation may have contributed to geologic record of the Naukluft Mts. The termination of the Marinoan Snowball Earth (∼635 Ma) represents a significant transition in Earth's climate. Cap carbonate strata, and underlying glaciogenic deposits, record global deglaciation and preserve diverse relative sea-level histories, representing the intersection of global mean sea-level rise with regional forcings such as glacial isostatic adjustment and sedimentation. For example, at cap carbonate outcrops in the Naukluft Mountains of central Namibia, facies transitions reveal two intervals of water-depth deepening and shallowing. While many factors may have contributed to this deglacial pattern of relative sea-level change, here we consider the possibility that this, and other, non-monotonic sea-level histories, were driven by glacial isostatic adjustment. We modeled relative sea-level change due to glacial isostatic adjustment for a globally synchronous and continuous Marinoan deglaciation, and explored how the duration of deglaciation impacts the range of resulting relative sea-level patterns across continental margins. Short Snowball deglaciation durations, on the order of ∼2 kyr, result in exclusive relative sea-level rise, or relative sea-level rise followed by relative sea-level fall but cannot drive two distinct phases of relative sea-level fall. However, longer duration Snowball deglaciations, of ∼10–30 kyr, can drive two distinct intervals of relative sea-level rise and fall across much of the width of a continental margin, which may have contributed to the stratal patterns observed in Naukluft Mountains cap carbonate, though we cannot exclude that the pattern arises from changes in sediment supply or other factors. This work underlines the need for better constraints on the areal distribution and volume of Marinoan ice sheets from field observations, as well as plausible deglacial durations from global climate models.

  PublisherDOI

Recent grants

• Bounding global ice volumes over the last glacial cycle using reconstructions of Bering Strait flooding

  NSF · $321k · 2021–2026

• Tracking Past Ice Sheets with North American River Drainage Basin Captures Induced by Glacial Isostatic Adjustment

  NSF · $413k · 2021–2026

• EAR-PF: Revisiting Megafloods: Insights From Glacial Isostatic Adjustment on Flood Size, Flow Routes, and Climate Response

  NSF · $174k · 2019–2021

Frequent coauthors

• J. X. Mitrovica

  83 shared

• Jacqueline Austermann

  32 shared

• Gino de Gelder

  Université Claude Bernard Lyon 1

  25 shared

• Laurent Husson

  Centre National de la Recherche Scientifique

  21 shared

• Jean Braun

  Helmholtz Centre Potsdam - GFZ German Research Centre for Geosciences

  20 shared

• Evelyn Powell

  19 shared

• Alan C Mix

  Oregon State University

  15 shared

• Denovan Chauveau

  15 shared

Labs

• Pico GroupPI

  Not provided