About

Lidya Tarhan is an Assistant Professor of Earth & Planetary Sciences at Yale University and an Assistant Curator of Invertebrate Paleontology at the Yale Peabody Museum. Her research focuses on using the sedimentary record to develop a multidisciplinary understanding of ancient life during key intervals in Earth’s history. She investigates the interplay between animals and environments and the role of animals as ecosystem engineers, spanning from the micron scale to landscape- and ocean-wide scales, in both ancient and modern settings. Her work combines sedimentological and paleontological approaches with geochemical and experimental tools, grounded in field work, specimen analysis, laboratory studies, and modeling.

Research topics

• Geology
• Chemistry
• Environmental chemistry
• Oceanography
• Ecology
• Biology
• Earth science
• Environmental science
• Paleontology
• Geochemistry

Selected publications

• The evolution of Earth's marine carbonate factory

  Palaeogeography Palaeoclimatology Palaeoecology · 2026-03-22

  article1st authorCorresponding
  PublisherDOI

• Author Correction: The history of Earth’s sulfur cycle

  Nature Reviews Earth & Environment · 2026-03-30

  articleOpen access
  PublisherOA PDFDOI

• Carbon/phosphorus burial ratio reveals a rapid spread of land plants during the Late Ordovician

  Figshare · 2026-01-01 · 1 citations

  datasetOpen access

  All compiled and newly analyzed data for the study: “Carbon/phosphorus burial ratio reveals a rapid spread of land plants during the Late Ordovician.”

  PublisherDOI

• Carbon/phosphorus burial ratio reveals a rapid spread of land plants during the Late Ordovician

  Nature Ecology & Evolution · 2026-02-24 · 1 citations

  article
  PublisherDOI

• New insights on the depositional environment and dynamics of the lowermost Triassic in Svalbard: linking the Sørkapp-Hornsund High to western and central Spitsbergen

  Sedimentologika · 2026-04-09 · 1 citations

  articleOpen access

  The area now known as the Barents Shelf region was strongly impacted by the End-Permian Mass Extinction and a fundamental reorganisation of source-to-sink systems along the northern margin of Pangaea. Here we integrate new sedimentological, ichnological, chemostratigraphic, and provenance data from western Spitsbergen, collected at Festningen, Reinodden, and the Sørkapp-Hornsund High (Hornsundneset, southern Spitsbergen), to reconstruct the timing and drivers of Early Triassic basin evolution. At Festningen and Reinodden, the sharp but conformable transition from Permian spiculitic Kapp Starostin Formation strata to siliciclastic mudstones and sandstones of the Lower Triassic Vardebukta Formation coincides with the onset of the negative δ13Corg excursion. The Vardebukta Formation preserves seven stacked transgressive–regressive packages within an Induan-age interval of ca 1.2 to 1.6 Myr. Individual cycle durations (ca 177 to 225 kyr) are incompatible with a single dominant Milankovitch component and instead suggest bundling of orbital frequencies and/or strong autogenic modulation of accommodation and sediment supply. On the Sørkapp-Hornsund High, a 75 Myr hiatus above Mississippian continental deposits is terminated by a 10 to 15 cm thick bentonitic tephra bed linked to the Siberian Traps Large Igneous Province. This is overlain by Induan-age polymictic alluvial-fan and ephemeral braided-river conglomerates (Brevassfjellet Beds), on which limited but recurrent vegetation cover developed. Detrital-zircon age spectra from the conglomerates closely match published data from the Vardebukta Formation at Festningen and the Induan-age Parish Bjerg Formation in Greenland, indicating a shared north Greenland Caledonian source and direct sediment routing during the latest Permian and earliest Triassic. These continental conglomerates are capped by fossiliferous shallow-marine limestones of Dienerian age, which are then overlain by the coarsening-upward shelfal succession of the Vardbukta Formation. The timing of Dienerian flooding of the Sørkapp-Hornsund High is not aligned with any individual transgressive-regressive package in the Vardebukta Formation, implying that local tectonic subsidence of a promontory-like high, rather than eustatic rise, governed its transgression. This research refines the palaeogeographical and tectonostratigraphical evolution of the northern margin of Pangaea during the latest Permian and earliest Triassic.

  PublisherDOI

• The deep-time climate archive of Svalbard (SVALGEOL 2)

  Zenodo (CERN European Organization for Nuclear Research) · 2026-01-26

  reportOpen access

  This is chapter 1 of the State of Environmental Science in Svalbard (SESS) report 2025. Palaeoclimatology refers to the study of Earth’s climate and related changes in the geological past. Svalbard’s rocks inform geoscientists about how the Earth system has functioned over our planet’s history, across timescales spanning thousands to millions of years. By better understanding past behaviour of our planet, we can more confidently predict how the global ecosystem will function in the future. It is only in the deep geological past that planet Earth had high atmospheric CO2 concentrations similar to those we are heading towards. Svalbard provides an excellent platform for these investigations, and an ongoing scientific drilling project (SVALCLIME) aims to acquire drill cores to provide a nearly continuous climate archive from 260 to 50 million years ago (ranging in geologic age from the Permian to Palaeogene periods)—a roughly 210 million year long interval that is particularly well preserved in Svalbard’s rock record. Geoscientists can use these records to decipher how the Earth responded to major changes caused by, for instance, large-scale volcanism, meteorite impacts or the movement of continents. This chapter update provides a synthesis of Svalbard’s rock record and an overview of the proxies that can be used to reconstruct past climate change and its impacts. In addition, the chapter provides curated data packages of several key palaeoenvironmental and palaeoclimate proxies (carbon and oxygen isotopes, pyrolysis and mercury) from 34 publications.

  PublisherDOI

• Carbon/phosphorus burial ratio reveals a rapid spread of land plants during the Late Ordovician

  Figshare · 2026-01-01

  datasetOpen access

  All compiled and newly analyzed data for the study: “Carbon/phosphorus burial ratio reveals a rapid spread of land plants during the Late Ordovician.”

  PublisherDOI

• The deep-time climate archive of Svalbard (SVALGEOL 2)

  Zenodo (CERN European Organization for Nuclear Research) · 2026-01-26

  reportOpen access

  This is chapter 1 of the State of Environmental Science in Svalbard (SESS) report 2025. Palaeoclimatology refers to the study of Earth’s climate and related changes in the geological past. Svalbard’s rocks inform geoscientists about how the Earth system has functioned over our planet’s history, across timescales spanning thousands to millions of years. By better understanding past behaviour of our planet, we can more confidently predict how the global ecosystem will function in the future. It is only in the deep geological past that planet Earth had high atmospheric CO2 concentrations similar to those we are heading towards. Svalbard provides an excellent platform for these investigations, and an ongoing scientific drilling project (SVALCLIME) aims to acquire drill cores to provide a nearly continuous climate archive from 260 to 50 million years ago (ranging in geologic age from the Permian to Palaeogene periods)—a roughly 210 million year long interval that is particularly well preserved in Svalbard’s rock record. Geoscientists can use these records to decipher how the Earth responded to major changes caused by, for instance, large-scale volcanism, meteorite impacts or the movement of continents. This chapter update provides a synthesis of Svalbard’s rock record and an overview of the proxies that can be used to reconstruct past climate change and its impacts. In addition, the chapter provides curated data packages of several key palaeoenvironmental and palaeoclimate proxies (carbon and oxygen isotopes, pyrolysis and mercury) from 34 publications.

  PublisherDOI

• Experimental Ge/Si partitioning during organic-mediated silica precipitation

  Chemical Geology · 2025-11-23

  articleSenior author
  PublisherDOI

• Bioturbation Shapes Marine Biogeochemical Cycling Following the End‐Permian Mass Extinction in Northern Pangea

  Geobiology · 2025-09-01 · 2 citations

  articleSenior author

  During the end-Permian mass extinction, a global decline in seafloor sediment mixing and burrowing (bioturbation) provides critical evidence for the collapse of marine ecosystems, likely triggered by rapid ocean warming and deoxygenation. However, the decline and subsequent recovery of bioturbation after the extinction event may not only have been a symptom of environmental change but also a driver, influencing nutrient exchange and reductant burial across the sediment-water interface and thus water column oxygen availability and seafloor habitability more broadly. Here we test this hypothesis through combined analyses of bioturbation and sedimentary geochemistry, focusing on marine siliciclastic records of the Permian-Triassic transition from Svalbard. We find that total organic carbon, total sulfur, and organic phosphorus decrease with increasing bioturbation intensity, whereas inorganic reactive phosphorus phases (authigenic and iron oxide-bound phosphorus) increase. These differences are most strongly associated with biodiffusion (particle mixing) rather than bioirrigation (solute exchange). Our findings suggest that bioturbation primarily influenced sediment chemistry by enhancing organic matter oxidation, in contrast to some modern settings where downward mixing may promote organic matter preservation within the anoxic portion of seafloor sediments. The early return of shallow-tier bioturbators in this region < 200 kyr after the extinction event likely promoted a rapid restoration of efficient carbon and sulfur cycling within benthic ecosystems. In contrast, efficient phosphorus burial via sink-switching may not have resumed until deeper-tier bioturbators achieved pre-extinction levels of sediment mixing > 1 Myr after the mass extinction.

  PublisherDOI

Recent grants

• EAR-PF: The Silicification of Soft-Bodied Biotas: Reconstructing the Preservation, Ecology and Environments of Earth's Earliest Animal Communities

  NSF · $174k · 2016–2017

Frequent coauthors

• Noah J. Planavsky

  Yale University

  108 shared

• Mingyu Zhao

  Chinese Academy of Sciences

  59 shared

• Mary L. Droser

  University of California, Riverside

  37 shared

• James G. Gehlîng

  33 shared

• Derek E. G. Briggs

  Yale University

  25 shared

• Dan Asael

  Planetary Science Institute

  23 shared

• Mojtaba Fakhraee

  Yale University

  23 shared

• Silvina Slagter

  Planetary Science Institute

  20 shared

Labs

• Tarhan Geobiology LabPI

Education

• Ph.D., Geological Sciences

  University of California, Riverside

  2013

• M.S., Geological Sciences

  University of California, Riverside

  2010

• B.A., magna cum laude, Geology and English

  Amherst College

  2008