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Daniel H Doctor

Daniel H. Doctor is a Research Geologist at the Florence Bascom Geoscience Center.

Dan is a research geologist conducting geologic mapping and specialized geologic research for the Appalachian Basin project. His current research interests include stratigraphy of the Appalachian Basin, landscape evolution within the Appalachian Valley and Ridge physiographic province, karst hydrology and geomorphology, sinkhole hazard studies, and paleoclimate records from karst regions.

Dan began a career with the USGS in 2002 as an NRC postdoc within the Isotope Tracers of Biogeochemical and Hydrologic Processes project of the National Research Program in Menlo Park, California. In 2006, he joined the Florence Bascom Geoscience Center in Reston, Virginia. 

Professional Experience

  • Research Geologist (2006-present). U.S. Geological Survey, KARST Project, Eastern Geology and Paleoclimate Science Center, Reston, VA

  • Hydrologist (2004-2006). U.S. Geological Survey, Isotope Tracers Group, Water Resources Division, Menlo Park, CA

  • Postdoctoral Research Associate, National Research Council (NRC) (2002-2004). U.S. Geological Survey, Isotope Tracers Group, Water Resources Division, Menlo Park, CA

  • Project Analyst (2001). Lands and Minerals Division, Minnesota Department of Natural Resources (MN-DNR).

Education and Certifications

  • Ph.D. (2002) in Hydrogeology/Geochemistry, with Doctoral Minor in Water Resources Science, University of Minnesota, Dept. of Geology and Geophysics, Minneapolis, MN

  • Bachelor of Arts (1994) in Geology, Minor in Environmental Studies, Colgate University, Hamilton, NY (Magna Cum Laude, Phi Beta Kappa)

Science and Products

Filter Total Items: 27

Karst geology of the Upper Midwest, USA

Karst in the Upper Midwest occurs within a thick sequence of mixed carbonate and siliciclastic Cambrian through Pennsylvanian sedimentary rocks, with a minor occurrence of karst in Proterozoic sandstone. Deposition of the sediments occurred on a marine epeiric ramp that spanned much of the North American continent through most of the Paleozoic. The Upper Midwest region experienced dramatic changes
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Florence Bascom Geoscience Center

Progress toward a preliminary karst depression density map for the conterminous United States

Most methods for the assessment of sinkhole hazard susceptibility are predicated upon knowledge of pre-existing closed depressions in karst areas. In the United States (U.S.), inventories of existing karst depressions are piecemeal, and are often obtained through inconsistent methodologies applied at the state or county level and at various scales. Here, we present a first attempt at defining a ka
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Science Analytics and Synthesis (SAS), Western Geographic Science Center, Florence Bascom Geoscience Center

Appalachian Basin stratigraphy, tectonics, and eustasy from the Blue Ridge to the Allegheny Front, Virginia and West Virginia

This guide is from a two-day field trip in western Virginia and eastern West Virginia held before the 2015 Geological Society of America annual meeting in Baltimore, Maryland. The field trip examines exposures of Paleozoic sedimentary strata in the Appalachian Basin starting in the Blue Ridge physiographic province, going through the Valley and Ridge physiographic province, and ending in the Appal
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Florence Bascom Geoscience Center

New insight into the origin of manganese oxide ore deposits in the Appalachian Valley and Ridge of northeastern Tennessee and northern Virginia, USA

Manganese oxide deposits have long been observed in association with carbonates within the Appalachian Mountains, but their origin has remained enigmatic for well over a century. Ore deposits of Mn oxides from several productive sites located in eastern Tennessee and northern Virginia display morphologies that include botryoidal and branching forms, massive nodules, breccia matrix cements, and fra
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Florence Bascom Geoscience Center

Hypogene caves of the central Appalachian Shenandoah Valley in Virginia

Several caves in the Shenandoah Valley in Virginia show evidence for early hypogenic conduit development with later-enhanced solution under partly confined phreatic conditions guided by geologic structures. Many (but not all) of these caves have been subsequently invaded by surface waters as a result of erosion and exhumation. Those not so affected are relict phreatic caves, bearing no relation to
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Florence Bascom Geoscience Center

Book review: Karst without boundaries

No abstract available.
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Florence Bascom Geoscience Center

Predicting the occurrence of cave-inhabiting fauna based on features of the earth surface environment

One of the most challenging fauna to study in situ is the obligate cave fauna because of the difficulty of sampling. Cave-limited species display patchy and restricted distributions, but it is often unclear whether the observed distribution is a sampling artifact or a true restriction in range. Further, the drivers of the distribution could be local environmental conditions, such as cave humidity,
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Ecosystems, Eastern Ecological Science Center

Analysis of hydrologic and geochemical time-series data at James Cave, Virginia: Implications for epikarst influence on recharge in Appalachian karst aquifers

The epikarst, which consists of highly weathered rock in the upper vadose zone of exposed karst systems, plays a critical role in determining the hydrologic and geochemical characteristics of recharge to an underlying karst aquifer. This study utilized time series (2007–2014) of hydrologic and geochemical data of drip water collected within James Cave, Virginia, to examine the influence of epikars
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Florence Bascom Geoscience Center

A semi-automated tool for reducing the creation of false closed depressions from a filled LIDAR-derived digital elevation model

Closed depressions on the land surface can be identified by ‘filling’ a digital elevation model (DEM) and subtracting the filled model from the original DEM. However, automated methods suffer from artificial ‘dams’ where surface streams cross under bridges and through culverts. Removal of these false depressions from an elevation model is difficult due to the lack of bridge and culvert inventories
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Florence Bascom Geoscience Center

Karst of the Mid-Atlantic region in Maryland, West Virginia, and Virginia

The Mid-Atlantic region hosts some of the most mature karst landscapes in North America, developed in highly deformed rocks within the Piedmont and Valley and Ridge physiographic provinces. This guide describes a three-day excursion to examine karst development in various carbonate rocks by following Interstate 70 west from Baltimore across the eastern Piedmont, across the Frederick Valley, and in
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Florence Bascom Geoscience Center

Hydrologic and geochemical dynamics of vadose zone recharge in a mantled karst aquifer: Results of monitoring drip waters in Mystery Cave, Minnesota

Caves provide direct access to flows through the vadose zone that recharge karst aquifers. Although many recent studies have documented the highly dynamic processes associated with vadose zone flows in karst settings, few have been conducted in mantled karst settings, such as that of southeastern Minnesota. Here we present some results of a long-term program of cave drip monitoring conducted withi
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Florence Bascom Geoscience Center

Karst mapping in the United States: Past, present and future

The earliest known comprehensive karst map of the entire USA was published by Stringfield and LeGrand (1969), based on compilations of William E. Davies of the U.S. Geological Survey (USGS). Various versions of essentially the same map have been published since. The USGS recently published new digital maps and databases depicting the extent of known karst, potential karst, and pseudokarst areas of
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Florence Bascom Geoscience Center
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Team of scientists stand in front of outcrop

Appalachian Basin Geologic Mapping Project

The Appalachian Basin Geologic Mapping Project performs geologic mapping at local and regional scales, and geologic research in The Valley and Ridge and Appalachian Plateaus physiographic provinces. These provinces include parts of 11 states and mainly borders the Blue Ridge / Piedmont and North Interior Lowlands Provinces. Two states have Valley and Ridge geology only (GA, NJ), two have...
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Core Science Systems, Water Resources, National Cooperative Geologic Mapping Program, Florence Bascom Geoscience Center
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Appalachian Basin Geologic Mapping Project

The Appalachian Basin Geologic Mapping Project performs geologic mapping at local and regional scales, and geologic research in The Valley and Ridge and Appalachian Plateaus physiographic provinces. These provinces include parts of 11 states and mainly borders the Blue Ridge / Piedmont and North Interior Lowlands Provinces. Two states have Valley and Ridge geology only (GA, NJ), two have...
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USGS science for a changing world logo

Subsidence Susceptibility Map for the Conterminous U.S.

Sinkholes present hazards to humans due to subsidence and by focusing contaminated surface water runoff into groundwater. Sinkholes create instability in the foundations of buildings, roads and other infrastructure, resulting in damage and in some cases loss of life, but may also play an important role as vernal pools in some ecosystems. This project created a prototype nationwide subsidence susc
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Community for Data Integration (CDI)
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Subsidence Susceptibility Map for the Conterminous U.S.

Sinkholes present hazards to humans due to subsidence and by focusing contaminated surface water runoff into groundwater. Sinkholes create instability in the foundations of buildings, roads and other infrastructure, resulting in damage and in some cases loss of life, but may also play an important role as vernal pools in some ecosystems. This project created a prototype nationwide subsidence susc
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Filter Total Items: 26

Stream temperature, dissolved radon, and stable water isotope data collected along headwater streams in the upper Neversink River watershed, NY, USA

The Neversink River watershed (above the Neversink Reservoir) has been a focus of U.S. Geological Survey research for decades regarding stream geochemistry, acidification, and ecology dynamics. In 2019, the Water Mission Area Next Generation Water Observing Systems Program (NGWOS) augmented the existing stream gage network to include multiscale instrumentation aimed at characterizing various aspec

Enhanced Terrain Imagery of the Sunbury 30 x 60 Minute Quadrangle from Lidar-Derived Elevation Models at 3-Meter Resolution

This imagery dataset consists of 3-meter resolution, lidar-derived imagery of the Sunbury 30 x 60 minute quadrangle Pennsylvania. It also covers part of the Delaware River Basin. The source data used to construct this imagery consists of 1-meter and 3-meter resolution Lidar-derived digital elevation models (DEMs). The lidar source data were compiled from different acquisitions published between 20
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Florence Bascom Geoscience Center

Enhanced Terrain Imagery of the York 30 x 60 Minute Quadrangle from Lidar-Derived Elevation Models at 3-Meter Resolution

This imagery dataset consists of 3-meter resolution, lidar-derived imagery of the York 30 x 60 minute quadrangle in Pennsylvania and Maryland. It also covers part of the Delaware River Basin. The source data used to construct this imagery consists of 1-meter and 2-meter resolution Lidar-derived digital elevation models (DEMs). The lidar source data were compiled from different acquisitions publish
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Florence Bascom Geoscience Center

Enhanced Terrain Imagery of the Hagerstown 30 x 60 Minute Quadrangle from Lidar-Derived Elevation Models at 3-Meter Resolution

This imagery dataset consists of 3-meter resolution, lidar-derived imagery of the Hagerstown 30 x 60 minute quadrangle in Pennsylvania, Maryland, and part of West Virginia. The source data used to construct this imagery consists of 1-meter and 3-meter resolution Lidar-derived digital elevation models (DEMs). The lidar source data were compiled from different acquisitions published between 2014 and
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Florence Bascom Geoscience Center

Enhanced Terrain Imagery of the Harrisburg 30 x 60 Minute Quadrangle from Lidar-Derived Elevation Models at 3-Meter Resolution

This imagery dataset consists of 3-meter resolution, lidar-derived imagery of the Harrisburg 30 x 60 minute quadrangle in Pennsylvania. It also covers part of the Delaware River Basin. The source data used to construct this imagery consist of 1-meter and 3-meter resolution lidar-derived digital elevation models (DEMs). The lidar source data were compiled from different acquisitions published betwe
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Florence Bascom Geoscience Center

Enhanced Terrain Imagery of the Reading 30 x 60 Minute Quadrangle from Lidar-Derived Elevation Models at 3-Meter Resolution

This imagery dataset consists of 3-meter resolution, lidar-derived imagery of the Reading 30 x 60 minute quadrangle in Pennsylvania and parts New Jersey. It also covers part of the Delaware River Basin. The source data used to construct this imagery consists of 1-meter and 3-meter resolution Lidar-derived digital elevation models (DEMs). The lidar source data were compiled from different acquisiti
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Florence Bascom Geoscience Center

Enhanced Terrain Imagery of the Wilmington 30 x 60 Minute Quadrangle from Lidar-Derived Elevation Models at 3-Meter Resolution

This imagery dataset consists of 3-meter resolution, lidar-derived imagery of the Wilmington 30 x 60 minute quadrangle in parts of Pennsylvania, Maryland, Delaware, and New Jersey. It also covers part of the Delaware River Basin. The source data used to construct this imagery consists of 1-meter and 3-meter resolution Lidar-derived digital elevation models (DEMs). The lidar source data were compil
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Florence Bascom Geoscience Center

2015-2017 lidar-derived imagery of karst areas in Puerto Rico at 1-meter resolution

This raster dataset contains 1-meter lidar-derived imagery of 7.5 minute quadrangles in karst areas of Puerto Rico and was created using geographic information systems (GIS) software. Lidar-derived elevation data, acquired between 2015 and 2017, were used to create a 1-meter resolution working digital elevation model (DEM). To create this imagery, a hillshade was applied and a topographic position
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Florence Bascom Geoscience Center

2018 lidar-derived imagery of karst areas in Puerto Rico at 1-meter resolution

This raster dataset contains 1-meter lidar-derived imagery of 7.5 minute quadrangles in karst areas of Puerto Rico and was created using geographic information systems (GIS) software. Lidar-derived elevation data, acquired in 2018, were used to create a 1-meter resolution working digital elevation model (DEM). To create this imagery, a hillshade was applied and a topographic position index (TPI) r
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Florence Bascom Geoscience Center

Enhanced Terrain Imagery of the Newark 30 x 60 Minute Quadrangle from Lidar-Derived Elevation Models at 3-Meter Resolution

This imagery dataset consists of 3-meter resolution, lidar-derived imagery of the Newark 30 x 60 minute quadrangle. It covers portions of New Jersey and New York, including parts of the Delaware River Basin. The source data used to construct this imagery consist of 1-meter, 2-meter, and 3-meter resolution lidar-derived digital elevation models (DEM). The lidar source data were compiled from differ
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Florence Bascom Geoscience Center

Lidar-derived closed depression vector and density raster in karst areas of the Winchester 30 x 60-minute quadrangle

The Winchester 30 x 60 minute quadrangle, covering northern Virginia, West Virginia, and Maryland, hosts karsts within carbonate units of Devonian to Cambrian age. Lidar-derived elevation data, acquired between 2011 and 2019, were used to create a mosaic of 1-meter resolution working digital elevation models (DEMs), from which surface depressions were identified using a semi-automated workflow in
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Florence Bascom Geoscience Center

Depth to bedrock determined from passive seismic measurements, Neversink River watershed, NY (USA)

This data release documents streambed sediment thickness in the Neversink watershed (NY) as determined by field observations and HVSR passive seismic measurements, and were collected as an extension of a previous data set collected in the same watershed (see Associated Items). These measurements were made between May 17, 2021 and May 21, 2021 using MOHO Tromino three-component seismometers (MOHO,
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New York Water Science Center

Geologic map of the Hayfield quadrangle, Frederick County, Virginia

The Hayfield 7.5-minute quadrangle is located within the Valley and Ridge physiographic province of northern Virginia. The quadrangle includes the topographical lowland area of the northern Great Valley to the southeast, the narrow ridge of Little North Mountain along the western edge of the Great Valley, and the broad region of elongated valleys and ridges west of Little North Mountain. The most
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Florence Bascom Geoscience Center
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National Preparedness Month 2020: Landslides and Sinkholes

Natural hazards have the potential to impact a majority of Americans every year. USGS science provides part of the foundation for emergency...

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