HomeMy WebLinkAboutCT 2024-0001; TYLER STREET HOMES - SB 330; PALEONTOLOGICAL RESOURCE TECHNICAL MEMORANDUM; 2024-04-23Paleontological Resource Assessment for the 3215-3225 Tyler Street Development Project.
City of Carlsbad, San Diego County, California
Regulatory Context
Paleontological resources (i.e., fossils) are considered nonrenewable scientific resources
because, once destroyed, they cannot be replaced. As such, paleontological resources are
afforded protection under various federal. state, and local laws and regulations. Laws pertinent to
this Project are discussed below.
State Laws and Regulations
California Environmental Quality Act
CE0A requires that public agencies and private interests identify the potential environmental
consequences of their projects on any object or site of significance to the scientific annals of
California (Division I, California Public Resources Code [ PRC] Section 5020.1 [j]). Appendix Gin
Section 15023 provides an Environmental Checklist of questions ( Section 15023, Append ix G,
Section XIV, Part A) that includes the following: "Would the project directly or indirectly destroy a
unique paleontological resource or site or unique geological feature?"
California Public Resources Code
Section 5097.5 of the Public Resources Code (PRC) states:
No person shall knowingly and willfully excavate upon, or remove, destroy, injure, or
deface any historic or prehistoric ruins, burial grounds, archaeolog ical or
vertebrate paleontological site, including fossilized footprints, inscriptions made
by human agency, or any other archaeological, paleontological, or historical
feature, situated on public lands, except with the express permission of the public
agency having jurisdiction over such lands. Violation of this section is a
misdemeanor. As used in this PRC section, 'public lands' means lands owned by, or
under the jurisdiction of, the state or any city, county, district, authority, or public
corporation, or any agency thereof.
Consequently, public agencies are required to comply with PRC 5097.5 for their activities including
construction and maintenance as well as for permit actions (e.g., encroachment permits)
undertaken by others.
Local
The City of Carlsbad General Plan, Arts, History, Culture, and Education (City of Carlsbad, 2015)
established the following policies with respect to archeological and paleontological resources:
7-P.7 Implement the City of Carlsbad Cultural Resources Guidelines to avoid or
substantially reduce impacts to archaeological and paleontological resources.
7-P.8 During construction of specific development projects, require monitoring
of grading, ground-disturbing, and other major earthmoving activities in previously
undisturbed areas or in areas with known archaeological or paleontological
resources by a qualified professional. as well as a tribal monitor during activities in
areas with cultural resources of interest to local Native American tribes. Both the
qualified professional and tribal monitor shall observe grading, ground-dist urbing,
and other earth-moving activities.
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Paleontological Resource Assessment for the 3215-3225 Tyler Street Development Project,
City of Carlsbad, San Diego County, California
Paleontological Resource s
Paleontological Resource Definition
Society of Vertebrate Paleontology (SVP) has provided guidance designed to support state and
federal environmental review. The SVP broadly defines significant paleontological resources as
follows:
Fossils and fossiliferous deposits consisting of identifiable vertebrate fossils, large
or small, uncommon invertebrate, plant, and trace fossils, and other data that
provide taphonomic, taxonomic, phylogenetic, paleoecologic, stratigraphic, and/or
biochronologic information. Paleontological resources are considered to be older
than recorded human history and/or older than middle Holocene (i.e., older than
about 5,000 radiocarbon years). (SVP, 2010)
Significant paleontological resources are determined to be fossils or assemblages of fossils that
are unique, unusual, rare, diagnostically important, or common but have the potential to provide
valuable scientific information for evaluating evolutionary patterns and processes, or which could
improve our understanding of paleochronology, paleoecology, paleophylogeography, or
depositional histories. New or unique specimens can provide new insights into evolutionary
history; however, additional specimens of even well-represented lineages can be equally
important for studying evolutionary patterns and processes, evolutionary rates, and
paleophylogeography. Even unidentifiable material can provide useful data for dating geologic
units if radiometric dating is possible. As such, common fossils (especially vertebrates) may be
scientifically important and therefore considered significant.
This definition is used for all projects that are subject CEOA since CEQA does not define "a unique
paleontological resource or site."
Paleontological Resource Potential
Absent specific agency guidelines, most professional paleontologists in California adhere to the
guidelines set forth by SVP {2010) to determine the course of paleontological mitigation for a given
project. These guidelines establish protocols for the assessment of the paleontological resource
potential of underlying geologic units and outline measures to mitigate adverse impacts that could
result from project development. Using baseline information gathered during a paleontological
resource assessment, the paleontological resource potential of geologic units (or members
thereof) underlying a project area can be assigned to one of four categories defined by SVP (2010).
Although these standards were written specifically to protect vertebrate paleontological
resources, all fields of paleontology have adopted the following guidelines.
High Potential (Sensitivity)
Rock units from which significant vertebrate or significant invertebrate fossils or significant suites
of plant fossils have been recovered have a high potential for containing significant nonrenewable
fossiliferous resources. These units include but are not limited to, sedimentary formations and
some volcanic formations that contain significant nonrenewable paleontological resources
anywhere within their geographical extent, and sediment ary rock units temporally or lithologically
su itable for the preservation of fossils. Sensitivity comprises both (a) the potential for yielding
abundant or significant vertebrate fossils or for yielding a few significant fossils, large or small,
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Paleontological Resource Assessment for the 3215-3225 Tyler Street Development Project,
City of Carlsbad , San Diego County, California
vertebrate, invertebrate, or botanical and (b) the importance of recovered evidence for new and
significant taxonomic, phylogenetic, ecologic, or stratigraphic data. Areas which contain
potentially datable organic remains older than recent, including deposits associated with nests or
middens, and areas which may contain new vertebrate deposits, traces, or trackways are also
classified as significant.
Low Potential (Sensitivity)
Sedimentary rock units that are potentially fossiliferous but have not yielded fossils in the past or
contain common and widespread invertebrate fossils of well-documented and understood
taphonomic, phylogenetic species, and habitat ecology are considered to have a low potential for
containing significant nonrenewable fossil iferous resources. Reports in the paleontological
literature or field surveys by a qualified vertebrate paleontologist may allow a determination that
some areas or units have a low potential for yielding significant fossils before the start of
construction. Generally, these units will be poorly represented by specimens in institutional
collections and will not require protection or salvage operations. However, as excavation for
construction is underway, it is possible that significant and unanticipated paleontological
resources might be encountered and require a change of classification from low to high potential
and thus require monitoring and mitigation if the resources are found to be significant.
Undetermined Potential (Sensitivity)
Specific areas underlain by sedimentary rock units for which little information is available have
undetermined fossiliferous potentials. Field surveys by a qualified vertebrate paleontologist to
determine the rock units' potential are required before programs of impact mitigation for such
areas can be developed.
No Potential
Rock units of metamorphic or igneous origin are commonly classified as having no potential for
containing significant paleontological resources.
Methods
To assess whether a particular area has the potential to contain significant fossil resources in the
subsurface, it is necessary to review published geologic mapping to determine the geology and
stratigraphy of the area. Geologic units are considered sensitive for paleontological resources if
they are known to contain significant fossils anywhere in their extent. Therefore, a search of
pertinent local and regional museum repositories for paleontological localities within and nearby
the Project area is necessary to determine whether fossil localities have been previously
discovered within a particular rock unit. For this Project, a records search was requested of the
SDNHM collections. Records searches were also conducted of the online University of California
Museum of Paleontology (UCMP) Collections, Paleo biology Database, FAUN MAP, iDigBio, and other
published and unpublished geological and paleontological literature of the area.
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Paleontological Resource Assessment for the 3215-3225 Tyler Street Development Project,
City of Carlsbad, San Diego County, California
Resource Context
Geologic Setting
The Project area is on the western edge of the Peninsular Ranges geomorphic province. A
geomorphic province is a region of unique topography and geology distinguished from other
regions based on its landforms and tectonic history. The Peninsular Ranges are a northwest-
southeast oriented complex of blocks that extend 125 miles (mi) from the Transverse Ranges and
Los Angeles Basin to the tip of Baja California. The Pen insular Ranges are bounded to the east by
the Colorado Desert and range from 30 to 100 mi wide (Woodford et al., 1971). Locally, the Project is
located on a thick sequence of marine and nonmarine rocks, divided into basal, nearshore, marine
deposits (Demere and Walsh, 1993) and older, high-elevation, terrestrial inland deposits placed on
wave-cut terraces that formed in response to regional uplift (Demere and Walsh, 1993; Kennedy
and Tan, 2007).
Site Specific Geology and Paleontology
The geology of the Project area is mapped by Kennedy and Tan (2007) at a scale of 1: 100,000
(Figure 3). The Project area is underlain by old paralic deposits (Oop) of the Middle to Late
Pleistocene Epoch (77,400 thousand years ago [Ka] to 11,700 Ka), composed of poorly sorted,
moderately permeable, reddish-brown, interfingered siltstone, sandstone, and conglomerate
(Kennedy and Tan, 2007). Elsewhere in San Diego County, similar deposits have produced diverse
marine invertebrates such as molluscs, crustaceans, and echinoids (Stephens, 1929; Grant and
Gale, 1931; Emerson and Chace, 1959; Valentine, 1960, 1961; Kern, 1977)and less commonly marine
vertebrates such as sharks, rays, and bony fish (Jefferson, 1991a) from the lower deposits, and
occasional remains of terrestrial mammals such as camel, horse, and mammoth (Grant and
Hertlein, 1944) from the higher inland deposits (Demere and Walsh, 1993).
Records Search Results
The SDNHM records search did not produce any fossil localities from within the Project or within a 1-
mi radius (M ueller, 2023)(Attachment A). Searches of on line databases and other literature produced
multiple fossil localities within 3 mi of the Project ( Miller, 1971; Jefferson, 1991a, 1991b; Graham and
Lundelius, 2010; iDigBio, 2023; Paleobiology Database [PBDB], 2023; UCMP, 2023)(Table 1). iOigBio
(2023) produced over 1,500 specimens from multiple localities approximately 3 mi northwest of the
Project area, but the results could not be organized by locality.
Table 1. Vertebrate Localities Documented in Vicinity of Project
Locality No. Age Taxa Depth
Buena Vista Creek1 Pleistocene Bivalves and malacostracans Not
specified
Robertson Ranch, East Pleistocene Pacific mastodon (Marnrnut pacificus) Not
Village2 specified
Oceanside3 Middle to Late Bison (Bison sp.) Not
Pleistocene specified
Multiple localities4 Pleistocene Terrestrial and marine vertebrates, marine Not
invertebrates (1,576 specimens) specified
1 UCMP (2023); 3 PBDB (2023); • Jefferson (1991b); 'iDigBio (2023).
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Pale ontological Resource Assessment for the 3215-3225 Tyler Street Development Project,
City of Carlsbad, San Diego County, California
Field Survey
Paleo West staff paleontologist Nick Oliver, A.S., conducted a pedestrian field survey of the Project
area on October 6, 2023. The purpose of the field survey was to visually inspect the ground surface
for exposed fossils and to evaluate geologic exposures for their potential to contain preserved
fossil material at the subsurface. The Project area has previously been developed and has been
significantly disturbed and graded. Portions of the ground surface are covered by imported gravel,
asphalt, or vegetation from landscaping (Figure 4). Exposed sediment at the ground surface was a
consistent medium-grained to coarse-grained sand with subangular to sub rounded granules and
pebbles (Figure 5). No paleontological resources were observed during the field survey.
Findings
This memorandum uses the SVP(2010) system to assess paleontological sensitivity and the level of
effort required to manage potential impacts to significant fossil resources. Using this system, the
sensitivity of geologic units was determined by the relative abundance and risk of adverse impacts to
vertebrate fossils and significant invertebrates and plants.
Based on the literature review and museum records search results, and in accordance with the SVP
(2010) sensitivity scale, the old paralic deposits (Oop) have high paleontological sensitivity because
similar deposits have yielded significant fossils in the vicinity. This sensitivity ranking is consistent with
the paleontological sensitivity of Demere and Walsh (1993), who assign similar deposits a moderate
to high sensitivity, and Mueller (2023), who recommends a high sensitivity for Qop in the Project
area. This sensitivity ranking is also consistent with City's paleontological resources guidelines
(ECO RP Consulting, 2017), which assigns a high paleontological sensitivity to the Project area.
Because of the presence of fossil localities in the vicinity, Project-related ground disturbance has the
potential to impact paleontological resources throughout the Project area.
Table 2. Geologic Units in the Project Area and their Paleontological Sensitivity
Geologic Unit Map Age Typical Fossils2 Paleo
Abbreviation 1 Sensitivity
Old paralic Qop Middle to Pacific mastodon (M. pacificus), bison High
deposits Late (Bison sp.), other terrestrial and marine
Pleistocene vertebrates, bivalves and
malacostracans, other marine
invertebrates
1 Kennedy and Tan ( 2007).
2 Mueller, 2023; UCMP, 2023: PBOB, 2023: Jefferson, 1991b; iOigBio, 2023.
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Paleontological Resource Assessment for the 3215-3225 Tyler Street Development Project.
City of Carlsbad, San Diego County, California
Recommendations
In general, the potential for a given project to result in negative impacts to paleontological resources is
directly proportional to the amount of ground disturbance associated with the project; thus, the higher
the amount of ground disturbances within geological deposits with a known paleontological sensitivity,
the greater the potential for negative impacts to paleontological resources. Since this Project entails
excavation and grading for family dwellings, significant ground disturbances are anticipated. The
presence of high sensitivity units at the surface suggests that ground disturbance may result in
significant impacts under CEOA to paleontological resources including destruction, damage, or loss of
scientifically important paleontological resources. A qualified paleontologist should be retained to
develop and implement the measures recommended below. These measures have been developed in
accordance with SVP guidelines; if implemented, these measures will satisfy the requirements of CEQA.
Worker's Environmental Awareness Program (WEAP)
Prior to the start of the proposed Project activities, all field personnel should receive a worker's
environmental awareness training on paleontological resources. The training should provide a
description of the laws and ordinances protecting fossil resources, the types of fossil resources that
may be encountered in the Project area, the role of the paleontological monitor, outline steps to follow if
a fossil discovery is made, and contact information for the project paleontologist. The training will be
developed by the project paleontologist and can be delivered concurrently with other training, including
cultural, biological, safety, and others.
Paleontological Mitigation Monitoring
Per Policy 7-P.7 and 7-P.8 of the City of Carlsbad (2015), construction monitoring is recommended for
geologic units with high sensitivity. Due to the previous disturbance associated with the current
development of the Project area, sediment shallower than 3 feet below ground surface (bgs) is likely
disturbed, and would not require monitoring. Prior to the commencement of ground-disturbing
activities below 3 feet bgs, a professional paleontologist should be retained to prepare and implement a
paleontological mitigation plan for the Project. The plan should describe the monitoring required during
ground-disturbing activities. Monitoring should entail the visual inspection of excavated or graded areas
and trench sidewalls. If the project paleontologist determines full-time monitoring is no longer
warranted based on the geologic conditions at depth, they may recommend that monitoring be reduced
or cease entirely.
Fossil Discoveries
If a paleontological resource is discovered, the monitor will have the authority to temporarily divert the
construction equipment around the find until it is assessed for scientific significance and, if
appropriate, collected. If the resource is determined to be of scientific significance, the project
paleontologist shall complete the following steps:
1. Salvage of Fossils. If fossils are discovered, all work in the immediate vicinity should be halted
to allow the paleontological monitor and project paleontologist to evaluate the discovery and
determine if the fossil may be considered significant. If the fossils are determined to be
potentially significant. the project paleontologist or paleontological monitor should recover
them following standard field procedures for collecting paleontological resources as outlined in
the paleontological mitigation plan for the Project. Typically, fossils can be safely salvaged
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Paleontological Resource Assessment for the 3215-3225 Tyler Street Development Project,
City of Carlsbad, San Diego County, California
References
City of Carlsbad, 2015, Arts, History, Culture, and Education Element, in City of Carlsbad General
Plan, Carlsbad, California, p. 28, Electronic document,
https://www.carlsbadca.gov/home/showpublisheddocument/3432/637434861113400000
(accessed October 2023).
Demere, T.A., and Walsh, S.L., 1993, Paleontological Resources, County of San Diego: Prepared for
the San Diego Planning Commission, 68 p.
ECORP Consulting, 2017, Carlsbad Tribal, Cultural, and Paleontological Resources Guidelines.
Prepared for The City of Carlsbad, California, with contributions from Cogstone Resource
Management, September.
Emerson, W.K., and Chace, E.P., 1959, Pleistocene mollusks from Tecolote Creek, San Diego,
California: San Diego Society of Natural History, Transactions, v. 12, p. 335-345.
Graham, R.W., and Lundelius, E.L., 2010, FAUN MAP II: New Data for North American with a
Temporal Extension for the Blancan, lrvingtonian and Early Rancholabrean: Overview,
https:/ /ucmp.berkeley.edu/faunmap/about/index.html (accessed October 2023).
Grant, U.S., IV, and Gale, H.R., 1931, Catalogue of the marine Pliocene and Pleistocene Mollusca of
California: San Diego, San Diego Society of Natural History, Memoirs of the San Diego
Society of Natural History Volume 1.
Grant, U.S., IV, and Hertlein, L.G., 1944, The geology and paleontology of the marine Pliocene of San
Diego, California, Part 1, Geology: San Diego, San Diego Society of Natural History,
Memoirs of the San Diego Society of Natural History Volume 2.
iOigBio, 2023, iDigBio: Integrated Digitized Biocollections: iDigBio Specimen Portal,
http:/ /portal.idigbio.org/portal (accessed July 2023).
Jefferson, G.T., 1991a, A Catal ogue of Late Quaternary Vertebrates from California : Part One,
Nonmarine Lower Vertebrate and Avian Taxa: Natural History Museum of Los Angeles
County Technical Reports 5, 135 p., http:/ /ibecproject.com/PREDEIR_0000133.pdf.
Jefferson, G. T., 1991b, A Catalogue of Late Quaternary Vertebrates from California: Part Two,
Mammals: Natural History Museum of Los Angeles County Technical Reports 7, 135 p.,
http:/ /ibecproject.com/PREDEIR_0000133.pdf.
Kennedy, M.P., and Tan, S.S., 2007, Geologic map of the Oceanside 30' x 60' quadrangle and
adjacent areas, California: California Geological Survey, California Department of
Conservation Regional Geologic Map Series, Map No. 2, scale 1:100,000.
Kern, J .P., 1977, Origin and history of upper Pleistocene marine terraces, San Diego, California:
GSA Bulletin, v. 88, p. 1533-1566, doi:10.1130/0016-
7606(1977)88%3Cl553:0AHOUP%3E2.0.C0;2.
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Paleontological Resource Assessment for the 3215-3225 Tyler Street Development Project,
City of Carlsbad, San Diego County, California
Miller, W.E., 1971, Pleistocene Vertebrates of the Los Angeles Basin and Vicinity: (exclusive of
Rancho La Brea): Los Angeles, Los Angeles County Museum of Natural History, Bulletin of
the Los Angeles County Museum of Natural History, Science No. 10, 136 p.
Mueller, K., 2023, Unpublished museum collections records for the Tyler Street Development
Project: San Diego Natural History Museum.
Paleobiology Database ( PBDB J, 2023, The Paleobiology Database: About the PBDB,
https://paleobiodb.org/#/ (accessed August 2023).
Society of Vertebrate Paleontology (SVPJ, 2010, Standard Procedures for the Assessment and
Mitigation of Adverse Impacts to Paleontological Resources: Society of Vertebrate
Paleontology, Impact Mitigation Guidelines Revision Committee,
https:/ /vertpaleo.org/wp-
content/uploads/2021/ 01/SVP _Im pacLMitigation_Guidelines. pdf (accessed October
2022).
Stephens, F., 1929, Notes on the marine Pleistocene of San Diego County, California: San Diego
Society of Natural History, Transactions, v. 5, p. 245-256.
University of California Museum of Paleontology [UCMPJ, 2023, UCMP Specimen Search: University
of California Museum of Paleontology, https:/ /ucmpdb.berkeley.edu/ (accessed October
2022).
Valentine, J.W., 1960, Habitats and sources of Pleistocene mollusks at Torrey Pines Park,
California: Ecology, v. 41, p. 161-165, doi:10.2307/1931949.
Valentine, J.W., 1961, Paleoecologic molluscan geography of the California Pleistocene: University
of California Publications in Geological Sciences, v. 34, p. 309-442.
Woodford, A.O., Shelton, J.S., Doehring, 0.0., and Morton, R.K., 1971, Pliocene-Pleistocene History
of the Perris Block, Southern California: GSA Bulletin, v. 82, p. 3421-3448,
doi :10.1130/0016-7606(1971)82( 3421: PHOTPB ]2.0.CO ;2.
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Attachment A.
SDNHM Record Search Results
26 September 2023
Ben Scherzer
Chronicle Heritage
SAN DIEGO NATURAL HISTORY MUSEUM
301 9th Street, Suite 114
Redlands, CA 92374
RE: Paleontological Records Search -Tyler Street Oceanside
Dear Mr. Scherzer:
This letter presents the results of a paleontological records search conducted for the Tyler Street
Carlsbad project (Project), located in the northwestern portion of the City of Carlsbad, San Diego
County, California. The Project site is bound to the northwest, southwest, and southeast by commercial
development and to the northeast by Tyler Street.
Methods
A review of published geological maps covering the Project site and surrounding area was
conducted to determine the specific geologic units underlying the Project site. Each geologic unit was
subsequently assigned a paleontological resource sensitivity (Demere and Walsh, 1993). In addition, a
search of the paleontological collection records housed at the San Diego Natural History Museum
(SDNHM) was conducted in order to determine if any documented fossil collection localities occur at the
Project site or within the immediate surrounding area.
Results
Published geological reports (e.g., Kennedy and Tan, 2007) covering the Project area indicate
that the proposed Project has the potential to impact late Pleistocene-age old paralic deposits, Units 2-6
(broadly equivalent to the Bay Point Formation of Kennedy, 1975). This geologic unit and its
paleontological sensitivity are summarized below. The SDNHM does not have any recorded fossil
collection localities that lie within a one-mile radius of the Project site. A map (Figure 1) is attached at
the end of this report.
Old paralic deposits, Units 2-6 (Bay Point Formation) -Middle to late Pleistocene-age
(approximately 413,000 to 120,000 years old) old paralic deposits, Units 2-6 underlie the entire Project
site at the surface, as mapped by Kennedy and Tan (2007), and are broadly equivalent to the nearshore
marine deposits of the Bay Point Formation of Kennedy (1975). The SDNHM does not have any fossil
collection localities from the Bay Point Formation within a one-mile radius of the Project site. More
broadly, the Bay Point Formation has been assigned a high paleontological sensitivity for the diverse and
well-preserved fossils of marine invertebrates, marine vertebrates, and occasional terrestrial
vertebrates that have been recovered from these deposits in western San Diego County.
Summary and Recommendations
The high paleontological sensitivity of the Bay Point Formation in San Diego County (Demere
and Walsh, 1993) suggests the potential for construction of the proposed Project to result in impacts to
paleontological resources. Any proposed excavation activities that extend deep enough to encounter
thenat P.O. BOX 121390, SAN DIEGO, CA 92112-1390
SDNAT.ORG 619.232.3821 619.232.0248