Irino et al. Progress in Earth and Planetary Science (2018) 5:23
https://doi.org/10.1186/s40645-018-0176-7

Progress in Earth andPlanetary Science

PAPER WITH FULL DATA ATTACHEDOpen Access

Construction of perfectly continuousrecords of physical properties for dark-light
sediment sequences collected from theJapan Sea during Integrated Ocean Drilling
Program Expedition 346 and their potential
utilities as paleoceanographic studies
Tomohisa Irino1* , Ryuji Tada2, Ken Ikehara3, Takuya Sagawa4, Akinori Karasuda2, Shunsuke Kurokawa2,
Arisa Seki2 and Song Lu5

Abstract
Establishment of sedimentary sequence is essential for the interpretation of the sedimentary records. Integrated
Ocean Drilling Program (IODP) Expedition (Exp.) 346 drilled high-quality sediment archives with more than threeholes each at nine sites that enable us to establish continuous sedimentary sequences through splicing technique.
After extensive efforts to replace the disturbed, missed, or duplicated intervals found in spliced sediment sequences
constructed onboard during IODP Exp. 346 to the corresponding undisturbed intervals, nearly perfectly continuous
sediment columns and physical property records for the Pleistocene intervals of Sites U1422-U1427 and U1430 collectedfrom the Japan Sea have been established. Same kind of efforts to correct the shipboard splices were also achieved for
Plio-Miocene intervals at Sites U1425 and U1430. The continuous records established for these sites will allow a much
more detailed understanding of the long-term variability in East Asian paleoclimate and North Pacific oceanography.
Keywords: IODP Expedition 346, The Japan Sea, Hemipelagic sediment, Stratigraphy, Splice, Composite depth, Visual coredescription, Physical property, Dark-light cycles

Introduction
Establishment of a continuous sedimentary sequence isan unavoidable starting point for the interpretation of
the sedimentary records as events in earth history (Doyleand Bennett 1998). Multi-hole drilling has been widelyused by scientific drilling operations such as Ocean
Drilling Program (ODP) and Integrated Ocean Drilling
Program (IODP) that allow us to establish continuous
sedimentary records through splicing fragmented intervals from top to bottom of the sequence (Ruddiman
et al. 1987). Splicing is usually performed onboard using* Correspondence: irino@ees.hokudai.ac.jp
1
Faculty of Environmental Earth Science, Hokkaido University, N10-W5
Kita-ku, Sapporo 060-0810, Japan
Full list of author information is available at the end of the article

physical properties such as magnetic susceptibility (MS),gamma-ray attenuation (GRA) density, natural gammaray radiation (NGR), and the lightness and color of
sediments measured immediately after drilling. Thesephysical properties are compared between the drilledholes, and inter-hole correlations are recognized according to the fluctuation patterns of these properties.
Revisions of spliced sequences after the cruise havebeen also common for the high-resolution paleoceanographic researches, which were required for a precise
orbital tuning and inter-site correlations. The splice for
ODP Site 964 (Emeis et al. 1996) was fully reassessedusing core photograph and shipboard color data and revised by Sakamoto et al. (1998). This revision was
further modified by choosing better intervals in different© The Author(s). 2018 Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0
International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, andreproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to
the Creative Commons license, and indicate if changes were made.

Irino et al. Progress in Earth and Planetary Science (2018) 5:23

holes (Lourens 2004). The original splice for ODP Site
982 (Jansen et al. 1996) was also revised by Khélifi et al.
(2012) through inspection of magnetostratigraphic reversals and the addition of epibenthic δ18O records although Lawrence et al. (2013) recommended to returnto the original splice based on the re-examination of adetailed shore-based magnetostratigraphy (Channell andGuyodo, 2004). Splices for IODP Expedition (Exp.) 320(Lyle et al., 2009) were revised in the Expedition research results and summarized by Westerhold et al.
(2012). Although these works gave their own revised
splice interval tables that describe the stratigraphic positions of top and bottom of chosen splice intervals as well
as offsets necessary for adjusting cores to the revised
depth, it was not easy to find correspondence between
the original depth scale and the revised one. In the caseof ODP Site 1092 (Gersonde et al. 1999), the shipboard
splice was revised using X-ray fluorescence (XRF) scanner data collected after the cruise to improve inter-holecorrelation for intervals with too uniform physical properties (Evans et al. 2004). In this example, differences
between the original composite depth and revised one
were listed in the table that may be helpful for the calculation of the revised depth. In all the examples above,
careful visual inspections of core images and/or higher
resolution measurements of sediment properties were
essential for greater improvement of splices.
IODP Exp. 346 also adopted multi-hole drilling where
high-quality splicing of sedimentary sequences at eachdrilled site has been performed (Tada et al. 2015). The
aims of this expedition were to test the hypothesis that
Pliocene–Pleistocene uplift of the Himalaya and Tibetan
Plateau and the consequent emergence of the two
discrete modes of Westerly Jet circulation could havecaused the amplification of millennial-scale variability of
the East Asian summer monsoon and East Asian wintermonsoon, which could also provide teleconnection
mechanisms for Dansgaard–Oeschger cycles. Multiple
time scales were targeted to reconstruct the onset andevolution of orbital- and millennial-scale variations ofsummer and winter monsoons, Westerly Jet position
and intensity, desertification in East and Central Asia,and their interrelationships since the middle Miocene. In
order to accomplish these initial purposes of this expedition, establishment of sediment record as continuous as
possible at each site was strongly required. Such continuous sediment records were also necessary to conduct
precise inter-site stratigraphic correlations in millennial
to orbital time scales to reconstruct spatio-temporalvariability of paleoceanographic and paleoclimatic conditions in this region (Tada et al. 2018).
Since the splicing of cores collected during Exp. 346 was
conducted by the correlations of physical properties
among the drilled holes, minor sediment disturbance that

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can be only recognized by a careful visual inspection
would be missed. In order to establish a more complete
and continuous spliced section and profiles of physicalproperties of sediment core, we tried to identify minor
disturbed, missing, or overlapped intervals unconsciously
involved in the spliced sequences and replace such intervals with the corresponding undisturbed intervals fromanother hole. We have also taken care of traceability ofprocesses of stratigraphic revisions to keep compatibility
between the newly revised depth scale and the originalone. Accomplishment of these tasks enabled the researchcommunity to access, examine, and utilize our revised
stratigraphic frameworks for the most of the sedimentcores collected in the Japan Sea during this expedition.
Materials and data
Drilled sites

The Japan Sea is a marginal sea located at the easternedge of the far-east Asia (Fig. 1). The sea is connected tothe outside through the Tsushima, Tsugaru, Soya, andMamiya Straits from south to north. The Tsushima
Warm Current (TWC) is an only ocean current flowing
into the Japan Sea from the outside in modern times.
TWC water flows out of the sea mostly from the
Tsugaru Strait, and the remaining water flows further
north to the Soya Strait (Hase et al. 1999). Salinity andnutrient in the TWC is controlled by the circulation in
the East China Sea and the Yangtze discharge which
could be controlled by precipitation over South China
during the East Asian summer monsoon season. The
deep water circulation in the Japan Sea is characterized
by intense ventilation due to severe cooling during winter monsoon season, which promotes the hyper-oxic
deep water condition and shallow carbonate compensation depth of the sea (Gamo et al. 2014). The Japan Sea
is also located at downwind of the Asian dust sources
and receives a significant amount of dust transported bywesterlies in spring or northwestern monsoon wind in
winter (Irino and Tada 2000, 2002). Therefore, the reconstructions of the spatio-temporal variation for fluxesof organic and carbonate carbon, bottom water redox
condition, and dust from sediment archives in the Japan
Sea are essential to understand the past variability of theEast Asian summer and winter monsoon as well as thestrength and latitudinal position of westerlies since themiddle Miocene (Tada et al. 2015).
We tried to revise the original spliced sequences
constructed at seven sites drilled during Exp. 346 such as
Sites U1422-U1427 and U1430 (Fig. 1). Sediments mainly
consist of silty clay to clayey silt with various amounts ofbiogenic silica and minor carbonate (Tada et al. 2015). Sites
U1422-U1426 and U1430 are located at bathyal depths
and characterized by decimeter to meter scale dark-lightbandings which correspond to Dansgaard–Oeschger cycles

Irino et al. Progress in Earth and Planetary Science (2018) 5:23

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Fig. 1 Locality map of drilled sites during IODP Exp. 346 (modified from Tada et al. (2015))(Tada et al. 1999), while Site U1427 is located at the upper
slope and its sediments consist of homogenous or bioturbated clayey silt (Fig. 1). Water depths are, in ascendingorder, 330 m at Site U1427, 903 m at Site U1426, 1072 m
at Site U1430, 1785 m at Site U1423, 1909 m at Site
U1425, 2808 m at Site U1424, and 3429 m at Site U1422(Tada et al. 2015). Therefore, an appropriate combinationof these cores could provide a suitable set of depth transect
to reconstruct the depth gradient of biogenic fluxes anddeep water ventilation in the past.

Collected data

Depth information and physical property data collectedduring Exp. 346 and used in this study are all downloadable from the Laboratory Information Management System (LIMS) database (http://web.iodp.tamu.edu/LORE/).
Depth scales used during the cruise were called CSF-A,
CCSF-A, and CCSF-D. CSF-A is the depth (m) drilledfrom the sea floor regardless of potential gaps and overlaps between cores. Since more than one hole were drilled
at one site during Exp. 346, the core gaps recognized at

Irino et al. Progress in Earth and Planetary Science (2018) 5:23

one hole could be fulfilled with the corresponding intervalfound at the other hole. In order to fill the core gap, offset
values were added to the original drilled depth (CSF-A) of
each core as to align the correlated horizons at the same
depth, and then, a composite depth scale (CCSF-A) was
defined for each core. The list of the offset values for adjustment of each core was called “affine table” which was
also downloadable from LIMS database. A single continuous sediment sequence was constructed by splicing continuous intervals chosen from the multi-hole sequences,whose depth scale was called CCSF-D. The term CCSF-D
is only used for splice and is same as CCSF-A for the intervals involved in the splice.
Physical properties utilized to establish composite
depth scale at each site were MS, GRA density, NGR as
well as red-green-blue (RGB) channel values extracted
from digital images and reflectance spectroscopy andcolorimetry (RSC). During Exp. 346, measurement intervals were routinely set as 2.5 cm for MS and GRA,
20 cm for NGR, and 1 cm for RSC. RSC was not measured for holes U1425E and U1427C due to time limitations. RGB values were routinely extracted onboard forevery 5 mm interval and uploaded to LIMS database.
These RGB values extracted onboard were different fromthose recorded in digital image of each section due toencoding procedure (Ebner 2007). Cores U1424C-1H
through 3H and U1425C-1H through 3H which were recovered for optically stimulated luminescence (OSL)
sampling in the dark further required collection of MS,
GRA, photographs (RGB), and RSC later in the Kochi
Core Center (KCC). NGR was not measured for thesecores (Tada et al. 2015).

Methods/experimental
Strategy

The strategy here was to establish continuous sedimentary
records for lithological subunits IA and IB intervals whichwere characterized by clear dark-light color banding at
Sites U1422-U1426 and U1430 (Tada et al. 2015). We
have also made same efforts for the intervals below 110 m
CCSF-D of Site U1425, below 80 m CCSF-D of Site
U1430, and 0 to 440 m CCSF-D of Site U1427 where
banded stratifications were not necessarily clear, in orderto establish precise age models for the Mio-Pliocene intervals at Sites U1425 and U1430 and for the whole spliced
intervals at Site U1427 at a shallower water depth (Sagawa
et al. 2018). As a result, we have worked out for revised
stratigraphy down to 100 m CCSF-D for U1422, 140 m
CCSF-D for U1423, 100 m CCSF-D for U1424, 350 m
CCSF-D for U1425, 235 m CCSF-D for U1426, 440 m
CCSF-D for U1427, and 260 m CCSF-D for U1430.
In this study, we aim to keep the correspondence between the original shipboard splice depth (m CCSF-D)
and the newly revised splice depth scale compatible. The

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revised stratigraphic positions should be easily recognized, and the conversion from the revised depth scale
to the shipboard original depth scale should be possible
for everyone. In order to realize this policy, the workflow
consisting of four steps is as follows:
1. Align all the core/section photographs in a same
scale based on the affine table,
2. Identify disturbed or missing intervals involved in
the spliced section,
3. Find the corresponding undisturbed intervals fromanother hole as the alternative “patch,” and4. Replace the disturbed or missing interval with this“patch,”through careful inspections of core-section photographs
available from IODP LIMS database. When aligning andconnecting core-section photographs, the section widths
were expanded and brightness and contrast were adjusted
to easily recognize the sediment qualities such as lithology,
stratification, and disturbance on the sediment split surface(Additional file 1: Figure S1; Additional file 2: Figure S2;
Additional file 3: Figure S3; Additional file 4: Figure S4;Additional file 5: Figure S5; Additional file 6: Figure S6;
Additional file 7: Figure S7).
On the inter-hole correlation photographs in Additional
file 1: Figure S1, Additional file 2: Figure S2, Additional file
3: Figure S3, Additional file 4: Figure S4, Additional file 5:
Figure S5; Additional file 6: Figure S6, and Additional file
7: Figure S7, originally spliced intervals are indicated byblue lines next to core photographs. Disturbed or missing
intervals found at step 2 are indicated by blue brokenlines. These disturbed or missing intervals were amended
by the corresponding undisturbed “patch” intervals indicated by pink lines.
The top and bottom depth of disturbed intervals found atstep 2 and “patch” intervals chosen at step 3 were definedin the precision of ± 5 mm. The correspondence between
the disturbed intervals and the “patch” intervals are summarized as tables for patched intervals (Additional file 8).
Patching may change the original composite depth (mCCSF-D) due to the difference of thickness between the
disturbed and patch intervals. Therefore, the newly revised
depth scale was defined as m CCSF-D_Patched_revYYYYMMDD where YYYYMMDD was the final date of the revision (Additional file 8). We also provide the revised spliceinterval table for each site (Additional file 9) defined as
the patched sequence.
Patching physical properties data

Construction of the patched stratigraphic column
resulted in the changes of depth values from theoriginal splice “CCSF-D.” The new “CCSF-D_Patched_
revYYYYMMDD” should be also applied to the spliced

Irino et al. Progress in Earth and Planetary Science (2018) 5:23

records of physical properties such as MS, GRA, NGR,
RGB, and RSC in order to obtain their nearly complete
depth profiles. For this purpose, we conducted thefollowing:
1. Translation of the splice (CCSF-D) depth-scale to the“CCSF-D_Pathced_revYYYYMMDD” depth-scale foreach physical property data.
2. Replacement of the physical property data in disturbed
intervals with those from the undisturbed patch
intervals
3. Removal of outliers due to tephra, locally concentrated
pyrites, or core disturbance such as core breaks, cracks,
and styrofoam.
Then, we obtained a “patched and cleaned” profiles ofphysical properties that are provided in Additional file 10:
Table S1, Additional file 11: Table S2, Additional file 12:
Table S3, Additional file 13: Table S4; Additional file 14:
Table S5, Additional file 15: Table S6, and Additional file 16:
Table S7, and the examples using RGB profile are shown in
Fig. 2a and b, Fig 2c and d, Fig 2e and f with “patched” sediment columns.
Compatibility of photographic RGB and RSC data

Color and brightness of the Japan Sea sediment has beentreated as an essential property because the dark-lightcolor cycles have been well-correlated basinwide (Tada
1994). Therefore, establishing completely continuouscolor profiles is essential for correlating between drillsites in the Japan Sea (Tada et al. 2018). When color datacollected from core-sections such as photographic RGB
values and RSC (L*, a*, b*, and tristimulus XYZ values)in disturbed intervals are patched by the data from another hole, it turned out that we need proper intercalibrations among RGB values collected onboard, RSC
data, and RGB values extracted from section images on
LIMS. Sections subjected to OSL sampling in the darkfurther required collection of physical properties andcolor data later in the KCC (Tada et al. 2015). Therefore,
additional calibrations were also necessary to use thedata for RGB and RSC taken from Cores U1424C-1H,
2H, and 3H and U1425C-1H, 2H, and 3H. Intercalibration between RGB and RSC is also necessary forholes U1425E and U1427C which were additionallydrilled at the last moment of Exp. 346, and RSC data
were not measured due to time limitations (Tada et al.
2015). Therefore, some special remarks related to color
data handlings are described below.
Depth adjustment for U1424B-2H-2 RGB data

The assigned depth scale of RGB value for Section
U1424B-2H-2 is 6.5 cm shallower in LIMS database

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because the top 6.5 cm interval of this section was notincluded in the cropped digital image due to an error
during the operation. Therefore, we added 0.065 m to
the depth of RGB values for Section U1424B-2H-2. The
missing data could be fulfilled with RGB values extracted
from the top 6.5 cm interval of the uncropped digital
images stored in LIMS database.

Inter-calibration among RGB values, RSC data, and digital
images collected onboard

RSC data on LIMS database include tristimulus X, Y,
and Z that are used to calculate L*, a*, and b*. Interrelationship between tristimulus XYZ and RGB (defined from 0 to 100) is defined under D65 illuminantand 2° observer:
R ¼ 3:2404542X−1:5371385Y−0:4985314Z
G ¼ −0:9692660X þ 1:8760108Y þ 0:0415560Z
B ¼ 0:0556434X−0:2040259Y þ 1:0572252Z
which means R = G = B = 100 when X = 95.047, Y = 100,and Z = 108.883 where D65 illuminant is reflected on aperfect white (International Electrotechnical Commission,1999). These “true” RGB (linear for our eyes) are encodedin color digital photograph as its own RGB color spacesuch as sRGB in the jpeg section images on LIMS.
Let the encoded RGB values calculated from raw
digital images on D/V JOIDES Resolution as RJR , GJR ,and BJR and those extracted from the jpeg section images on LIMS as Rphoto, Gphoto, and Bphoto, where theseencoded RGB are defined from 0 to 255 (8 bit). Transformations between “true” RGB and these encoded
RGBs can be conducted with equations:
R
¼
100
G
¼
100
B
¼
100



γ JRRγ JRGγ JRB

RJR
255
GJR
255
BJR
255

and

 photoRphoto γ R255 photoGphoto γ G
G
¼
255
100

 photoBphoto γ B
B
¼
255
100
R
¼
100

Irino et al. Progress in Earth and Planetary Science (2018) 5:23

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Fig. 2 Patched splices with RGB_B (brightness) profiles for IODP Exp. 346 Sites U1422 (a), U1423 (b), U1424 (c), U1425 (d), U1426 (e), and U1430(f). Patched intervals are indicated by pink lines. For the full size figure 2 please see Additional file 24

Irino et al. Progress in Earth and Planetary Science (2018) 5:23

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Fig. 2 Patched splices with RGB_B (brightness) profiles for IODP Exp. 346 Sites U1422 (a), U1423 (b), U1424 (c), U1425 (d), U1426 (e), and U1430(f). Patched intervals are indicated by pink lines. For the full size figure 2 please see Additional file 24

Irino et al. Progress in Earth and Planetary Science (2018) 5:23

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Fig. 2 Patched splices with RGB_B (brightness) profiles for IODP Exp. 346 Sites U1422 (a), U1423 (b), U1424 (c), U1425 (d), U1426 (e), and U1430(f). Patched intervals are indicated by pink lines. For the full size figure 2 please see Additional file 24

Irino et al. Progress in Earth and Planetary Science (2018) 5:23

where power terms γ are known as decoding gamma values(Ebner 2007). In the case that we could control the condition of data collection such as illumination and surface
condition of sediments for digital image scanning and RSC
measurement, these gamma values could be calibrated anddefined well before data collection. However, actual scanning and measurement conditions were not consistent because of difference in illumination and use of GladWrap™
for RSC, and therefore, these decoding gamma values haveto be estimated through direct comparisons between “true”
RGB and the encoded RGB using actual data.
In order to determine practical gamma values, wechose the Core U1424A-1H and compared the RGB
calculated from the tristimulus XYZ to the encoded
RGB values taken onboard and extracted from the jpeg
section images. Figure 3 shows the relationships between
the RGB calculated from the tristimulus XYZ and theencoded RGB from digital images. Power function fitting
could determine practical gamma values as
JR
JR
γ JR
R ¼ 1:2961; γ G ¼ 1:3107; γ B ¼ 1:3320

for the RGB collected onboard, and¼ 1:7748; γ photo¼ 1:7815; γ photo¼ 1:8146
γ photoR
B
G
for the RGB extracted from the jpeg section images.
Since the tristimulus XYZ can be calculated from“true” RGB using equations
X ¼ 0:4124564R þ 0:3575761G þ 0:1804375B
Y ¼ 0:2126729R þ 0:7151522G þ 0:0721750B
Z ¼ 0:0193339R þ 0:1191920G þ 0:9503041B
we could transform the encoded RGB to XYZ using
gamma values determined above. Under D65 illuminantand 2° observer conditions, L*, a*, and b* are defined as(CIE, 2004)
8
>
>
>
<



8
>
>
>
<



8
>
>
>
<



1 

Y 3 Y
>
0:00885600100  100 L ¼ 116Y −16; Y ¼
>
Y
16
Y
>
>
þ
≤0:008856: 7:787100
116 100
 0 0 0a ¼ 500 X −Y ; X ¼

 0 0 0b ¼ 200 Y −Z ; Z ¼

13 

X
X
> 0:008856
95:047  95:047


>
X
16
X
>
>
þ
≤0:008856: 7:787
95:047
116 95:047


13 
Z
Z
> 0:008856

108:883  108:883
>
Z
16
Z
>
>
≤ 0:008856
þ: 7:787
108:883
116 108:883

Then, we can inter-calibrate among RGB values collected onboard, RSC, and digital images.

Page 9 of 16

In Fig. 4, blue and orange lines indicate the calculated
L*, a*, and b* from RGB taken onboard and extracted
from the jpeg section images, respectively, and are compared with the measured RSC data (red dots). The threedatasets agree well with one another. RGB and RSC data
for lost or disturbed intervals could be amended or replaced using the RGB extracted from the jpeg section
images for the corresponding intervals.
For the top 6.5 cm of Section U1424B-2H-2 where
digital image was miscropped and RGB was missed,
we calculated the RGB values equivalent to those collected onboard using the RGB extracted from the jpeg
digital image of this section. For the top 8 cm of Section U1424B-2H-3, a light-colored sediment penetrated into a dark layer at the center of the core due
to disturbance and the onboard RGB data were collected on the light color portion (not on the proper
dark portion) because the data were routinely takenfrom the center of the core (shown as dotted lines inFig. 5). Therefore, we extracted the RGB values fromproper dark portion of this interval using the jpeg
image, calculated the RGB values equivalent to thosetaken onboard by the gamma corrections describedabove (solid lines in Fig. 5), and replaced the data. L*,a*, and b* were replaced with those calculated fromthe jpeg extracted RGB at the proper dark portion asshown in Fig. 5 where L* was reasonably low for thedark layer in the top 8 cm interval.

Inter-calibration of RGB values and RSC data between
JOIDES Resolution (JR) and KCC

For the patched interval from 1.22 to 1.53 m CCSF-D,
the corresponding interval from the Core U1424C-1H
was used to amend the data. Since physical properties
for Cores U1424C-1H, 2H, and 3H were measured at
KCC after Exp. 346, the RGB values were extracted fromthe digital images taken by the core scanner at KCC,
and L*, a*, and b* (and tristimulus XYZ) values weretransformed from those measured by the spectrophotometer used at KCC. In order to establish intercalibration between data taken onboard at JR and thosefrom KCC, we first construct peak by peak matching between B splice profile and B values extracted from digital
images of Cores U1424C-1H, 2H, and 3H as shown in
Fig. 6. Then, RGB and XYZ data for corresponding
stratigraphic positions were compared between the
splice data taken onboard and U1424C data taken at
KCC (Fig. 7). Figure 7a–c shows that RGBJR do notconverge to zero when RGBKCC get close to zero. This isprobably due to the difference in sensitivity of scanners
under very dark condition. Therefore, the transformation of RGB data from KCC values to JR ones requires
the form of power function with bias factors a as

Irino et al. Progress in Earth and Planetary Science (2018) 5:23

Page 10 of 16

a

d

b

e

c

f

Fig. 3 Relationships between linear RGB estimated from RSC measurements and shipboard R (a), G (b), and B (c) or photo R (d), G (e),and B (f)Irino et al. Progress in Earth and Planetary Science (2018) 5:23

Page 11 of 16

a

b

c

Fig. 4 Comparison between L* (a), a* (b), and b* (c) measured onboard (red dots) and those calculated from shipboard RGB (blue line) andphoto RGB (orange line) in IODP Exp. 346 Site U1424A 1H



RGBJR
RGBKCC γ¼ a þ ð1−aÞ
255
255
where bias factors a are set as to RGBJR be 255 when
RGBKCC is 255. The bias factors a are 0.0849,
0.080895, and 0.080709 for R, G, and B, respectively,
while the power terms γ are 1.6572, 1.6212, and1.5914 for R, G, and B, respectively (Fig. 7a–c).
Tristimulus XYZ are principally consistent between
JR and KCC, but transparent film used in KCC was
SaranWrap™ while GladWrap™ was used on JR. Therefore, we assumed that small bias factors have to be
added to or subtracted from XYZ measured in KCC
to match to those on JR such as
XYZ JR ¼ XYZ KCC þ b
The best estimates of this bias factors b are − 5.1763,− 5.6081, and − 5.7142 for X, Y, and Z, respectively(Fig. 7d–f). Negative bias factors suggest stronger surface
reflection of SaranWrap™ than that of GladWrap™.

Results and discussions
Overview of patched splices
U1422

Fourteen disturbed intervals were patched (Additional
file 8). The total length of the revised spliced sequence
was 0.057 m shorter than the original shipboard splice at
72.21 m CCSF-D.
U1423

Fifteen disturbed intervals were patched (Additional
file 8). The total length of the revised spliced sequence
was 0.584 m longer than the original shipboard splice at
132.83 m CCSF-D.
U1424

Nine disturbed intervals were patched (Additional file 8).
The total length of the revised spliced sequence was
1.310 m longer than the original shipboard splice at
83.76 m CCSF-D.

Irino et al. Progress in Earth and Planetary Science (2018) 5:23

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Fig. 5 Example of re-sampling of RGB from section photograph (U1424B-2H-3, top 8 cm) and the calculated L*a*b*

U1425

Twelve disturbed intervals were patched (Additional
file 8). The total length of the revised spliced sequence
was 0.827 m longer than the original shipboard splice at
320.86 m CCSF-D.
U1426

Five disturbed intervals were patched (Additional file 8).
The total length of the revised spliced sequence was
4.212 m longer than the original shipboard splice at
105.95 m CCSF-D.
U1427

Thirteen disturbed intervals were patched (Additional
file 8). The total length of the revised spliced sequence
was 11.753 m longer than the original shipboard spliceat 257.95 m CCSF-D.
U1430

Seven disturbed intervals recognized below 96.15 m
CCSF-D were patched (Additional file 8). The total lengthof the revised spliced sequence was 1.071 m shorter thanthe original shipboard splice at 257.19 m CCSF-D.
Potential utilities of perfectly continuous stratigraphic
records

Sediment sequences characterized by dark-light color cycles exhibit similar patterns of color banding (Fig. 2).
After correction, each core-section is nearly continuous

such that correlation among these sites using their color
banding patterns allows reasonably isochronous horizons
to be studied across wide regions of the Japan Sea overmillennial time scales (Tada 1994; Tada et al. 1999; Tada
et al. 2018). Combination of the reliably continuous stratigraphy at each site and its correlation to the referencesite such as U1424 (Tada et al. 2018) enabled more precise tuning age construction at other drilled sites in theJapan Sea.
After inter-site correlations, differences in linear
sedimentation rates, GRA densities, and other oceanographic and climatological variability and distribution
can be examined for any combination of depth, latitudinal, and longitudinal transects. Further correlation
between these dark-light banding sites and Site U1427
with no clear dark-light banding using other correlation
tools such as tephrochronology would enable us to
examine how the shallower sites such as U1427 respondto millennial-scale climate and oceanographic variability
exhibited as dark-light cycles observed at sites with larger water depth (Sagawa et al. 2018).
Maintenance of revised splice records

Perfectly continuous physical properties’ data such as
GRA, MS, NGR, RGB, and RSC are summarized in
Microsoft Excel books and provided here as
Additional file 10: Table S1, Additional file 11: Table S2,
Additional file 12: Table S3, Additional file 13: Table S4,Additional file 14: Table S5, Additional file 15: Table S6,

Irino et al. Progress in Earth and Planetary Science (2018) 5:23

Page 13 of 16abFig. 6 Correlation of RGB_B profile between U1424 splice measured onboard (a) and Section U1424C-2H measured at Kochi Core Center (KCC)(b). RGB_B profile of KCC (blue line in b) was correlated to RGB_B of the splice (red line in a) at black vertical lines and was projected to splice
depth scale (light blue line in a)and Additional file 16: Table S7 for further research
usage. Microsoft Excel workbooks which automate thecalculation of the newly patched depth are also available
as Additional file 17: Table S8, Additional file 18: Table
S9, Additional file 19: Table S10, Additional file 20: Table
S11, Additional file 21: Table S12, Additional file 22:
Table S13, and Additional file 23: Table S14. These tables enabled the users to access, examine, and utilize ourrevised stratigraphic frameworks for the most of thesediment cores collected in the Japan Sea during this expedition. However, the users of these information should
notice that the depth scale calculation for the interval
out of splice is not necessarily consistent to the spliced
section because perfect correlation among holes using
dark-light color cycle has not been conducted. The users
should check the patched depth on the spliced section
corresponding to the horizon out of splice.
Since our policy for the revision of stratigraphic splice istraceability, we put the date of revision to our revised
depth scale such as m CCSF-D_Patched_revYYYYMM
DD. This means that we are always ready for (potential)

further revision of stratigraphic sequences and provide revised “patch” tables to improve the stratigraphy of thedrilled cores collected during Exp. 346.

Conclusions
After extensive efforts for improvement of sediment sequences drilled during IODP Exp. 346, nearly perfectly
continuous sediment columns and physical property records for Sites U1422-U1427 and U1430 over the
Pleistocene have been established. Stratigraphic revisions
were also achieved for Plio-Miocene intervals at Sites
U1425 and U1430. All the “patching” processes wereclearly demonstrated in patch tables in this study tokeep compatibility between depth scales of the originaland revised splices. Revised depth scales and patched
continuous physical property records are also available
as additional file tables (Additional file 10: Table S1;
Additional file 11: Table S2; Additional file 12: Table S3;
Additional file 13: Table S4; Additional file 14: Table S5;
Additional file 15: Table S6; Additional file 16: Table S7).
Therefore, the users can access, examine, and utilize ourIrino et al. Progress in Earth and Planetary Science (2018) 5:23

Page 14 of 16

a

d

b

e

c

f

Fig. 7 Relationships between shipboard R (a), G (b), and B (c) and those measured at Kochi Core Center (KCC) and between shipboard X(d), Y (e), and Z (f) and those measured at KCC

Irino et al. Progress in Earth and Planetary Science (2018) 5:23

revised stratigraphic frameworks. Continuous sedimentary records are exceedingly useful for inter-site correlation and enable the examination of the spatial andtemporal distribution of material fluxes across wide
areas of the Japan Sea for the entire Pleistocene. The
continuous record established at these sites will allow amuch more detailed understanding of the long-term variability in East Asian paleoclimate and North Pacificoceanography.

Additional files
Additional file 1: Figure S1. Graphic representations of inter-holecorrelations for IODP Exp. 346 Sites U1422. Originally spliced intervals
are indicated by blue lines next to core photographs. Disturbed or missing
intervals found during visual inspection are indicated by blue broken lines.
These disturbed or missing intervals were amended by the corresponding
undisturbed “patch” intervals indicated by pink lines. (PDF 1908 kb)
Additional file 2: Figure S2. Graphic representations of inter-holecorrelations for IODP Exp. 346 Sites U1423. Originally spliced intervals
are indicated by blue lines next to core photographs. Disturbed or missing
intervals found during visual inspection are indicated by blue broken lines.
These disturbed or missing intervals were amended by the corresponding
undisturbed “patch” intervals indicated by pink lines. (PDF 1469 kb)
Additional file 3: Figure S3. Graphic representations of inter-holecorrelations for IODP Exp. 346 Sites U1424. Originally spliced intervals
are indicated by blue lines next to core photographs. Disturbed or
missing intervals found during visual inspection are indicated by blue brokenlines. These disturbed or missing intervals were amended by the corresponding
undisturbed “patch” intervals indicated by pink lines. (PDF 1806 kb)
Additional file 4: Figure S4. Graphic representations of inter-holecorrelations for IODP Exp. 346 Sites U1425. Originally spliced intervals areindicated by blue lines next to core photographs. Disturbed or missing
intervals found during visual inspection are indicated by blue broken lines.
These disturbed or missing intervals were amended by the corresponding
undisturbed “patch” intervals indicated by pink lines. (PDF 8638 kb)
Additional file 5: Figure S5. Graphic representations of inter-holecorrelations for IODP Exp. 346 Sites U1426. Originally spliced intervals areindicated by blue lines next to core photographs. Disturbed or missing
intervals found during visual inspection are indicated by blue broken lines.
These disturbed or missing intervals were amended by the corresponding
undisturbed “patch” intervals indicated by pink lines. (PDF 1853 kb)
Additional file 6: Figure S6. Graphic representations of inter-holecorrelations for IODP Exp. 346 Sites U1427. Originally spliced intervals
are indicated by blue lines next to core photographs. Disturbed or
missing intervals found during visual inspection are indicated by blue
broken lines. These disturbed or missing intervals were amended by
the corresponding undisturbed “patch” intervals indicated by pinklines. (PDF 13721 kb)
Additional file 7: Figure S7. Graphic representations of inter-holecorrelations for IODP Exp. 346 Sites U1430. Originally spliced intervals
are indicated by blue lines next to core photographs. Disturbed or
missing intervals found during visual inspection are indicated by blue
broken lines. These disturbed or missing intervals were amended by
the corresponding undisturbed “patch” intervals indicated by pinklines. (PDF 9896 kb)
Additional file 8: Patch tables for IODP Exp. 346 Sites U1422-U1427 and
U1430. (XLSX 97 kb)
Additional file 9: Revised splice interval tables for IODP Exp. 346 Sites
U1422-U1427 and U1430. (XLSX 137 kb)
Additional file 10: Table S1. Physical properties such as MS, GRA,
NGR, RGB, and RSC for U1422. Revised depth scale version is CCSF-

Page 15 of 16

D_Patched_rev20150416. L*a*b* values calculated from RGB are also
given. (XLSX 5620 kb)
Additional file 11: Table S2. Physical properties such as MS, GRA,
NGR, RGB, and RSC for U1423. Revised depth scale version is CCSFD_Patched_rev20150416. L*a*b* values calculated from RGB are also
given. (XLSX 6509 kb)
Additional file 12: Table S3. Physical properties such as MS, GRA,
NGR, RGB, and RSC for U1424. Revised depth scale version is CCSFD_Patched_rev20170308. L*a*b* values calculated from RGB are also
given. (XLSX 4497 kb)
Additional file 13: Table S4. Physical properties such as MS, GRA,
NGR, RGB, and RSC for U1425. Revised depth scale version is CCSFD_Patched_rev20170309. L*a*b* values calculated from RGB are also
given. (XLSX 13643 kb)
Additional file 14: Table S5. Physical properties such as MS, GRA,
NGR, RGB, and RSC for U1426. Revised depth scale version is CCSFD_Patched_rev20150519. L*a*b* values calculated from RGB are also
given. (XLSX 8648 kb)
Additional file 15: Table S6. Physical properties such as MS, GRA,
NGR, RGB, and RSC for U1427. Revised depth scale version is CCSFD_Patched_rev20170310. L*a*b* values calculated from RGB are also
given. (XLSX 11638 kb)
Additional file 16: Table S7. Physical properties such as MS, GRA,
NGR, RGB, and RSC for U1430. Revised depth scale version is CCSFD_Patched_rev20160113. L*a*b* values calculated from RGB are also
given. (XLSX 9048 kb)
Additional file 17: Table S8. Calculation worksheet for U1422 revised
depth scale (CCSF-D_Patched_rev20150416). (XLSX 98 kb)
Additional file 18: Table S9. Calculation worksheet for U1423 revised
depth scale (CCSF-D_Patched_rev20150416). (XLSX 96 kb)
Additional file 19: Table S10. Calculation worksheet for U1424 revised
depth scale (CCSF-D_Patched_rev20170308). (XLSX 87 kb)
Additional file 20: Table S11. Calculation worksheet for U1425 revised
depth scale (CCSF-D_Patched_rev20170309). (XLSX 141 kb)
Additional file 21: Table S12. Calculation worksheet for U1426 revised
depth scale (CCSF-D_Patched_rev20150519). (XLSX 117 kb)
Additional file 22: Table S13. Calculation worksheet for U1427 revised
depth scale (CCSF-D_Patched_rev20170310). (XLSX 172 kb)
Additional file 23: Table S14. Calculation worksheet for U1430 revised
depth scale (CCSF-D_Patched_rev20160113). (XLSX 110 kb)
Additional file 24: Figure S8. Full size version of Figure 2. (PDF 21887 kb)
Abbreviations
Exp.: Expedition; GRA: Gamma-ray attenuation density; IODP: Integrated
Ocean Drilling Program; KCC: Kochi Core Center; LIMS: Laboratory Information
Management System; MS: Magnetic susceptibility; NGR: Natural gamma-ray
radiation; ODP: Ocean Drilling Program; OSL: Optically stimulated luminescence;
RGB: Red-green-blue channel of digital image; RSC: Reflectance spectroscopy
and colorimetry; TWC: Tsushima Warm Current
Acknowledgements
We would like to express our sincere thanks to all of the scientists, technicians,
and crews of D/V JOIDES resolution during IODP Expedition 346. This work was
financially supported by IODP Exp. 346 After Cruise Research Program, JAMSTEC.
Funding
Not applicable.
Authors’ contributions
TI supervised each stratigraphic patching task, summarized the patch tables,
calibrated and patched physical properties, and established the data sharewebsites for all the drilled sites. RT and KI also supervised all the course of
stratigraphic revisions and advised for improvement. TS mainly worked forthe stratigraphic revision and figure drawing for U1427. AK and AS compiled
core photographs and revised stratigraphy for U1424, U1425, U1426, andIrino et al. Progress in Earth and Planetary Science (2018) 5:23

U1430 mainly for Pleistocene intervals. SK worked for the Plio-Miocene
intervals for U1425 and U1430. SL exclusively compiled the core photographs
and revised the stratigraphy for U1422 and U1423. All authors read andapproved the final manuscript.
Authors’ information
RT was a co-chief scientist, TI was a stratigraphic correlator, and KI, TS, andAK were sedimentologists onboard for Exp. 346. RT is a supervisor for AK, AS,
and SK in Graduate School of Science, University of Tokyo. TI is a supervisor
for SL in Graduate School of Environmental Science, Hokkaido University.
Competing interests
The authors declare that they have no competing interest.

Publisher’s NoteSpringer Nature remains neutral with regard to jurisdictional claims inpublished maps and institutional affiliations.
Author details
1
Faculty of Environmental Earth Science, Hokkaido University, N10-W5
Kita-ku, Sapporo 060-0810, Japan. 2Graduate School of Science, the Universityof Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan. 3Geological
Survey of Japan, National Institute of Advanced Industrial Science andTechnology, Tsukuba Central 7, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8567,
Japan. 4Institute of Science and Engineering, Kanazawa University,
Kakuma-machi, Kanazawa, Ishikawa 920-1192, Japan. 5Graduate School ofEnvironmental Science, Hokkaido University, N10-W5 Kita-ku, Sapporo
060-0810, Japan.
Received: 5 October 2017 Accepted: 21 February 2018

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