diff --git a/chunkenc/chunk.go b/chunkenc/chunk.go
index 5e807b4f..bc6c2010 100644
--- a/chunkenc/chunk.go
+++ b/chunkenc/chunk.go
@@ -56,7 +56,7 @@ type Appender interface {
 	Append(int64, float64)
 }
 
-// Iterator is a simple iterator that can only get the next value.
+// Iterator iterates over the data of a time series.
 type Iterator interface {
 	// Seek advances the iterator forward to the given timestamp.
 	// If there's no value exactly at t, it advances to the first value
diff --git a/head_test.go b/head_test.go
index 040ae828..34bdd57b 100644
--- a/head_test.go
+++ b/head_test.go
@@ -740,7 +740,7 @@ func TestDelete_e2e(t *testing.T) {
 				smpls = deletedSamples(smpls, del.drange)
 				// Only append those series for which samples exist as mockSeriesSet
 				// doesn't skip series with no samples.
-				// TODO: But sometimes SeriesSet returns an empty SeriesIterator
+				// TODO: But sometimes SeriesSet returns an empty chunkenc.Iterator
 				if len(smpls) > 0 {
 					matchedSeries = append(matchedSeries, newSeries(
 						m.Map(),
diff --git a/querier.go b/querier.go
index 5b218c3d..a39b41d7 100644
--- a/querier.go
+++ b/querier.go
@@ -54,9 +54,9 @@ type Series interface {
 	Labels() labels.Labels
 
 	// Iterator returns a new iterator of the data of the series.
-	Iterator() SeriesIterator
+	Iterator() chunkenc.Iterator
 
-	// ChunkIterator returns a new iterator for the non-overlapping chunks of the series.
+	// ChunkIterator returns a new iterator that iterates over non-overlapping chunks of the series.
 	ChunkIterator() ChunkIterator
 }
 
@@ -876,7 +876,7 @@ func (s *chunkSeries) Labels() labels.Labels {
 	return s.labels
 }
 
-func (s *chunkSeries) Iterator() SeriesIterator {
+func (s *chunkSeries) Iterator() chunkenc.Iterator {
 	return newChunkSeriesIterator(s.chunks, s.intervals, s.mint, s.maxt)
 }
 
@@ -884,20 +884,6 @@ func (s *chunkSeries) ChunkIterator() ChunkIterator {
 	return &chunkIterator{chunks: s.chunks}
 }
 
-// SeriesIterator iterates over the data of a time series.
-type SeriesIterator interface {
-	// Seek advances the iterator forward to the given timestamp.
-	// If there's no value exactly at t, it advances to the first value
-	// after t.
-	Seek(t int64) bool
-	// At returns the current timestamp/value pair.
-	At() (t int64, v float64)
-	// Next advances the iterator by one.
-	Next() bool
-	// Err returns the current error.
-	Err() error
-}
-
 // chainedSeries implements a series for a list of time-sorted series.
 // They all must have the same labels.
 type chainedSeries struct {
@@ -908,7 +894,7 @@ func (s *chainedSeries) Labels() labels.Labels {
 	return s.series[0].Labels()
 }
 
-func (s *chainedSeries) Iterator() SeriesIterator {
+func (s *chainedSeries) Iterator() chunkenc.Iterator {
 	return newChainedSeriesIterator(s.series...)
 }
 
@@ -926,7 +912,7 @@ type chainedSeriesIterator struct {
 	series []Series // series in time order
 
 	i   int
-	cur SeriesIterator
+	cur chunkenc.Iterator
 }
 
 func newChainedSeriesIterator(s ...Series) *chainedSeriesIterator {
@@ -987,7 +973,7 @@ func (s *verticalChainedSeries) Labels() labels.Labels {
 	return s.series[0].Labels()
 }
 
-func (s *verticalChainedSeries) Iterator() SeriesIterator {
+func (s *verticalChainedSeries) Iterator() chunkenc.Iterator {
 	return newVerticalMergeSeriesIterator(s.series...)
 }
 
@@ -998,14 +984,14 @@ func (s *verticalChainedSeries) ChunkIterator() ChunkIterator {
 // verticalMergeSeriesIterator implements a series iterator over a list
 // of time-sorted, time-overlapping iterators.
 type verticalMergeSeriesIterator struct {
-	a, b                  SeriesIterator
+	a, b                  chunkenc.Iterator
 	aok, bok, initialized bool
 
 	curT int64
 	curV float64
 }
 
-func newVerticalMergeSeriesIterator(s ...Series) SeriesIterator {
+func newVerticalMergeSeriesIterator(s ...Series) chunkenc.Iterator {
 	if len(s) == 1 {
 		return s[0].Iterator()
 	} else if len(s) == 2 {
@@ -1148,7 +1134,6 @@ func (it *verticalMergeChunkIterator) Next() bool {
 		return true
 	}
 
-
 	it.curMeta, it.err = mergeOverlappingChunks(aCurMeta, bCurMeta, it.aReuseIter, it.bReuseIter)
 	if it.err != nil {
 		return false
@@ -1189,9 +1174,9 @@ func mergeOverlappingChunks(a, b chunks.Meta, aReuseIter, bReuseIter chunkenc.It
 	}
 
 	return chunks.Meta{
-			MinTime: mint,
-			MaxTime: maxt,
-			Chunk:   chk,
+		MinTime: mint,
+		MaxTime: maxt,
+		Chunk:   chk,
 	}, nil
 }
 
diff --git a/querier_test.go b/querier_test.go
index 15e4f27e..cc48c95d 100644
--- a/querier_test.go
+++ b/querier_test.go
@@ -179,7 +179,7 @@ Outer:
 	}
 }
 
-func expandSeriesIterator(it SeriesIterator) (r []tsdbutil.Sample, err error) {
+func expandSeriesIterator(it chunkenc.Iterator) (r []tsdbutil.Sample, err error) {
 	for it.Next() {
 		t, v := it.At()
 		r = append(r, sample{t: t, v: v})
@@ -271,7 +271,7 @@ func TestBlockQuerier(t *testing.T) {
 	newSeries := func(l map[string]string, s []tsdbutil.Sample) Series {
 		return &mockSeries{
 			labels:   func() labels.Labels { return labels.FromMap(l) },
-			iterator: func() SeriesIterator { return newListSeriesIterator(s) },
+			iterator: func() chunkenc.Iterator { return newListSeriesIterator(s) },
 		}
 	}
 
@@ -409,7 +409,7 @@ func TestBlockQuerierDelete(t *testing.T) {
 	newSeries := func(l map[string]string, s []tsdbutil.Sample) Series {
 		return &mockSeries{
 			labels:   func() labels.Labels { return labels.FromMap(l) },
-			iterator: func() SeriesIterator { return newListSeriesIterator(s) },
+			iterator: func() chunkenc.Iterator { return newListSeriesIterator(s) },
 		}
 	}
 
@@ -665,10 +665,10 @@ func TestBaseChunkSeries(t *testing.T) {
 
 // TODO: Remove after simpleSeries is merged
 type itSeries struct {
-	si SeriesIterator
+	si chunkenc.Iterator
 }
 
-func (s itSeries) Iterator() SeriesIterator     { return s.si }
+func (s itSeries) Iterator() chunkenc.Iterator  { return s.si }
 func (s itSeries) Labels() labels.Labels        { return labels.Labels{} }
 func (s itSeries) ChunkIterator() ChunkIterator { return nil }
 
@@ -1013,7 +1013,7 @@ func TestSeriesIterator(t *testing.T) {
 
 		t.Run("Seek", func(t *testing.T) {
 			for _, tc := range seekcases {
-				ress := []SeriesIterator{
+				ress := []chunkenc.Iterator{
 					newChainedSeriesIterator(
 						itSeries{newListSeriesIterator(tc.a)},
 						itSeries{newListSeriesIterator(tc.b)},
@@ -1478,17 +1478,17 @@ func (m mockIndex) LabelNames() ([]string, error) {
 
 type mockSeries struct {
 	labels   func() labels.Labels
-	iterator func() SeriesIterator
+	iterator func() chunkenc.Iterator
 }
 
 func newSeries(l map[string]string, s []tsdbutil.Sample) Series {
 	return &mockSeries{
 		labels:   func() labels.Labels { return labels.FromMap(l) },
-		iterator: func() SeriesIterator { return newListSeriesIterator(s) },
+		iterator: func() chunkenc.Iterator { return newListSeriesIterator(s) },
 	}
 }
 func (m *mockSeries) Labels() labels.Labels        { return m.labels() }
-func (m *mockSeries) Iterator() SeriesIterator     { return m.iterator() }
+func (m *mockSeries) Iterator() chunkenc.Iterator  { return m.iterator() }
 func (m *mockSeries) ChunkIterator() ChunkIterator { return nil }
 
 type listSeriesIterator struct {
diff --git a/tsdbutil/buffer.go b/tsdbutil/buffer.go
index dc2d960d..8f615d8e 100644
--- a/tsdbutil/buffer.go
+++ b/tsdbutil/buffer.go
@@ -15,25 +15,13 @@ package tsdbutil
 
 import (
 	"math"
-)
 
-// SeriesIterator iterates over the data of a time series.
-type SeriesIterator interface {
-	// Seek advances the iterator forward to the given timestamp.
-	// If there's no value exactly at t, it advances to the first value
-	// after t.
-	Seek(t int64) bool
-	// At returns the current timestamp/value pair.
-	At() (t int64, v float64)
-	// Next advances the iterator by one.
-	Next() bool
-	// Err returns the current error.
-	Err() error
-}
+	"github.com/prometheus/tsdb/chunkenc"
+)
 
 // BufferedSeriesIterator wraps an iterator with a look-back buffer.
 type BufferedSeriesIterator struct {
-	it  SeriesIterator
+	it  chunkenc.Iterator
 	buf *sampleRing
 
 	lastTime int64
@@ -41,7 +29,7 @@ type BufferedSeriesIterator struct {
 
 // NewBuffer returns a new iterator that buffers the values within the time range
 // of the current element and the duration of delta before.
-func NewBuffer(it SeriesIterator, delta int64) *BufferedSeriesIterator {
+func NewBuffer(it chunkenc.Iterator, delta int64) *BufferedSeriesIterator {
 	return &BufferedSeriesIterator{
 		it:       it,
 		buf:      newSampleRing(delta, 16),
@@ -56,7 +44,7 @@ func (b *BufferedSeriesIterator) PeekBack() (t int64, v float64, ok bool) {
 }
 
 // Buffer returns an iterator over the buffered data.
-func (b *BufferedSeriesIterator) Buffer() SeriesIterator {
+func (b *BufferedSeriesIterator) Buffer() chunkenc.Iterator {
 	return b.buf.iterator()
 }
 
@@ -145,7 +133,7 @@ func (r *sampleRing) reset() {
 	r.f = 0
 }
 
-func (r *sampleRing) iterator() SeriesIterator {
+func (r *sampleRing) iterator() chunkenc.Iterator {
 	return &sampleRingIterator{r: r, i: -1}
 }